I have a small stock of NOS 6gk5 tubes (GE) and I was thinking they could be used as first tube in a guitar amp, or may be as concertina phase inverter anyone have tried it? what should I expect. ECC8X prices are always rising and I'm thinking about alternatives.
wow, overwhelming so many responses 😀
here are the guys
they seem to have the plate inside that grey shield
I'm sure the suggestion would be "try it yourself" just don't know what to expect
here are the guys
they seem to have the plate inside that grey shield
I'm sure the suggestion would be "try it yourself" just don't know what to expect
Expect that it will work well if you've designed a good circuit and have done the layout and bypassing well enough to avoid oscillation.
Anything and everything will work in a guitar amp if you spend time tweaking, though personally I would not naturally choose high-gm (i.e. high grid current) valves.
Appears to be semi-remote cutoff, so will distort with large signals. OK for an input stage if you can keep it stable. Probably not so good as a phase splitter, although I suppose a guitar amp wants some added distortion.
Well, it's an input stage, so the distortion is likely to be low at small swings. At 10mA current, a 70V p-p swing looks to have about 2.5% distortion. Assuming that this is mostly second harmonic, a 7V p-p swing should have less than 0.3%.
Concertina has 100% feedback and the mu is 78. High gm, so it would probably work very well in that service.
Haha! good stuff guys, I will definitely try it and share the results, it's a quite obscure valve for audio isn't it? found little as preamp, only a couple and as RIAA. Mine are made in England despite the GE markings.
Check out the curves and decide on the bias you want for the linearity/non linearity you would like.
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