Well, I decided to see how some early versions of popular valves would sound for a small studio /practice amp. It had to be class A, use only real NOS valves from the great makers and not look like a guitar amp. Controls are minimal, Tone, Volume, switchable cathode bypass on the pre stage, switchable global feedback. Valves as shown are a 1947 Brimar 6L6G for output, late 40s Brimar 6SL7 octal dual triode, late 40s Brimar 5V4 full wave rectifier. Transformers are Hammond. The audio is in one sealed diecast box, Power supply and O/T are in a separate box with 2 cables. One carries heater and Gnd,the other HT, Feedback and Plate supply for the output bottle. HT is around 375 V, on the limit for original 6L6G. Sound is warm, has good bite. Power is around 7 Watts.
I also have tried it using a late 60's GEC KT66 and an RCA Black plate 6SL7 with an AWA 5Y3GT for the rectifier. This gives a bit more of a "mellow" sound.
Wiring is all point to point, caps are orange drop, silver mica and sprague electros.Sounds nice through a vintage JBL K120.
A fun little distraction...
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Small Class A guitar Amp- old school-
Moderators: rick, Mark Bassett
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Small Class A guitar Amp- old school-
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Alastair Reynolds
Broadcast Radio Engineer
Master of the Dark Arts (Broadcast)
Broadcast Radio Engineer
Master of the Dark Arts (Broadcast)
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Alastair Reynolds - TRM Endorsed

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Re: Small Class A guitar Amp- old school-
Nice one Alastair!
Nick Franklin
Record Producer: http://www.nickfranklin.net
Custom Built Audio Electronics: http://www.nfaudio.com
Record Producer: http://www.nickfranklin.net
Custom Built Audio Electronics: http://www.nfaudio.com
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waitup - Frequent Contributor

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Re: Small Class A guitar Amp- old school-
mission accomplished
it certainly doesnt look like a guitar amp
it certainly doesnt look like a guitar amp

Rick O'Neil
I think we went to different schools together
turtlerockmastering.com
we listen
I think we went to different schools together
turtlerockmastering.com
we listen
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rick - Moderator

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Re: Small Class A guitar Amp- old school-
i love it
wez prictor
composure music
http://www.composuremusic.com.au/
Australian importer of Crumar Mojo keyboards & accessories. Vintage keyboard fetishist.
composure music
http://www.composuremusic.com.au/
Australian importer of Crumar Mojo keyboards & accessories. Vintage keyboard fetishist.
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wez - Valued Contributor

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Re: Small Class A guitar Amp- old school-
Now I want to see you rocking it at a gig!
Nick Franklin
Record Producer: http://www.nickfranklin.net
Custom Built Audio Electronics: http://www.nfaudio.com
Record Producer: http://www.nickfranklin.net
Custom Built Audio Electronics: http://www.nfaudio.com
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waitup - Frequent Contributor

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