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Leak Stereo 20

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

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Page 45 of 49
  1. Alex S

    Alex S carbon based lifeform

    Tony advised, others too, and with my limited experience (amounting to four), I can confirm that it’s that ECC83 on the input that has the most dramatic effect on this amp. It is the used, older Mullard that is giving me the best result. Invest here I think.
     
    Alex S, Aug 18, 2022
    #881
    Mike P likes this.
  2. kevinrt

    kevinrt pfm Member

    Which one is that? The one adjacent to the RCA input sockets?

    Kevin
     
    kevinrt, Aug 18, 2022
    #882
  3. Tony L

    Tony L Administrator

    Yes, that is the input stage. The best sounding and quietist ECC83 you can find belongs there. To my ears I’ve not found anything I prefer to good vintage Mullards in the Stereo 20. It is by nature a bright and tight amp, very different to say a pair of Quad IIs. The best Mullards bring a beautiful natural timbre and open the soundstage up in a wonderfully 3d way without impacting the lively and fun nature of the amp. I’ve run mine with a full set of ‘60s Mullards and it sounds stunning, unquestionably real high-end. Day to day I compromise and run Russian 6P14P-ER power valves rather than wear the Mullard EL84s, and they are different rather than better/worse (they are brighter and more forward which can translate to more exciting on rock/electronica but maybe a bit much on some classical strings recordings). I run vintage Mullards everywhere else though, but if I had to have just one it would be the first ECC83. I’d happily pay £100 for a really good one as they just last and last.

    I don’t think I have ever worn out a ‘50s or ‘60s Mullard ECC83. All the ones I’ve scavenged out of used vintage kit have all tested and work fine. Every last one. To the extent it doesn’t concern me that my Verdier preamp is stuffed with a date matched trio of 1960 Blackburn I61 type of Mullard ECC83 and by the nature of that pre are still ‘on’ whilst I’m playing CDs!

    Sovteks, EI, JJ etc all wear, and some pretty fast. I’ve had actual fails of all of these, and every single EI went noisy within a few months. Every Mullard is fine, as are most US military (RCA, GE, Sylvania etc) 12AX7s too. I’d personally stick to Mullards in the Leak though, the US ‘tubes’ are often absolutely superb, but for me a bit too bright for a Stereo 20 or TL12 Plus unless you have very warm and laid-back speakers. Great in EAR, Prima Luna, Audio Research etc though.

    PS I’ve never blown a Mullard GZ34 either. One of the main reasons I run them is reliability. Again they just last and last. I’m still too cowardly to sell any of my stash (I think I have six of them!).
     
    Tony L, Aug 18, 2022
    #883
    Alex S and kevinrt like this.
  4. kevinrt

    kevinrt pfm Member

    I have a Leak Stereo 20 but I’m somewhat ignorant on the subject of the valves themselves.

    I’ve got a GZ34, 4 x EL84 & 3 x ECC83.

    I’ve noticed some valves listed as E83CC. Is that the same as an ECC83?

    When I need to replace any of the valves in future, will any ECC83/EL84/GZ34 fit and work, or only specific ones.

    I aware that they may sound different/better/worse etc., but in principle, if it has the same name will it do the job?

    In which positions on the Leak is it a good idea to fit ‘matched’ valves?

    regards

    Kevin
     
    kevinrt, Aug 22, 2022
    #884
  5. Tony L

    Tony L Administrator

    Yes. It is just a military ruggedised grading, but same valve. I have several.

    Yes, any, but…

    You don’t technically have to use matched pairs, quads etc, but it makes sense to. Think of the Stereo 20 as two channels; you have a stereo input ECC83 by the RCAs (put the best 83 you have here!), then the next pair of 83s are phase splitter/drivers, then you have a pair of EL84s as power valves, then the GZ34 PSU rectifier.

    I think of the input 83 as its own thing, then a matched pair of 83s in the next position, then a matched quad of EL84s. I’d not want different brands or ages of valves on either side, though splitting by section is fine, e.g. a Mullard 83 in the first position, a pair of JJs next and then a quad of 6P14P-ER or whatever.
     
    Tony L, Aug 22, 2022
    #885
    kevinrt likes this.
  6. Nagraboy

    Nagraboy Ausculta fili

    Trying out the Leak 20 owned by @Ianp of this parish. The 10 Watts of power are certainly sufficient for the Klipsch Cornwall III (102dB?).

