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DRD Amps

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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
 
Disabled Account
Joined 2002
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
 
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!
 
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
 
diyAudio Senior Member
Joined 2002
Hi,

Rick started a thread on DRD amp here before...much to my surprise not that many people contributed to it.

For all of you who like SE amps DRD is really the best way to go IMHO.

DRD

I like some SE amps but certainly not all and view them as best suite for bi-amping unless you have the rright speakers for them.

Either way the DRD is the best I've ever experienced, add a good PSU and you have audio nirvana....well almost.

Cheers,;)
 
Disabled Account
Joined 2002
Hello I will use one 10.000 ohm non-inductive wirewound ( M. Percy ), one Mills w.w., the others Audio Note. Ultrapath capacitor General Electric foil in oil, Tango permalloy anodechoke, Tamura permalloy opt, Powersupply using double c costumwound, Tango chokes, paper in oil and Black Gates. Just to bring the threads back to the original subject. In the future maybe i will try to change the ultrapath cap or change the power supply into 100 % choke input. Now the first cap is one micro because the transformer was made for another vt-25 circuit. Succes, Ed
 
Hi Frank,

I'm just a copycat...well not always but to build my very own RIAA amp is just to much.

I've selected Kurt Strain's RIAA as built by Gary Pimm. He posted here and at AA when finished.

You can follow my progress via my site if you like:nod:

It's there under phono amp..:) Not much though...just redrew GP'S schematics. Was thinking of changing the last tube to 7AF7 but the decided to stick with the original design. After all the ALLMIGHTY THORSTEN..had contributed a little to the last tube..wrt to the 22meg resistor and no cathode resistor..

Cheers,
Bas
 
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