Amp discovery!

[Kinski]

Man, back in Brooklyn. This thing sounds so damn good. Even competes with my tube amps, as much as I cringe to admit it!

[Bolsyo]

Awesome builds! Really considering building something like this. I am a bit skeptical though, how are these cheap Chinese amp-modules holding up over time? Also wondering what kinda speakers people are using, and is it 4 Ohm or 8 Ohm?

I found a version of the module where the heat-sink is screwed on, since I saw someone had problems with them delaminating. It also has a huge through-hole filter cap that I could just swap right away to some top quality brand, as long as the solder pads hold up: https://www.aliexpress.com/item/4001290053519.html

I see Pedalpcb is coming out with an amp-module I could upgrade to later. Probably higher quality, but it's using the TPA3118 version which does not have a heatsink, instead the heat is dissipated through the bottom of the chip and to the board, probably why it's also lower rated at 60W: https://www.pedalpcb.com/product/tpa3118m/

[Kinski]

Ive had no problem with these boards. And the Pedalpcb link looks like they are just stocking the same board I posted at the start of this entire thread. It’s a small 60w board not much larger than a guitar pick.

[rocket88]

Have to say, I’ve built 6 mini amps using a 100watt class d amp I posted earlier. Not one problem over the last few years. Side note, I’m running mine through a 4x12 wired for 8ohm, but will be adding a switch to make it run at 2ohm for these amps.

[Sensei Tim]

Same. I've built a few 100W versions over the years with no problems.

[Bolsyo]

Sweet, I'm going for it then! I got hold of this little tweed style combo-amp cheap as a repair object. The plan is to upgrade the speaker to 10" and rip out all electronics from the amp-chassis and see if I can reuse it to house the poweramp, a preamp or two that I can switch between, maybe an overdrive and boost, and a modded Box of Hall reverb. Would save me both a couple pedal enclosures and space on my pedalboard. Hopefully it will become an awesome practice combo-amp. If I'm not happy with it in the end, I could probably fit a small tube amp (5E1, 5E3, Madamp G3 Blues) instead.

[Kinski]

Hey, so I’m getting a loud pop out of my speakers when I turn my amp on with the recent build I posted a few weeks ago. Anyone know how to work around this without installing some complicated relays?

Can these amps be run without a speaker load? If so, perhaps I could add a “stand by” switch that connects/disconnects the speakers to avoid the pop?

[Kinski]

I think illl add that switch on the speaker outs, but add a dummy load resistor to be safe.

[Sensei Tim]

it's been a long time, but i have a vague memory of someone on a different forum (or maybe it was in some of the TI application notes for those power amps) that if you added a cap somewhere that it would eliminate the speaker pop.

I don't recall where that cap was placed - might have been on the power/ground pads or on the +/- speaker out pads.

[Kinski]

Hmmm... thanks for your response. I did find this, and seems it works with lots of 3116 designs. But I’m not sure how to add this to the blue board module I used. Anyone know?

Looks like a 1uf cap and a diode?

http://www.360customs.de/en/2015/02/tpa3132d2-einschaltverzoegerung-und-schnellabschaltung-anti-pop-auch-fuer-tpa3116-tpa3118/

[Kinski]

I meant this one found lower down on the link I posted.

[Kinski]

Well, I solved the POP issue by wiring the outputs to a switch to toggle between the speaker jack or an 8 ohm 100w resistor as a dummy load. I guess it’s kind of like a standby-by switch. Works beautifully.

[thewool]

I just wired a switch to the mute on the board. Much simpler. Although it would better to not have to put it in standby every time before turning off.

[Kinski]

The board I used does not have a mute connection. I know one of the 3116 pins is for mute but it’s hard to access the chip on this board. And it was easy to wire up the dummy resistor anyway.

And most of my tube amps have standby switches, so I’m used to flipping a 2nd switch already.

[cjonesplay]

I know I’m late to the game, but I finally got a 3118 and combined it with Ripthorn’s FB-2 preamp (a great pre btw) w/ a switchable drive channel of  Superbolt and a Condor cab sim. I used the 1032L box from Tayda and it’s not getting hot at all. I’m running 24 Volts and it’s so loud my speaker fails before I max out the volume:) There is no 60 kHz hum, either, which takes some getting used to This truly is an amazing little amp!

I fried one of these boards already bc I accidentally plugged in a reverse polarity 9v for about 20 seconds too long. These things are very fragile! I am thinking I need a couple of 5817’s in series with the power to keep this from happening again. Also, every time I plug in a little spark shoots out of the plug. I am wondering there is a way to add a resistor or cap to ground to keep this from happening every time? Anyone else experience this?