TPA3118 60W Power Amp Module

[Mike McLane]

Thx! Actually I was going to make up the Simple JFET Buffer off of PPCB rather that an IC based circuit (unless somebody has a reason to go with the IC based solution). I was most curious about a) ID'ing the right voltage regulator and b) the calrifying the caps linking the pins on it. The cap btw pins 2 & 3 is 100u, but I can't make out the value of the one btw pins 1 & 2. Pls clarify.

 

[Willybomb]

Thx! Actually I was going to make up the Simple JFET Buffer off of PPCB rather that an IC based circuit (unless somebody has a reason to go with the IC based solution). I was most curious about a) ID'ing the right voltage regulator and b) the calrifying the caps linking the pins on it. The cap btw pins 2 & 3 is 100u, but I can't make out the value of the one btw pins 1 & 2. Pls clarify.

On the regulator? 330n between pins 1 + 2. 100n between 2 + 3.

I used an IC buffer as I could use the 2 sections in a TL072. The current amp I'm building has a TL074 as a 3 way splitter, and a separate buffer. It splits to the (external) amp, cabsim and XLR driver, plus a send/return for the volume control. It's not labelled yet, but it works.

I'm using the schematic here for my buffers

Buffered Y Splitter Stripboard Veroboard

Electronics Projects For Hobbyists Makers And Hackers With Stripboard Layouts

paulinthelab.blogspot.com

 

[devito]

Been 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!



Two big switches are power (left) and mute (right). Mute just disconnects the two mute pads from the TPA3118 module.



Top switch is an FX loop that is bypassed when the switch is down or when there is nothing plugged in.



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.

 

[Robert]

Been following this thread for a while so I thought I would post my test results as well!

That looks and sounds awesome.

 

[devito]

That looks and sounds awesome.

From the horse's mouth! Thank you. All my creations are made in honor of your hard work!

 

[Willybomb]

Ok, so I get a few stupid pedal ideas occasionally and things like this happen:

- Direct (buffered) pass through to normal amp.
- Larts Simple Cabsim to THCustoms Linedriver XLR
- TPA3118 output.

The volume knob only affects the TPA3118. The guitar signal is split using the vero layout I posted above.

Guitar output goes to Buffer A input, Output 1 goes to Volume 1, Output 2 goes to the Cabsim, output 3 goes to the passthrough output.
Buffer B Input is used for the volume knob return (pin 2), Buffer B Out goes to the TPA. Volume pin3 goes to ground.

 

[Mike McLane]

Willy - I built the attached and am wondering where/how to insert the PPCB JFET buffer. I assume either immediately upstream or downstream of the 220n cap/volume pot. Pull power directly off of the DC jack into the 7809 assembly then to the buffer? Any feedback would be appreciated. . . . FROM ANYBODY!?!?!? Hells bells, if somebody could draw a schematic that incorporates the voltage regulator and buffer into this mess it would be HUGELY appreciated.

 

[Willybomb]

I don't *know* that it matters where the buffer goes as the amp works properly with a buffered pedal in front of it but I would certainly put one between the volume pot and the amp at a minimum. I just put a buffer on either side of the volume pot to make sure the pot doesn't interfere with anything other than the level going into the amp.

This is the schematic I used with the 100lolwhaats and forms the basis of what I did in the post above.

The buffers I use are basically the ones shown here: https://paulinthelab.blogspot.com/2012/04/buffered-y-splitter-veroboard.html or as in the next pic.

You just run the 24v to pin 1 of the 7809, and to the +ve of the 3118.

I've also just had a couple of 24v@5A power supplies arrive, so that should be fun...

 

[Elijah-Baley]

The newx year I want to buy a TPA3118. I looked at that for a long time.
To make it sounds good and reasonably loud I hoped it was enough put in front of it a kind of preamp like Dr. Boogie or Tight Metal, or something less distorted like a Guv'Nor or a Bluesbreaker. And of course a clean preamp like the Tonemender or a simple Fetzer Valve.
I have still understand well the Willybomb's buffer story.

In this moment I have just a cheap homemade 1x8 cab with a cheap guitar speaker 15w 8 Ohm. But I guess that is too little for the TPA3118.
Could I use the one of both the 12" speakers of my amp with a flying connection?

 

[Willybomb]

The newx year I want to buy a TPA3118. I looked at that for a long time.
To make it sounds good and reasonably loud I hoped it was enough put in front of it a kind of preamp like Dr. Boogie or Tight Metal, or something less distorted like a Guv'Nor or a Bluesbreaker. And of course a clean preamp like the Tonemender or a simple Fetzer Valve.
I have still understand well the Willybomb's buffer story.

In this moment I have just a cheap homemade 1x8 cab with a cheap guitar speaker 15w 8 Ohm. But I guess that is too little for the TPA3118.
Could I use the one of both the 12" speakers of my amp with a flying connection?

It'll push the 15w@8ohm without issue and you can fly a speaker to it, just don't run it into the amp itself. The 4x12 cab in the video I'm playing the TPA3118 into measured 15ohms, and the wedge I test on at home is 10ohm (12inch woofer + tweeter). I haven't opened it up fully but it keeps up with bass, acoustic drums, and vocals without issue.

