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DeathTrap400™ : : A Pretty Damn Good 300B Amp

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Sure. You can do that. Just short out the CL-90 on the DG300B supply board. You can omit the relay on the DG300B supply board as well.

Take the mains output of the ISS from terminals 1 and 4 on the transformer primary connector. Bring those to the mains input terminals of the DG300B supply board.

It sounds more complicated than it is. :)

Tom
 
No. I don't like to give away my work.

If you're interested in organizing a group buy and you're willing to buy at least 12 board sets and handle all the support, toss me a line. You would need to figure something out for the DC heater/filament supply, though. I'm not starting the Universal Filament Regulator back up. I have plenty of 21st Century Maida Boards. That part of the project is still going strong.

Tom
 
Hallo Tom


You seem to know a lot about audio technology. ;-)
When I read the threads here, your products get a lot of praise from your customers.
You worked with valve and class-D technology.

My I ask if you are intereseted in combining these in one amplifier? A hybrids with driver tubes at the input and class-D technology at the output.
I like what tubes do with music. But I consider tubes to be suboptimal for final amplification in the sense of resource conservation.
 
Sorry to break it to you, but tubes and resource (energy) conservation don't exactly jive. The DG300B consumed about 100 W at idle to deliver 2x10 W to the speaker. :)

If you like the tube sound but not the energy consumption, I suggest trying a simple JFET buffer stage. Just keep lowering the supply voltage until you get the "tubeness" you want. Nelson Pass has a circuit like that.
You can also get lots of second order harmonic distortion if you make a gentle clipping circuit that only clips on one half of the cycle. An opamp gain stage with a diode across the feedback resistor would be a crude example of such a circuit. It'll sound "tubey" to many. Reproducing the exact signature of a specific tube will require much more work, though, and may not be possible.

Or, as you say, use a tube preamp. I have no plans to pursue a design that involves tubes. I've had my fun. Designing the DG300B was a fun experience - especially as I at the time was working full-time at the completely opposite end of the spectrum designing precision timing chips for the cellphone infrastructure.

Tom
 
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