View Full Version : Tube amp conversion for guitar...essentially finished (pics)

scott spencer
12-17-2006, 9:39 AM
Not a whole lotta wwing involved with this project but it was associated with the guitar I made for my 16 year old son last October. http://sawmillcreek.org/showthread.php?t=43739&highlight=finally

It's a ~ 3 watt class A tube amp made on a 1939 Stromberg-Carlson radio chassis, which was made right here in Rochester, NY. I salvaged the power transformer, rectifier tube, and 6V6G output tube from the S-C. Other parts were obtained from Ebay, spare parts, and a local electronics surplus place...the pre-amp tube is a 12AX7 that I plucked from my Mom's old intercom. It's got an on/off switch w/light, standby switch, master volume, gain control, bass, mid, and treble. It's currently mated to a 12" EV speaker cabinet we roughed out several weeks ago, which is something we'll finish into a presentable package this winter. The guitar, amp, and speaker cab were all custom built by us.

The schematic is a modified version of the P1 Extreme from the AX84 project amp website...fairly similar to the old Fender Champ or Les Paul Junior. We're tossing around the idea of calling it the "Fender Bender", "Night Light", or "Glow Worm". The chassis is stuffed inside an old American Bosch radio....built roughly between 1928 and 1941. I still plan to cover up some of the scratches, add a handle, and just generally spiff it up a bit, but it's working and essentially finished.

It sounds awesome and is surprisingly loud. Never built anything like this before....a very cool project, and best of all "Mr. Santana" seems happy with it.

Total cost for the amp was maybe $50, the guitar ~ $150, and the speaker was < $20. I should probably add a safety warning/disclaimer....the voltages in these amps are high and can be fatal if you're not careful. If you ever build one and need to probe, be cautious and keep one hand behind your back to avoid having the charge jolting your heart....keep in mind that the filter caps can store a voltage for a very long time....I got zapped twice so far!

Here's the "before" (an identical file photo...not the actual):

Here's "after":

Jim Becker
12-17-2006, 10:42 AM
Nice!! Not only does it sound like it does a good job audibly per your previous posts, it really looks great! Very "classic"...

Al Willits
12-17-2006, 5:15 PM
Pretty nice Scott, I bet both ya gotta be happy, enjoy!


scott spencer
12-20-2006, 8:30 AM
Now doesn't the handle just make all the difference?! ...comes in handy for like carry it around and stuff... prolly even sounds better! :rolleyes:


Tom Pritchard
12-21-2006, 10:16 PM
Great looking project Scott, I can't wait to hear it! We'll have a Christmas brew and let Cullen play it for us!

You did a super job on all parts of this project Scott!

Tyler Howell
12-22-2006, 8:31 AM
Nice Retro Look:cool: