Willsenton R8 Owners & Discussion Thread

[08Boss302]

Very interesting read @Zed Zed thank you for posting your experience and findings.  I am also new to the Tube world and your experiment is one I am going to consider further,  I have not rolled the stock Willsenton Tubes as yet and have approx 60hrs up also.

 

Not to derail this thread entirely but I have one question before I trial the 4ohm tap....My speakers can drop to 3.2ohm but are 8ohm nominal.  Will this drop to 3.2ohm have any detrimental or negative affect on anything compared to your drop down to 5ohm? 

*Sensitivity 91dB (2.83V/1m)

* Nominal Impedance 8 Ohms (min.3.2 Ohms)

[Wisker]

The R8 arrived last night late,  1 day early . Shipping container had normal wear and tear for traveling 7400 miles, Upon gaining access to the contents I commenced  the extraction from the box, I think that if I would have opened the bottom also it would have slid right out,  The tubes were individually wrapped in a bubble bag the wrapped in a sheet of foam and all stuffed in the cage.

The amp was very cold and I decided to wait till daybreak to bring this to life, I biased the tubes a couple minutes after start up, All 4 were in the middle range high right,  

 

After about 1 hour I re- biased, all tubes crept up a little so I tweaked them back to center, the adjustment is sensitive. After about 5 hours of running all tubes remain centered..

Output tube temp after 5 hours has been fairly constant at roughly 280 degrees or 137 Celsius . Power tubes are the stock Wilsenton KT88..

I went with the optional PSVANE cv 181's  for pre. Wife will be leaving shortly, so I have about a 3 hour window......... here are some pics all seemed well inside, and solder points look good, no scratches, so far so good... Nght pic coming ..

Edited February 3, 2021 by Wisker

[Zed Zed]

3 hours ago, echorec said:

Great write-up @ZedZed Great test tracks as well, especially for "emotion".

 

Interestingly, my 6ohm speakers sound better on the 8ohm taps. I feel like I get more space between sounds/instruments, but it is very subtle. I also get a bit more output volume relative to volume position. I'll have to switch back to 4ohm taps now that I have a completely different tube configuration than when I first experimented with the taps. Maybe my preference will change. It's good to experiment with these things and choose whatever sounds best to your ears.

 

Yes, the air and space between instruments is astonishingly good with the R8. Of course, I am the opposite wrt to output volume - running 8 ohm speakers off the 4 ohm taps gives me less output, so I have to turn up the volume a bit. 

 

I spent a whole day researching this and everything I read indicated that I would do no harm to the amp by running this configuration, so all i can suggest is that you experiment and let your ears guide you. Whichever sounds best to you, is best for you.

[Zed Zed]

1 hour ago, 08Boss302 said:

Very interesting read @Zed Zed thank you for posting your experience and findings.  I am also new to the Tube world and your experiment is one I am going to consider further,  I have not rolled the stock Willsenton Tubes as yet and have approx 60hrs up also.

 

Not to derail this thread entirely but I have one question before I trial the 4ohm tap....My speakers can drop to 3.2ohm but are 8ohm nominal.  Will this drop to 3.2ohm have any detrimental or negative affect on anything compared to your drop down to 5ohm? 

*Sensitivity 91dB (2.83V/1m)

* Nominal Impedance 8 Ohms (min.3.2 Ohms)

 

I'd say that you results will, theoretically at least, be better than mine because from 4 ohm to 3.2 ohms, the 4 ohm tap will actually be a better match for your speakers than the 8 ohm taps. With my speakers, they never reach below 5 ohms so, in theory, the 4 ohm tap never matches at all. I think this shows that you have to let your ears guide you. There is zero doubt in my mind that the config I am using is demonstrably superior - it is easy to appreciate the improvement within even a few seconds of listening. 

