Vexed by Valves

[Mike Hanson]

There are those here who may recall that I was hankering after more "texture" from my Cornwalls. I was told that I needed tubes, specifically in the power amp stage, as my speakers were intended for old-timey amplifiers (even though the Cornwall IV was released in the last decade). I went ahead and auditioned a few, and ended up with a Cary SLI-100 integrated. It had the boogie that I required, and more of that textural nuance that I desired. I was irritated, though, because it meant I couldn't use any of the many solid state power amps that I've built over the years.

There was a fair bit of hiss from one channel, though, and swapping input tubes highlighted that it was a poor 6922 tube. I replaced them with Electro Harmonix Gold, and things improved. However, I was still irked that tubes can go gradually like this, and the big KT-150 tubes in the SLI-100 would be expensive to replace.

During my initial investigation, some dissenters said that I should go with a tube preamp, fed into a solid state amp. Given my aforementioned irritation, I decided to look for something suitable to try. I discovered a Cary SLP-2002 for a good price, and set it up to compare against the SLI-100. I was pleased to discover it was at least as good, so I was happy to move away from the integrated.

Deja vu: the pre-amp was making low level hissy-spitty noises, so I decided to try swapping tubes. Conveniently, both amps use the 6922 for the input stage. The existing tubes were in the pre were Amperex ECC88/6DJ8, which I replaced with the Electro Harmonix from the integrated. Unexpectedly, my left channel wasn't outputting any sound. I tried swapping sides, but the problem remained on the left side. Then I tried putting the Amperex back in, and sound resumed. I popped the EH tubes back into the integrated, and they were fine there.

So the pre-amp that's supposed to work with 6922 tubes doesn't work with 6922 tubes.

Perhaps the pre-amp is on the edge, and can't quite manage the different tubes. I was already planning to send it into Cary, so they could fiddle with the volume resistors to give me more range. I'll ask them to do a full once over, to ensure that everything's fine.

So far, my experience with tubes has been frustratingly fiddly. Any web search brings up ambiguous or conflicting results. Is my life with tubes destined to filled with annoying problems?

As a sidenote, I'm currently using a Ferrum Wandla DAC. They're about to release a GoldenSound upgrade, including a "tube" mode that adds even order harmonics to simulate the distortion inherent in tubes. Perhaps that's where I'm headed.

 

[Darren L]

To give a little balance, I've never had any bother with the valve gear that I've owned (touch wood) no noise, no hiss, etc but that's only been one integrated amp, a couple of phono stages, two hybrid integrated, a couple of valve preamps and a CD player with a valve output stage, maybe it's down to luck or some stuff is just well designed or poorly designed. I'm not a valve only purist , I'll pretty much try any sort of amp(s) and have found that I like all different sorts as well.

 

[Juancho]

To give a little balance, I've never had any bother with the valve gear that I've owned (touch wood) no noise, no hiss, etc but that's only been one integrated amp, a couple of phono stages, two hybrid integrated, a couple of valve preamps and a CD player with a valve output stage, maybe it's down to luck or some stuff is just well designed or poorly designed. I'm not a valve only purist , I'll pretty much try any sort of amp(s) and have found that I like all different sorts as well.

That's my experience too with my own brand DACs and preamps and commercial power amps. As I noted elsewhere I think the Starkrimson GAN amp does 95% what the best tube amps do, so it makes a great summer amp or alternate. Not without issues tho, as sold it cuts out when the mains goes above 243v approx and my mains varies between 243 and 250v. But you really shouldn't get any bother from decent 6922 tubes

 

[cb01]

I'm sorry to hear of your troubles, Mike.

Across several tube systems, the only issue I've ever had was a coupling cap in my tube preamp went to the afterlife and this resulted in a completely covered warranty repair. But it was the first repair of that type that the NA head had seen. So, it happens to the best of us.

