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Leak Stereo 20

Discussion in 'classic' started by Tony L, Jan 31, 2012.

  1. Tony L

    Tony L Administrator

    Another piece of the jigsaw landed yesterday:


    A 1961 Leak Stereo 20. It is in really tidy condition, barely a mark on it, and was apparently sympathetically serviced a couple of years ago with new caps etc. Thankfully no modifications other than a decent set of RCA input sockets and speaker posts (the original leak ones are naff to the extent of being barely usable), as such it's exactly what I've been looking for – I've been looking for a while, but held off buying a few that were a bit tattier or had been “tweaked” in any way – I want my Leak Stereo 20 to sound like one. It's stuffed with a decent set of tubes too: a Brimar ECC83 on the input, two Mullard ECC83s as phase splitters, a Mullard GZ34 rectifier and a set of Harma EL84s. I plan to stock up on these tubes a bit now, I'd certainly like a decent NOS set of 84s and a spare Mullard GZ34 as they are getting pretty scarce. It runs very nice and cool too, even after playing for many hours the mains transformer is barely lukewarm and the OP transformers remain cold to the touch. No signs of any heat issues underneath either, so looks like this one has had an easy life and behaved itself. I've got the manual and inspection tag too (20th March 1961, so it's got a couple of years on me!).


    It seems very happy partnered with my Audio Synthesis PAS 02 stepped attenuator, the Stereo 20 is so high-gain I've no idea how anyone could actually use an active preamp with it.

    I'm still getting my head around the sound as the differences between it and the Prima Luna Prologue 2 are quite subtle, yet I suspect rather important. Being honest I bought this as I wanted to 'finish' my vintage system, not because I was unhappy with the PL2 in any way. In many ways I was expecting a side-grade, maybe even a slight downgrade, but I just wanted to own a classic vintage amp. The first thing that is blindingly obvious is it sounds no less powerful. This has surprised me given we are talking 10 watts a channel vs. 35. Yet there it is. It just has bags of grunt into my, admittedly efficient, loudspeakers (15” Tannoy Monitor Golds). There is some real welly and scale on tap here, if anything it sounds bigger and more powerful than the PL2. Next thing that is evident is just how 'right' this thing sounds, it has a flowing, organic and liquid sound that doesn't shout 'hi-fi detail' at you in any way, but everything is there for the hearing in a beautifully natural and open way. The mid in particular is superb, so natural and believable on voice, acoustic guitar, sax etc. I'm loving this thing so far and I'm beginning to understand fully why the Leak / Tannoy combo is so coveted in the Japanese audio marketplace. I guess I've been following their lead for years now!

    The only negative aspect is it is not as deathly quiet as the impeccably behaved Prima Luna. I live in a quiet area with hardly any ambient noise, especially late at night when I do much of my listening, and I can, just, hear a hiss from the listening seat, and more bizarrely, a slight hum on the phono stage that was simply not there previously with the PL. I assume the latter must be a proximity effect with either the phono stage or deck picking up the Leak a little electrically. It's not intrusive, so no huge deal.

    I now plan to learn everything I can about these old amps, so any experiences from those who love / hate / are indifferent to them would be very welcome.

    PS will update grainy dull photos if Greater Manchester ever sees proper daylight again.
  2. eguth

    eguth pfm Member

    Congratulations on getting a superb amp in superb condition.

    As far as the residual hum is concerned have you thought about a mains conditioner? The hum may be caused by or increased by something on the mains. Even if not, installing one may well improve the sound of your whole system.

    As far as valves are concerned I can recommend JJ as superb, when purchased from Eurotubes. The proprietor has a special relationship with the factory and the grapevine has it that they send him only selected valves, thereby avoiding some complaints about inconsistencies in JJs.

    I expect you will keep this amp for at least the next 60 years.
  3. PaulMB

    PaulMB pfm Member

    Congratulations! Lovely looking, seems in perfect shape, and would not be out of place as part of the dashboard radio in a Lancaster bomber. And it also looks perfect on the very modern, but actually timeless wooden table. Why not put the Leak up next to the Garrard and hide all the modern stuff underneath?
  4. pqpq

    pqpq pfm Member

    I'm reading this with interest. I have a totally original Stereo 20, thick with dust but in perfect cosmetic condition which is the next part of my Grandfather's gear I'll be bringing back into service. It's on hold right now because I haven't quite figured out what sort of system it should be a part of.

