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Leak Stereo 20 and a Thank You

Have to reply to leak thread here as "strangely enough" I can't reply in that thread.... must be a bit in invisible ink where the AUP bans you from offering tech advice on modding them....

Anyhow there's a "love in" on Mullard ECC83's going on there and all my experience makes me say the exact opposite!! I VERY strongly disagree with both Alex S and TonyL on the matter of Mullard ECC83's in a St20. The Blackburn 16I is the worst ECC83 in existence on sound quality to my ears, although superbly reliable. It's pipe and slippers city!
Brimar is about the best with EI very close indeed of the one's I've tried. I haven't personally had any reliability problems with EI, even with ones pulled from Marshall guitar amps that have been rattled about in the back of transit vans and no doubt had a severe time from the SPL's and vibration of live band use. No way will they be as reliable as Mullard but like I say no problems so far.
I find the Russian 6P14P-EV as good as Mullard and expect similar reliability from 70's and 80's made mil spec ones.

If you really want to be in no doubt that you are listening to a 1960's valve amp (a bit grannys warm sounding old radio) and are not bothered about proper treble transients, transparency, speed etc then the Mullards are just the thing...

I found much the same in the Arkless Electronics valve hybrid line stage... I use a Brimar here but both silver and dark anode EI sound good but different to one another
 
Alex S said:
Jez, Bollox. Will elucidate later.
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Nothing you or anyone else says will sway me and I'll continue to be anti Mullard ECC83 as, like I said, I consider them now't special and way over priced as NOS. They are maybe (and I struggle for the right adverbs here) "more of a whole" than the cheapest Sovteks and Chinese ones, if that makes any sense... but even they have a slight edge over the Mullards in dynamics and detail. It's a free country (ha! as if!) and would be a boring world if we all agreed on everything:)

NB I'm referring to the most common 16I and 163 types. I've heard stunning sounds from the special quality M8137 variety and no doubt there are other varieties that are great.
 
Jez, it’s clear you like a bright and forward sound. Actually quite understandable given the big ‘70s Spendors I think you use which are very warm and smooth. I’m running huge and very dynamic Tannoy studio monitors which are a whole different thing, Alex is running high efficiency Zu. It all makes a difference. Also our Stereo 20s are Stereo 20s, yours has been altered and modified to your taste/room/system. You will obviously get different results.

No absolutes here. It is all about system matching and context. The I61 is a stunningly good valve IMO (the I63 rather less so). I have a M8137 box plate (plus a couple of ‘50s long plates etc) and they are very good, but too bright, thin and forward for my taste/system. I certainly prefer the I61 in the Stereo 20. The box plate is actually in P1 my guitar amp (a Rift PR6) and sounds stunning there.
 
Alex S said:
Okay Jez, send me a nice ECC83 for impartial comparison. I’ll tell it how it is
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You need three as the phase splitter ones are nearly as important IMHO. Sorry ain't risking mine in transit or making the 2 mile round trip on foot to post office for the sake of proving a point but the EI shiny anode one's should be relatively easily and cheaply available and as I said were used as the standard ECC83 by Marshall for a while.
They look weird compared to normal grey anode valves and I didn't even try any of mine for years cos I was basically thinking "these are so cheap and nasty that they haven't even used the right metal for the anodes".
I used to fix loads of guitar amps and guitarists are just as weird about valves as audiophiles so I had many jobs replacing all the valves and resetting bias... usually I'd get to keep the old valves... hence having these and several other "odd" types.

The Brimars are the most common Brimar ones and whilst probably not cheap now NOS they are no doubt cheaper than the Mullards. They match Mullard reliability. They have

"Made in
England
BVA"

in three rows like that in relatively large print on the back if that helps... (there's one glowing in my Arkless Electronics line stage which is playing about a metre to my right as I type)
 
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Old valves is proper Black Arts in my book and I'm genuinely grateful when the initiated share their arcane knowledge.