My preamps uses 6922's and I've got quite a lot of experience with them and compatible types if you ever want to chat about it. My tube preamp came with Gold Lion 6922's and, though competent, they offered maybe 30% of what my tube preamp was actually capable of, in SQ terms.

 

[cb01]

...But you really shouldn't get any bother from decent 6922 tubes

Agreed. The 6DJ8 is the original noval tube type here, with the 6922 being a much improved (and longer life) version of it that was developed later. IIRC, a true 6922 should have a 10k hour heater life (the limiting factor for tube life). Other 6DJ8 variants like the cCA, 7308/E188CC, 7DJ8/PCC88, etc also have 10k hour heaters.

The european designation for the 6922 is E88CC. Same same. The designation for the 6DJ8 is ECC88. Note the different order.

 

[Tony L]

FWIW I’ve had no issue here beyond a couple of cheap modern Russian valves going noisy. I’ve rebuilt a Stereo 20, two TL12 Plus (one cracked valve base pin caused me a lot of grief in diagnosis), a Leak Point One Stereo and I’ve diagnosed and fixed my Verdier preamp. I also have a valve guitar amp, that again I feel I could probably fix myself if it went wrong as it is a fundamentally simple tried and tested design. During this process I’ve ended up with a real respect for valve kit. It is simple, solid, pretty much understandable, (IME) reliable, and serviceable almost indefinitely. Conversely I remain absolutely baffled by transistors and their incomprehensible substitutions!

That said with ultra high-efficiency speakers such as Klipsch it is unlikely one will obtain truly silent backgrounds. Just live with it and enjoy what is so right/so much better about a valve amp with such speakers. In time you learn not to obsess over tiny audiophile details and get right back into enjoying music. At least I did. My system changes and tweaks have become glacially slow since shifting mainly to valves.

PS I still think Mike should just have bought a Leben 300. All the power he’d ever need in a beautiful easy to live with, cheap to run and reliable integrated amp. You need a good 5-10 Watts with Cornwalls. More than that is just adding extra gain for no reason.

 

[joe9407]

PS I still think Mike should just have bought a Leben 300. All the power he’d ever need in a beautiful easy to live with, cheap to run and reliable integrated amp.

I was just going to say the same!

My Leben CS-600 has been at Chez Joe for almost a year now and it's a joy. I've done a bit of tube rolling and enjoyed the subtle differences among them -- but all the same, I suspect the circuit itself is what's so good. Handmade in Japan by a true enthusiast and artisan, completely point-to-point wired, infinitely repairable. I think I'm good for a long, long time!

 

[Juancho]

A Leben would do the trick very nicely. But my 845 PSEs are also silent. No hum no hiss-just a growl as the voltage comes up. Cayin amps I know also turn in 90db signal to noise ratios

 

[chiily]

Yep, having high efficiency speakers and valves can really highlight noisy valves. That said I've only had one particularly noisy valve, and strangely a ECC88 in Jez's cracking DIY pre-amp, and that was more of a crackle and a "sigh" as the valve warmed up - I can't remember the make now. Other than that my Fortes are near enough silent with the valve power amps I have; yeah okay, if you place your ear right up against the speaker, almost touching there is a very faint hum, but it can't be heard when more than 25cm away.

Deja vu: the pre-amp was making low level hissy-spitty noises, so I decided to try swapping tubes. Conveniently, both amps use the 6922 for the input stage. The existing tubes were in the pre were Amperex ECC88/6DJ8, which I replaced with the Electro Harmonix from the integrated. Unexpectedly, my left channel wasn't outputting any sound. I tried swapping sides, but the problem remained on the left side. Then I tried putting the Amperex back in, and sound resumed. I popped the EH tubes back into the integrated, and they were fine there.

That's very strange with the left hand channel stopping working when you replaced the valves and even when you swapped them over. Well, I think I read that you swapped the valves between channels when you said, "...I tried swapping sides, but the problem remained on the left side...". Certainly something that needs a bit more investigation methinks.

