Power tube substitution

[Andy]

Has anyone tried replacing the EL84s with 6GK6s? As far as I can tell they're identical, per the RCA book.

[zaphod_phil]

Has anyone tried replacing the EL84s with 6GK6s? As far as I can tell they're identical, per the RCA book.

[zaphod_phil]

OK, let's try that again. I don't know if anyone has tried 6GK6s, as they have a different pinout to EL84s. They also have a max plate dissipation of 13.2W vs the EL84's 12W, which makes them more like 7189As in that respect. However, they're max plate voltage is a more EL84-like 330V.

Has anyone tried replacing the EL84s with 6GK6s? As far as I can tell they're identical, per the RCA book.

[Andy]

The pinout would be minor to rework or build up, though. But, Phil, where do you get the plate dissipation from? My copy of the RCA receiving tube manual has identical specs for these two types. I mean for two tubes in class AB1, the data are identical, right down the line. I'm not arguing, I'm curious to know.

[markh]

These numbers are out of TDSL

6GK6 - VpMax 330, Vg2Max 330, PaMax 13.2, Pg2Max 2
6BQ5 - VpMax 300, Vg2Max 300, PaMax 12, Pg2Max 2
EL84 - VpMax 300, Vg2Max 300, PaMax 12, Pg2Max 2
7189 - VpMax 400, Vg2Max 300, PaMax 12, Pg2Max 2

--mark

[zaphod_phil]

Yes, I also took the figures from Duncan's TDSL, and also, yes, it would be a simple re-wiring job to convert to these tubes.

I went to Frank's Elctron Tube Datasheets site, and according to both the Sylvania and GE specs the anode dissipation is 13.2W. Interstingly both manufacturers call it a Beam Pentode - ie a form of power tetrode, which would make it a little different from a regular EL84/6BQ5, which is a 'true' Pentode.

.... And to complet the set, TDSL shows for the 7189A,
VaMax 440V, Vg2Max 400V, PaMax 13.2, Pg2Max 2.2

----------------------------------------------------------------------

These numbers are out of TDSL

6GK6 - VpMax 330, Vg2Max 330, PaMax 13.2, Pg2Max 2
6BQ5 - VpMax 300, Vg2Max 300, PaMax 12, Pg2Max 2
EL84 - VpMax 300, Vg2Max 300, PaMax 12, Pg2Max 2
7189 - VpMax 400, Vg2Max 300, PaMax 12, Pg2Max 2

--mark