First Act MA104 Amp with LED Distortion Mod

Here's the second round of mods to my thrift store MA104 amp. The previous mods were to add an external speaker jack and make a pigtail to run it off a 9v battery. In this mod I added a DPDT switch and two red LEDs for clipping diodes. The switch lets me choose between the original clipping diodes and the red LEDs. The red LEDs give a much louder sound and better distortion with a lot less sizzle than the originals. In the video I play first with original distortion and regular speaker. Next is the LED distortion with regular speaker. Third is original distortion into external speaker (jumpered into the Peavey speaker). And last is the LED distortion. I took the 4558 IC out, soldered in a socket and replaced the 4558 with a TL082 IC. The amps seems quieter and more responsive with the TL082, but that could be imagination. With the LEDs switched in and the gain turned down, the volume is better and cleaner on the clean sound. It was another worthwhile round of mods on the little amp. Now I'm eyeballing my Crate GX-15...

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Comments

Mike Bingham January 16, 2012 at 3:26pm

Thank you Wes!
Mike Bingham January 16, 2012 at 6:15am

Thanks Roadkill! I found some schematics on the Internet and they helped me do the mods. I have a new Boss DS-1 pedal coming today I hope. Gonna make it my next hot rod project. See Ya!
Roadkill a.k.a. John Maw January 15, 2012 at 2:41pm

You have certainly found a way of getting a very good sound from that little amp. I wouldn't know where to start.
Mike Bingham January 15, 2012 at 10:41am

Thank you Kevin! Gonna try to build a hum eliminator later today for my pedal board power supply. Gotta keep the pot boiling...
Mike Bingham January 15, 2012 at 10:38am

Thanks for the comment Uncle John. At 30 seconds I plugged the Peavey amp's speaker into the external speaker jack I added to the small amp. The first riff after that was on the amps original distortion diodes and the next was on the LED distortion diodes. I highly recommend the LED clipping diodes to give an additional voice to an amp.
Mike Bingham January 15, 2012 at 10:34am

Thank you James. That amp has been a lot of fun and a great learning tool.
jeff maurer January 15, 2012 at 10:33am

i have that same amp
Uncle John January 14, 2012 at 6:56pm

Mike, whatever you did at 30 seconds in sounded great. My fave tones are warm and human voice sounding. You got it.
James January 14, 2012 at 5:19pm

you are a very industrious one, with all those modifications mike, sounds really good.

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