I agree with Tony, you don't need many watts for those Cornwall IVs and there's a whole world of low power, high quality iron out there. That Leben 300 looks amazing. From what I've read about valve amps is that the quality of the amp is dictated by the performance of the mains and particularly the output transformers - OP transformers being complex and hence costly beasts to manufacture, to the point that over on Vintage Radio Repair and Restoration forum members were discussing that Arthur Radford was more of a transformer designer than he was the designer of amplifiers!

 

[Mike Hanson]

I'm sorry to hear of your troubles, Mike.

Across several tube systems, the only issue I've ever had was a coupling cap in my tube preamp went to the afterlife and this resulted in a completely covered warranty repair. But it was the first repair of that type that the NA head had seen. So, it happens to the best of us.

My preamps uses 6922's and I've got quite a lot of experience with them and compatible types if you ever want to chat about it. My tube preamp came with Gold Lion 6922's and, though competent, they offered maybe 30% of what my tube preamp was actually capable of, in SQ terms.

I may take you up on that. The Cary SLP-2002 that I bought is probably 20 years old, so I suspect it's drifted out of spec. I'm hoping that it's better once it comes back from the shop. I'm also going to ask if they would suggest any improvements to components, like capacitors, etc. I notice that there are a couple Solens in there already.

I have four different 6922 pairs, which I purchased to roll in the SLI-100. I never got around to do that, but they'll come in handy with the preamp. It also takes 5814 tubes in the driver stage. It currently has Sylvania 6189W there.

 

[Mike Hanson]

FWIW I’ve had no issue here beyond a couple of cheap modern Russian valves going noisy. I’ve rebuilt a Stereo 20, two TL12 Plus (one cracked valve base pin caused me a lot of grief in diagnosis), a Leak Point One Stereo and I’ve diagnosed and fixed my Verdier preamp. I also have a valve guitar amp, that again I feel I could probably fix myself if it went wrong as it is a fundamentally simple tried and tested design. During this process I’ve ended up with a real respect for valve kit. It is simple, solid, pretty much understandable, (IME) reliable, and serviceable almost indefinitely. Conversely I remain absolutely baffled by transistors and their incomprehensible substitutions!

That said with ultra high-efficiency speakers such as Klipsch it is unlikely one will obtain truly silent backgrounds. Just live with it and enjoy what is so right/so much better about a valve amp with such speakers. In time you learn not to obsess over tiny audiophile details and get right back into enjoying music. At least I did. My system changes and tweaks have become glacially slow since shifting mainly to valves.

PS I still think Mike should just have bought a Leben 300. All the power he’d ever need in a beautiful easy to live with, cheap to run and reliable integrated amp. You need a good 5-10 Watts with Cornwalls. More than that is just adding extra gain for no reason.

If a Leben had shown up when I was looking, I would have tried it. The Cary appeared first, and I was happy with its performance. It's only the ancillary aspects that spoiled the experience for me.

I don't mind a bit of hiss. In this case, I was hearing notable hiss, sputtering, and popping from across the room, even while music was playing. I'm hoping it'll be resolved by a trip back to the factory.

 

[Mike Hanson]

Yep, having high efficiency speakers and valves can really highlight noisy valves. That said I've only had one particularly noisy valve, and strangely a ECC88 in Jez's cracking DIY pre-amp, and that was more of a crackle and a "sigh" as the valve warmed up - I can't remember the make now. Other than that my Fortes are near enough silent with the valve power amps I have; yeah okay, if you place your ear right up against the speaker, almost touching there is a very faint hum, but it can't be heard when more than 25cm away.



That's very strange with the left hand channel stopping working when you replaced the valves and even when you swapped them over. Well, I think I read that you swapped the valves between channels when you said, "...I tried swapping sides, but the problem remained on the left side...". Certainly something that needs a bit more investigation methinks.