I quite liked the sound of an old RCA or GE tube in the first position of my ST20 but I realise using American valves may be heresy : )
 
paulfromcamden said:
I quite liked the sound of an old RCA or GE tube in the first position of my ST20 but I realise using American valves may be heresy : )
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They are very good, though again very different from one another. There is really no alternative to just diving in and trying as much as possible. The good thing with vintage valves is they tend to be long lasting, vintage American valves are certainly top quality. I really like most of the ones I tried. Again amazing how different they sound within brands e.g. I’ve got/had a few sets of RCA 12AU7 (ECC82). Clear tops (very thin, bright and airy), late ‘60s and 70s grey plates (more balanced to my ears), and old ‘50s black-plates, (weighty, powerful, dynamic and smooth, my favs). As different character-wise as say a Mullard box plate, ‘50s F91, very early-60s I61, or late-60s-early-70s I63.
 
Tony L said:
Jez, it’s clear you like a bright and forward sound. Actually quite understandable given the big ‘70s Spendors I think you use which are very warm and smooth. I’m running huge and very dynamic Tannoy studio monitors which are a whole different thing, Alex is running high efficiency Zu. It all makes a difference. Also our Stereo 20s are Stereo 20s, yours has been altered and modified to your taste/room/system. You will obviously get different results.

No absolutes here. It is all about system matching and context. The I61 is a stunningly good valve IMO (the I63 rather less so). I have a M8137 box plate (plus a couple of ‘50s long plates etc) and they are very good, but too bright, thin and forward for my taste/system. I certainly prefer the I61 in the Stereo 20. The box plate is actually in P1 my guitar amp (a Rift PR6) and sounds stunning there.
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Actually I like a balanced and accurate sound. I have many amps of my own design, many commercial amps, and get loads of customers amps in so I get a real good handle on what accuracy and neutrality sounds like and which amps maybe sound rather forward or pipe and slippers. I've had (with a 10 year or so gap) Stereo 20's since I was about 17 -18 so very familiar with them with a wide variety of speakers and systems... even tried a pair of them in bridge mode once! I tend to think of my st20 as my reference in as much as I'm so familiar with their sound and although there are better amps available they do nothing badly wrong and a lot right so if a new prototype or any other amp sounds VERY different to the '20 then it's probably wrong!

A standard st20, especially with Mullard ECC83's, does err on the side of "old fashioned","edges rounded off", "pipe and slippers" etc... more modern sounding than Quad II's but a little more old fashioned than the Radford amps.

Mine is currently (been like this for a few years now) back to standard topology and component values BUT a massively improved power supply (for each stage). It therefore sounds rather more modern than a standard one and has noticeably better bass grip, slam and dynamics and better detail and focus. Rather more like a Radford STA25 in many ways but tonality should be as standard really.

I use 70's Spendors yes. Ex BBC BC2's. Most of them went to the BBC in fact and you don't hear much about them...
Mine are real piano lacquered by a pro piano refinisher who my (late:() pal in Leeds that I got them from knew

The combination of the Celestion HF1300 tweeter and Coles super tweeter is still pretty much SOTA today IMHO for treble accuracy and for overall HF balance.

Personally I find Tannoy treble (the ones I've heard anyway) the bit I really can't get on with.... forward, "brassy" a bit "clangy"... a bit too "obvious", hence yes I can see why you prefer the Mullards in your system... and why you find a Quad 33 acceptable... the Tannoys no doubt have more than enough dynamics to put back what the 33 steals! I concur with LesW's thoughts on the 33 in the thread in "Classic" FWIW.

