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Partial tear down of Willsenton R8


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I am not an expert on tube amp like many on this forum however writing this blog to help those who are thinking of buying Willsenton R8 or those who owns it and want to know bit more about it. I am no

An unexpected development here. Last night, I removed my MELZ 6SL7 tubes and replaced them with the Tung Sol 6C8G. I do not think I will go back to the MELZ.    I can hear the thuds of Stere

It came!!     😲😲😲😲😲😲   Ordered November 22nd.  Arrived January 26th, by ocean.  (I was too cheap to pay the airfreight)    Off we go!  

1 hour ago, Rali said:

I cant upload audio file here due to site restrictions. Here is what happened. I bought Melz 6sl7 tubes as recommended by forum members. replaced the 2 stock 6sl7. then started the krr.. Trr.. Brr.. Noise on one channel.

 

1.I interchanged the tubes and the noise shifted to another channel. This told me the issue is isolated with one tube.

 

2.connected the stock 6sl7 , no noise.

 

3. From an aerial view the problematic tube glows little mild. Rest guys are doing good.

 

4.my speakers are forte iii and this stupid speakers picks up these noises very well and is annoying.

 

5.i connnecetd PSB imagine T2, same observation with the tube but not that annoying.

 

So what you guys think?

 

Between, thank you moderators your suggestion to buy melz 6sl7 is perfect for me. This has mellow down my forte iii and sound is amazing. So tube rolling has significant impact.

Sounds like a bad tube, or the pins are dirty, clean the pins with some fine steel wool and try again, if the same a bad tube.

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56 minutes ago, Lam Pham said:

Hi All-

 

As I get a very good deal on this at the local store:

https://reverb.com/ca/item/18895835-melz-6h8c-6sn7-c-1953-metal-base-audio-tube-nos-russian-holy-grail-military

 

Any one here try these and /or have any idea on these.

 

Thanks,

That's expensive!

 

These are good but from what I gather not quite as nice as the hole plate 6SN7 Russian type, likely 90% of what you get with the hole plate types.

 

@xlr8or had these ones in his DAC so he can tell you about them

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1 hour ago, muon* said:

That's expensive!

 

These are good but from what I gather not quite as nice as the hole plate 6SN7 Russian type, likely 90% of what you get with the hole plate types.

 

@xlr8or had these ones in his DAC so he can tell you about them

 

Ah .... bleh. 🤣

 

Very nice sounding tube with deep rich bass and smooth sounding mids and highs. It's definitely not coloured across the frequency spectrum. It presents itself very nicely with some authority. Where it loses out slightly is in the harmonic texture of the midrange and top end regions. Imaging is also slightly compromised.

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14 hours ago, echorec said:

Interestingly, the 4ohm taps on my R8 measure at 6ohm on the multimeter. The 8 measure at 8...

Like the impedance of a speaker, one cannot measure the resistance of such and proclaim this is the resistance.

Impedance unlike resistance is opposing the flow of AC current because of any three components, resistance, induction or capacitance.

So measurements become a bit more complicated.

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1 hour ago, xlr8or said:

 

Ah .... bleh. 🤣

 

Very nice sounding tube with deep rich bass and smooth sounding mids and highs. It's definitely not coloured across the frequency spectrum. It presents itself very nicely with some authority. Where it loses out slightly is in the harmonic texture of the midrange and top end regions. Imaging is also slightly compromised.

Thank you All, my always guru

 

With that said, I may try it as I can get it here for 60$ a pair.

How do these compare with SYLVANIA JAN CHS 6SN7GT VT-231 (80$  a pair here)?

Have fun.

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11 hours ago, Rali said:

I cant upload audio file here due to site restrictions. Here is what happened. I bought Melz 6sl7 tubes as recommended by forum members. replaced the 2 stock 6sl7. then started the krr.. Trr.. Brr.. Noise on one channel.

 

1.I interchanged the tubes and the noise shifted to another channel. This told me the issue is isolated with one tube.

 

2.connected the stock 6sl7 , no noise.

 

3. From an aerial view the problematic tube glows little mild. Rest guys are doing good.

 

4.my speakers are forte iii and this stupid speakers picks up these noises very well and is annoying.

 

5.i connnecetd PSB imagine T2, same observation with the tube but not that annoying.

 

So what you guys think?

 

Between, thank you moderators your suggestion to buy melz 6sl7 is perfect for me. This has mellow down my forte iii and sound is amazing. So tube rolling has significant impact.

 

Faulty tube seems most likely to me, since the 'noise' follows the tube.

21 hours ago, echorec said:

Interestingly, the 4ohm taps on my R8 measure at 6ohm on the multimeter. The 8 measure at 8...

 

I'll stick the meter across mine next time and I am around the back and see what it shows. Not so much to discover the actual impedance, but more to see if they are consistent one with the other.

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@Rali I also had noise issues with Melz 6SL7 (6N9S). They were 1950s metal base. On my first NOS matched set, one tube was noisy and extremely microphonic. The seller in Ukraine is sending me a replacement. It turns out many of these sellers do not test for noise and microphony, so I asked specifically to test the replacement for these things. I'm really curious about this tube, since people elsewhere are saying it was the be-all end-all 6SL7 for their R8s. Most of those people liked it so much that they bought multiple matched pairs as extras. They are also inexpensive. I'll be putting it up against some heavy hitters from my collection. Replacement should be here in a couple weeks.

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1 hour ago, echorec said:

@Rali I also had noise issues with Melz 6SL7 (6N9S). They were 1950s metal base. On my first NOS matched set, one tube was noisy and extremely microphonic. The seller in Ukraine is sending me a replacement. It turns out many of these sellers do not test for noise and microphony, so I asked specifically to test the replacement for these things. I'm really curious about this tube, since people elsewhere are saying it was the be-all end-all 6SL7 for their R8s. Most of those people liked it so much that they bought multiple matched pairs as extras. They are also inexpensive. I'll be putting it up against some heavy hitters from my collection. Replacement should be here in a couple weeks.