I agree with Tony, you don't need many watts for those Cornwall IVs and there's a whole world of low power, high quality iron out there. That Leben 300 looks amazing. From what I've read about valve amps is that the quality of the amp is dictated by the performance of the mains and particularly the output transformers - OP transformers being complex and hence costly beasts to manufacture, to the point that over on Vintage Radio Repair and Restoration forum members were discussing that Arthur Radford was more of a transformer designer than he was the designer of amplifiers!

Given all my work building power amps, I've decided that I'm not willing to forego them. I'm just happy that I was able to get the effect that I wanted from the tube preamp. Now I just have to get the glitches sorted.

 

[Salamander]

Let's hope Cary can sort this pre out for you, I don't think you will have to change anything once they do.

 

[Roog]

Whilst I understand the allure of Valve kit, I still have some, there is a reason why the world outside of guitar amps has largely moved on.

Consistency and reliability were just two of those reasons.

 

[Kostas]

There are those here who may recall that I was hankering after more "texture" from my Cornwalls. I was told that I needed tubes, specifically in the power amp stage, as my speakers were intended for old-timey amplifiers (even though the Cornwall IV was released in the last decade).

You are not obliged to use valves with Klipsch speakers. The local distributor for Klipsch is also for Accuphase and have auditioned all the Heritage models with various Accuphase (A + AB class) models, it's a very nice combination. He used to be a distributor for the equally expensive Hovland amps, have heard Hovland + Klipsch and the sound was slightly different, not better or worse.

I like valve amps myself but I don't view them as superior to solid state. Since I believe power is important I have a valve preamp with a solid state amp, only because the specific pre worked better in my system than all the others that I tried. As far as the valves you tried, the EH are the noisiest in mine and by that I mean putting my ear to the tweeter to hear the noise. Vintage Mullard are slightly sweeter sounding and quieter. Genalex have also worked good in mine.

 

[Mike Hanson]

Whilst I understand the allure of Valve kit, I still have some, there is a reason why the world outside of guitar amps has largely moved on.

Consistency and reliability were just two of those reasons.

Even in the world of guitars, DSP simulations are becoming more common. We shall see...

 

[Juancho]

You are not obliged to use valves with Klipsch speakers. The local distributor for Klipsch is also for Accuphase and have auditioned all the Heritage models with various Accuphase (A + AB class) models, it's a very nice combination. He used to be a distributor for the equally expensive Hovland amps, have heard Hovland + Klipsch and the sound was slightly different, not better or worse.

I like valve amps myself but I don't view them as superior to solid state. Since I believe power is important I have a valve preamp with a solid state amp, only because the specific pre worked better in my system than all the others that I tried. As far as the valves you tried, the EH are the noisiest in mine and by that I mean putting my ear to the tweeter to hear the noise. Vintage Mullard are slightly sweeter sounding and quieter. Genalex have also worked good in mine.

What he says. Also, different valve manufacturers seem to have different strengths. I've never liked EH valves or found them to be good sounding, but their gold pin 6SN7s sound great and are robust enough to withstand the demands of my Mastersounds where most NOS don't. For 6922s/ ECC88 Genalex are one of my favourites + original Tesla NOS

 

[Kostas]

Even in the world of guitars, DSP simulations are becoming more common. We shall see...

To be fair, guitar DSP emulates valve amps and they are doing it well, at least soundwise but still lack that feeling of a valve amp. It's much different than solid state guitar amps of the 80's that couldn't compete with valve amps.

By the way, when I mentioned the valves in my preamp I should have clarified there are all in the 12Ax7 family, no 6992 in mine. I've also had excellent results with Sylvania valves in my 70's Bassman, they were affordable compared to other vintage ones and they refuse to die.

 

[Juancho]

For 12AX7s or ECC83s as we call them, Watford Valves do the very fine sounding Harma strs

 

[Roog]

Even in the world of guitars, DSP simulations are becoming more common. We shall see...

Yes this is true, I have a Fender valve combo amp but mainly use a Line 6 Helix rack mount with active Yamaha monitors. You can dial in noise, sag and hum if required! :0)