congrats for the build. A tube amp is done when they are more capacitors in the power supplies than tubes in the circuit ;-)
Thank you! Of course there are more pictures
As far as I know the only russan PIO caps that come in that nice blue colour are the 250nF 630V ones.
The circuit is really very simple. The 24A screen grids are connected to the anode with 100 ohm resistors and biased at 2.5mA and 100V, I have attached the tube curves below so you can see. The 45s are biased at 33mA and 250V with a 6K load giving about 1.3Watts.
The preamp tubes are really nice but nobody ever uses them. They are very linear as you can see in the curves, and plentiful and cheap. The biggest downside is the high heater current.
Nice amp simple but very nice
I’m working on another OTL headphone amp with 17 tubes, no more caps on top
I’m very happy how it turns out, have been spending a month just for thinking how to make it look good. I’ve plan for a Sakuma 845 driving 845 headphone amp on mind, but that will take time.
Thank you! I’m still tuning the operation point but so far so far really pleased with it.
Thank you.
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Second PP amplifier EL 34 , toroidal mains transformer, and output transformer, from Toroidy Poland. Power 2x50W, distorsion less 1% ,HV=500V .Round, vintage transformer cover, from China, will arrive soon. It's singing now.
Regards
Alex
Regards
Alex
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Just finished new build 6W6 SE, 12AU7 driver, 6CA4 rectifier, 3.9W x channel, double volume pot front/rear selectable because will operate in a restaurant. Very interesting tube the 6W6 and inexpensive, still lots of NOS out there, impressive sound stage and surprisingly even in over drive condition very low distortion, much better than the 6V6, the only negative of this tube is the very hungry heather 1.2A. Aluminium enclosure with a touch of wood on top because I think the listening experience start with our eyes. Ciao a tutti
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Kiss congratulations for the nice build, the plywood gives a soft-touch on it ! The 6W6 seems indeed an interesting tube. Would you agree to publish the schema for your build ?
On the other side, a restaurant is a challenging place, the amp will run for many hours a day, Better not run the tubes at their limit if you want to achieve more than 1-2 years with a set.
On the other side, a restaurant is a challenging place, the amp will run for many hours a day, Better not run the tubes at their limit if you want to achieve more than 1-2 years with a set.
Thanks CBUECHE for the good suggestion, they will use the amp just as a feature in the restaurant and use it just sometimes for audiophile client. Sure here the schema, the circuit is very simple and more tubes can be used instead of 6W6 and 12AU7, I personally tested also with 12AX7 and 6L6 and work very well without any changes.All the best.
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Sure.
This is a schematic for the 2 tube version. The one I built is 4 tubes. Just build two of these and parallel all tubes. In my case, I used a single 0.47u cap instead of 2 0.22u in parallel.
EDIT: Included the PPP output ( load is 1k3, not 650R ) and PS schematic.
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Another headphone amp for Stax headphone. An OTL P-P EL34, a pretty good sounding space heater. This time I experimented with tube voltage regulator for the input stage. Dead quiet and very musical sound, to my surprise.
This time I experimented with tube voltage regulator for the input stage. Dead quiet and very musical sound, to my surprise.Attachments
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It's done !
It's low B+ voltage version Aikido Hybrid headphone amp designed by John Broskie.
However, I replaced the tube, 6GM8, with 12FM6, due to the price of the former is so high to me.
Now, I still fight for terrible hum issue !
It's low B+ voltage version Aikido Hybrid headphone amp designed by John Broskie.
However, I replaced the tube, 6GM8, with 12FM6, due to the price of the former is so high to me.
Now, I still fight for terrible hum issue !