[08Boss302]

3 minutes ago, Zed Zed said:

 

I'd say that you results will, theoretically at least, be better than mine because from 4 ohm to 3.2 ohms, the 4 ohm tap will actually be a better match for your speakers than the 8 ohm taps. With my speakers, they never reach below 5 ohms so, in theory, the 4 ohm tap never matches at all. I think this shows that you have to let your ears guide you. There is zero doubt in my mind that the config I am using is demonstrably superior - it is easy to appreciate the improvement within even a few seconds of listening. 

Thanks @Zed Zed I am home next week and can do this  and see what my ears tell me. 

 

[Zed Zed]

13 minutes ago, Wisker said:

The R8 arrived last night late,  1 day early . Shipping container had normal wear and tear for traveling 7400 miles, Upon gaining access to the contents I commenced  the extraction from the box, I think that if I would have opened the bottom also it would have slid right out,  The tubes were individually wrapped in a bubble bag the wrapped in a sheet of foam and all stuffed in the cage.

The amp was very cold and I decided to wait till daybreak to bring this to life, I biased the tubes a couple minutes after start up, All 4 were in the middle range high right,  

 

After about 1 hour I re- biased, all tubes crept up a little so I tweaked them back to center, the adjustment is sensitive. After about 5 hours of running all tubes remain centered..

Output tube temp after 5 hours has been fairly constant at roughly 280 degrees or 137 Celsius . Power tubes are the stock Wilsenton KT88..

I went with the optional PSVANE cv 181's  for pre. Wife will be leaving shortly, so I have about a 3 hour window......... here are some pics all seemed well inside, and solder points look good, no scratches, so far so good... Nght pic coming ..

 

 

 

 

Thanks for sharing the pics! I did the same as you - biased the tubes a few minutes after start-up and then, a few hours later checked again and there had been a little 'creep'. I re-biased and centred the needle for each tube. I haven't touched the bias again and now, after 70 hours, the needles are still dead centre.

 

I hadn't thought to check the tube temps, but will do so. Since switching to the 4 ohm taps my unit runs a little hotter - if I put my hand on the power transformer it is quite warm - not so hot you have to remove your hand, but quite hot nonetheless. Having said that, it was quite hot with the 8 ohm tap setting too. I am using all stock tubes throughout.

 

Enjoy!

[Wisker]

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..

[Zed Zed]

6 minutes ago, 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..

 

Thanks for the info. I'll check mine with my infra-red digital thermometer tomorrow and report back. 

[muon*]

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

Edited July 22, 2021 by muon*

[xlr8or]

The power transformer getting hot on the 8 ohm tap doesn't sound right. It may be warm but should be lukewarm to touch.

 

Me thinks you may have a 220v unit running at 240v AC mains. Might also explain why the 4 ohm tap sounds better.

 

This is just a guess that also requires data to confirm if this is true. Please ignore this comment as I'm trying to work out why the 4 ohm sounds better based on my own 40+ years experience telling me otherwise. Yes - it will be cleaner sounding, have less power output but also sound too SS in tonal character in particular when using triode over UL mode.

 

I guess what I'm trying to say is that tube magic comes from the 8 ohm tap. I use 8 and 16 ohms and in the good old days even tried 32 ohm as that along with 16 ohm were the most regular taps found on 1960's 2nd hand tube/valve amps.

Edited February 4, 2021 by xlr8or

[Rali]

Been using R8-el34 for a month with forte iii. Recently i hear "kirr.. Drr.. Trr" noises in one of the channels. is anyone seeing this behavior? all stock tubes 

[Zed Zed]

1 hour ago, xlr8or said:

The power transformer getting hot on the 8 ohm tap doesn't sound right. It may be warm but should be lukewarm to touch.

 

It gets hotter on the 4 ohm tap, cooler on the 8 ohm. (I suspect you made a typo there?) It is hotter than lukewarm for sure. I will measure it both ways so we know what we're looking at.

 

Quote

 

Me thinks you may have a 220v unit running at 240v AC mains. Might also explain why the 4 ohm tap sounds better.

