Is there anything in the battery tube (7-pin) world that even comes close to a normal hi-mu triode like a 12AT7 or 12AX7 when used in pentode configuration? The problem I've found with the battery tubes is that they all seem to have rather low amplification factors. This appears to preclude their use in things like phono or guitar amps without using a bunch of stages....
Quickie phonostage Idea, will it work?
- Thread starter balancedtriode
- Start date
Paul Joppa
Moderator
Yes, that's the problem. Tiny cathodes need little heater power but can't muster very many electrons. So you need either very high impedance loads, or you settle for low gain.
Example: 1LH4, mu is 65 but rp is 240K. That's nearly 100 times higher than the 6922 used in Seduction!
Example: 1LH4, mu is 65 but rp is 240K. That's nearly 100 times higher than the 6922 used in Seduction!
Steve is a very smart and very nice guy. I "licensed" a hum cancellation circuit from him years ago, for our long since retired Parabee amp (I think I traded a kit to him). It worked for me, but for some reason it didn't work too well in the field. So I would simply suggest that one might do their own due diligence when trying his very intriguing ideas. They are often tantalizingly off the wall. Could very well be that we had some other issues in our designs that didn't allow his circuit to work. I think that he is one of the most cutting edge guys out there.
