| Author |
Topic: Homemade amp Class D 60W |
Tim Toberer
From:
Nebraska, USA
|
Posted 21 Jul 2023 2:03 pm |
|
I finished up my experimental project and I am over the moon with how good it sounds! It is basically Fetzer Valve type preamp and buffer in front of this cheap little TPA 3118 60W power amp. The power supply is a 19v laptop supply hardwired in the chassis. It works wonderful for guitar and absolutely amazing for steel. The only thing missing is reverb and honestly I don't miss it. This sounds as good as any of my other amps including Tweed Deluxe, Princeton and a Superblock. The tone is very mid focused like many old tube amps. Not mid scooped, but with a different preamp I am sure this could be accomplished. Baxandall, Dumble, or 3 band would do this I believe.
I have been searching for the amp that just feels right, and this could be it. This is a great platform and could be built into a very small enclosure. You could easily add reverb or any other effect. Volume wise I feel it compares to a 30 to 40W tube amp. It is insanely loud and can go from sparky clean to quite dirty with a long range in between. The breakup is very tubelike and I personally could not tell the difference. When I first started playing I instantly thought of all those great old steel recordings from the 40's and 50's.
This was a very simple build. The preamp is based on a popular octal type preamp pedal and the buffer is just a EH lpb-1 pedal circuit. Both very simple circuits with low part counts. I also included a "dying batter simulator" where the Presence knob is and it adds a very nice saggy compression to the circuit. I only have about $50 to 75 bucks in this and that includes an extra power amp and buck converter (for converting 19v to 9v). It would be nice to add a line out, or XLR, and maybe an effects loop, but I wanted to keep it simple.
This idea came about from watching numerous Youtube videos and reading a ton on DIY Audio and PedalPCB about people doing similar projects. I wasn't expecting it to sound this good, honestly I was hoping it worked at all! I plan on building another with another Fetzer Valve type preamp the Professor Tweed or possibly something with 3 band EQ, In a smaller cabinet. I am having too much fun with this!! |
|
|
 |
Tim Toberer
From:
Nebraska, USA
|
Posted 21 Jul 2023 2:06 pm
|
|
 |
|
|
|
Karl Paulsen
From:
Chicago
|
|
|
|
Tim Toberer
From:
Nebraska, USA
|
Posted 22 Jul 2023 5:09 am
|
|
| Karl Paulsen wrote: |
| Impressive work. Neat to see what can be done on a small budget. |
Thanks! While money wasn't my prime motivation, it was in the back of my mind. A similar tube build would cost around $500 so literally 10 times as much. My two tube amp projects set me back at least that much. They both have issues right now, one has a bad tube and the other I am not quite sure, I think the speaker blew.
Soundwise it is so close to an old tube tweed era amp it is scary. The Fetzer Valve design is a game changer for solid state IMHO. This amp weighs about 3 lbs. I feel anyone with a few basic tools and skills could do this. I did do a bunch of reading, and built the preamp as a pedal first. I don't own a breadboard, but I should probably get one if I keep doing this.
I read through this thread about 10 times. https://forum.pedalpcb.com/threads/tpa3118-60w-power-amp-module.2015/
http://www.runoffgroove.com.
Here is a preamp I think would give a very similar result http://www.runoffgroove.com/professor.html |
|
|
|
Tim Toberer
From:
Nebraska, USA
|
Posted 22 Jul 2023 5:26 am
|
|
 |
|
|
|
Ken Morgan
From:
Midland, Texas, USA
|
Posted 22 Jul 2023 6:50 am
|
|
This is the coolest thing I’ve seen today
_________________
67 Shobud Blue Darling III, scads of pedals and such, more 6 strings than I got room for
Ken Morgan
Midland, TX |
|
|
|