I guess that people with speakers that make most genuinely accurate SS amps sound a bit bright and in yer face may prefer the Mullards but I find that in comparison with known accurate, neutral power amps the Brimar and EI sound more correct. YMMV

Oh the "best St20 ever" (IMHO and as it happens everyone who has heard it thought it truly stunning. In fact most who heard it thought it the best power amp they have ever heard), yep the one with all the regulated supplies, one for each stage of each channel, that I did for, as it happens, the same late mate in Leeds I got the speakers from, had all Mullards in it but all the 83's were box anode M8137, the EL84's were the gold pin SQ 6BQ5's (as fitted standard in my Marconi Instruments sig gen).
 
Arkless Electronics said:
You need three as the phase splitter ones are nearly as important IMHO. Sorry ain't risking mine in transit or making the 2 mile round trip on foot to post office for the sake of proving a point but the EI shiny anode one's should be relatively easily and cheaply available and as I said were used as the standard ECC83 by Marshall for a while.
They look weird compared to normal grey anode valves and I didn't even try any of mine for years cos I was basically thinking "these are so cheap and nasty that they haven't even used the right metal for the anodes".
I used to fix loads of guitar amps and guitarists are just as weird about valves as audiophiles so I had many jobs replacing all the valves and resetting bias... usually I'd get to keep the old valves... hence having these and several other "odd" types.

The Brimars are the most common Brimar ones and whilst probably not cheap now NOS they are no doubt cheaper than the Mullards. They match Mullard reliability. They have
"Made in
England
BVA" in three rows like that in relatively large print on the back if that helps... (there's one glowing in my Arkless Electronics line stage which is playing about a metre to my right as I type)
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I quite understand (although I thought you’d climb every mountain to prove a point). Just give me a purchase link and I’ll do the rest.
 
Alex S said:
I quite understand (although I thought you’d climb every mountain to prove a point). Just give me a purchase link and I’ll do the rest.
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:):rolleyes: OK Alex I'll have a look for some of the ones I'm referring to, Brimar and EI, so you can see exactly which ones I mean, and hopefully from a source that has them for sale but it will no doubt be from someone I have no connection with and have not dealt with... Maybe see what I mean and start with a shout out here in classifieds? For use specifically in the ST20 I found , IMHO, an all EI shiny anode ECC83 line up to be best to my ears. Now we may be looking for way different things from our amps of course! The st20 tends towards slight excessive softness, warmth, "old fashioned valve sound", "rose tinted niceness" etc etc, though in fact more modern sounding than many valve amps of the era. If that's what you really like about the St20 then you won't like it with all EI 83's (maybe your speakers are rather forward, bright, fierce even, hence the St20 with Mullards is the best you've heard them!?).

I tried all sorts of combinations but the all EI 83 line up sounds the most like a modern valve amp or a class A SS amp to me. Bass is tightest, grip greatest, dynamics least sat on and treble most transparent and airy (no not forward and bright... a st20 is subtly but noticeably dulled and soft in the HF. EI's make it sound as close as possible to then-recently-used Radford STA25, Krell KSA50 etc to me).
FWIW it was TonyL saying how good EI's sounded in the St20, and a pic of one he added IIRC, some time ago,(no he didn't prefer them to Mullards even then but said he liked them a lot in a st20... the thread will still be there I'm sure) that prompted me to actually try those odd shiny cheap looking ECC83's I had maybe 6-7 of! I believe the original Telefunkens which they are a copy of and made on the original Telefunken machines, moved to Yugoslavia, actually looked the same.... (so quite old now and getting spendier. The machinery was blown up in the war so no more...)
 
The silver plate EIs are very good, big, open, 3d if a little wooly in the low bass, but every one of the three I’ve had went noisy or microphonic pretty fast. Not good enough for P1 of the Leak IMO. I’d like very much like to hear the real Telefunken upon which they are based, but none have found their way here (I have an ECC81 and an 82). The grey plate EIs I tried (I had a matched pair, though I think I moved them on) were nowhere near as good, they just don’t have the scale to my ears, plus they have a brightness. Didn’t go noisy in the short time I used them though. So yes, I do like the silver plates a lot, but I’d not pay more than say a tenner a throw for them as I just don’t expect them to last.