His were the 6H8C not the 6H9C, granted both are 50's production MELZ.

 

But agree some sellers don't test, I used to look for ones where they have tested and stated the measurements of each tube in the sale.

 

In the 6H8C the holy grail are the hole plate ones, and these command a high price, usually 100 dollars each or more depending on seller and condition of tubes and dates for new old stock.

 

Were these used or new old stock?

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Update on operating temperature of power transformer when running 8 ohm speakers via 4 ohm and 8 ohm taps.

 

The unit has been powered on and running for 11 hours. The temperature stabilises well before this time, but this is how I have chosen to do it. Temperature was read using an accurate digital infrared thermometer with the laser spot aimed at the top centre of the power transformer. 

 

For all tests ambient temperature was the same +/- 1 degree C.

 

Readings are as follows.

 

  1. Using 4 ohm taps: 44.1 degrees Celsius (111 Fahrenheit).
  2. Using 8 ohm taps: 43.9 degrees Celsius (110 Fahrenheit).

 

So, contrary to my subjective impression reported earlier, the power transformer is not running any hotter whether using the 4 ohm or the 8 ohm taps.

 

I also measured the temperature on the top centres of the output transformers. 

 

Readings are as follows.

 

  1. Using 4 ohm taps, Left OPT : 32.7 degrees Celsius (90.9 Fahrenheit)
  2. Using 4 ohm tap, Right OPT s: 34.9 degrees Celsius (94.8 Fahrenheit

 

  1. Using 8 ohm taps, Left OPT : 32.9 degrees Celsius (90.9 Fahrenheit)
  2. Using 8 ohm taps, Right OPT : 33.3 degrees Celsius (91.9 Fahrenheit)

 

One of my concerns about using the 4 ohm taps was that doing so made the unit run hotter but this seems to unfounded.

 

Is there any value in measuring the temperatures of the power tubes in both modes, or will this be expected to be similar, as per above? Advice appreciated.

 

Now, knowing next to nothing about tube amps, I have no idea how to interpret these data, or even if they have any value, so again, comments would be appreciated.

 

If any other members have the means to measure these things and would be interested in posting the results, at least we will know if the units measure consistently.

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Was the amp passing a signal for a time before these readings were taken?

 

Edit: or was it just on?

 

Did you leave it on and went to bed?

Edited by muon*
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A precaution before using any NOS tube is to make sure the tube pins are free of corrosion, which inevitably occurs with age even if packed away in a tube box for 65+ or more years. Use 0000 grade steel wool to give the pins a good clean and then finish off with Deoxit and cotton buds. This procedure in most cases will remove unwanted 'noise' from the tube.

 

Most tube sellers around the world do not test for noise in tubes as it's a painstakingly long process of hearing the tube in circuit. Some modern tube testers such as the Maximatcher series from the USA have a noise testing feature built in. Microphony is extremely difficult to test without inserting the tube inside a circuit and tapping it very gently on its side along its height profile and over the top surafce area of the glass envelope with a chopstick or similar to evaluate its susceptibility to microphonics.

 

Edit: The thin oxide layer that forms even though a few micron (um) thick is non-conductive. This layer is very difficult to see without a microscope as it looks 'tinned' and hued into the surface of the metal tube pins whether silver or gold in colour. The problem is exacerbated when UOS tubes are inserted into tube sockets and the spring tensioned contact points induce compressive stresses onto the tube pins. Coupled with cyclic heating on and off this causes a galvanic coupling on indifferent metals with corrosion inevitable in the long run.

Edited by xlr8or
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Chiming in with a bit of tube info.


I've owned Melz 6H8C (6sn7) for years. I have 4 total, two grey plate, two black plate, both hole plates.

I haven't tried the Melz non hole plates.

 

In general, 6SL7 is a much noisier (microphonic) tube than a 6SN7. Even with 6sn7 usually being a clean tube, all four of my Melz have slight noise floor (microphonic) issues.

I can only image the problems Melz 6SL7 have with noise.


While I think Melz sound good (at least the hole plate I own), I would not buy them if you're looking for noise free tubes. I own hundreds of NOS tubes, and Melz is just one of those brands that are very noisy.

 

I also don't think they're anywhere near worth $200, I'd pay max $150 for a pair. Especially since it's a gamble you're going to get noisy tubes.

 

A month ago (because I didn't want to burn hours on my holy grail 6sn7) I bought 5 pairs (so 10 tubes total) 6sn7 NOS.

All of them I got for $50-60 a pair, (so $25-30 per tube). They all perform exceptionally. Most of them are run of the mill RCA flat plates. All of them whisper quiet, no microphonics.

I'm highly recommending people do the same. Don't go holy grail, don't spend over $50 a tube for this amp, also, don't get new production inputs.

While I think the new production Psvane CV181 (grey bottle) is one of the best new production 6sn7 out there (yes I own them, and have owned them for years), a cheap $50-60 pair of NOS RCA 6sn7 (personal opinion obviously) crush them, and the CV181 are around $200 a pair, ouch.

 

When you can still pick up "run of the mill" NOS 6sn7 / 6sl7 pairs for $50-60, I just don't see a reason to pay over that for new production inputs.

 

6sn7 as a tube in general, from my experience, isn't worth chasing for ultimate SQ. DHT inputs (like type 26) are worth to really dig into, as the performance is there.

 

AND, the 6sl7 means WAY more in the R8 than the 6sn7. So even less reason to spend $$$ on 6sn7 for this amp.

AND, I might get some hate for this, but the R8 does not perform to the level of ultimate tube scaling. I know some people would like to believe this amp is $5-10k bespoke level, it's not..... even...... close.....

