E88CC. Suggestions

[Edward]

Mulling over an alternative driver valve for my Trilogy 968 amp.

Currently sporting 6 x Edicron E88CC (code D8G08). No complaints at all. Great at all frequencies, fast, rich, detailed but not clinical. But you know how it is - that itch. :)

I see here and there various vintage stock (Siemens, GEC, Mullard, Phillips) but at prices that hurt - especially as I need six.

So I was wondering what current crop of E88CCs are worth considering? Perhaps I'm just dreaming that different driver valves will make a noticeable difference? Maybe I should just focus on different output valves (the Trilogy takes either EL34 or KT88)?

:wave:

[Lawrence001]

Hi Edward. If you want to try some tube rolling on a budget you might like to go for the Russian 6N23P or Jan Philips 6922. I've not tried the former much but they are supposed to be giant slayers, although the better EV/EB variants go for a fair whack these days. I used the Jan Philips in a few amps in the past and they are very transparent, verging on the bright, so possibly not much different from the Edicrons if I've interpreted your description correctly.

As always it's just worth checking that different tube variants work with your amp but these generally tend to be drop in replacements for an ECC88 (of which I believe the E88CC is a higher spec variant itself).

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[User211]

I have some Rocket logo 6N23P and have no idea why they are raved about.

Lotta deaf dudes about I guess:D

Tesla E88CC factory code 32 yellow print gold pins are what you want;) The Siemens are almost exactly the same sonically - at least the ones I had were.

[anubisgrau]

get someone to rework your amp and skip these overhyped, overpriced glass.

[Lawrence001]

get someone to rework your amp and skip these overhyped, overpriced glass.What, you mean stick some transistors in and turn it into a solid state amp? Go for it Edward, Alan could probably do it for you [emoji23]

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[anthonyTD]

A frame Mullards have a nice over-all presentation, the Tesla's already mentioned seem to get good press too, there are many versions of this valve out there, if you buy from a dealer; the main thing is to make sure they have been tested for noise and microphonics, this valve having a high GM MA/V is very prone to be noisy, it wasnt intented for use in audio, so for many aplications noise was a secondary concern.
Good luck with your quest. :)

[Edward]

Hi Edward. If you want to try some tube rolling on a budget you might like to go for the Russian 6N23P or Jan Philips 6922. I've not tried the former much but they are supposed to be giant slayers, although the better EV/EB variants go for a fair whack these days. I used the Jan Philips in a few amps in the past and they are very transparent, verging on the bright, so possibly not much different from the Edicrons if I've interpreted your description correctly.

As always it's just worth checking that different tube variants work with your amp but these generally tend to be drop in replacements for an ECC88 (of which I believe the E88CC is a higher spec variant itself).



Reading around I get confused what are drop in replacements versus equivalents. Seems like the 6922 are USA equivalents of E88CC (Euro designations). Not sure how EC88s and 6N23P fit in.


I have some Rocket logo 6N23P and have no idea why they are raved about.

Lotta deaf dudes about I guess:D

Tesla E88CC factory code 32 yellow print gold pins are what you want;) The Siemens are almost exactly the same sonically - at least the ones I had were.


The Tesla code 32 seems largely unobtanium (or silly prices). They certainly seem highly regarded. Do you know of a current manufactured crop that gets near these in terms of SQ Justin?


get someone to rework your amp and skip these overhyped, overpriced glass.


What, you mean stick some transistors in and turn it into a solid state amp? Go for it Edward, Alan could probably do it for you [emoji23]



:) I think Nic Poulson (who had this amp over earlier this year and liked how it sounded) would throw a fit if I started mucking around with his circuit. And anyway Alan has another project on for me. Can't have Alan start raising his charges due to him having too much work. :lol:


A frame Mullards have a nice over-all presentation, the Tesla's already mentioned seem to get good press too, there are many versions of this valve out there, if you buy from a dealer; the main thing is to make sure they have been tested for noise and microphonics, this valve having a high GM MA/V is very prone to be noisy, it wasnt intented for use in audio, so for many aplications noise was a secondary concern.
Good luck with your quest. :)

Thanks. I may in time get some vintage glass, but for now looking for current crop. Any suggestions?

[struth]

6DJ8 should be drop in, and probably the russian 6H23P as well.


but what do i know :D

[Edward]

6DJ8 should be drop in, and probably the russian 6H23P as well.


but what do i know :D

Ah thanks Grant. Let me look at that.

I'm sure you know a lot Grant, or is that caveat you just covering yourself in case I blow up the house by using your suggestion? :eyebrows: :)

[anthonyTD]

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.
Reading around I get confused what are drop in replacements versus equivalents. Seems like the 6922 are USA equivalents of E88CC (Euro designations). Not sure how EC88s and 6N23P fit in.




The Tesla code 32 seems largely unobtanium (or silly prices). They certainly seem highly regarded. Do you know of a current manufactured crop that gets near these in terms of SQ Justin?





:) I think Nic Poulson (who had this amp over earlier this year and liked how it sounded) would throw a fit if I started mucking around with his circuit. And anyway Alan has another project on for me. Can't have Alan start raising his charges due to him having too much work. :lol:



Thanks. I may in time get some vintage glass, but for now looking for current crop. Any suggestions?

[Edward]

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

[anthonyTD]

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
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

[Floyddroid]

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

[Edward]

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.


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. :)

[Edward]

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

https://uploads.tapatalk-cdn.com/20201001/4c01ce5f93d41286831570e6b3ce815e.jpg

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[Barry]

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.

[Edward]

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.

[Yomanze]

These ones: https://www.thetubestore.com/6h23n-eb-6922

[Flo]

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.

[Edward]

Thanks Neil and Laurie.

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[sailor]

Brimar are great and very good value. (British manufactured American Radio) Warm and rich with a beautiful midrange.

The Electro Harmonix, I find, are a bit hard and brittle sounding.

Can also try JJ and they will match your EL34's. I have not heard the JJ ECC88 but have some JJ ECC81's which are surprisingly good for their price.

[Edward]

Brimar are great and very good value. (British manufactured American Radio) Warm and rich with a beautiful midrange.

The Electro Harmonix, I find, are a bit hard and brittle sounding.

Can also try JJ and they will match your EL34's. I have not heard the JJ ECC88 but have some JJ ECC81's which are surprisingly good for their price.Thanks very much Charles.

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