    [​IMG]
     
    Nagraboy, Aug 25, 2022
    #886
    Tarzan likes this.
  7. kevinrt

    kevinrt pfm Member

    Are you using a Croft pre-amplifier with reduced gain with the Leak? How do you find it?

    regards

    Kevin
     
    kevinrt, Aug 25, 2022
    #887
  8. Nagraboy

    Nagraboy Ausculta fili

    @kevinrt

    Yes, the Croft is a 25 (non-R version) with the cathode follower mod, which - so I’m told - gives slightly less than unity gain. We’re using JAN 5751 valves for the phono stage and a JJ valve for the cathode follower. Source is my TD124 with SPU (0.18mV) and SUT (1:26 ratio).

    It’s working very nicely, despite the high sensitivity speakers. A lot of depth, power and colour. It’s not a totally silent setup, but a bit better than other amps I’ve tried with the Klipsch. I’m happy with it as a pairing with one caveat - as standard there will be a ground loop, so we’ve taken out the earth wire in the Leak mains lead. This is not recommended due to electrical safety reasons but we’re just trying it for the afternoon. I think the longer term solution will be to get a ground lift switch fitted to the Croft by Deco Audio or similarly competent party. Hopefully they can also add a mono switch by rewiring the mute switch too.
     
    Nagraboy, Aug 25, 2022
    #888
  9. kevinrt

    kevinrt pfm Member

    That’s interesting. I’ve tried the Stereo 20 with a TD124/Croft Micro 25 on one side and some ESL57s on the other.
    The previously quiet setup (with a Khozmo), started to hum as soon as the Croft went in.
    Also the volume control required very little movement from silent to loud.
    My Croft is currently with Deco Audio with a view to fitting remote control volume and adjusting the gain. Maybe I should ask them about ground lift as well.

    regards

    Kevin
     
    kevinrt, Aug 25, 2022
    #889
  10. Nagraboy

    Nagraboy Ausculta fili

    @kevinrt

    You’ll need a ground lift switch or the hum will always be there. I’d be interested to know how much they charge for that, and also the mono switch option.
     
    Nagraboy, Aug 25, 2022
    #890
  11. kevinrt

    kevinrt pfm Member

    The Leak Stereo 20 is such a lovely sounding amplifier I’m now curious to play around the edges to try and get the best out of it.
    Replaced the pair of Mazda ECC83s with some yellow print 1960s Mullards yesterday evening. First impression was I preferred the Mullards, but need a bit more time with them.
    One of the Mullard ECC83s glows very brightly for a second on switch on, then settles to a low glow like the others. I understand this is not uncommon with valves, but is that particular one likely to fail sooner?

    regards

    Kevin
     
    kevinrt, Aug 25, 2022
    #891
  12. Nagraboy

    Nagraboy Ausculta fili

    Don’t know Kevin, I’m no valve expert. I do know the input valve near the rca sockets is the key to lowest distortion and best sound. I’m running 3 vintage Mullards, 4 Genelex Goldlion EL84 and a Genelex GZ34 in this one.
     
    Nagraboy, Aug 25, 2022
    #892
  13. kevinrt

    kevinrt pfm Member

    They are busy at the moment but I should know in a couple of weeks.

    Kevin
     
    kevinrt, Aug 25, 2022
    #893
    Nagraboy likes this.
  14. Darmok

    Darmok "In Lation, Trans Lost."

    Do not worry, the 6.3 volt heater wiring is wired in series, first in line lights up before the followers catch up.

    Its their nature.
     
    Darmok, Aug 25, 2022
    #894
    Nagraboy likes this.
  15. snowman_al

    snowman_al pfm Member

    It will last as long as its fellows, as you say not uncommon for Mullard/Philips ECC8x to 'light up' at switch on.
    By the way the heaters are wired in Parallel across the 6.3 volt heater winding.
     
    snowman_al, Aug 25, 2022
    #895
    Alex S likes this.
  16. Barrymagrec

    Barrymagrec pfm Member

    Que?
     
    Barrymagrec, Aug 25, 2022
    #896
  17. Darmok

    Darmok "In Lation, Trans Lost."


    Parallel

    :rolleyes:
     
    Darmok, Aug 25, 2022
    #897
  18. Amormusic

    Amormusic pfm Member

    Can anyone point me to where I can buy a Mullard ECC83?
     
    Amormusic, Sep 8, 2022
    #898
  19. Mike P

    Mike P Trade: Pickwell Audio

    New reproduction or original old one? Budget?
     
    Mike P, Sep 8, 2022
    #899
  20. Amormusic

    Amormusic pfm Member

    Original ideally. See PM
     
    Amormusic, Sep 8, 2022
    #900
Page 45 of 49

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