It's a fantastic, freaking fantastic amp for around $1k-1.5k, but putting extremely expensive tubes in it, I don't see the point. It's not even going to expose their full performance (like my $500 pair of tung-sol black round plate 6sn7).

 

TLDR: Buy NOS RCA 6sn7/6sl7 pairs (while you still can) for $50-60. They outperform anything new production, and in my experience, don't have microphonic issues.

 

 

Edited by Comzee
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@ZedZed As muon* has shared a signal is required to be running through the circuit. All that is required for the evaluation is to run both taps for exactly 60 minutes each and take the temperature at the same location (presumably a location on surface of the OPT that radiates the most heat). 

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Adding to @Comzee's excellent post above, which I'm giving a massive hi-five for, there are some other cost effective tube variants that can also be used with tube adapters for the 6SN7 and 6SL7 if used in external positions. These include 7N7 and 7F7, and 6F8G and 6C8G tubes with the former '7' series even more cost effective. Here is one that I picked up for $30 AUD.

 

20210127_231508.jpg

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4 hours ago, muon* said:

Was the amp passing a signal for a time before these readings were taken?

 

Edit: or was it just on?

 

Did you leave it on and went to bed?

 

Yes, the amp was playing music from Tidal all day. I have music on at all times, either at background levels or at 'serious' listening levels. So it had been playing content for 12 hours prior to my taking the measurements.

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1 hour ago, xlr8or said:

@ZedZed As muon* has shared a signal is required to be running through the circuit. All that is required for the evaluation is to run both taps for exactly 60 minutes each and take the temperature at the same location (presumably a location on surface of the OPT that radiates the most heat). 

 

Yes, the amp was passing a signal for 12 hours. Sorry I didn't make that clear in my earlier post.

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5 hours ago, Comzee said:

Chiming in with a bit of tube info.


I've owned Melz 6H8C (6sn7) for years. I have 4 total, two grey plate, two black plate, both hole plates.

I haven't tried the Melz non hole plates.

 

In general, 6SL7 is a much noisier (microphonic) tube than a 6SN7. Even with 6sn7 usually being a clean tube, all four of my Melz have slight noise floor (microphonic) issues.

I can only image the problems Melz 6SL7 have with noise.


While I think Melz sound good (at least the hole plate I own), I would not buy them if you're looking for noise free tubes. I own hundreds of NOS tubes, and Melz is just one of those brands that are very noisy.

 

I also don't think they're anywhere near worth $200, I'd pay max $150 for a pair. Especially since it's a gamble you're going to get noisy tubes.

 

A month ago (because I didn't want to burn hours on my holy grail 6sn7) I bought 5 pairs (so 10 tubes total) 6sn7 NOS.

All of them I got for $50-60 a pair, (so $25-30 per tube). They all perform exceptionally. Most of them are run of the mill RCA flat plates. All of them whisper quiet, no microphonics.

I'm highly recommending people do the same. Don't go holy grail, don't spend over $50 a tube for this amp, also, don't get new production inputs.

While I think the new production Psvane CV181 (grey bottle) is one of the best new production 6sn7 out there (yes I own them, and have owned them for years), a cheap $50-60 pair of NOS RCA 6sn7 (personal opinion obviously) crush them, and the CV181 are around $200 a pair, ouch.

 

When you can still pick up "run of the mill" NOS 6sn7 / 6sl7 pairs for $50-60, I just don't see a reason to pay over that for new production inputs.

 

6sn7 as a tube in general, from my experience, isn't worth chasing for ultimate SQ. DHT inputs (like type 26) are worth to really dig into, as the performance is there.

 

AND, the 6sl7 means WAY more in the R8 than the 6sn7. So even less reason to spend $$$ on 6sn7 for this amp.

AND, I might get some hate for this, but the R8 does not perform to the level of ultimate tube scaling. I know some people would like to believe this amp is $5-10k bespoke level, it's not..... even...... close.....

It's a fantastic, freaking fantastic amp for around $1k-1.5k, but putting extremely expensive tubes in it, I don't see the point. It's not even going to expose their full performance (like my $500 pair of tung-sol black round plate 6sn7).

 

TLDR: Buy NOS RCA 6sn7/6sl7 pairs (while you still can) for $50-60. They outperform anything new production, and in my experience, don't have microphonic issues.

 

 

@Comzee That was a great help considering R8 is my first tube amplifier.

i see 3x6H8C in the R8. Shall i order Melz 6H8C. Do i need to replace all the 3?

 

I bought this amp cause its in my budget, do not want to order PSVANE.

 

Between, the ebay guy will send the replacement for 6H9C. Melz 1950's.

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On 03/02/2021 at 11:11 PM, Wisker said:

Hey Zed,  Yes the middle transformer runs about 130 degrees or 54 Celsius. the outer ones seem to be about 15-20 degrees cooler, but all are steady..😎

 

My power transformer (after c 12 hours use) is running at 44 Celsius, measured off the top centre of the transformer. It measures hotter off the front centre of the transformer (but I usually run with the cage on, hence measuring it off the top). Where are you reading the temperature?

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You also need to have a baseline of ambient temps that are the same in both rooms, if comparing these things.

My view *shrug*

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5 hours ago, muon* said:

You also need to have a baseline of ambient temps that are the same in both rooms, if comparing these things.

My view *shrug*

 

Agreed. The ambient temp for both tests was the same.  (Added to earlier post)

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Thought I'd try the 4 ohm taps and I'm glad I did.  

 

My speakers (91db nominal 8 ohms, that dip to 2.9)

 

I don't like to use tone controls, but with the 8 ohm taps I had to take treble all the way down as far as possible on my Bluesound Node, to avoid awful brightness and fatiguing shine.  Even then, the highs were far too shrill and metallic.  Especially when you push up the volume.

