Tube Amp Doctor EL84 High failure rate

[blindboybenton]

Hi all
Not sure if you lot have been having any problems with the TAD EL84's Forget if its the EL84-STR or EL84-CZ
In the past 6 months ive have had far to many sets of these and had a fair amount of amps come in with TADs in that have failed early

The problem i have found is that they go micro-phonic / Noisy it has happen a lot for me in the warranty period
As i do a fair few Marshall's i have been buying them from Marshall and this was happening to Marshall branded and from uk suppliers

I have now stopped buying them and will switch over to other brands

I recently questioned Marshall UK about every time i order shugaung tubes from you i get JJ. They told me that they have stopped using them and have gone back to JJ . I used to ask for Tung sol or Shugaung ,
I was never a lover of JJ EL34 , but to be fair i never had an issue with the Marshall branded JJ EL34

Have been happy with other TAD tubes just had this issue with the EL84's

anyone else have an issue

BBB

[Pedro Vecino]

Which are the EL84 TAD Shuguang? The Chinese EL84 TADs are the STRs.
I imagine that if they are Chinese they must be the same.

[blindboybenton]

Well the marshall ones i get are Tube amp doctor as there is a TAD sticker on them and they have always called the shuguang
these have failed and the other TAD EL84 i get from my UK supplier have failed too in the same way I don't remember if they were STR or CZ
I know ive bought both types

[Pedro Vecino]

Ok. TAD supplies in two different ways: one of them is labeled with the relative plate current (PC) and transconductance (orange boxes) and the other simply shows the mark and a number between 1 and 10. The models are the same.
The Chinese EL84 is still stronger mechanically than the Slovak (JJ, Cz ...) and is the one used by Vox and Orange in their combos. Even stronger are the classic Sovtek and the top one in that sense is the Russian 6n14n-EP that TAD distributes as EL84M-R. Very expensive.
It's a good idea (I've been doing it for a long time) to use silicone tube dampers when installed. At least in critical situations.