• 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 45, 300b

Status
Not open for further replies.
Jump to Latest
#2
Are you planning to build or buy?

I've built a pair of DRD 300Bs and I am in awe of the performance. I've never heard an amp with such detail or such dynamics. I've played on 4 different speakers, all fairly high efficiency, say 95-97 dB SPL, and it has been more than I ever expected. Just now I'm getting ready to connect to my main speakers which are Norelco 9710s on a baffle with dipole subs.

I have installed internally an Ashley passive series crossover, but all speakers but one have been full-range. Last night I had them connected to a friends biamped setup and I have never heard a main/sub system integrate so completely. But, this last is about the crossover rather than the amp.

The amp is fabulous. BTW, for a driver I used a WE 417. Have you seen these circuits on Jack Eliano's site? He shows 45, 2A3, and 300B circuits. Quite easy to build.

Cheers/The Fader
 
#8
John Fader said:

I've built a pair of DRD 300Bs and I am in awe of the performance.
Click to expand...

i too, built a drd 300b.

but with siemens c3g as driver with battery bias(2XAA), rca 83 mercury rectifier, vv302 output tube(KR enterprise), GE oil caps for psu, GE oil caps for ultrapath, audionote output trans. B+ is at 636vdc.

Angel, if you intend to build the 45, make sure you have some relatively high efficiency speakers for them.

i ran my drd 300b with totem model 1 (87db). not a perfect match... eventually i sold it and got a pair of audionote az2 (93db).
 
#11
garbage,

as much as I like my DRD 300Bs, I am having noise problems with the ultrapath cap connected. I am using it right now above 330 Hz, and with no UP cap and no cathode bypass. However, I'd like to be able to use it FR easily, which would require UP or a bypass.

Would you mind reading my long post from yesterday on Audio Asylum, Tube DIY? If you have any ideas, I'd appreciate hearing them. If you can't get to that site, I'll cross-post my message from there.

Cheers/Fader
 
#12
I am one that does not like the DRD amp. Well put it this way there are better.
I used top quality parts but gave up on the amps. I think that the huge cathode resistor does not help sound wise, and I admit that I do not like the sound of high Mu tubes .
My amps were 300B with 6C45pi biased by a resistor under the cathode of the 300B. Thorsten's idea.
Just my humble opinion.
Make it simple but not too simple..
 
#16
I use a DRD 300b as per Jack's circuit, I find it very good,
even better than the Reichert Flesh & Blood which I used for a very long time.
I use Jack's transformers also, a little pricey though but good.
I am using TJ mesh plate 300b's
 
#18
DRD lookalike, but perhaps better

Gentlemen,

May I draw your attention to the Beta-follower designed by Martin Huber:
http://home.t-online.de/home/MHuber/se45beta.htm

It looks quite a bit on the drd-amp but uses a very clever constant current source on the driver tube which gives in return the full mu.

I just built one mono-block and I am flabbergasted (if this is the right word in English). It is far better than I expected. I use a 2A3 (Sovtek), Philips ECC40, Amplimo (=Plitron) toroid 2K3 OT, GZ37 rectifier and a CR300 current diode on advise from Martin Huber.

I do not find any reviews on the web, I suppose people have overlooked this topology because tubies do not trust the CR diode. Also read Glass Audio 1998 nr. 4 for a Beta-follower. I can only say that this amp is a keeper in my shack.
 
#19
I can add

that this beta-follower sounds about 10 times better than the "Flesh and Blood" which I also built in the past (with Amplimo OT) and which chassis I now happily use for the superior "Oyster and Champagne" beta-follower:judge:
 
#20
Jaap

I guess that it's 3 watts (2a3), and integrated (personally I’m only interested in the power side).

Can someone elaborate on problems/ no problems with the CR diode?

What would the total complete cost have been; did you build it per Huber’s schematic?

Thanks

PS: nice avatar!
 
Status
Not open for further replies.
Top Bottom