 

These speakers never sounded this shiny with any SS 8 ohm amp.

 

However, using the 4ohm taps on the R8 takes all that shine off, I can leave the tone controls where they should be (+/- 0).  The sound is balanced, warm, tight and controlled now through the entire range.

 

After an hour of play, temps appear to be in the mid 30sC with an ambient temp of about 22C.  I've not compared 8 ohm temps at this point. 

 

But provided it's safe for the amp, based on sound quality benefits, I won't be going back.

 

Thanks for the initial suggestion @Zed Zed I was feeling that these speakers with this amp don't play together  Now they really, really do and it sounds terrific.

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2 hours ago, Candan said:

Thought I'd try the 4 ohm taps and I'm glad I did.  

 

My speakers (91db nominal 8 ohms, that dip to 2.9)

 

I don't like to use tone controls, but with the 8 ohm taps I had to take treble all the way down as far as possible on my Bluesound Node, to avoid awful brightness and fatiguing shine.  Even then, the highs were far too shrill and metallic.  Especially when you push up the volume.

 

These speakers never sounded this shiny with any SS 8 ohm amp.

 

I am glad that swapping to the 4 ohm taps has improved the SQ for you. I wonder what was causing the "shrill and metallic" highs you were hearing? My speakers don't dip below 5 ohms (200Hz), so are very different to yours. But in my case, although I hear clear differences when using the 4 ohm taps, they are much more subtle than yours.

 

Quote

 

However, using the 4ohm taps on the R8 takes all that shine off, I can leave the tone controls where they should be (+/- 0).  The sound is balanced, warm, tight and controlled now through the entire range.

 

After an hour of play, temps appear to be in the mid 30sC with an ambient temp of about 22C.  I've not compared 8 ohm temps at this point. 

 

In my case, the amp doesn't get anywhere near its maximum temperature after an hour. The power transformer gets gradually hotter and hotter until it peaks at about 44 degrees Celsius here (about 110 Fahrenheit). Here it reaches that temperature after playing music all day - about 12 hours. If you look back a few posts, you'll see my comparison between temperatures when using the 4 ohm taps vs the 8 ohm taps (with 8 ohm speakers) - there's no significant difference, so you won't be running the unit hotter by switching to the 4 ohm taps. My ambient temperature is about 22 Celsius as well for what it's worth.

 

Quote

 

But provided it's safe for the amp, based on sound quality benefits, I won't be going back.

 

Thanks for the initial suggestion @Zed Zed I was feeling that these speakers with this amp don't play together  Now they really, really do and it sounds terrific.

 

Good to hear.

 

I don't recall what tubes you specified for your unit - KT88? If so, maybe swapping out to EL34s would bring further improvement?

 

2021-02-07_18-34-57.png.e845890da907dc4968cfbda83b951536.png

 

 

On that point, I have succumbed to the rabbit hole after 10 days of ownership of my R8. Today I have ordered the following tubes, for evaluation.

 

4 x EH 6CA7 Fat Bottle power tubes

3 x Tung Sol 6SN7 GTB tubes

2 x Sylvania 6SL7 GT (NOS)

 

This will give me a few combinations to try. I intend to swap out the 6SL7s first, as I am led to believe these have a significant impact on SQ, and these particular tubes seem to have a reputation for being very sweet. I'll run them with the KT88s for a few days and then swap out those for the 6CA7s. Depending on how this affects the sound, I will then try the 6SL7s - I intend to do these last as I believe they have less impact on SQ than the others. (More experienced members might correct me if I am wrong on this - or indeed give any advice at all, which is gratefully received).

 

Anyone wondering why I chose the 6CA& Fat Boys over the (more usual?) EL34s?  Don't ask :)  I am not sure why - maybe just wanted to go against the flow (after reading various online reviews of different power tubes). If these are not to my taste, I may try some EL34s later. I have read that the old Mullard EL34s (or their modern copies??) give a particularly lovely 'British' sound, so maybe those will be worth a try. Any comments anyone?

 

All the best, Zed.

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1 hour ago, Zed Zed said:

 

I am glad that swapping to the 4 ohm taps has improved the SQ for you. I wonder what was causing the "shrill and metallic" highs you were hearing? My speakers don't dip below 5 ohms (200Hz), so are very different to yours. But in my case, although I hear clear differences when using the 4 ohm taps, they are much more subtle than yours.

 

 

In my case, the amp doesn't get anywhere near its maximum temperature after an hour. The power transformer gets gradually hotter and hotter until it peaks at about 44 degrees Celsius here (about 110 Fahrenheit). Here it reaches that temperature after playing music all day - about 12 hours. If you look back a few posts, you'll see my comparison between temperatures when using the 4 ohm taps vs the 8 ohm taps (with 8 ohm speakers) - there's no significant difference, so you won't be running the unit hotter by switching to the 4 ohm taps. My ambient temperature is about 22 Celsius as well for what it's worth.

 

 

Good to hear.

 

I don't recall what tubes you specified for your unit - KT88? If so, maybe swapping out to EL34s would bring further improvement?

 

2021-02-07_18-34-57.png.e845890da907dc4968cfbda83b951536.png

 

 

On that point, I have succumbed to the rabbit hole after 10 days of ownership of my R8. Today I have ordered the following tubes, for evaluation.

 

4 x EH 6CA7 Fat Bottle power tubes

3 x Tung Sol 6SN7 GTB tubes

2 x Sylvania 6SL7 GT (NOS)

 

This will give me a few combinations to try. I intend to swap out the 6SL7s first, as I am led to believe these have a significant impact on SQ, and these particular tubes seem to have a reputation for being very sweet. I'll run them with the KT88s for a few days and then swap out those for the 6CA7s. Depending on how this affects the sound, I will then try the 6SL7s - I intend to do these last as I believe they have less impact on SQ than the others. (More experienced members might correct me if I am wrong on this - or indeed give any advice at all, which is gratefully received).

