No-R No-C Power Supply

[terrydaniel]

Steve Bench drew up a wonderful no-r no-c power supply, using EL509's to augment gas regulator current handling.

Well, EL509s turn out to be less expensive than NOS WE 300Bs, so I guess that's a plus. But I'm in a position that promotes frugality

It strikes me that the EL509 in the Bench supply is not really a critical part, at least as regards curves and such, and that there ought to be a number of alternatives for considerably less money. Does anyone have any ideas that they would like to share?

[Colt45]

big, ugly, high dissipation, high perveance. sweep tube. unfortunately, apart from TV's, a lot of ham rigs use them, so some types can be pricy, some are dirt cheap though.

[tubelab.com]

This circuit depends on the high sensitivity of the screen grid in a sweep tube. I would guess that depending on the load and voltage requirements many other sweep tubes could be used. As with any other " unusual" circuit, plan on doing some experimenting. I would start with whatever sweep tube that I could find cheap. Often tubes with odd heater voltages can be found for cheap.

[terrydaniel]

Thanks for the feedback, guys. At the risk of sounding incredibly foolish, I happen to have some 7027s in an Ampeg Combo. Would these work, ya think? Would it damage them?

[tubewade]

I wouldn't "waste" those expensive 7027s doing that. Also, their cathode current abilities are not really that high. 6CD6GAs should probably work well in this application and they are dirt cheap. The only penalty is that they have very heavy heaters; 2.5 amps at 6.3 volts, vs. 2.0 amps for the EL509/6KG6.

As Tubelab stated above, start with cheap valves and experiment a lot.

[tubelab.com]

I second what Tubewade says. Whenever you experiment with tubes you run the risk of blowing something up. The tubes could oscillate and draw far too much current leading to a glowing meltdown.

7027's are too valuable to experiment on. As stated 6CD6's should work, 6DQ6's too. I have some of these that I use for experiments like these. You don't cry too much when you blow up a $1 or $2 tube.

[terrydaniel]

COOL! I got 20A of 6.3 in one filament tranny, no problem there.

What I'm trying to do is build a new amp for some Audio Nirvana full range drivers I picked up.

I'm trying to satisfy champagne taste on a beer budget. (Satisfy??!! If God handed me a plate of everything I've always wanted, I'd bitch about the size of the plate.)

I managed to score a couple of HSM-189 Triad outputs (10K with screen taps, 7-50KHz) for next to nothing. I got a box full of 6V6s. I'm on a quest for Shangra La.

You dudes have helped tremendously. Thanks for your help. May Murphy give you a pass this year!

As The Bear once said,
I'm on the road again...