This is my first attempt at designing truly from scratch. I currently have it assembled and "working", although it's in more of a breadboard state. I was hoping a kind soul might be willing to look over my design, and offer feedback, criticism, or helpful guidance.
The output stage power should come from the C tap, and the driver stage should use the B tap.
Also the secondary common should be grounded, to avoid shock hazard.
Also the secondary common should be grounded, to avoid shock hazard.
Thank you for the reply. It is wired in that configuration to allow the phase inverter b+ 650v, in order for it to output 150v of swing from idle
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I would change from Concertina to an LTP, reducing the need for such high voltage for the phase splitter.
Also the transformer seems to have a very high secondary voltage. Not sure of you are using a centre-tapped one end-to-end, with a bridge. Maybe changing to choke-input can save you from those 50W resistors.
Also the transformer seems to have a very high secondary voltage. Not sure of you are using a centre-tapped one end-to-end, with a bridge. Maybe changing to choke-input can save you from those 50W resistors.
I agree about the LTP. The transformer is very high voltage. I suspect it was powering a field coil, and possibly running on 110vac. The iron is what I'm trying to avoid replacing. It's intended to be a learning project. I previously had it through a tube rectifier, and choke but still ended up with too high of voltage. I decided to roll with it and utilize the diodes to up the capacitance, and reduce noise. Also the concertina configured utilizes the excess voltage. At this point I'm sort of doing it. Just because I can, and I'm learning a lot. The output transformer has also been a struggle at about 45:1. It hogs a lot of power, for a low output
The 6SN7 has a max 500V, so it could be damaged under some conditions.
Agree that the LTP is preferable.
Agree that the LTP is preferable.
I've been wondering about the voltage on that tube. I was operating under the assumption that the cathode resistors are dropping 200v, so it's actually seeing 450v. 200 of which is dropped on the plate load resistor, idling at "250v". I may be to be educated on that
Elevating the heater is next on my to do list. I overlooked that. The transformers have no specs. I'm pretty sure it was a push pull AB 6V6 setup. The only info I have to go on is measuring the winding ratio, abs calculating the reflected impedance. I can provide load lines asap. I'm currently at work.
The supply DC voltage should never be higher than the maximum rated tube DC plate voltage.
That's poor design practice. During warmup the tube sees the entire DC power supply voltage.
Same conditions exist for the coupling capacitor DC voltage ratings.
There always will be voltage transients higher than those during quiescent conditions.
The only thing I can say in regard to warmup, is that the 6AS7 likes to see a 30 second plus heater warmup before b+ is applied. So I am currently doing that via a switch
Moved to Instrument & Amps per forum policy.
I think you are OK as long as B+ stays below 250VDC, 200VDC is probably safer. Watch out for dissipation. I have attached some data sheets, suspect you probably have them.
Interesting project!
Interesting project!
I don't see your sim loadline numbers matching the schematic. You have 200v on the K, not 91v.
From my understanding the grid is referenced between the two cathode resistors, which is 91v negative of the cathode