 

Anyone wondering why I chose the 6CA& Fat Boys over the (more usual?) EL34s?  Don't ask :)  I am not sure why - maybe just wanted to go against the flow (after reading various online reviews of different power tubes). If these are not to my taste, I may try some EL34s later. I have read that the old Mullard EL34s (or their modern copies??) give a particularly lovely 'British' sound, so maybe those will be worth a try. Any comments anyone?

 

All the best, Zed.

 

I had tried my Brimar CV1985 NOS (6SL7GT) because of the shrill highs I was getting with the stock Willsenton with the 8 ohm taps, with similar results.  Now I've addressed that issue, I'll be more focused on having a proper listen.

 

Will eventually try out the EL34 I have too.  Mullard reissues.

 

But enjoying where I'm at now for the moment!

 

Keep us posted on your new tubes!

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3 hours ago, Zed Zed said:

 

I am glad that swapping to the 4 ohm taps has improved the SQ for you. I wonder what was causing the "shrill and metallic" highs you were hearing? My speakers don't dip below 5 ohms (200Hz), so are very different to yours. But in my case, although I hear clear differences when using the 4 ohm taps, they are much more subtle than yours.

 

 

In my case, the amp doesn't get anywhere near its maximum temperature after an hour. The power transformer gets gradually hotter and hotter until it peaks at about 44 degrees Celsius here (about 110 Fahrenheit). Here it reaches that temperature after playing music all day - about 12 hours. If you look back a few posts, you'll see my comparison between temperatures when using the 4 ohm taps vs the 8 ohm taps (with 8 ohm speakers) - there's no significant difference, so you won't be running the unit hotter by switching to the 4 ohm taps. My ambient temperature is about 22 Celsius as well for what it's worth.

 

 

Good to hear.

 

I don't recall what tubes you specified for your unit - KT88? If so, maybe swapping out to EL34s would bring further improvement?

 

2021-02-07_18-34-57.png.e845890da907dc4968cfbda83b951536.png

 

 

On that point, I have succumbed to the rabbit hole after 10 days of ownership of my R8. Today I have ordered the following tubes, for evaluation.

 

4 x EH 6CA7 Fat Bottle power tubes

3 x Tung Sol 6SN7 GTB tubes

2 x Sylvania 6SL7 GT (NOS)

 

This will give me a few combinations to try. I intend to swap out the 6SL7s first, as I am led to believe these have a significant impact on SQ, and these particular tubes seem to have a reputation for being very sweet. I'll run them with the KT88s for a few days and then swap out those for the 6CA7s. Depending on how this affects the sound, I will then try the 6SL7s - I intend to do these last as I believe they have less impact on SQ than the others. (More experienced members might correct me if I am wrong on this - or indeed give any advice at all, which is gratefully received).

 

Anyone wondering why I chose the 6CA& Fat Boys over the (more usual?) EL34s?  Don't ask :)  I am not sure why - maybe just wanted to go against the flow (after reading various online reviews of different power tubes). If these are not to my taste, I may try some EL34s later. I have read that the old Mullard EL34s (or their modern copies??) give a particularly lovely 'British' sound, so maybe those will be worth a try. Any comments anyone?

 

All the best, Zed.

Look's like a good selection there, I also have a pair of Sylvania  old stock waiting to go in once I get a base line on the  Wilsenton tubes,  Also useing the  CV- 181 on the pre. Looking forward to your review ...  🤓

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18 hours ago, Candan said:

 

I had tried my Brimar CV1985 NOS (6SL7GT) because of the shrill highs I was getting with the stock Willsenton with the 8 ohm taps, with similar results.  Now I've addressed that issue, I'll be more focused on having a proper listen.

 

Will eventually try out the EL34 I have too.  Mullard reissues.

 

But enjoying where I'm at now for the moment!

 

Keep us posted on your new tubes!

 

@Candan - I wonder if you'd share an experiment with me so that I can get a better idea of those 'shrill' highs you are hearing?  (If not, no worries buddy).

 

With the amp connected via its 8 ohm taps, could you play Tonight I Celebrate my Love for You by Roberta Flack and Peabo Bryson?  (I assume you stream in hi-res from Tidal or similar). At what seems like a 'natural' volume, pay attention to RF's singing and also to the overdubs. Does her voice sound powerful but beautiful, with no hint of strain even when she reaches for the high notes? Or is it 'shrill' or 'bright' or 'shiny'?  Does it have a 'metallic' edge to it, or does it sound 'real'?  

 

Then swap to the 4 ohm taps and describe the difference for me. I am trying to get a handle on what you are hearing and where in the frequency range this 'brightness' kicks in and causes the listening fatigue you mentioned.

 

In my case here, using the 8 ohm taps I detect a slight 'edge' to RF's voice when she goes loud and high at the same time. It isn't terrible but IMO it shouldn't be there. Switching to the 4 ohm taps removes it here and the genuine beauty of her voice comes through, much as I imagine it would if she were singing live in a similar acoustic environment.

 

I am wondering, when I swap tubes, especially the NOS Sylvanias, if I can recreate my 4 ohm tap experience with the 8 ohm taps, or if I will hear even more insights and nuances in RF's voice on this revealing track if I stick with the 4 ohm taps.

 

If you have no time or inclination to do this, I totally understand and no worries. :)

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To add to the above comments @Candan: Your Focals use a Beryllium tweeter I believe and I wonder if this is a mismatch with the R8? My speakers use titanium tweeters. I have always had a love-hate relationship with metal tweeters. I play a lot of jazz - sax, piano, trumpet being my favourite instruments and with the brass, I feel the titanium tweeter adds to the reproduction of the characteristic 'metal' sound of the instruments. That is the 'love' part.