 

Well, I ordered a 230v unit and the sticker on the back says 230v. Of course, what it actually is could be anyone's guess   Here in the UK, as in Oz too, the nominal mains voltage is 230v but the permitted tolerances are +10%/-6% so the actual voltage delivered could be anywhere between 253v and 216v, although I wouldn't expect to see such a swing from nominal.

 

Quote

 

This is just a guess that also requires data to confirm if this is true. Please ignore this comment as I'm trying to work out why the 4 ohm sounds better based on my own 40+ years experience telling me otherwise. Yes - it will be cleaner sounding, have less power output but also sound too SS in tonal character in particular when using triode over UL mode.

 

My experience with tube amps is about 5 days so there is no way I am going to disagree with you  But I'll make a couple of observations - I have decades of experience with SS amps and I can say that what I am hearing here (on 4 ohm taps or 8 ohm taps) is nothing like what I have heard on SS amps. There is a world of difference. My last-used SS amp was a pure Class A Alchemist Kraken, which I have owned for many years and has been in and out of my various systems over that time. The Kraken (55 watts per channel dual mono design) has a beautiful 'Class A' sound and is smooth and refined. Some might even say 'tube like' . But the R8 sounds nothing like it, in numerous ways. I don't hear the R8 sounding more like SS, tonally, in either 4 ohm or 8 ohm operating mode,

 

Second, I'd say that I am not alone in coming to the conclusion that the 4 ohm taps sound better. While researching the topic, I came across various forum discussions, some knowledgeable, some less convincing, but they all fell on the side that using 4 ohm taps with 8 ohm speakers was sonically beneficial (and caused no harm to the amp). I won't list the sites, but anyone googling '8 ohm vs 4 ohm taps' or similar will find the same sites that I found. On one or two, (apparently) respected designers of valve amps said similar things too.

 

Of course, one never listens to just one component in any hifi system, so my particular choice of speakers and how they interact with the amp will be significant, and will differ from yours, and probably everyone else's too. This will account for differences in what each individual hears. This is why I couldn't recommend using 4 ohm taps with 8 ohm speakers (even if I was confident that I know what I am talking about, which currently is not the case) but why I do feel comfortable recommending that others try it, if they feel so inclined., since every site I explored confirmed that no damage would ensue. 

 

Quote

 

I guess what I'm trying to say is that tube magic comes from the 8 ohm tap. I use 8 and 16 ohms and in the good old days even tried 32 ohm as that along with 16 ohm were the most regular taps found on 1960's 2nd hand tube/valve amps.

 

I am grateful for your comments and perspective - the sheer amount of experience you have cannot be ignored. Although common sense would suggest that your infinitely greater experience with tube amps massively outweighs my total newb status with these devices, I am hearing what I am hearing, even though my lack of experience/knowledge with tube amps cannot provide a satisfactory reason why. (Although a newb with tube amps, I have decades of listening experience on systems going from midrange (say at current pricing, £2-3,000 GDP) to, a couple of times, ultra-systems costing in excess of £500,000 GDP (sadly not my own system!!) 

 

Your comments are well-received here, and will inspire me to keep searching and learning, as best as I am able. I may go back to the 8 ohm taps - not really planning to at this stage, but I will certainly swap back for evaluation, maybe on a wider range of test tracks. BTW, the reason I used that list of tracks (see earlier post) is that, a) I am very familiar with most of them and b) I invariably find that if I get vocals (especially female vocals) right, then pretty much everything else falls into place. As you know, human hearing is most sensitive in the frequencies where the human voice reigns supreme, so I have always used this type of music for initial listening tests, broadening the field out later to see if anything different comes to light (almost never does).

 

I have to say, that this forum, or this thread to be more specific, is one of the best I have used, anywhere, both for the quality of the content and the pleasant and helpful nature of the contributors. (I have about 28,000 posts on the American AVS Forums site - in a different user name) and the atmosphere there is often, how shall I say it, confrontational  ).