    I'd assumed that it would be happier with an analogue source - lacking, I thought, the oomph to cope with the higher peaks of digital. But there's yours in a system with both an analogue and a digital source - how is it?
  5. ian r

    ian r 401's Nakman

    I had the slightly later grey model TL12 for 14 years and sold it once I had the radford esl's first time round in the late 80's 0

    Like yours there was a slight hiss too but I used it with the related pre which would only allow crap rca's due to lack of space - the mighty Bulgin was off putting too

    I used it with my TV an tuner and only rarely with phono - it never needed new valves in 14 years and was flawless - unlike my world design monobloks I now use

    Less sexy than the Radford - in hindsight I think it sounded better - but it didnt have F*** off big chrome handles or a chunky transformer cage

    Which counted for a lot in my mind - its cracker to look at mine came from a Thomas Heinitz cab the owner who had a private cinema and swimming pool was getting something with a remote as he was too old to be getting out of his chair

    I told him he was being duped into buying a technics stacking system complete with equaliser but he said I was nuts
  6. Tony L

    Tony L Administrator

    I'm toying with that - the top level of the table looks clunky, so I might try swapping the CD player out for the SACD in the other room, another Sony, but one which is more conventional in size / shape, stack that under the phono stage, then move the leak up a shelf and the preamp down. Would probably look more ordered and may make wiring easier (I have a daft Spectral interconnect that's larger and heavier than the passive pre!). I need to first figure out whether it's the deck or phono stage picking up the hum and work around that really.

    It sounds lovely with both sources, though don't assume digital is any more dynamic than that 301 with the right record on it! I far prefer CD once it's gone through a tube or two. As to suitability that's all down to speakers, a Stereo 20 is probably not going to be that great into small inefficient modern speakers, it dates from a time when speakers were much bigger didn't put up much of a fight. Also bare in mind that the Leak is exceptionally high gain, IIRC 125mv for full output, which is insane by modern 2v line level standards, i.e. if you want an active preamp you'll need to choose one very carefully indeed otherwise it will be blowing you out of the room with the slightest touch of the volume knob. Luckily a simple passive preamp sounds great in this context.
  7. pqpq

    pqpq pfm Member

    I'd figured out the passive pre part of the jigsaw, and I'll be using it with the original Lowther Acousticas so I'm not expecting problems there. The source thing I hadn't figured out - and it's why the Leak is still gathering dust. Until I've worked that out, I don't know what I'll use the system for or where in the house I'll put it.

    If it's happy with a digital source, it'll get a hell of a lot more use if I have it in my office hooked up to a Squeezebox touch. If it's vinyl only, I'm not sure where I'd put it, nor whether I'd use it that much - it would be my 3rd vinyl playing system. I'm very persuaded by your experience that a valve element to the system makes the digital source more listenable.

    It would be a weird combination of the old and the new, but if it sounds good and I use it regularly, why not? After all, there's nothing to stop me taking it upstairs and partnering it with the 301 it spent most of its life with.
  8. Tony L

    Tony L Administrator

    The Stereo 20 has no knowledge of whether a source is digital or not, it's all analogue by the time it reaches it's input sockets, so no need to worry about such things at all. FWIW it's happy with live music too:


    I visited the London Science Museum a couple of weeks ago to take a peep at the exhibition about early electronic music pioneer Daphne Oram (Oramics). In the photo above you can just make out a Stereo 20 next to a Varioslope preamp, in the picture on the right she's playing a fair sized gig with one! It's on the table right in front of her. If the amp can cope with that spinning a couple of CDs is no issue at all.
  9. Jonathan Ribee

    Jonathan Ribee Unavailable at present

    It looks fantastic Tony.

    Wow - that is scary. I had thought you could use a variable output device and miss out the pre to see if that changed the hum, AE and reote even, but 125mv would make that hard to achieve.

    Might explain the 10W sounding meaty.

    Lovely looking thing.
  10. pqpq

    pqpq pfm Member

    Weird. I've just ordered a very nice vinyl set of Daphne Oram stuff. Eventually it'll get played through my Leak...

    Yes, I know that the amp won't "know" whether the source is digital or not because by the time it gets this far it's been converted to analogue. It was more the dynamic range of digital (and yes I know most of it is horribly compressed now).

    I've also not long bought new amplification for my main system, which has ended up being way more powerful than I ever thought I'd want, and was all to do with coping with the peaks. So now to start thinking about a 20 WPC system is making my head hurt.

    However, you've persuaded me, so the Leak will be dusted down and taken for a refurb.
  11. Simonms

    Simonms Registered user

    Nice one Tony, I did the same thing a month back and Paul set it to Triode mode for the Belles-great amp, i also popped some Mullards in but did not notice a huge difference between them and the original valves.
    I don't like the open bottom (sorry) so thinking of building a nice wooden box for it.

    When i got mine there were some Russian caps that were leaky and Paul had actually fitted them 10 or so years back and said that some managed to leak within a few days.

    KR Si
  12. Joe P

    Joe P Memory Alpha incarnate / mod

    Looks real spiffy, Tony. I bet that amp's a keeper for life.

    <Jedi mind trick> Can I have it? </Jedi mind trick>

  13. Kt77

    Kt77 pfm Member

    Hi TonyL, I just wanted to add that's a Beautiful looking amp you've there. We in the USA can only wish we had access to what I'd call the better sounding tube ( valve ) gear from the Golden Era. As many here for whatever reason - feel McIntrash is the bees knee. You guys are very fortunate to reside in a country that has produced some of the very best sounding components in the entire World. While some countries have merely lost there way and are more concerned about power and size. To my mind keeping a system as simple as possible assures if nothing else a cleaner path as well as a greater sense of obtaining Musicality. Great find indeed. Regards, Oscar
  14. Markus S

    Markus S 41 - 29

    Oscar, a Mc 230 or 275 are just fine. No need to envy the Brits.

    Tony, good find. I may have said this before, but the EL84 is one of my fave tubes, it sounds alive and fun. Where'd you get it?
  15. Tony L

    Tony L Administrator

    There's a cool little iPhone Oramics app, well worth getting if you have such a thing, it's free IIRC.

    Your Leak will be happy as can be into Lowthers, way more headroom in that context than you'll ever need.

    Ok, had a go at this now:


    Whilst I don't like stacking stuff I think this works a bit better. I had no issue with the Leak on the bottom, but the 301, pre and CD looked really uncomfortable up top somehow, the Garrard is just so big. I suspect that layout would work great with my TD-124 though, which is how things will eventually end up if I ever slim down to one system. Doesn't seem to have altered the hum at all though, I need to do a little more fiddling here, though it's no real issue in use, I can't hear it when a record is playing, I just noticed it as the PL2 is quite remarkably quiet. I suspect humming a bit is just what Stereo 20s do.


    Easier to take a half-decent pic of it up top too!
    torstoi likes this.
  16. Tony L

    Tony L Administrator

    I got it over on that WigWam thingy next door on t'internet. The owner lived locally so dropped it round yesterday. I've always liked 84s too - I liked Richard's Manley Stingray (always kind of regretted not buying that to be honest) and also loved Darren W's Leben when I've heard it. Robin from WigWam, who bought a pair of Tannoys from me, brought his Stereo 20 around a while back, so I knew it worked both with my speakers and with the Audio Synthesis PAS 02. I've just been waiting for the right one to come up. Another real bonus is that this Stereo 20 came with a 4 input stepped attenuator in a little DIY plastic box, so I can still use my 303 in the other system without buying anything!
  17. Joe P

    Joe P Memory Alpha incarnate / mod


    If you try some Mullard EL84s let me know what you think.

    I've been tempted a couple of times to Mullard up my Stingray, but with eight EL84s I'd spend as much on the tubes as I did on the amp.

  18. Tony L

    Tony L Administrator

    If I can find a nice set at a fair price I'll have them I think. As I understand it the Stereo 20 runs it's output tubes well under their max output of so they should last a good length of time. I plan to spend some time on AudioAsylum etc learning about EL84s as I've no real idea what's good and bad here, but I get the impression from comments I've read elsewhere that Leaks sound at their best with Mullard all the way through.
  19. Joe P

    Joe P Memory Alpha incarnate / mod


    You can buy NOS Mullards -- including EL84s -- but the price is nuts.

    The Mullard dude is in my part of the world, so shipping would be cheap, but not nearly enough to offset the cost of the tubes.

  20. Markus S

    Markus S 41 - 29

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