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Tonight I finally just about got my 26-26 DC 45 amp working after a long struggle fighting oscillations and crap.. My test bed is now sounding pretty good ...... All DHT!
I have a pair of all DHT PP45 amps, but All DHT SE is another story..
I had first just used a single 26 driving the 45 Directly Coupled. But that didn't have enough drive. Now with the Dual 26's .... I like it a lot.
I still need to adjust the voltages a bit but it's close..
Have fun
Willie
Follow Ups:
I found the schematic through Google.
The Asylum search didn't find it.
But its impossible to decipher some of the values.
Drummerwill's email is caput as well.
I guess DIY can be taken literally.
If there is someone out there who loves 45s, but classic SE is slightly underpowered for his needs, I would like to draw some attention to the RH45 version of the RH2A3/TTA.
For details please check out my blog. The 45 sounds great in this setup, and listening volume is quite acceptable with the RH45 even on rather low efficiency speakers.
******
http://rh-amps.blogspot.com/
I'm sure I a am not the only person who would like to see a schematic of this circuit that's working so well for you.
I have never posted on here before.
Hello to all I enjoy reading about your adventures in audio.
Bill Larson
Just sayin'...
--------------------------
Buy Chinese. Bury freedom.
He is only sayin' it ONE time, there is NO pluralization I can see.
LMAO, I thought you were an EE type, you also an English teacher ????
Wow.
Jeff Medwin
" NO pluralization I can see. "
What's the "s" for? And yes, I've worked professionally as a managing technical writer.
--------------------------
Buy Chinese. Bury freedom.
I was referring only to your response " just sayin' ", as though the O.P. wrote it.
Looking over the actual O.P., you are correct. Good boy.
Jeff Medwin
Will,
What speakers are you driving with those beautiful creations??
I want to build with the 45, just lacking the sensitivity in my system to get the magic out...
Very Nice
Stuben
GPA 604's in MLTL cabs.
Willie
What differences did you note between the PP 45 and the SE 45? I was just considering doing a PP 45 on my bread board.
Yo Vinnie
I love my PP45 amps. One is a Stereo 417A Electra-Print I.T's with E-P
Solid Silver Secondary OPT's. This amp has Triode sound up the wazzou ... and great dynamics. ...
Note: I built and sold 3 other PP45 amps.
The other PP45 amps I keep are a pair of 1930's Wurlitzer Jukebox amps, that I rebuilt over the years. They are All DHT powered, 30 CC 30 CC 45 (E-P)IT PP45 with E-P PSSS OPT's. This amp puts out about 7watts cause it runs close to Class AB. It has the Triode sound and power to deal with impedance loads, I used them with my A7's and a little EQ, " KickA*** Yeah!
But with both PP45 amps I could hear something that clouded the sound. This I didn't hear in the many SET 45 builds I had done. .... as to assure myself I compared my best PP45 amp( the Stereo amp ) to one of my 45 IT coupled SET .... I could not hear the clouded sound when listening to the SET amp ................JMHO
OK Vinnie that's it .... I can only tell you what I heard. I do love the sound of a good PP DHT amp. but for me it's SET .
Willie
I will probably come to the same conclusion, but the last PP I listened to was a restored Eico el84 many years ago, and I have never heard a PP with dht triode output tubes. Guess I will have to bread board it just so I know what it sounds like.
Thanks
Edits: 11/09/14
Good to hear about your success. Spread the love and post a schematic and more pics...Please!
David
Edits: 11/08/14
Thanks for posting that, awfully nice to see, and know you are hard at it !! Big surprise. Any possibility for you to email me a schematic when you can, / have one !!? For my DrummerWill file.
Jeff
I've got the schemo drawn, now I'm playing with resistor values to dial in the best sound. I'll get back to ya !
Willie
Doesn't a parallel input stage induce "skewing" effects audible on better high efficiency speakers?
Or is it a 3 stage circuit?
I am surprised that you did not comment on that design element.
DT667 :
Type 26 is medium mu, so I am guessing its a three stage ALL DHT amp. One can parallel low mu Finals fairly easily with DHTs, ( as Andy Evans does ) but the front end stage is a different matter.
Will see. Cool he did it !!
Jeff
I thought Drummerwill has 604 duplex similar to DF's with your special audio wires.Why not stick to a 2-stage single triode driver stage design with those speakers?
Or maybe I am in error.
Edits: 11/09/14
Yes I use GPA 604's in an MLTL cabinet..
Yes I did try just a single 26 DC'd to a 45. Yes 2 stage was really
good.
But it always left me wanting more. I tried using a preamp and that seemed to get me closer , but not quite what I wanted to hear.... That's why I've been playing with trying to get the 3 stage working for so long. Now that I'm this close I'm so glad I continued on this route.
The 3 stage has all the drive I need and some, it really kicks the 45 in the A** and gets it moving.
Note : I would not even consider a 3 stage if it were not All DHT !
The sweetness and purity of tone the 26 produces is well worth the effort !.
Willie
HCorrect, Willie does run GPA 604s in MLTLs. We are not so rigid. Willie does what he wants, as far as building amps, he builds em all !!! Notice, no breadboarding, he does a finished amp...very good.
Yes, DT667, we rewired his speakers, AC cords, over the last year.
Jeff
It is no easy task doing what you have done. Kudos. Glad you are enjoying it! I reckon all DHT is likely the ultimate... at least for me.
I would love to put together a decent all DHT amp, but would need to invest in a testing set-up and the knowledge of how to use it. Maybe after my next project, but the learning would be immense!
Again, nicely done.
Cheers,
Ray
"In the beginner's mind there are many possibilities, in the expert's mind there are few." Shunryo Suzuki
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