 

The 'hate' part is that I always feel that a ribbon tweeter is the best for 'sweetness' which does assist with the higher registers of the human voice, especially the female voice., adding a 'sweetness' I can't seem, to get from a titanium tweeter. Given that a C6 'High C' is only just over 1,000 Hz, I am not sure why this should be the case. I imagine that it's something to do with harmonics, but in any event it is what I hear.* I suppose, ideally, I'd have both types of speaker connected to a switch and choose according to content. But even I think that is too geeky, let alone what my wife would think! The R8 (on the 4 ohm taps) has given me the best of both worlds, which is basically a first for me.

 

*There may be an element of expectation bias creeping in here. I fully admit this - we are human beings not computers, and it is impossible to control our biases.

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12 hours ago, Zed Zed said:

 

@Candan - I wonder if you'd share an experiment with me so that I can get a better idea of those 'shrill' highs you are hearing?  (If not, no worries buddy).

 

With the amp connected via its 8 ohm taps, could you play Tonight I Celebrate my Love for You by Roberta Flack and Peabo Bryson?  (I assume you stream in hi-res from Tidal or similar). At what seems like a 'natural' volume, pay attention to RF's singing and also to the overdubs. Does her voice sound powerful but beautiful, with no hint of strain even when she reaches for the high notes? Or is it 'shrill' or 'bright' or 'shiny'?  Does it have a 'metallic' edge to it, or does it sound 'real'?  

 

Then swap to the 4 ohm taps and describe the difference for me. I am trying to get a handle on what you are hearing and where in the frequency range this 'brightness' kicks in and causes the listening fatigue you mentioned.

 

In my case here, using the 8 ohm taps I detect a slight 'edge' to RF's voice when she goes loud and high at the same time. It isn't terrible but IMO it shouldn't be there. Switching to the 4 ohm taps removes it here and the genuine beauty of her voice comes through, much as I imagine it would if she were singing live in a similar acoustic environment.

 

I am wondering, when I swap tubes, especially the NOS Sylvanias, if I can recreate my 4 ohm tap experience with the 8 ohm taps, or if I will hear even more insights and nuances in RF's voice on this revealing track if I stick with the 4 ohm taps.

 

If you have no time or inclination to do this, I totally understand and no worries. :)

Yeah I'll rustle something up.  But might need some time though.  

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12 hours ago, Zed Zed said:

 

To add to the above comments @Candan: Your Focals use a Beryllium tweeter I believe and I wonder if this is a mismatch with the R8? My speakers use titanium tweeters. I have always had a love-hate relationship with metal tweeters. I play a lot of jazz - sax, piano, trumpet being my favourite instruments and with the brass, I feel the titanium tweeter adds to the reproduction of the characteristic 'metal' sound of the instruments. That is the 'love' part.

 

The 'hate' part is that I always feel that a ribbon tweeter is the best for 'sweetness' which does assist with the higher registers of the human voice, especially the female voice., adding a 'sweetness' I can't seem, to get from a titanium tweeter. Given that a C6 'High C' is only just over 1,000 Hz, I am not sure why this should be the case. I imagine that it's something to do with harmonics, but in any event it is what I hear.* I suppose, ideally, I'd have both types of speaker connected to a switch and choose according to content. But even I think that is too geeky, let alone what my wife would think! The R8 (on the 4 ohm taps) has given me the best of both worlds, which is basically a first for me.

 

*There may be an element of expectation bias creeping in here. I fully admit this - we are human beings not computers, and it is impossible to control our biases.

 

This eases my concerns and supports my findings.  However, it doesn't explain the sound difference being so big compared to solid state amps.

 

https://www.stereophile.com/content/focal-kanta-no2-loudspeaker-measurements

 

"Focal specifies the nominal impedance as 8 ohms. The impedance does stay above 8 ohms through the treble, and above 6 ohms in the low- and midbass regions. However, the Kanta No.2's impedance drops below 4 ohms between 80 and 180Hz, with a minimum magnitude of 2.97 ohms at 105Hz (fig.1). In addition, the electrical phase angle has an extremely high value between 70 and 90Hz, where the impedance magnitude is low. This speaker will work best with amplifiers comfortable with a 4 ohm load."

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45 minutes ago, Candan said:

 

This eases my concerns and supports my findings.  However, it doesn't explain the sound difference being so big compared to solid state amps.

 

https://www.stereophile.com/content/focal-kanta-no2-loudspeaker-measurements

 

"Focal specifies the nominal impedance as 8 ohms. The impedance does stay above 8 ohms through the treble, and above 6 ohms in the low- and midbass regions. However, the Kanta No.2's impedance drops below 4 ohms between 80 and 180Hz, with a minimum magnitude of 2.97 ohms at 105Hz (fig.1). In addition, the electrical phase angle has an extremely high value between 70 and 90Hz, where the impedance magnitude is low. This speaker will work best with amplifiers comfortable with a 4 ohm load."

 

Yes, that makes sense (the Stereophile conclusion).  As for your question about the big tonal difference when using SS amps, I can only speculate.  Tonal balance is affected by the interaction between the amp's output impedance with the speaker's frequency-induced impedance variations. In the case of a SS amp, the output impedance is vanishingly small - a fraction of an ohm. It is more than likely that the designer of your speaker voiced it using a SS amplifier, so maybe when you use the 4 ohm taps, the interaction between the R8 and the Focals is closer to the designer's intention?  As I say, I am just spitballing here really. HST, I'd expect the difference to be more subtle, not a change from 'ear-splitting, harsh highs' to 'acceptably smooth', which is what you are experiencing.

 

Maybe reaching out to the manufacturer of your speaker would provide some answers? I have invariably found speaker manufacturers to be more than willing to help with questions like these.  It is certainly an interesting question.

