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Thread: E88CC. Suggestions

  1. #11
    Join Date: Mar 2017

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    Quote Originally Posted by anthonyTD View Post
    ECC88, E88CC, 6DJ8, 6922, 7308, and a few others are drop in replacements in most equipment, there are a few modern production versions that get mentioned, one i have seen mentioned is the Electro-Harmonics one, but might be a bit forward for some tastes, also worth considering is the original standard steel pin Tesla E88CC.
    Cheers Anthony. Very helpful. Let me dig into that together with the other suggestions in this thread. I may also ask Nic P what suggestions he has for this amp. In any event, judging from the date code, the existing E88CC looks like originals he put in when building the amp.

    Small unrelated question if I may? Absent an expensive valve tester is there any reasonable way to judge if a valve is going out of spec? I'm thinking of output valves here (EL34, KT88). Perhaps simply if it is getting to the limits of its bias adjustment? But would prefer judging things away from an amp.

    cheers
    E
    Current: [P20] Roon/Tidal > Custom PC> Chevron Paradox NDF16 > Phast Pre > Neuro. 686 > Tannoy Berkley (RFC tweaks)


  2. #12
    Join Date: Feb 2008

    Location: South Wales

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    Hi Edward,
    Unfortunetly without a decent valve tester, its very dificult to tell when a valve is on its way out or going to fail, however with Pentode and Tetrode power valves [EL84, EL34, 6V6, 6L6, KT88, 6550, KT120, KT150 etc] a good indication of how much use its had is how well the silver gettering is holding up,ie; if its yellowing, or showing signs of it becoming transparent in places, then it may be time for a change, sometimes power valves can start to draw more current before they fail too, also they may start to become noisy, but as i said earlier its very difficult to know for sure what's happening inside a valve without a tester. I recomend Keeping a record of the amount of hours you use your system, at least then you have an idea of how much use the valves have had.
    Hope this helps.
    A
    Quote Originally Posted by Edward View Post
    Cheers Anthony. Very helpful. Let me dig into that together with the other suggestions in this thread. I may also ask Nic P what suggestions he has for this amp. In any event, judging from the date code, the existing E88CC looks like originals he put in when building the amp.

    Small unrelated question if I may? Absent an expensive valve tester is there any reasonable way to judge if a valve is going out of spec? I'm thinking of output valves here (EL34, KT88). Perhaps simply if it is getting to the limits of its bias adjustment? But would prefer judging things away from an amp.

    cheers
    E
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  3. #13
    Join Date: Aug 2012

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    I'm Steve.

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    I have a matched pair of those i am selling Genelex Gold Dragons. Though i see you need six.

  4. #14
    Join Date: Mar 2017

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    Quote Originally Posted by anthonyTD View Post
    Hi Edward,
    Unfortunetly without a decent valve tester, its very dificult to tell when a valve is on its way out or going to fail, however with Pentode and Tetrode power valves [EL84, EL34, 6V6, 6L6, KT88, 6550, KT120, KT150 etc] a good indication of how much use its had is how well the silver gettering is holding up,ie; if its yellowing, or showing signs of it becoming transparent in places, then it may be time for a change, sometimes power valves can start to draw more current before they fail too, also they may start to become noisy, but as i said earlier its very difficult to know for sure what's happening inside a valve without a tester. I recomend Keeping a record of the amount of hours you use your system, at least then you have an idea of how much use the valves have had.
    Hope this helps.
    A
    Thanks Anthony. Yes that does help. I'll certainly pay more attention to any yellowing and transparency.

    What prompted me to start this thread as I was getting some crackling noise (very slight and not at all apparent when music playing). I removed all output valves and dexoed them which cured the noise. I guess there was some oxidisation and/or the reseating did the trick. I also did the E88CCs which made me think of alternatives.

    Quote Originally Posted by Floyddroid View Post
    I have a matched pair of those i am selling Genelex Gold Dragons. Though i see you need six.
    Thanks Steve. Yeah six - the amp is greedy.
    Current: [P20] Roon/Tidal > Custom PC> Chevron Paradox NDF16 > Phast Pre > Neuro. 686 > Tannoy Berkley (RFC tweaks)


  5. #15
    Join Date: Mar 2017

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    Just for interest here is a nude picture of the Trilogy 968.



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    Current: [P20] Roon/Tidal > Custom PC> Chevron Paradox NDF16 > Phast Pre > Neuro. 686 > Tannoy Berkley (RFC tweaks)


  6. #16
    Join Date: Jan 2009

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    Of the substitutes suggested for the E88CC, only the 6922, CCa, E88CC/01, ECC868, CV10320, CV2492, CV2493 and CV8065 are identical or have a very close specification.

    The 6DJ8, 6H23P (sometimes written as 6N23P), ECC88 and CV5358 have a different rating or performance, but are probably close enough to be a 'drop in repacement'.

    The ECC88 is described as a frame-grid double triode with separate cathodes for use as a cascode RF amplifier at frequencies up to 220Mc/s in television receivers.
    (Mullard Maintenance Manual, 2nd ed. Technical Service Department, 1961)

    The E88CC is described as a special quality double triode with separate cathodes for use as a cascode amplifier and in pulse circuits, where stability of characteristics and long life are required.
    (Mullard Technical Handbook, Book 2 - Valves and Tubes, Part 1: Special Quality Receiving Valves. Central Technical Services, Mullard Limited, November 1970)

    The differences are small, for example the heater of the E88CC draws 365mA, whereas the heater of the ECC88 draws 300mA.
    Barry

  7. #17
    Join Date: Mar 2017

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    Quote Originally Posted by Barry View Post
    Of the substitutes suggested for the E88CC, only the 6922, CCa, E88CC/01, ECC868, CV10320, CV2492, CV2493 and CV8065 are identical or have a very close specification.

    The 6DJ8, 6H23P (sometimes written as 6N23P), ECC88 and CV5358 have a different rating or performance, but are probably close enough to be a 'drop in repacement'.

    The ECC88 is described as a frame-grid double triode with separate cathodes for use as a cascode RF amplifier at frequencies up to 220Mc/s in television receivers.
    (Mullard Maintenance Manual, 2nd ed. Technical Service Department, 1961)

    The E88CC is described as a special quality double triode with separate cathodes for use as a cascode amplifier and in pulse circuits, where stability of characteristics and long life are required.
    (Mullard Technical Handbook, Book 2 - Valves and Tubes, Part 1: Special Quality Receiving Valves. Central Technical Services, Mullard Limited, November 1970)

    The differences are small, for example the heater of the E88CC draws 365mA, whereas the heater of the ECC88 draws 300mA.
    Wow Barry. A veritable feast of information.

    Thanks for that.
    Current: [P20] Roon/Tidal > Custom PC> Chevron Paradox NDF16 > Phast Pre > Neuro. 686 > Tannoy Berkley (RFC tweaks)


  8. #18
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    Mana Acoustics Racks / Bright Star IsoNodes Decoupling >> Allo DigiOne Player >> Pedja Rogic's Audial Model S DAC + Pioneer PL-71 turntable / Vista Audio phono-1 mk II / Denon PCL-5 headshell / Reson Reca >> LFD DLS >> LFD PA2M (SE) >> Royd RR3s.

  9. #19
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    Try some USA , many rca and GE ARE penny’s compared to European Types, not up to euro standards but still good and plentiful, hence cheap.
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  10. #20
    Join Date: Mar 2017

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    Thanks Neil and Laurie.

    §
    Current: [P20] Roon/Tidal > Custom PC> Chevron Paradox NDF16 > Phast Pre > Neuro. 686 > Tannoy Berkley (RFC tweaks)


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