Willsenton R8 Owners & Discussion Thread

[Lam Pham]

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.

Edited February 5, 2021 by Lam Pham

[Zed Zed]

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.

Edited February 5, 2021 by Zed Zed

[echorec]

@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.

[muon*]

................

Edited July 22, 2021 by muon*

[Zed Zed]

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.

Edited February 6, 2021 by Zed Zed

[muon*]

.............

Edited July 22, 2021 by muon*

[echorec]

31 minutes ago, muon* said:

Were these used or new old stock?

 

They were NOS military surplus.

[xlr8or]

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 February 5, 2021 by xlr8or

[Comzee]

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 February 5, 2021 by Comzee

[xlr8or]

@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). 

Edited February 5, 2021 by xlr8or

[xlr8or]

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.

 

Edited February 5, 2021 by xlr8or

[Zed Zed]

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.

[Zed Zed]

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.

[Rali]

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.

[Zed Zed]

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?

[muon*]

................

Edited July 22, 2021 by muon*

[Zed Zed]

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)

Edited February 6, 2021 by Zed Zed

[Candan]

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.

[Zed Zed]

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?

 

 

 

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.

Edited February 7, 2021 by Zed Zed

[Candan]

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?

 

 

 

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!

[Wisker]

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?

 

 

 

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 ...  

[Zed Zed]

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.

[Zed Zed]

 

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.

Edited February 8, 2021 by Zed Zed

[Candan]

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.  

[Candan]

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."