 

Edited February 4, 2021 by Zed Zed

[Zed Zed]

6 minutes ago, Rali said:

Been using R8-el34 for a month with forte iii. Recently i hear "kirr.. Drr.. Trr" noises in one of the channels. is anyone seeing this behavior? all stock tubes 

 

Could you maybe record the noises (recorder app on your phone would be good enough) and post the sound files?

[Ihearmusic]

22 hours ago, Zed Zed said:

 

Bear in mind that, despite having decades of experience with high end and ultra high end audio, I am a newb when it comes to tube amps.  So please don't think I am in any way contradicting your comments above - and I note and entirely agree with your last two sentences. That said, from my recent research, this is what I have learned so far. When using the 4 ohm taps to drive (some) 8 ohm speakers:

 

• The 4 ohm taps will drive more current, whereas the 8 ohm taps will drive more voltage.
• For a given speaker impedance the damping factor will be twice as high for the 4 ohm tap as for the 8 ohm tap. (Damping factor is inversely proportional to output impedance). This may explain why I am hearing a noticeably tighter bass - the amp has more grip on the woofers.
• As we know, the impedance of most nominal 8 ohm speakers varies significantly as a function of frequency - so the 4 ohm tap may be a better match at some frequencies than the 8 ohm tap. This will result in a less linear output, but possibly a more pleasing or satisfying one.
• Tonal balance is affected by the interaction of the amp's output impedance with the speaker's frequency-induced impedance variations. Now it is very likely that most modern speakers have been voiced with the expectation that they will be used with SS amps. Since SS have have vanishingly small output impedances (a fraction of an ohm), it may be that the impact on FR by using the 4 ohm taps comes closer to the interaction intended by the designer - this may noticeably impact the 'sound'.
• Distortion introduced by the amplifier will depend to some extent on how well matched (or mismatched) the tap and the speaker impedance are at various frequencies.
• Using the 4 ohm taps with (nominal) 8 ohm speakers reduces the output current demand on the output tubes, which may allow them (the tubes). to be more linear.
• An obvious potential downside is that the power output will be reduced (possibly by as much as 3dB) - whether this is a real downside or not will depend, among other things, on the sensitivity of the speakers, size of room, preferred SPLs etc.
• I should also say that the amp runs warmer. So far, this doesn't seem to be a major issue, but it is worth noting.
   

Now all of the above are just summaries of what I have read. As I say, my experience with tube amps is very limited. Nonetheless, I do understand the issues involved and all of the above seems to make sense to me, based on what I (think) I know.

 

I'll post some listening impressions later, based on a dozen or more female vocalist tracks which I think are particularly revealing. 

 

Since I  am hearing a significantly superior sound using the 4 ohm taps with my 8 ohm speakers, I would recommend people give this a try, experimentally, to see if they also hear any sonic improvements. It will depend on the speakers used and their interaction with the amp, and this will be different for pretty much everyone so it has to be a 'suck it and see' basis I think.

 

My speakers are not a difficult load and they do not dip below 5 ohms at any point in their frequency range. Below is the manufacturer's impedance curve, for reference. Clearly, what anyone else hears if they try this experiment will greatly depend on the characteristics of their own speakers.

 

 

 

 

May I take this opportunity to thank everyone for their contributions to my understanding of this issue. It is a learning process for me, which is ongoing.

 

 

The Speaker impedance gets reflected back through the OPT via a formula that takes the turns ratio primary to secondary in to consideration. The reflected impedance is the load on the tube. The load on the tube is part of how the operating point of the tube is calculated.

Most of your points are generalizations and might have some truth to it depending on how the tube is operated.

If you want to get down to the heart of it you will have draw out the circuit and to take a multi meter to the internals and start to take some measurements and while the amp is live.

From there you can start working what the implications are of using the 4 Ohm tap. Everything else is speculation.

If you want to learn about tube amps get your self a good book and start building.

 

In most forums you will get only opinions. 

