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 NEW  Bruce Heran outlines the details and construction of his simple DIY 6DJ8 (ECC88) Tube Hi-Fi Headphone Amplifier Project.

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PostPosted: 07 Jan 2010, 00:18 
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Joined: 28 Oct 2009, 02:34
Posts: 501
Location: Utrecht Nederland
Hallo Everybody,

I did it, I build the 4 tube version of this amp, here it is:


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Greetings from Holland, Ben

My DIY Audio Projects:
- Single-Ended 12B4A tube amp with ECC802S driver
- DIY Push-Pull KT88 tube amp (OddWatt amp from scratch)
- 832 / GU32 tube push-pull amplifier project


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PostPosted: 07 Jan 2010, 00:35 
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Joined: 26 May 2009, 18:51
Posts: 110
Location: Lilburn, Georgia USA
Good looking amp and you didn`t waste any time either. I like the tube layout and might just do my own just like it. How does it sound and please post pictures of the bottom. Good listening, Robert Parzych from Georgia, USA


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PostPosted: 07 Jan 2010, 00:47 
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Joined: 28 Oct 2009, 02:34
Posts: 501
Location: Utrecht Nederland
Hallo everybody,

here are some pictures, the 4 tube version with Edcor output transformers and UL, yes UL is working on this amplifier. :) :D I am very happy about that, that was also my goal, to have such an amplifier 100% class A (the LM317 forces the amp to operate in class A mode) and UL, but UL cannot be done with the 2 tube version because of the shared grid2. So my goal I achieved, it is a total success, but the output power s much lower than expected, well, I will loose sme for UL. Having both amplifiers running next to each other, my little amp scores surprisingly good. Actually, it almost performs as good as the big amp with 4 tubes. The ittle amp has output transformers which should be around 10 k, I do not know for sure, those are the S5 kit amp output transformers, but they work for whatever reason very good with those GU32 pp. I am very happy that I build both amps and I really love the looks of the new amp, and the sound, but knowing what I know now, I would not build it again, the two tube version is good enough, really


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Greetings from Holland, Ben

My DIY Audio Projects:
- Single-Ended 12B4A tube amp with ECC802S driver
- DIY Push-Pull KT88 tube amp (OddWatt amp from scratch)
- 832 / GU32 tube push-pull amplifier project


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PostPosted: 07 Jan 2010, 04:15 
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Joined: 02 Mar 2009, 12:41
Posts: 790
Location: Vänersborg, Sweden
Well done Benny Buizen!
Glad you made it and that it worked. I guess theoretically the 832 is like a twin 6V6 and that a "normal" 6V6-PP should give some 10W, while a 6V6 PPP could blast some 20W. Now that it is running in classA your amp could possible have a max power of 8-10W I guess.

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Magnus

“If you don't know where you are going, any road will get you there.”
―Lewis Carroll


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PostPosted: 07 Jan 2010, 04:37 
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Joined: 24 Feb 2009, 03:24
Posts: 505
Location: Bulgaria - EU
Hi, Benny!
It looks incredibly!
Congratulation for nice work!
8-10 wts is fully enough! /some wires are little bit longer....but I don't doubt pauses are noiseless, and sound amazing!/
What's Your next project? I believe You can't stop on this ampli!? :thumbsup: 8-) :idea:

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Hi End is back proportional to the number of composite parts!
Projects: OTL 6AS7 Gen, Electric, SEs 2A3 RCA, 300B JJ, 6S4S, 4P1L, EL11 Telefunken, 6AS7 RCA, 6S33S, 6S41S, 6S19P, PP 6005 Gen. Ellectric , headphone ampl. OTL Loftin White 6AS7 RCA....SE E84L& E80CC Siemens&Tel-n.
http://azazello-sound.blogspot.com/


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PostPosted: 07 Jan 2010, 14:16 
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Joined: 28 Oct 2009, 02:34
Posts: 501
Location: Utrecht Nederland
Hallo everybody,
now that it is done, I wanna thank Bruce Heran from OddWatt for making that project possible. Bruce designed and also build that amp a few days before I did and put it on the scope, too. The results are as follows:
Attachment:
What-Watt Plus Specifications.doc


