TPA3118 60W Power Amp Module

ThePanda said:
Could you plug in a preamp pedal/modeler like a Dream65?

oooo boards??

You have a Volume only one coming? You selling the TMB version?
Click to expand...
Yep. You can plug in just about anything.
I have 6 different boards coming... They are split into either TMB or Volume only. And then each of those has 3 different methods of soft-touch mute: Digispark; Direct ATtiny chip; or discrete components to implement it. I ordered 10 of each because the boards are really cheap. Shipping costs more than all 10 boards. So... I will have a pile to share with folks who want to try them out.
 
Paul.Ruby said:
Yep. You can plug in just about anything.
I have 6 different boards coming... They are split into either TMB or Volume only. And then each of those has 3 different methods of soft-touch mute: Digispark; Direct ATtiny chip; or discrete components to implement it. I ordered 10 of each because the boards are really cheap. Shipping costs more than all 10 boards. So... I will have a pile to share with folks who what to try them out.
Click to expand...
Cool!
 
Paul.Ruby said:
These can drive 4-ohm and no less. 8-ohm is best. 16 ohm will work but won't get full power.

Being in a pedal, there is no power switch. Only a foot switch to mute or unmute.

You absolutely need some form of front-end preamp to go with these to accept instrument level in. The simplest thing to do in the very near future will be to use one of the PCBs I've designed to build into a 125B case.

My first batch of PCBs arrived today. It's the TMB variant using a digispark for soft-touch mute. I populated one board today. Testing it now and, at the same time, documenting what I'm doing to serve as a build document. Other versions will be here over the next week or so. I'm willing to sell you just a board or a kit of parts for very reasonable price. And willing to answer questions and such. Would really like to have someone try these out and get some feedback.
Click to expand...
Sure, I could buy a board from you!

I went back and read more on this thread about it needing a buffer in front, so I ordered 2 JFET buffer boards from pedalpcb.

My plan is to use these with my HX Stomp either into a guitar/bass cabinet or into a passive PA cab.

Honestly, I may not even need to wire a volume control.

Why do you say 8 ohm works better than 4 ohm?
 
I've posted the beginning of a build guide and Arduino sketch file to google drive for the TMB+Digispark version of the board. Feedback welcome. It's not complete but has plenty of pictures of progress on the board and shows the build process. Has almost nothing related to mounting in the 125B except for drill guides. I'll do the same for the other versions as well. I have all the electronics and willing to make a few kits. Cost will be just to cover what I paid for stuff. This ain't about money... It's a hobby.

TMB and Volume Only PCBs - Google Drive

drive.google.com drive.google.com
 
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megatrav said:
Sure, I could buy a board from you!

I went back and read more on this thread about it needing a buffer in front, so I ordered 2 JFET buffer boards from pedalpcb.

My plan is to use these with my HX Stomp either into a guitar/bass cabinet or into a passive PA cab.

Honestly, I may not even need to wire a volume control.

Why do you say 8 ohm works better than 4 ohm?
Click to expand...
Just because 8-ohm seems to be a sweet spot for this amplifier. Perfect amount of power for gigs and sounds really nice when paired with the right preamp pedal (such as AMT Legend series 2). The preamp is very important, of course.

EDIT: I have been using one of these for gigs for a couple years now. It's always driving my 8-ohm 2x12 cab behind me and sometimes an 8-ohm 1x12 cab in parallel with it for better direct monitoring. So, it works fine with 4-ohm or 8-ohm. I wasn't trying to say 4-ohm is bad at all.

The jfet buffer boards are unity gain. Not useful unless you modify them to work with 24V and get some gain. Need about 10X voltage gain to drive the amplifier board. Instrument level is around 200mV but the amp wants about 2V signal. Everything on a pedal board is going to be instrument level all the way to the final stage.
 
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Paul.Ruby said:
The jfet buffer boards are unity gain. Not useful unless you modify them to work with 24V and get some gain. Need about 10X voltage gain to drive the amplifier board. Instrument level is around 200mV but the amp wants about 2V signal. Everything on a pedal board is going to be instrument level all the way to the final stage.
Click to expand...
So, is it possible to up the gain on the board?

Also, my HX Stomp does Instrument or Line Output, so no worries there.

I just wanted to make it more universally ready in case I didn’t want to use my Stomp
 
megatrav said:
So, is it possible to up the gain on the board?

Also, my HX Stomp does Instrument or Line Output, so no worries there.

I just wanted to make it more universally ready in case I didn’t want to use my Stomp
Click to expand...
The buffer board is a source-follower circuit. It's only option is unity gain. It's of no value. The line-output of the HX stomp can drive the TPA3118 directly. But, I would still suggest building something a bit more versatile.
 
I'd be down for one of each volume-only board. I have a bunch of ATTiny85s and a couple OG Digispark boards that aren't currently in use.

I have a bunch of travel coming up so I can wait until after the holidays. Just let me know what the cost is. Thanks for all the dev work!
 
I know this is climbing a mountain just because it's there but... I don't have to worry about the real boards going extinct now. Soldering the TPA3118 wasn't so hard using solder paste, a hot plate and a USB microscope.
(Updated the picture. I can't even follow my own BOM. 680nf caps on the right side.)
1701540252138.png
 
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ThePanda said:
Did you design that?

What kind of hot plate you got?
Click to expand...
There's really nothing to design. The circuit is right out of the TPA3118 datasheet. So it's just a clone of the boards we've been buying but using thru-hole components. Only did it because... Why not?

And I have a very cheap hot plate that gets too hot, so need to work fast.

FYI, a close up of the result. Just did 9 more boards all at once. This wasn't hard at all, but absolutely need a USB microscope to see the pins close up while the the solder is melted and getting it lined up. I used a toothpick to put a very little bit of solder paste along the pins and on the heat sink pad on the PCB and on the pad on the bottom of the IC. When the solder paste melts it wicks onto the pads and is ready for the IC. Then some pointy tweezers to place and nudge the IC until perfect. Same tweezers to move the board carefully up off the hot plate. After they cooled, used a tooth pick to buff off any tiny solder balls stuck around the pins.
1701561609302.png
 
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