• WARNING: Tube/Valve amplifiers use potentially LETHAL HIGH VOLTAGES.
    Building, troubleshooting and testing of these amplifiers should only be
    performed by someone who is thoroughly familiar with
    the safety precautions around high voltages.

DRD: Simpler path to bliss?

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Direct Reactance Drive amp:

http://my.execpc.com/~n9zes/drd300b.html
And in kit form:
http://www.welbornelabs.com/drd.htm

The circuit was in Vacuum Tube Valley Magazine a while back.

Welborne Labs have stopped selling other circuits in favour of this, possibly mainly to lower costs. They claim it sounds better than there previous well rated kits (Moondog, etc).

They’ve done a low voltage version in 2A3, 300B & 45s, with either SS or tube rectifier.

Supposed to give excellent detail. No NFB.

I guess that the comparable parts cost is maybe 40% of the Welborne pricing. What do you think?

Cheers
 
I have built an amp using that topology and I´m utterly impressed! I´m using 6C4 (EC90) input stages and 12B4A power tubes, chokes and transformers are Hammonds (the cheap 125 and 15X series).

The sound is quite marvellous, in some aspects better than my "serious" 6B4G SE amp.

Give it a try, it´s an extremly clever topology!
 
I guess that the comparable parts cost is maybe 40% of the Welborne pricing. What do you think?

I Think that all in all you can hardly do it cheaper (Top plate and wooden chassis...transformers dual mono setup) never mind 40% cheaper... If you consider shipping costs etc..etc..

[edit] Ooops saw the nude kits are without the chassis...still think it is priced pretty well.

It sure looks like an interesting topology...will try it in the not too distant future..

Cheers,
Bas
 
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