TPA3118 60W Power Amp Module
- Thread starter falzhobel
- Start date
Paul.Ruby
Well-known member
You mean a mute switch or a power switch? My preamp boards all have some form of mute with an LED to indicate if on or off. A power switch can be added in series with the incoming power from the jack and an LED, with resistor, on the other side of the switch.
Rattle&Hum
New member
Hello all! Dropping into to thank you all (special thanks to @Willybomb and @Paul.Ruby) for all the helpful information and contribute my recent build.
My main tube-based rig is a Helix (as a pedalboard) -> Bad Cat Cub 15R head -> Matchless ESS112 (H75 Creamback-equipped). When impractical to haul the amp head, I use Matchless (and some Marshall) amp models (without IR) and the power section of a Quilter Superblock US to power the Matchless cabinet with great results. When I do run direct, the IRs I use are remarkably similar to my cabinet (York Audio Matchless IRs). From what I read on here and The Gear Page, the 3118 amps looked like a great option as a leave-in power amp for the cabinet and I couldn't be happier so far.
Notes and observations: UPDATED JUNE 5, 2025
1) With my Helix's output set to Line Level, there is PLENTY of volume on tap. It is louder than the Quilter Superblock at full voltage/volume and sounds just as good. Anyone reporting lower-than-expected volume is using the wrong input signal (level, impedance, or both), imposter 3118 board or error in their construction. I ordered mine from this seller and both boards are legit 32-pin boards.
****UPDATE: Even with the Helix at line level, there is an impedance imbalance. A buffer is still needed with a Helix or HX Stomp. I tested with a TC buffer and decided to build one into the amp.
2) I used the schematic posted earlier in this thread. I added a power switch and LED but omitted the 200nF input DC filter cap. 50K Log taper volume pot is just right. I am using a 35V 4700uF capacitor to let me safely use a 24V 3A power supply. I've used my Quilter's 24V 3A supply (reads exactly 24V output) as well as the Amazon supply (output measures 24.4V).
3) I replaced the standard 1/4" input jack of the cabinet with a shunted jack. Unplugged, the amp is directly connected to the speaker. When another amp is plugged in, the 3118 amp is disconnected automatically.
4) Hammond enclosure is 1590WXXFLBK
5) I wanted a discrete install but able to access the switches/knob easily from the front (power and standby switches are same placement and distance apart as my Bad Cat). Because the input jack is vertical, I used a PureTone jack for the extra grip/security.
6) I also built an adapter to use a standard 2.1mm 9V center-negative power supply with it - like the Quilter. Quilter claims it yields about 1W w/ 8-ohm speaker. The TPA3118 board with 9V is very similar - very usable in smaller quieter settings and more than enough juice for home practice.
Great little build that's lived up to the hype. I'm building one to install in my Suhr Bella cabinet, as well.
My main tube-based rig is a Helix (as a pedalboard) -> Bad Cat Cub 15R head -> Matchless ESS112 (H75 Creamback-equipped). When impractical to haul the amp head, I use Matchless (and some Marshall) amp models (without IR) and the power section of a Quilter Superblock US to power the Matchless cabinet with great results. When I do run direct, the IRs I use are remarkably similar to my cabinet (York Audio Matchless IRs). From what I read on here and The Gear Page, the 3118 amps looked like a great option as a leave-in power amp for the cabinet and I couldn't be happier so far.
Notes and observations: UPDATED JUNE 5, 2025
1) With my Helix's output set to Line Level, there is PLENTY of volume on tap. It is louder than the Quilter Superblock at full voltage/volume and sounds just as good. Anyone reporting lower-than-expected volume is using the wrong input signal (level, impedance, or both), imposter 3118 board or error in their construction. I ordered mine from this seller and both boards are legit 32-pin boards.
****UPDATE: Even with the Helix at line level, there is an impedance imbalance. A buffer is still needed with a Helix or HX Stomp. I tested with a TC buffer and decided to build one into the amp.
2) I used the schematic posted earlier in this thread. I added a power switch and LED but omitted the 200nF input DC filter cap. 50K Log taper volume pot is just right. I am using a 35V 4700uF capacitor to let me safely use a 24V 3A power supply. I've used my Quilter's 24V 3A supply (reads exactly 24V output) as well as the Amazon supply (output measures 24.4V).
3) I replaced the standard 1/4" input jack of the cabinet with a shunted jack. Unplugged, the amp is directly connected to the speaker. When another amp is plugged in, the 3118 amp is disconnected automatically.
4) Hammond enclosure is 1590WXXFLBK
5) I wanted a discrete install but able to access the switches/knob easily from the front (power and standby switches are same placement and distance apart as my Bad Cat). Because the input jack is vertical, I used a PureTone jack for the extra grip/security.
6) I also built an adapter to use a standard 2.1mm 9V center-negative power supply with it - like the Quilter. Quilter claims it yields about 1W w/ 8-ohm speaker. The TPA3118 board with 9V is very similar - very usable in smaller quieter settings and more than enough juice for home practice.
Great little build that's lived up to the hype. I'm building one to install in my Suhr Bella cabinet, as well.
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fopoman
New member
Awesome build!
As you noticed, supply voltages do not match, *at all*.
