Im starting up a new project building my first push pull amplifier.
The chematics i have found and wanted to start with for this project is : DIY Push-Pull (PP) 6V6 / 6V6GT Tube Amplifier Schematic
The schematic is a edited version of a dynaco A 410 amp schematic.
Edit: after reading this post 6V6 pp design comparison i kinda walked away from this schematic,
so if anyone have a good schematic suggestion or a schematic they want to share. go for it.
the tubes i have are: 12ax7,12at7,12au7,807, 6v6g, 6v6gt, 6v6gta, 6j5gt, 6sj7gt, 6sn7gt, el84, 6aq8, 6cw5
power transformers i have: Hammond 372JX . unknown 250-0-250v transformer,
Output transformers i have: Hammond 1608A , uknown chinese brand, came from a amp that run kt88 in push pull without ul tap. (williamson design(ish)
The chematics i have found and wanted to start with for this project is : DIY Push-Pull (PP) 6V6 / 6V6GT Tube Amplifier Schematic
The schematic is a edited version of a dynaco A 410 amp schematic.
Edit: after reading this post 6V6 pp design comparison i kinda walked away from this schematic,
so if anyone have a good schematic suggestion or a schematic they want to share. go for it.
the tubes i have are: 12ax7,12at7,12au7,807, 6v6g, 6v6gt, 6v6gta, 6j5gt, 6sj7gt, 6sn7gt, el84, 6aq8, 6cw5
power transformers i have: Hammond 372JX . unknown 250-0-250v transformer,
Output transformers i have: Hammond 1608A , uknown chinese brand, came from a amp that run kt88 in push pull without ul tap. (williamson design(ish)
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So you did not state whether you have any previous build experience - what made you choose a PP amp?
I would not change anything in the schematic that way you can troubleshoot the amp if it does not work as expected.
Having said that, 6SL7 tubes are cheap and abundant, but you can sub in a 12AX7 for testing purpposes.
The only other change would be to replace the first 100 ohm, 10 watt resistor by a choke to obtain better filtering, but it is not necessary.
Again, depending on your building skills and prior experience, build as is, learn, and the tweak.
The first question that should be asked to anyone who tries to build an amp with global feedback loop: do you have an oscilloscope or at least access to one?
I have built one SE amp previous to this one.
The reason i choose the pp was that i found this simple schematic and im also a fast learner and love a challenge. While searching for parts , i got a hold on a big load of old nos tubes. Mostly old philips tubes, but altso some italian ones (fivre) and other types. And a few mullard.
Got the transformers dirt cheap. 120$ for all three included shipping.
The 100ohm 10w is getting replaced with a 100ohm 20w . It was recommended in the schematics
The reason i choose the pp was that i found this simple schematic and im also a fast learner and love a challenge. While searching for parts , i got a hold on a big load of old nos tubes. Mostly old philips tubes, but altso some italian ones (fivre) and other types. And a few mullard.
Got the transformers dirt cheap. 120$ for all three included shipping.
The 100ohm 10w is getting replaced with a 100ohm 20w . It was recommended in the schematics
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I think you will gain by reading this thread and the final version of the circuit implemented. It is an improved version of the schematic you chose.
See: 6v6 PP UL bias point
Klimon found that he preferred the amp without GNF. Good luck with your build.
See: 6v6 PP UL bias point
Klimon found that he preferred the amp without GNF. Good luck with your build.
i have read through the post in that thread now. i see the mods are done so the amp runs more smoothly in general and even better with the 6sl7 tube. the circuit was originally intended for use of a 12ax7 so. and the guy that did the schematic i posted did not change anything when he changed te chematic for 6sl7 use.
The design you posted has been around a while. It was published in the “Super Fidelity Transformer” catalog (published around 1960) and probably existed before that.
See: http://www.tubebooks.org/file_downloads/dynaco_transformers.pdf.
It is interesting to observe that it was published for use with either 6SL7 or 12AX7 as the front tube without any change, and EL84, 6V6 or 6AQ5 as output with cathode resistor change for the latter two.
See: http://www.tubebooks.org/file_downloads/dynaco_transformers.pdf.
It is interesting to observe that it was published for use with either 6SL7 or 12AX7 as the front tube without any change, and EL84, 6V6 or 6AQ5 as output with cathode resistor change for the latter two.
intresting indeed. thank you for all the nice feedback and info guys. any suggestion on chassis size to use? i live in a industrial town so if i have some measurements i can have one made. cost me 30usd. thats dirt cheap.
Are you building a pair of monoblocks or a single amp?
Build a breadboard (one channel only) so you can listen and evaluate and then put into an enclosure if you like it.
Unless you have size restrictions in your listening room, I'd recommend a standard size like Hammond 18x12x3 inches so you have enough room for ventilation, wiring, and to hide stuff inside the chassis.
Also, while harder to work than aluminum, choose a steel chassis that can take the weight of the multiple transformers and chokes.
single amp. stainless steel chassis was the plan. but im not sure about the circuit yet. i found alot of info about it. and some say it plays well. and some say the circuit is cheap and too simple and gives alot of humm and trouble. so im not sure what i would do. its not easy to choose between all the different schematics that are here and other places on the net.
Here's a novel way of building a breadboard on a wooden base:
More examples here:
OTOMON Laboratory (音門ラボ) / 717A-71A/10Y/VT-25/45/2A3 tube amplifier with wooden board
More examples here:
OTOMON Laboratory (音門ラボ) / 717A-71A/10Y/VT-25/45/2A3 tube amplifier with wooden board