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Ya so now we get to use tube topologies...
SRPP? Circlotron? (Yes, Circlotron!) Single ended with an active load? It'll be my first attempt at a transistorized output. As long as they don't explode and maybe make sound, I'll be encouraged.
I'm thinking to start, using 24V across two devices, one as a load, the other as the active device and I'll go from there... Capacitor coupled to start because I have zero knowledge of DC servos even though I know about split supplies... Maybe I'll get 5W out of the first amp. How do you sum the output without a transformer? I don't think push pull is possible without it. Am I wrong?
EDIT: What about using a transformer with dual secondaries? amp in on one side, speakers on the other. primary disconnected? I have two coils I might get to work... I'll report back
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Hi kodabmx,
Yes, you can sum the output without a transformer. The outputs are placed in push pull with the top device used for positive waveform excursions, the bottom device for negative excursions. Using two N-channel devices means that the drain of the top one goes to the + supply, the source to the drain of the bottom device and the source of the bottom device going to the - supply. Driver stages differ, but the most common and easiest would be a complimentary pair of BJT transistors. It gets very complicated after this, you should look at diagrams of some commercial amplifiers for the rest. Creek (early) used this design.
-Chris
Yes, you can sum the output without a transformer. The outputs are placed in push pull with the top device used for positive waveform excursions, the bottom device for negative excursions. Using two N-channel devices means that the drain of the top one goes to the + supply, the source to the drain of the bottom device and the source of the bottom device going to the - supply. Driver stages differ, but the most common and easiest would be a complimentary pair of BJT transistors. It gets very complicated after this, you should look at diagrams of some commercial amplifiers for the rest. Creek (early) used this design.
-Chris
Depending on the floor, you have to be careful of standing water. ie: pee. It can swell the joints and they don't go back down like they swell up. Trust me.
The last time I installed a laminate floor in a house we would be living in (that means spilling things regularly, cleaning up irregularly), I used a common clear polyurethane coating brushed on to the edges as I installed the pieces, wiping off the excess before it dried on the surface.
The next home, had some laminate floors in the kids rooms, and the joints have suffered the swelling during the several years (autism) before toilet training was a success.
Next time you get the itch for a t-shirt ride, try ‘the rattler’
Starts in hot springs NC (not too far from you) go out of town on hgwy 209 to spring creek, stop at Dave’s 209 (in the old school house) for a burger, get gas at trust general store, continue to Ferguson’s supply in fines creek......t shirts are available at any of those places.
From our old farm we could see (and sometimes smell!)Dave’s!
There’s some nice gravel forest service roads up by max patch you could make into a loop.
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Hi kodabmx,
Then look at a Counterpoint SA-100 (the SA-220 is more complicated with a lot of extra, unused circuitry).
What I would change is the horrible output stage - you have to using those depletion Mosfets anyway. Drive the gates with another stage to get the low impedance required to charge and discharge the gate charge. It will work with a high impedance driver, but not very well considering distortion. Grounding the gates isn't what you want to do either, but using a DPDT replay to provide heavier negative gate bias during start up would kill start-up and shut-down noise. If you elect to leave the output normally biased during up and down transitions, you might want to short the signal path to the output stage drivers.
Good luck with this. I would love to see what you come up with!
-Chris
Then look at a Counterpoint SA-100 (the SA-220 is more complicated with a lot of extra, unused circuitry).
What I would change is the horrible output stage - you have to using those depletion Mosfets anyway. Drive the gates with another stage to get the low impedance required to charge and discharge the gate charge. It will work with a high impedance driver, but not very well considering distortion. Grounding the gates isn't what you want to do either, but using a DPDT replay to provide heavier negative gate bias during start up would kill start-up and shut-down noise. If you elect to leave the output normally biased during up and down transitions, you might want to short the signal path to the output stage drivers.
Good luck with this. I would love to see what you come up with!
-Chris
The size of an entire cow (Bigun had the right idea).What is beef-sized?
Around these parts we have breakfast sized and dinner sized.
Sorry Cal, I was being a bit facetious after finding the local grocer was out of my favorite coffee...
I thought about doing an Asheville run on old 23. It is still open and has lots of twisties as well. The first time I came to Johnson City (from Clemson SC) my wife was pregnant, and I had to make two stops at pull-outs for her to puke.
I will check out the Rattler.