The 1590B warning... Don't threaten me with a good time lolBuild doc updated with a page of links to various parts...
TMB and Volume Only PCBs - Google Drive
drive.google.com
The 1590B warning... Don't threaten me with a good time lolBuild doc updated with a page of links to various parts...
TMB and Volume Only PCBs - Google Drive
drive.google.com
By the way, I'm willing to sell some of these, too, but it's kinda pointless with the real ones still available for cheap. I've already soldered the 3118 on all 10 of them. I would have to sell each for $6 as they are (no other components), which is already the same price the real ones. So, this would only be for folks that really want to build the whole deal themselves (like me). I'm wondering if it's worth designing an all-in-one board with preamp and 3118 but the board-sandwich method works really well and makes great use of space in the 125B.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.
View attachment 62124
Certainly not. The first op-amp stage has a voltage gain of about 9X to get instrument level up to line level into the EQ, which has a significant attenuation. Should not be anywhere near clipping. What signal level are you feeding in?I'm running the circuit from post #161 - the TMB. Is it expected that each half of the opamp clips and introduces significant distortion? Powering mine with 23V+. 1in+ and 2in+ are both at 1/2VCC. I've soldered onto perfboard and breadboarded it. From most of what I understand is that this should be mostly a clean power amp.
Something is wrong with your circuit. My guess is at least one of the op amps has the wrong (or missing) feedback resistors to set the gain. It should not have enough gain to do this.Update, tried another 3118 module., one of the ones with "35v" caps and no mute pad. No problems. It gets a bit of mild clipping when running at very high volumes through my 16ohm speaker. Not really sure what was going on there. Maybe an input gain knob would help to limit some high volume clipping
hi friend, sorry to call you back after years have passed. im wanting to build something very similar and i really liked your approach, very simple and effective. i was wondering, did you use a regulator for the preamp power supply or did you feed it 18v same as the power amp? thanks a lot keep it rocckin lml siick riffsBeen following this thread for a while so I thought I would post my test results as well! I decided to go full-bore and make a little amp in the box with the PedalPCB Valhalla Distortion (based off the Diezel VH4 preamp pedal).
Took a few days and a lot of planning - I added a switchable FX loop as well and wanted the volume/presence/depth knobs all in different locations. But everything turned out really well! Using a 18v 3.5 amp power supply I got off Amazon. Center positive!
The result: Very impressed... it is insanely loud! Amazing we have come this far in technology... A cheap and easy to use module!
There was someone saying they were unsure if this could keep up with a drummer and to them I say... you are either crazy or you have to put a stronger preamp in front. It is deafening and I have 100 watt tube amps to compare it to. Without my attenuation I couldn't even get it to 1/5th of the way up. Even with earplugs, I couldn't go past halfway because I was worried my paint would start to peel and the people in the next town over might hear.
I think I will switch the output to be the line out pad instead of dedicated output for going to a power amp (see the Valhalla Distortion schematic to know what Im talking about) because the volume is really just too much. I intend for this to be a practice amp with a 1x12 cab I'm building.
All in all, a really easy way to have a great versatile amp. Can't wait to build more!
View attachment 19853
Two big switches are power (left) and mute (right). Mute just disconnects the two mute pads from the TPA3118 module.
View attachment 19854
Top switch is an FX loop that is bypassed when the switch is down or when there is nothing plugged in.
View attachment 19855
She lives!
Sound test!!!! Don't judge the playing too much. First sound is NON-attenuated at 1/6th of the volume or so and then I attenuate the signal with the Two Notes Torpedo Captor X at -20db. Thank goodness, because it is still loud as hell! Sorry the first still in the video is upside down haha.