Completed SN10 - All Octal Philco Amp Conversion

 Guitar Amps   September 28, 2023



A Philco battery tube radio from 1936 converted into a beautiful vintage guitar amp. The seemingly appropriate name “PhuelCel8” is derived from Philco Celestion 8”. The guitar amp is an all tube vintage design, using original tubes for that really great vintage tone. A period correct power transformer and a new output transformer complete the design. More on the circuit is included later in this writeup. 


The Radio

The Philco 41-841 is a 1936 battery radio that could also be run on 117vac.  It was a 5 tube design with additional details here It was originally priced at $26 in 1936 which would have been $572 in 2023. Quite a luxury item.


The radio was purchased from a fellow in Red Creek NY and at one point the radio was serviced by Fred’s Radio Service in Newark NY. Made its way to So Cal to start a new life as a beautiful vintage guitar amp

As can be seen from the photos, the radio itself was in very poor shape and would have been very difficult to restore. So a guitar amp was born.

The Guitar Amp

Attention to detail



The cabinet was modified to house a modern 8” Celestion speaker. Originally there was a plan for a 10” speaker, but that was abandoned as the chassis could not be adapted for such a large speaker.

Speaker Baffle

The front of the radio cabinet was thin wood not intended to secure a heavy guitar speaker so a speaker baffle of baltic birch plywood was fabricated to fit the front on the cabinet and attached to the original wood ply. This provides extra rigidity for the cabinet and a solid surface to mount the speaker for good resonance.

Handle Repair

The original was broken when received so a repair was in order. This was easily accomplished by gluing a piece of matching marine vinyl to the underside of the handle for exceptional strength as well as gluing the separated handle pieces together. The final result is strong and permanent. After some vintage leather dressing the handle became supple and is very comfortable to carry 




The original chassis was somewhat narrow for the needs of the guitar amp, so an extension was added to widen the chassis.





The PhuelCel8 circuit was based on the Weekender design As mentioned earlier a different Power Transformer was used as well as a new Output Transformer.


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