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Leak Stereo 20 and a Thank You

Discussion in 'audio' started by Alex S, Aug 4, 2022.

  1. Alex S

    Alex S carbon based lifeform

    Some years ago I had a Vellemen kit amp with 8 EL34s that was 80W per channel, kindly built for me, and it sounded great. It drove Neat MF9s better than anything else (just - Dynavectors and Patrick Dixon’s amps got close). Since those days I’ve moved to efficient speakers (Zu Druid MKIV, a marmite speaker but I like marmite) and a passive pre (Khozmo dual mono) using Class D/T amps like the Temple Audio and Amptastic that are bang-for-buck-tastic but clearly a move back to valves was an obvious progression, and this time I didn’t need 80W.

    So what to get for somewhere near £1000? Vintage and second hand seemed obvious (think I’m done with Chi-Fi anyway). Where better to look for inspiration and purchase than PFM? So: A beautifully restored Leak Stereo 20 being sold by Mike P in the Classifieds. I dithered, knowing a drive to Sheffield and back isn’t the funnest thing from SE London. Luckily, post dithering it was still available (a different story) so I bought it and collected it on Monday.

    Except I didn’t. I don’t really want to eulogise about how good this amp is if your system suits it and I’d done enough research to know mine would. It’s everything a clichéd valve amp is: sweet, textured, wide soundstage, fine imaging, and everything it isn’t: dynamic, punchy, pr&ty, plenty enough at frequency extremes (I’m old anyway so don’t perhaps do those). Nor is it just for vinyl, marries brilliantly with my Audial Dac.

    No, this thread is really about Mike P who sold me the amp. You may have seen the Classified: rebuilt (perfectly) repainted (perfectly) S20 for sale, and up I went to get it. Except it made a nasty(ish) noise on fire up. So Mike, clearly a little upset, went upstairs to see if he could find the fault whilst I went for a walk and scared a few sheep. Mike thought he’d found the issue and did a bit more fiddling, sadly to no avail. We arranged that he’d sort the problem and drive it down to London or attempt to ship it. I could hardly ask for more. Of course, Sod’s law dictated that Mike found the problem - one small resistor joint - and fixed it an hour after I’d left.

    But Mike offered more: did I want his S20 instead? He didn’t want me to drive away empty handed. This was a dilemma since I’m fairly honourable and didn’t want to take his amp if really he wanted to keep it. Nonetheless, I’m not quite honourable enough to refuse such an offer. Not only that but his amp didn’t take spades, my only real option since I’ve lent my banannared Mogami. So Mike went upstairs and soldered terminals that would take spades and off I went.

    So this thread is to say the Leak Stereo 20 is a wonderful amplifier but more than that, it is a thank you to Mike.

    A couple of additions: Mike’s system is gorgeous, especially in the near field: S20 (or Radford), passive pre, breathed on CDP, idler TT (you’ll find details in Classic threads), vintage Tannoys. Since I did not leave with the amp I actually bought, please don’t be surprised if it’s relisted at some future time.
  2. Mike P

    Mike P Trade: Pickwell Audio

    Thank you for the kind words Alex.

    It's sod's law isn't it. The amp that Alex came up to buy had been behaving perfectly for months and then the day he drives all the way up from London to buy it, it suddenly develops a fault. Suffice to say I was terribly embarrassed!

    Once Alex left and I was less flustered I found the fault, which was a dry joint on R6 L that was making an intermittent connection. I honestly can't remember the last time I made a bad solder joint but there you go, it was my fault.

    I must say that Alex was a total gent about it and was extraordinarily patient and understanding.

    And yes, the fully restored and repainted Stereo 20 that Alex meant to buy is now available to buy again (now with new Deltron banana sockets fitted).
    Ellenor, martin clark, koi and 11 others like this.
  3. Alex S

    Alex S carbon based lifeform

    And here it is, with the Khozmo dual mono above:

  4. chiily

    chiily PFM Special Builder

    That really does look the part!
  5. Alex S

    Alex S carbon based lifeform

    Thanks. BTW, I don't have a fixation with putting slate slabs everywhere apart from sometimes under speakers and always under turntables but they were lying around...
  6. Alex S