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Greetings from Holland, Ben

My DIY Audio Projects:
- Single-Ended 12B4A tube amp with ECC802S driver
- DIY Push-Pull KT88 tube amp (OddWatt amp from scratch)
- 832 / GU32 tube push-pull amplifier project


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PostPosted: 14 Feb 2010, 12:43 
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Joined: 01 Sep 2009, 19:10
Posts: 29
Hello Ben -

Could you tell me the primary impedence for the OTs you ordered from edcore for this project? These were ordered for the two gu32 project - correct??

Maybe the reason the 4 tube version had no power is because u would need to use a OT with half the impedence.

Just a thought --


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PostPosted: 14 Feb 2010, 13:46 
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Joined: 28 Oct 2009, 02:34
Posts: 501
Location: Utrecht Nederland
Hi Jim,

here it comes. For the 2 tube version I used the output trannys I got with the K16 LS kit amp, yes that were push pull trannies, rated 10 watts but I do not know the primary impedance. For the 4 tube version I used Edcors 5 k 8ohm 25 watter, the same ones that are now in use in my KT88 amp, which rocks, the best amp I have ever heard. No Bruce build the 4 tube version of the GU 32 amp as well and had the same results tan I did. These tubes were never designed for audio amplification and for some reason they don't behave very well in the 4 tube version. Maybe with some tweaks you can make something nice of it. But the 2 tube version goes almost just as loud and it sounds much nicer. The two tube version I will definitely build again, I got 4 tubes and sockets laying around now, but the 4 tube version, see for all the money, you need everything biig transformer for the filaments and so on, it should sound nice. Buy 4 KT77 or KT88, a bit of extra money to begin with, but boy, you are not going to regret it. I got those GU50 and they plug and play in my KT88 amp (almost, wrong socket and heater voltage) so I tried them out with alligator clips, perfect, they are balance able, and not all tubes are, but having one channel running with KT88 and the other with GU50, the KT88 do sound so much better and richer, that are audio tubes, made for amplification. And I use only the very best parts I know of, so it must be good. I built quite a few amplifiers by now trying to save money, what a joke, I spent thousands of € to get there where I am now (gotta watch out that my wife don't read that ;) ) just to end up with a KT88 amp at the end. Nonetheless, you are going to love the two tube version, I did love it and still do. It performs well and loud. Success.

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Greetings from Holland, Ben

My DIY Audio Projects:
- Single-Ended 12B4A tube amp with ECC802S driver
- DIY Push-Pull KT88 tube amp (OddWatt amp from scratch)
- 832 / GU32 tube push-pull amplifier project


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PostPosted: 17 Feb 2010, 12:36 
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Joined: 04 Jan 2010, 13:02
Posts: 3
Hello,
I want to try the some GU-32 tubes, with Audax TU101 output transformer:

http://pagesperso-orange.fr/michel.terr ... mpel84.htm

puissance nominale 10 Watts -------------------------------- NOMINAL POWER
self primaire totale: 200 Henrys ----------------------------- PRIMARY INDUCTANCE
bande passante à +/- 1 dB de 15 Hz à 40 000 Hz--------------
circuit magnétique 62,5 x 75 mm sans entrefer, noyau 6,25 cm²
impédance primaire: 8000 ohms PRIMARY IMPEDANCE de plaque à plaque,
impédances secondaires: 4 ; 9 ; 16 ohms

Do you think that the 8000ohms primary impedace are too low? I used those transformers with a EL84 PP, and sounded nice.

Thaks all.


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PostPosted: 17 Feb 2010, 16:34 
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Joined: 01 Sep 2009, 19:10
Posts: 29
Here is URL for a useful spec - the 832A is the US version of the GU-32. Not sure which came first.

http://scottbecker.net/tube/sheets/049/8/832A.pdf


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