Just finished the schematics for 3 amps I want to build. Two I'm going for lower voltage, higher current. I have all the parts except the transformers for the express.
first is a low powered Express with 6K6's or 6V6's. 12.5x8" chassis
second, a simple 6L6 amp cathode biased pretty hot. 12.5x6.5" chassis
third, another El84 two channel amp with my favorite preamp and a somewhat Mazerati GT preamp. This time SS rectified, little bit lower voltage. 17.5x6.5" chassis
If you have any thoughts or comments please share.
thanks
rp
What to build next?
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randalp3000
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What to build next?
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Stevem
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uf value`s
In regards to the output(s) tubes cathode bypass caps I haveplayed around a ton with them and for me Ifind that untill you get to a 200 uf value little in added bass responce takes place.
Re: What to build next?
I've played around a lot with a 6P1P based Wreck. The extra sensitivity of the 6P1Ps meant I needed split plate dividers on the PI plates to reduce the signal into the power grids. You won't have that problem so much because of of the 6K6 characteristics. But you will need to adjust the screen supply dropping resistor for good clean to mean performance. It will need to be more than 1K for the screen current to drop the PI supply node sufficiently when overdriven. I landed on 5K6 for a B+ of 300Vdc or 4K7 for 250Vdc. The 6P1Ps are tetrodes so they don't draw as much screen current, therefore the resistor had to be bigger. In your case the 6K6 is a pentode and will draw a decent amount of screen current but still not as much as a big bottle. The screen supply resistor will probably need to be somewhere in between the stock Express 1K and the values I had to use for the 6P1Ps.