 

EDIT:

 

I just read the full Stereophile report you linked to. This paragraph is interesting:

 

For most of my listening to the Kanta No.2s I used a pair of PS Audio M700 monoblocks, which I'd found to work well with the Monitor PL300 IIs. When I switched to the McIntosh Laboratory MC275 LE tubed stereo amp (4-ohm terminals), the sound changed in ways that were largely predictable. The MC275 LE is one of my favorite amplifiers, with the easy-on-the-ears quality of tubes at their best, but without an excessively "tubey" sound that becomes a coloration. These characteristics were evident through the Kanta No.2s. The bottom end was not as well defined as with the PS Audios, but the difference was not as great as I might have expected. Dynamics were somewhat subdued with the McIntosh, but this was apparent only in direct comparisons. If I had to choose one of these amplifiers to use with the Kanta No.2s, it would be the Mac—and I'd be quite happy with the PS Audios.

 

 

This not only supports the concept of using 4 ohm taps with nominally 8 ohm speakers, but also suggests that there should be no huge difference in tonality when using a tube amp. I am sure the reviewer would have commented if he had experienced what you did. So, something odd is going on and I hope that you get to the bottom of it, even if for academic interest only.

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4 hours ago, Zed Zed said:

So, something odd is going on and I hope that you get to the bottom of it, even if for academic interest only.

 

I tell my wife that all of the tubes I keep buying are strictly for academic purposes and for the betterment of science.

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2 hours ago, echorec said:

 

I tell my wife that all of the tubes I keep buying are strictly for academic purposes and for the betterment of science.

 

This is very relevant to what I was just about to post. I have just rolled my first tubes! I am no longer a tube virgin, and it feels just great 😍

 

I ordered a batch of tubes, from different sellers, and the first arrived today. These are my NOS Sylvania 6SL7GT and I fitted them about 3 hours ago. I'm looking now for some guidance from more experienced members . . . 

 

As soon as I fired up my favourite test playlist, a huge smile cracked across my face. My first thought was 'smoother'. Followed by 'more beauty'. I can hear the decay of some instruments going on for a little longer. The music seems to appear, as if by magic, from a truly black background. The separation between instruments seems a little greater. There is more 'space' and 'air' around the instruments and the human voice seems to hang in space between my speakers. Now all of this was there before, but it now seems to be enhanced, as if a thin veil has been removed from my speakers. Importantly, on some tracks I used to hear a slight glare at times. I figured this was in the recording, but now it has pretty much vanished, so the overall result is 'sweeter'.

 

This is the thing: is this expectation bias at work?  Am I really hearing this sort of difference from swapping the stock Willsenton tubes to these NOS Sylvanias?

 

I assume that the 6SL7s are pre-amp tubes?  Now, I know from other experiences that the pre-amp can make a big difference. After all, the power amp/power tubes can only work with what they are given.  So the question to you gurus is  . . . is this the sort of thing you experience when you roll your preamp tubs?

 

If it is, then boy, am I looking forward to my 6CA7 Fat Boys arriving!

 

 

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Rolling the input tube, in this case the 6SL7 for the R8, will have the greatest influence in changing the tonal character. Rolling the other valves will be less significant.

 

Since you live in the UK you should hunt down some Xf1 B coded revision 4 Mullard Blackburn fat base dark brown phenolic base EL34’s with double O-shaped getters made from 1960-61. 👍👍👍

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21 minutes ago, Zed Zed said:

This is the thing: is this expectation bias at work?  Am I really hearing this sort of difference from swapping the stock Willsenton tubes to these NOS Sylvanias?

 

I assume that the 6SL7s are pre-amp tubes?  Now, I know from other experiences that the pre-amp can make a big difference. After all, the power amp/power tubes can only work with what they are given.  So the question to you gurus is  . . . is this the sort of thing you experience when you roll your preamp tubs?

 

Expectation bias is definitely possible for some.  The changes I experience with tube rolling are always very subtle and require deep listening to identify. Sometimes I can't explain exactly what it is that is actually going on, or why I like one tube over the other, and that is completely fine. I just know I like it (or dislike it), and that's all that really matters.

 

The other thing I've learned is that no matter what people say about one tube or the other, you will never know until you try it yourself. Some loved the 6550s in the R8. I hated them. Some dislike RCA 5691s, but I love them in tandem with KT88s.

 

It almost makes me want to stop posting my thoughts on tubes because... what's the point? If you don't have my ears, speakers, cartridge, etc., etc., you will likely have a different experience. But I do anyway... for academic purposes. 😁 And because it's fun to share experiences with the good people on this forum.

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48 minutes ago, xlr8or said:

Rolling the input tube, in this case the 6SL7 for the R8, will have the greatest influence in changing the tonal character. Rolling the other valves will be less significant.

 

 

Interesting - thanks. So it seems that I started in the right place (purely by accident of course).

 

48 minutes ago, xlr8or said:

Since you live in the UK you should hunt down some Xf1 B coded revision 4 Mullard Blackburn fat base dark brown phenolic base EL34’s with double O-shaped getters made from 1960-61. 👍👍👍

 

:) I will memorise that sentence and trot it out when appropriate LOL :) 

 

RARE Matched Pair Fat Base Mullard El34 Blackburn OO Getter Xf1 1961 NOS for sale | eBay

 

These are almost the same as you describe - they are xf2 not xf1. Since I have no idea what that means, is it significant?  The four for sale are not entirely stupidly priced, so I could be tempted . . . are these some sort of holy grail tube?

 

Thanks for the advice BTW. 👍

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51 minutes ago, echorec said:

 

Expectation bias is definitely possible for some.  The changes I experience with tube rolling are always very subtle and require deep listening to identify. Sometimes I can't explain exactly what it is that is actually going on, or why I like one tube over the other, and that is completely fine. I just know I like it (or dislike it), and that's all that really matters.