 

Enjoy the journey

Edited February 4, 2021 by Ihearmusic

[Zed Zed]

45 minutes ago, Ihearmusic said:

The Speaker impedance gets reflected back through the OPT via a formula that takes the turns ratio primary to secondary in to consideration. The reflected impedance is the load on the tube. The load on the tube is part of how the operating point of the tube is calculated.

Most of your points are generalizations and might have some truth to it depending on how the tube is operated.

If you want to get down to the heart of it you will have draw out the circuit and to take a multi meter to the internals and start to take some measurements and while the amp is live.

From there you can start working what the implications are of using the 4 Ohm tap. Everything else is speculation.

If you want to learn about tube amps get your self a good book and start building.

 

In most forums you will get only opinions. 

 

Enjoy the journey

 

Thank you. I wonder if anyone has already done the tests you suggest?  I'll take a look around. I am entirely in agreement with you that only objective testing gives reliable data. Unfortunately, while I am experienced in measuring acoustics and analysing and acting on the resultant data, I am far from an electrical engineer (about as far as it's possible to get TBH) so I won't be pushing my hands into a live unit .  The last time I did something like this, there was a loud bang and I accidentally let all the smoke out of the unit which resulted in the instant demise of the unit, but fortunately not of me. . . 

 

I may follow your advice to get a good book about designing and building tube amps though, just to add to my knowledge. Meanwhile, I am still of the view that the 4 ohm taps are delivering a more seductive sound, but I will do further (listening) tests, this time taking notes, to see if I really want to stick with the 4 ohm taps long term.

 

Thanks for your reply - I will do my best to enjoy this new journey, at the same time rediscovering some of my favourite music via the magic of tubes.

[Zed Zed]

 

I wonder if @Atmaj (the thread's OP) is around? Based on the thread's first post Atmaj is knowledgeable on the issues we are currently discussing and if he has the time to respond, I'd like to see his views. This is a great learning curve for me!

[echorec]

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

[jgunner]

@Zed Zed what speakers are you running the with the 4ohm tap?

[Zed Zed]

2 hours ago, jgunner said:

@Zed Zed what speakers are you running the with the 4ohm tap?

 

Fyne Audio F500 standmounts. Nominal 8 ohm (see the impedance curve graph a few posts back). About 90dB/1w/1m sensitivity and very easy to drive. At no point does the impedance dip below 5 ohms (at 200Hz).

 

Today I switched back to the 8 ohm taps for further testing. SQ still better on the 4 ohm taps IMO. 

 

I (mistakenly) posted earlier that the R8 runs significantly hotter on the 4 ohm taps, but, as if to demonstrate the unreliability of subjective testing, I now believe this not to be the case (again subjectively). However, I have now properly recorded the temperature of the power transformer and will revert back to 4 ohm taps tomorrow, take the temperature again (after 12 hours running, as today) and post the results. I would be surprised if the two readings are all that different to each other. 

 

I think what confused me before is that the output transformer gets gradually hotter over the 12 hour period the amp is in use each day. What I did was (stupidly) take the temperature by resting my hand on the transformer after it had only been on for a couple of hours or so, and then compared that with the 'feel' on the 4 ohm taps, but after considerably longer running time. This time I will read the temperature with my infra-red thermometer using the exact same spot on the transformer casing and after exactly the same running time. IOW, with at least a nod to scientific method

 

If I am right, and there is no excess heat penalty by using the 4 ohm taps, then I will revert back to 4 ohm and stay with it.

 

My unit now has 85 hours on it BTW.

Edited February 4, 2021 by Zed Zed

[Rali]

15 hours ago, Rali said:

Been using R8-el34 for a month with forte iii. Recently i hear "kirr.. Drr.. Trr" noises in one of the channels. is anyone seeing this behavior? all stock tubes 

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.

[Lam Pham]

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,

[muon*]

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

Edited July 22, 2021 by muon*

[muon*]

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

Edited July 22, 2021 by muon*

[xlr8or]

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.

Edited February 5, 2021 by xlr8or

[Ihearmusic]

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.