A voltage converter is technically possible but not practical.
Best is to repair original VOX/Silvertone/whatever power amp.
IF driver transformer goes bad , not impossible but unlikely, you can rewind it at home, it is not too complicated, or have it rewound by a skilled guy.
RG Keen is the undisputed Authority on VOX SS/Thomas amps and he kindly supplies this set of instructions:
as mentioned in the article, there are different sizes, he just shows how to make the 120W Vox Beatle one, since it works fine on smaller ones, also on Silverone, Standel, early Acoustic Control amps, etc.
As a side note, he also offers replacement power amp boards, if yours is way too damaged.
Those old warriors sound very good and deserve being repaired and used.
Congratulations on your build
You mention "board damage/destruction" elsewhere, even when using original/"good" chipamps while others (such as Paul Ruby) mention high reliability.
But now I see you apparently use a conventional "iron" supply: mains transformer (visible in pictures) > bridge? > main filter cap?
IF so, those do not offer stable regulated voltages by any means, so if you made a nominal 24V one, it will easily go above, at least for a few seconds, either at turn-on, with high mains voltage or simply when a large fridge turns OFF.
These chipamps *barely* stand 24V and anything above will nuke them.
It is not a "capacitor" problem (those stand a little extra voltage for a short time) but an chipamp "silicon" problem, which we can not solve.
Successful builders use 24V SMPS which are *tightly* regulated at 24V and some have added a series diode (1N540x for 3A, I suggest 6A2 for 6A); apparently "small" 1V or so drop seems to be the key.
I guess EI/iron transformer supplies are safe IF they aim low, say nominal 18-19Vdc, 20Vdc TOPS, so they stay in the safe zone.
19 Vdc * .707 would mean a 13.5Vac (or LOWER) transformer winding.
A 12Vac (nominal) PT would be cheap , available and safe.
They usually are wound for *more* than 12Vac, which is the full load rated voltage, at, say, 3A , so they often measure 13Vac or slightly more unloaded.
I wouldn´t go higher than that.
19Vdc notebook brick supplies are of course within the safe zone.
Again, congratulations on your build
Elijah-Baley
Active member
I have to buy a TPA3118 (the first one was a fake and I didn't try it!) but I still have any power supply 19/24v, and I don't know if or what I have to buy. I afraid about noise, of course.
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Paul.Ruby
Well-known member
I always add a 5A diode inside my amps to drop a volt and have used at least 5 different cheap 24V 2A or 3A supplies from amazon that have all been fine. That said, you must be careful with ground loops. On my real pedal board for gigs, I have a cioks DC7 and it's aux 24V output is perfect for these. If you use a separate supply, you must have exactly one earth ground path from any/all the power supplies to the board.
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Elijah-Baley
Active member
I never had a 5A diode, but I found on Musikding web site this one: SB560.
About the ground loops, you mean that I could have problem if I use the TPA3118 amp, power up with an Amazon 19-24v, with my pedalboard? Now I have just a 1-Spot as PSU, and my pedals are in daisy chain.
P.S. about the noise, of course, I think I'll use that diode in line and as filter a 470uF and in parallel a 100nF ceramic monolithic.
About the ground loops, you mean that I could have problem if I use the TPA3118 amp, power up with an Amazon 19-24v, with my pedalboard? Now I have just a 1-Spot as PSU, and my pedals are in daisy chain.
P.S. about the noise, of course, I think I'll use that diode in line and as filter a 470uF and in parallel a 100nF ceramic monolithic.
Paul.Ruby
Well-known member
I use 1N5408 soldered directly to the power jack in the amp. You can get 24V power supplies with or without an earth ground. If your power supply for the other pedals has an earth ground that is tied to the negative rail, then get a 24V supply that only uses a 2-prong plug, no earth ground. The point is it only have a single earth ground connected to the negative line of the guitar signal at your pedal board.
Elijah-Baley
Active member
My 1-Spot has an Italian plug without the central pin, so no earth ground. I see a lot of PSU 24v with Italian plug with no earth ground.
But I could prefer a PSU with German plug, pretty common in Italy, that has the two lateral "tabs" that do the earth ground.
Am I right?
But I could prefer a PSU with German plug, pretty common in Italy, that has the two lateral "tabs" that do the earth ground.
Am I right?
Paul.Ruby
Well-known member
And verify the earth ground pin on the mains is connected to the negative of the output voltage.
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aarchuleta91
New member
Any recommendations for a prebuilt preamp? I’m 3d printing a custom rack mount case to use with my band. Using with a modeler I don’t need anything other than helping shape some of the tone on the fly so I’m not glued to my modeler dialing tones in lol also any recommendations on a good internal switching power supply? This all needs to fit in a 1u chassis I do have a few old laptop power supply’s from some gaming laptops but I want less clutter in our road case. The picture is a rough design I have
Elijah-Baley
Active member
My pedal power supply 1-Spot doesn't have the earth ground, so for the TPA3118 I need a PSU with earth ground, but I can't go over this, the cheaper PSU 24v I can find on Amazon (Italy) have Italian plug with no ground, or Schuko plug with no clue about ground connection. Perhaps more of them have no ground.
