Powerful Pedalboard Amp in a 1590B

[Marshall Arts]

I was looking for a versatile, yet simple pedalboard amp. This one uses a TDA7266M IC and a simplified ROG Tonemender as a preamp / tone stack. Controls are Treble (bottom right), Mid (bottom left), Bass (top left) and Volume (top right). The tiny hole below the controls can be used to contol the overall preamp volume (there's a trim pot below that). The thing runs on 12 volts, but 9 volts work as well if enough current can be provided by the power supply.

Soundwise, I could not be more happy - the tonestack is effective, the overall volume is way to loud to practice.

All that in a 1590B package with top mounted jacks.




I had to bend the TDA7266M to fit in the box, which I did before soldering it on the pcb. I put a little piece of wood between the pin rows, put it in a vice and bent the plastic part back. Unfortunately, the footprint for the TDA from the internet had too tiny holes to push the pins through. They went in, but not through. Not a big deal.

I have a few PCBs left and can provide a BOM and even a drill template. PM me, if you are interested.

[danfrank]

Do you have the TDA attached to the enclosure? It needs some sort of heatsinking so it doesn't overheat

[Marshall Arts]

No... I checked it after a while of playing and could still Touch it... It's Not gering too hot, seriously.

[gordo]

That is seriously cool.

[cooder]

Awesome! It looks like you designed the board all yourself, right?
Would you share or point to a schematic for the whole circuit please? Cheers

[Marshall Arts]

Yes, I Made the Board. I will Share the circuit Anne the Layout when I'm Back in my Computer.

[cooder]

Awesome, thanks!

[Willybomb]

I'd be up for a board.  How many watts do those things generally put out?

[Marshall Arts]

Here we go:




Some more build notes, if somebody goes for a similar approach: C9 (220 uF) should better be lying, not standing for a 1590b. I had one (!) of these very low profile caps here, all the others would have been too high! I had to replace it at assembly time when the pots were already mounted. Now you know, why one of the film caps next to C6 has burn marks ;-)

Use an INSULATED output jack! Shield of the output is not GND!

As said above: Bending and mounting the TDA is a bit tricky.

[Marshall Arts]

I'd be up for a board.  How many watts do those things generally put out?

The spec sheet (https://www.mouser.de/datasheet/2/389/cd00001560-1795812.pdf) says 7 Watt. On a 1x12" speaker in a living room, you will have it on 10´o´clock (1/3 of max). I´d say it´s loud enough for an acoustic band with vocals and so, but maybe not for you next slayer rehearsal.

[Marshall Arts]

Here is everything in one PDF, including the BOM, Pitures and the build notes from this thread.

https://drive.google.com/file/d/1BVvzoLJPlCQG_DycDLihTPnHhYoCmCXr/view?usp=sharing

[cooder]

Fab, thanks so much for putting it together! Cheers!

[gordo]

You should keep the name: "Anne the Layout"

[Marshall Arts]

You should keep the name: "Anne the Layout"

Yes... Bloody German Autocorrect.

[Marshall Arts]

Enclosure painted and labelled. Sounds Better than it looks.