    Alex S carbon based lifeform

    I'll also add that there was a slight buzz from the left channel. Last night I decided to return to transformer coupling as opposed to capacitor coupling on the Audial dac. Sounds a little better perhaps but now the S20 is completely silent unless my ear is literally 2 inches from a 101dB efficient driver. Nice.
  7. Mike P

    Mike P Trade: Pickwell Audio

    So the cause of that left channel buzz (when capacitor coupled) must be with the Audial DAC (or cables). If you go back to capacitor coupled and swap the interconnects at either the DAC output or Leak input, and the buzz travels from the left to the right speaker then that confirms it.
  8. Alex S

    Alex S carbon based lifeform

    Thanks Mike, I'll do that when I can bring myself to fiddle with more cables.
  9. Alex S

    Alex S carbon based lifeform

    Swapping the cable didn't change anything. I had the old amp with capacitor coupling and it was silent. There's an earth fitment like on phono stages on the back of the Audial, perhaps I could rig something up from there. Having said that, I'm very happy sticking with noiseless transformer coupling.

    The only thing I'll do is change the tap from 16 (where I've been up to now) to 8. Speakers are rated 12. Oh, and try to hunt down a Mullard GZ34 from somewhere reliable for not silly money.
  10. Alex S

    Alex S carbon based lifeform

    Okay I’ve been on the 8ohm tap for an hour or so. Firstly, any differences are slight. I had no expectation bias since I’m clueless.

    There seems a smidge less gain. The amp sounds slightly more grown up and in control, image placement marginally more precise, but also a tiny bit less open and fun. So swings and roundabouts. It seems even quieter.

    I’ll stick here for a few days but are these findings in any way consistent with what people who know stuff might expect, running 12ohm rated speakers?
  11. Arkless Electronics

    Arkless Electronics Trade: Amp design and repairs.

    All as expected for 8R tap.
  12. Alex S

    Alex S carbon based lifeform

    Great. I’ll just pick the one I prefer in due course. Is there any point at all in trying the 4, would the amp mind?
  13. Arkless Electronics

    Arkless Electronics Trade: Amp design and repairs.

    The amp won't mind but you will get considerably less power on 4R. But better damping factor and control plus lower still gain. I used to use mine on 4R taps with Mission 770's so no problem with 100dB/W speakers.
  14. Alex S

    Alex S carbon based lifeform

    Thanks, Jez. No harm in giving it a try at some point then.

    Any further posts I’ll make on the resurrected S20 thread in Classic, more appropriate I think.

    I’ve also posted a WTD ad for tasty valves.
  15. Alex S

    Alex S carbon based lifeform

    Counter to a slight expectation bias, I actually really like the S20 on 4. Strangely (to me) it’s probably this or 16 for the long haul. Right now I prefer this but, you know, a couple of glasses…

    Had to say this here since my only superstition is 13.
    chiily likes this.
  16. Alex S

    Alex S carbon based lifeform

    I have gone back to 16R and here I will stay. It’s just more fun-ky.
    Salamander likes this.
  17. Tony L

    Tony L Administrator

    16 Ohms with LS3/5As and JR149s, 8 Ohms with the Tannoy MG15s here.
  18. Arkless Electronics

    Arkless Electronics Trade: Amp design and repairs.

    I'd avoid Mullard ECC83's. They are my least liked of all ECC83's. Very reliable but "pipe and slippers" sound. Yeah there's mil spec ones and SQ ones like M8137 etc but I'm talking about yer everyday cooking version. (M8137 and other Mullard SQ valves, all rare as a decent tory, were in the best sounding St20 I ever heard.... the 3 Arkless Electronics regulated PSU's would have made the biggest improvement though!). I like Brimar and EI best of those I've tried and I also prefer these in my Arkless Electronics line stage. IIRC EI were made with Telefunken gear so basically a (MUCH!) cheaper copy of the Telefunken. The shiny anode versions can sometimes be found with "Marshall" markings (yes the guitar amps).
  19. Alex S

    Alex S carbon based lifeform

    Reliable seems to be what I'm after, given 3000 hours per annum. I'll be able to try over the coming days to see if I agree. (Much as I'm a huge admirer of your work, you're not getting anywhere near this - it will remain 'restoration stock'. Mike has done a fabulous job with it).
  20. Arkless Electronics

    Arkless Electronics Trade: Amp design and repairs.

    I wasn't offering!:D That applies to anyone who IS interested in such work as well! Too many more important things to do ATM.

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