The bizarre thing is to my ears I think they sound somewhere between a Mullard F91 and I61! They get a lot of the same 3d soundstage and scale. Very nice valve, I’d take them a lot more seriously if they had the reliability. I view the Mullards as far better value as they sound lovely and really last.

PS FWIW I suggest Jez reevaluates the I61. Find a really nice early ‘60s Blackburn example, make sure the rods are copper not nickel, and give it a go. They are just not as he describes them. Not even close. I can certainly see where he is coming from with the I63, which can be a rather soft and warm valve a little lacking in dynamic range (it still has its uses). They are absolutely not the same valve! The open natural timbre and walk around soundstage of a good I61 is really something special.
 
Good, further research and hunting. A quick scan tells me eBay is not the place to look!

Jez, no need to debate my tastes or equipment. The Mullards sound great to me and they’re not even the best Mullards, but in my case, this is a sample of three. I simply seek further enlightenment, especially if cheaper good options are available.

PS Tony, I have decided to limit the Leak to 2-3 hours per day. When I get the ProAcs back I’ll have a very nice near field system. The only problem is it’ll be in the same room.
 
As an aside, I decided to plug my Goldenjack 14dB attenuators (all I have and I’m not buying others) into the Khozmo passive from the dac since computer audio from hot tracks is barely possible (around 7:30 already quite loud).

I can’t decide if they’re ‘squashing’ the music. Is there any technical reason why they should? I was convinced Rothwells I had were detrimental but it could easily have been a level matching issue.
 
I've had hundreds of Leak ST20s here over the years including many modified ones from the likes of Croft etc. The best sounding ST20's were ones that were completely standard but very carefully and sympathetically restored.
 
Alex S said:
As an aside, I decided to plug my Goldenjack 14dB attenuators (all I have and I’m not buying others) into the Khozmo passive from the dac since computer audio from hot tracks is barely possible (around 7:30 already quite loud).

I can’t decide if they’re ‘squashing’ the music. Is there any technical reason why they should? I was convinced Rothwells I had were detrimental but it could easily have been a level matching issue.
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Assuming you can get the level you require there is absolutely no benefit in doubling up resistors by using the Goldenjacks. I’d just run the Khozmo alone unless you really can’t find a level setting that works for you. Certainly don’t worry about using it on its lowest couple of settings. I have no issue here with the Audio Synthesis stepped attenuators though they do choose their steps pretty carefully. I obviously end up at very different steps with the Tannoys and LS3/5As, but still plenty of adjustment with both. I suspect your Zus might be more efficient than my Lockwoods though.
 
Ha, they are out already - I'm pretty convinced inline attenuators are the Devil's work.

GT Thanks to Mike that's what I have.
 
Alex S said:
Good, further research and hunting. A quick scan tells me eBay is not the place to look!

Jez, no need to debate my tastes or equipment. The Mullards sound great to me and they’re not even the best Mullards, but in my case, this is a sample of three. I simply seek further enlightenment, especially if cheaper good options are available.

PS Tony, I have decided to limit the Leak to 2-3 hours per day. When I get the ProAcs back I’ll have a very nice near field system. The only problem is it’ll be in the same room.
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I assume you've sussed which valves I am referring to and don't need me to point them out then? I would simply have gone on ebay and said "like these ones"...

I've sold most of my Mullard's FWIW as "the herd" are willing to pay such silly money for them! Kept a few examples for comparative purposes.

A funny thing with hi fi is "that which the majority agree on" is very often wrong!!!... it stems from over influential reviewers or internet personalities and the way that Chinese whispers then propagate ideas. There are many things which 90% of audiophiles will tell you is "how it is" or "the best way to do XYZ" that are utterly wrong and can be traced back to a specific magazine article in 1991 (whatever). Many do date back to pre internet times when reviewers were "god" etc.
 
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