you´re shooting yourself in the foot, with this decision. tubes have max cathode current ratings.. choke will last ages unless you do something very stupid. i advise thyratron regulated supply and fat choke+ capacitors.
I'm assuming you haven't read the rest of the thread. That idea has been wholly abandoned, and now no cathode current ratings will be exceeded. In fact it will have 1.5 times that needed. Using 701As.
I am doing this specifically to negate the need for a fat choke. I want to be able to use a smaller choke so that it isn't a total boat anchor. That is the point here.
Can a thyratron regulated supply reduce ripple? Also how do they work?
I am doing this specifically to negate the need for a fat choke. I want to be able to use a smaller choke so that it isn't a total boat anchor. That is the point here.
Can a thyratron regulated supply reduce ripple? Also how do they work?
can you share the operating points? plate volts, cathode currents, g2 volts and anode to anode loads? i am planning to make one this year...
4D32's always gets my attention..
I'd also like to know those specs. Don't know if I'll be making one that soon, but it'd be cool to know. That's actually a pretty good efficiency too come to think of it.
They got my attention too, I've decided to use them for each of the 3 smaller regulators, and 701As for the big one. If I wasn't planning on running ultra linear I'd likely use them on the output too. I honestly haven't done that much comparison on distortion figures on ultra linear vs standard pentode operation, or people's impressions of one vs the other for that matter. It was quite a while ago, but I'd read that ultra linear was the "best", and while I don't necessarily believe that anymore, I've planned on building one ever since. My mind can certainly be changed if something else can give roughly equal performance.
They got my attention too, I've decided to use them for each of the 3 smaller regulators, and 701As for the big one. If I wasn't planning on running ultra linear I'd likely use them on the output too. I honestly haven't done that much comparison on distortion figures on ultra linear vs standard pentode operation, or people's impressions of one vs the other for that matter. It was quite a while ago, but I'd read that ultra linear was the "best", and while I don't necessarily believe that anymore, I've planned on building one ever since. My mind can certainly be changed if something else can give roughly equal performance.
That's power output, to the speakers. They are rated to 140w per pair dissipation though. That voltage and current doesn't correspond to plate dissipation, that's total power input to the tubes. Some will be dissipated in the plates, but slightly more will go to the load. Not all of the input power is dissipated in the plate. If it was there'd be no music.
I will attempt once I'm home (not at work) . First I need to learn how.
To correct myself earlier, it is 250mA per tube. 500mA for the pair.
So 400W input power, assuming 50% efficiency, 200w would be dissipated. Correct? If the efficiency is higher (which it should be), say 62.5%, 150w would be dissipated. In reality however, the plate current won't be 250mA per tube, it will be slightly less for 200w output. Am I mistaken?
To correct myself earlier, it is 250mA per tube. 500mA for the pair.
So 400W input power, assuming 50% efficiency, 200w would be dissipated. Correct? If the efficiency is higher (which it should be), say 62.5%, 150w would be dissipated. In reality however, the plate current won't be 250mA per tube, it will be slightly less for 200w output. Am I mistaken?
As stated some results and pictures were in the 6L6GC in AB2 thread posts # 654 and #660. The plate voltage was 650 volts, load impedance 3300 ohms, and plate supply current was around 500 mA (reading the meter in a picture). What I didn't post was the screen voltage. The data sheet shows 350 volts for AB1 and 250 volts for AB2. After looking as hi-res photos of the experiments I see the range switch on the power supply set to a range that goes from 250 to 300 volts. I didn't record the bias current, but I usually run the amp at 1 watt or so and turn up the bias until the distortion stops dropping with no feedback applied (minimizing crossover).
Photo of the test equipment in post #654 of AB2 thread shows 202 watts @ 3.62%. I usually quote max power output at a something around 3% unless I make a power VS distortion chart, or am working specifically on a guitar amp.
I currently have the same breadboard set up om my workbench for developmental testing on a 6550 / KT88 triode mode amp. It will run within datasheet specs and makes 75 WPC on 450 volts in AB2.
The breadboard has been used for some extreme testing of small tubes that I have lots of for a potential guitar amp design while the chassis and power supply are being worked out for the KT88 amp. That's where the power VS distortion data for the 6AQ5's came from. I have several hundred of them. I may hook the 4D32's, and other big tubes back up once I have my FFT box running again. I finally got the hardware working.
Tony, follow along in the driver board thread in the Tubelab forum. An early adopter on my driver board has chosen 4D32's for his output tubes, and already started his build. Post #105 here:
Tubelab Universal Driver Board, 2015 version
So I stand corrected, the distortion was much lower than what I thought...
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