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Old 24th July 2003, 02:13 PM   #1
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Thumbs up DRD Amps

Hello to all! Just getting back into tubes and it's great to read your posts and see what's new. Just finishing a Dyna 70 clone to kind of get back into the thick of it, but am interested in DRD SET amp thing. Read Bill Gaw's review of Jack Eliano's amp as well as Ron Welbourne's comments, but I would like to hear opinions from the "serious folk" as well as suggestions, tech data etc. Hope to hear from y'all.
Pete
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Old 24th July 2003, 05:30 PM   #2
dhaen is offline dhaen  Europe
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Peter,

Please excuse my ignorance, DRD?

Cheers,
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Old 24th July 2003, 05:39 PM   #3
eduard is offline eduard  Netherlands
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Hello, with search button you can find some information about this circuit using the word monkey. Right now i am building one with e80cc ( one half ) and vt-25. I am very curious what it will do in my system. Usually people will use more powerfull tubes. But in the end i will only use it above 600 hetz with a Tad-2001 horn. Succes, Ed
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Old 24th July 2003, 05:49 PM   #4
dhaen is offline dhaen  Europe
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Aha,

Direct Reactance Drive! Yes..of course..
Unfortunately no experience yet. - sorry.
However, I'm dying to try one, and probably will this year.
There have been a couple of threads in the last couple of months:

A Choked Monkey Please!
and
Chokless Monkey

Cheers,
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Old 24th July 2003, 05:59 PM   #5
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Picked up the notation from the Electroprint site, short for "Direct Reactance Drive". It is a 300B amp by Jack Eliano using what I would describe as a plate loading choke for the driver (6N1P or 6AQ8) instead of the normal R-C coupling, and also couples the primary return of the OPT directly to the 300B Cathode through an oil filled cap. Fascinated by two things; (1) the simplicity of the circuit (I counted only 12 components in the amp section-including the tubes!) and (2) It appears to isolate the Power Supply from the signal amp. There are also claims for more output (12Watts?) from this circuit topology. Don't know of anyone who has heard one, would love to know if it sounds as good as it looks!
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Old 24th July 2003, 06:01 PM   #6
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John thanks for the scoop and Ed I would like to know how your project turns out. Thanks again to you both.
Pete
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Old 24th July 2003, 08:40 PM   #7
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Quote:
It appears to isolate the Power Supply from the signal amp
Hi Peter,

That is the Ultrapath part of the DRD. Theoretically it does "isolate" the PSU from the amp...but not completely. Differences in SS rectification/Tube rectification will all be heard I'm sure...but that is just a little sidenote.

Just like Dhaen I've been dying to do a DRD as well. Building your own is slightly harder the it seems at first, as several threads at the AA and here have shown me.

Cheers,
Bas
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Old 24th July 2003, 08:49 PM   #8
dhaen is offline dhaen  Europe
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Bas,

Did you ever ask Wil to wind you a choke?

Cheers,
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Old 24th July 2003, 08:53 PM   #9
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Hi John,

Nope, not yet...gave my phono project priority...

Cheers,
Bas

plus want to do something on the cheap...not that Wil is expensive.. so probably something parafeed with 10:1 toroïdals will happen before the DRD..But I allready have sockets and 300b's for my DRD and some 7N7 or 7AF7 as drivers.

Your 845 amp up and running yet?
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Old 24th July 2003, 09:01 PM   #10
dhaen is offline dhaen  Europe
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Default monkeying around....

Hi Bas,

How is your Phono project?
My 845 is beautiful, except that the PSU is still spread all over the bench
Actually I just fixed someones 211 SE amp. Wow it sounds sweet!
I suppose I'll have to tell him it's fixed soon.....

Cheers,
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