 

Yes, agreed. I have done further listening now and am also noticing a bigger soundstage with improved imaging, along with a little more attack on the leading edges of transients (very noticeable with BB King and Muddy Waters guitars). IDK how much of this is expectation bias - I try hard to be objective and I have decades of critical listening to draw on, but it's hard to be sure. Either way, as you rightly say, there's no real need to explain (or even understand) it - so long as we hear it, that is all that matters.

 

Quote

 

The other thing I've learned is that no matter what people say about one tube or the other, you will never know until you try it yourself. Some loved the 6550s in the R8. I hated them. Some dislike RCA 5691s, but I love them in tandem with KT88s.

 

It almost makes me want to stop posting my thoughts on tubes because... what's the point? If you don't have my ears, speakers, cartridge, etc., etc., you will likely have a different experience. But I do anyway... for academic purposes. 😁 And because it's fun to share experiences with the good people on this forum.

 

Agreed again. Please keep sharing. Even though you are 100% right that nobody else will have the same gear as you do, your insights are valuable and, as you say, it's good fun to share. And we do see trends emerging. Everywhere I keep reading that the EL34 is the most 'musical' tube. I know it won't suit everyone, and it all depends on what it is partnered with etc etc, but if this is a more or less universally held view, then it gives people (especially newbs like me) something to work with.

 

I am waiting delivery on four EH 6CA7 Fat Boys and really I have no idea what to expect when I install them - but it will be fun finding out and if I don't like them, I can always sell them on and get most of my money back. Then there are those Mullards . . . :) 

 

----------------

 

@xlr8or WRT to those Mullards in the eBay link - are they a 'safe' purchase? I mean, that since they are 'used', how would I know if they are near the end of their life or not, for example? Or does this not matter all that much? (I assume they eventually wear out, like light bulbs).

 

I have seen the re-issue Mullards on the internet and they seem to be about half the price of the used set on eBay. Paying double for something significantly better makes sense to me, but not if they decide to expire two weeks in. As ever, all advice gratefully received.

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@Zed Zed Please see the link below for the 4 different revisions of the Xf1 fat base EL34.

 

I would also suggest hunting down some Mullard Blackburn straight bottle ECC35's for the 6SL7 position and Mullard Blackburn ST shaped ECC32's for the 6SN7 positions.

 

NOS (and even some UOS) valves will last as long if not longer compared to new tubes. Nothing to worry about there. 👍👍👍

 

No - I wouldn't purchase that Xf2 quad set as they are a bit too pricey. You can start collecting singles. 😁

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12 hours ago, Zed Zed said:

 

Yes, that makes sense (the Stereophile conclusion).  As for your question about the big tonal difference when using SS amps, I can only speculate.  Tonal balance is affected by the interaction between the amp's output impedance with the speaker's frequency-induced impedance variations. In the case of a SS amp, the output impedance is vanishingly small - a fraction of an ohm. It is more than likely that the designer of your speaker voiced it using a SS amplifier, so maybe when you use the 4 ohm taps, the interaction between the R8 and the Focals is closer to the designer's intention?  As I say, I am just spitballing here really. HST, I'd expect the difference to be more subtle, not a change from 'ear-splitting, harsh highs' to 'acceptably smooth', which is what you are experiencing.

 

Maybe reaching out to the manufacturer of your speaker would provide some answers? I have invariably found speaker manufacturers to be more than willing to help with questions like these.  It is certainly an interesting question.

 

EDIT:

 

I just read the full Stereophile report you linked to. This paragraph is interesting:

 

For most of my listening to the Kanta No.2s I used a pair of PS Audio M700 monoblocks, which I'd found to work well with the Monitor PL300 IIs. When I switched to the McIntosh Laboratory MC275 LE tubed stereo amp (4-ohm terminals), the sound changed in ways that were largely predictable. The MC275 LE is one of my favorite amplifiers, with the easy-on-the-ears quality of tubes at their best, but without an excessively "tubey" sound that becomes a coloration. These characteristics were evident through the Kanta No.2s. The bottom end was not as well defined as with the PS Audios, but the difference was not as great as I might have expected. Dynamics were somewhat subdued with the McIntosh, but this was apparent only in direct comparisons. If I had to choose one of these amplifiers to use with the Kanta No.2s, it would be the Mac—and I'd be quite happy with the PS Audios.

 

 

This not only supports the concept of using 4 ohm taps with nominally 8 ohm speakers, but also suggests that there should be no huge difference in tonality when using a tube amp. I am sure the reviewer would have commented if he had experienced what you did. So, something odd is going on and I hope that you get to the bottom of it, even if for academic interest only.

Good suggestions, I can see your logic!

 

Asking Focal on what they think, is a great idea!  I'll do that!

 

I'd also read that piece on the McIntosh and also experienced slightly less on the bottom end vs an SS amp, and expected as such, but not the highs I'm finding.  If I get a valid response from them, I'll follow-up.

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Just on the MELZ 6H9C metal base tubes and noise, I had three new old stock bought off a ebay seller in the Ukraine in a phono stage with each tube doing L/R channels and there was zero noise, if there was noise it would have been evident in this application.

So I'd suggest pick your sellers wisely :D

 

But there are other good 6SL7's out there and Kirk mentions one above also, but some may also like the RCA RED Base 5691 though they are not cheap. (black plates sound a little better than the gray plate ones)

 

With EL34's if you can't get hold of the holy grail NOS Blackburn tubes above, try for some NOS Svetlana Winged C's, they are very good and well balanced from top to bottom doing it all well without over doing any particular thing.

 

Tube differences are quite noticeable in my experience, but like many things in this hobby, experiences vary.

 

Edit: oh, and do let new tubes, even new old stock tubes run in before passing judgement on them ;)

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