Hoffman Amplifiers Tube Amplifier Forum
Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: zendragon63 on August 23, 2012, 10:19:51 pm
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So I built the attached Bluesbreaker/5F6a class amp and decided to add a reverb midway though. I had old tank marked only 'Hammond type IV' tank, chose a 6DX8 and lifted much if it from a circuit that Heinz did some time ago. The inductor portion is the primary windings of a little 5W SE 7K:3 ohm OT--just because it was sitting around and I guessed that it might be enough inductance to load the plate.
Amp turned out great and the reverb actually sounds very full and plenty of it so I got lucky. BUT I have no idea as to whether it is optimized to drive a (1.4K) tank. So how does one determine inductance value--in henries?--to which I could then calculate the impedance load (I generally figure a pentode Zout~Ra).
I like it when things work out but it's like guessing lucky on a high school algebra test. Any thoughts? TIA Regards
dennis
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I don't know the answer to that, but I think that is a very cool circuit & I appreciate your sharing it with us.
Thanks, Tubenit
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Thanks for your response tubenit. FWIW, from what I have been able to find, measuring the actual inductance of a coil is not simple unless you have specific test equipment that I do not have easy access to so it ends up a bit more complicated than I anticipated. I should have remembered that it is dependant on functions of current and frequency. Me thinks that the guess was close enough because the circuit works well enough and doesn't burn things up so I will take it. Regards.
dennis
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> primary windings of a little 5W SE 7K:3 ohm OT
> to drive a (1.4K) tank
Close enough.