My son wants to build his first vacuum tube amp. He is a senior mechanical engineering student. I'm thinking something with a minimum power rating of 20 watts so something in the push-pull camp using 6SN7s and 6L6/5881 only because I have a good inventory of each. I also have many of the 9 pin 12 family but I prefer to use the 6SN7 on the front end. I only need the audio portion of the schematic as I can help him design the power supply from scratch. If anyone has any ideas, I'd be very appreciative.
Regards,
Milkduds
Regards,
Milkduds
I have always like the western electric 142 amps. However I am guessing that it is probably too complex of an amplifier for a first build. Although he would learn a heck of a lot in one project. (scroll down on the page until you see the 142).
100 Amplifiers, part 2 , 1945 – 54 | Lilienthal Engineering
Also want to point out that a single ended KT120 could be a really good choice. In single ended ultra linear it can give you ~20 watts depending on how you run it, and you could throw in a switch to go back and forth between triode mode and UL mode.
KT120s are kinda pricey, but it would cut cost in other places and it could be a smaller overall amp which would be nice for student housing and what not.
100 Amplifiers, part 2 , 1945 – 54 | Lilienthal Engineering
Also want to point out that a single ended KT120 could be a really good choice. In single ended ultra linear it can give you ~20 watts depending on how you run it, and you could throw in a switch to go back and forth between triode mode and UL mode.
KT120s are kinda pricey, but it would cut cost in other places and it could be a smaller overall amp which would be nice for student housing and what not.
This looks quite nice - and remember that a 7N7 is equivalent to 6SN7, so tubes are exactly what you want
Push-Pull 5881/6L6 Amplifier | Evil Science Audio
The Oddblock octal is also quite intriguing, I like the 317HV as the cathode CCS
OddWatt Audio 5751 SRPP / KT88 Push-Pull Monoblock Tube Amplifier Kits
It's hard to argue against the classic Williamson -
Push-Pull 5881/6L6 Amplifier | Evil Science Audio
The Oddblock octal is also quite intriguing, I like the 317HV as the cathode CCS
OddWatt Audio 5751 SRPP / KT88 Push-Pull Monoblock Tube Amplifier Kits
It's hard to argue against the classic Williamson -
If you can source a good pair of output transformers with screen taps, you could recreate an original Williamson amplifier modified for Ultralinear operation. That's a classic using 6L6 type output tubes and 6SN7s.
Page 8 in the Acrosound catalog, using the Acro TO-300 output transformer (6.6k:16,8,4):
http://www.tubebooks.org/file_downloads/acrosound.pdf
https://www.pearl-hifi.com/06_Lit_Archive/02_PEARL_Arch/Vol_01/Sec_02/105_UL-ing_the_Williamson.pdf
http://www.tubebooks.org/file_downloads/stancor_ul_schematics.pdf
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Page 8 in the Acrosound catalog, using the Acro TO-300 output transformer (6.6k:16,8,4):
http://www.tubebooks.org/file_downloads/acrosound.pdf
https://www.pearl-hifi.com/06_Lit_Archive/02_PEARL_Arch/Vol_01/Sec_02/105_UL-ing_the_Williamson.pdf
http://www.tubebooks.org/file_downloads/stancor_ul_schematics.pdf
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Ketje - that schematic looks great but absolutely requires 807's as it's B+ will be somewhere north of 700V.
Thanks guys for all the intel! Lots of good info here to digest. I especially like the Evil Science schemo except with a tube rectifier. The 1947 Radiotron design is also simple with a strong taste of nostalgia!
Milkduds
Milkduds
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