 

[PBWilson1970]

The layout posted above looks very do-able and I've got a few extra enclosures laying around...

I'm planning on building a JHS Little Black Buffer clone or possibly a dual one to put near the front and also at the end of my signal chain so I guess I'll be covered.

As people build these, I'd love to know what preamps you'll be using. Within the next few weeks I oughta have a handful finished and ready to try out. So far I've got an Alembic F-1X, Intersound IVP, Acoustic 360+ and a few other amp-in-a-box circuits in the works.

 

[Elijah-Baley]

It'll push the 15w@8ohm without issue and you can fly a speaker to it, just don't run it into the amp itself. The 4x12 cab in the video I'm playing the TPA3118 into measured 15ohms, and the wedge I test on at home is 10ohm (12inch woofer + tweeter). I haven't opened it up fully but it keeps up with bass, acoustic drums, and vocals without issue.

But, if I supply the TPA3118 at 18v (and that could be even something more) it should be over 15w output power, isn't it? I thought it was a problem for the 15w speaker.
I want to be very careful with it, because the speaker it's very low cost and the cabinet it's just a wood box I found. If I ruin the speaker I can't and I don't want to replace it with another expensive speaker and put it into a box of wood that is not a real cabinet.
I use this cabinet just to play with some mini 9v amp like LM386 or similar.

Once I clarified this, I'm still worry about the PSU I can use with this amp. I don't have any laptop power supply, I have to buy it, probably I can find it only new. I'm thinking to buy it from ebay or amazon in EU.
Do you can advice some tested models that will work fine? I afraid to buy and find it noisy and useless.

 

[Willybomb]

But, if I supply the TPA3118 at 18v (and that could be even something more) it should be over 15w output power, isn't it? I thought it was a problem for the 15w speaker.
I want to be very careful with it, because the speaker it's very low cost and the cabinet it's just a wood box I found. If I ruin the speaker I can't and I don't want to replace it with another expensive speaker and put it into a box of wood that is not a real cabinet.
I use this cabinet just to play with some mini 9v amp like LM386 or similar.

Once I clarified this, I'm still worry about the PSU I can use with this amp. I don't have any laptop power supply, I have to buy it, probably I can find it only new. I'm thinking to buy it from ebay or amazon in EU.
Do you can advice some tested models that will work fine? I afraid to buy and find it noisy and useless.

My understanding is that you want your amp to have more headroom that the speaker so the speaker doesn't get a squarewave sent to it. You'll be able to try it out carefully as I was initially testing these on some little stereospeakers.

As far as powersupplies are concerned, I've picked a few up from the local "tip shop", mostly [email protected], cutting the jack off and replacing with a 2.1mm wired for center negative. They work fine. I have picked up two of these 24v@5A just the other day so I can get the max out of the boards I have. I've been in covid isolation this week so I haven't put the new jacks on them to try them out.

DC 24V 2.5A 3A 4A 5A 6A Transformer Power Supply Adapter For LED Strip 5.5x2.5mm | eBay

3.24V 4A (96W). 2.24V 3A (72W). 24V 6A(144W). 4.24V 5A (120W). So, 24V 6A power adapter Support the LED Strip(60LEDs/m, 0.2W/LED) Length (Max)=12m to 15m light. Strong built for heavy duty and long usage performance.

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The layout posted above looks very do-able and I've got a few extra enclosures laying around...

I'm planning on building a JHS Little Black Buffer clone or possibly a dual one to put near the front and also at the end of my signal chain so I guess I'll be covered.

As people build these, I'd love to know what preamps you'll be using. Within the next few weeks I oughta have a handful finished and ready to try out. So far I've got an Alembic F-1X, Intersound IVP, Acoustic 360+ and a few other amp-in-a-box circuits in the works.

I've got a couple of Effectslayouts' JC-120 preamp clones that I'm going to pair up with a Freedman Supreme from Pcbmania in a DD, switching between the two. I've also got a couple of M800 pcbs in the cart here to try out, again swapping between the two.

I'm currently running a Mooer Preamp Live into these amps.

 

[Elijah-Baley]

Thanks for your reply.

I have two question: one about the speaker, seen the higher wattage I could get with this amp than my 1w - 2w amps I built until now; and another one about a good and right PSU to use with it, being laptop PSU are not made for audio application, though volts and amperes are often more than good.

Maybe it's something I still don't know, but I thought that if I use a 60w amp with a 15w speaker, the speaker can't resist to the power of the amp and I will damage it. Am I wrong? I have a pair of tv speaker 8 Ohm 30w, and my amp is a 120w with two 12" speaker 8 Ohm (individually), I can't read anything about the wattage, but the amp is 120w, and those works in parallel and are ok, of course.

About the headroom, I think it depends from the voltage of the PSU. The laptop type PSU are the better thing we could use with this amp, I assume. At least 2.5A, better 3A or over. And 18v at least, but often it has around 19v, that is good enough. I guess with a 24v I'll get even more headroom, I mean more watt, so more volume and less distortion. If I have to replace the plug and/or invert the polarity I can do it, I'd buy the PSU for that, so no problem with it, I guess.

About the preamp I'm not too much worried about it. I want to make some experiment and I think I'll build this amp stand alone to try it with the pedals I can use as preamp, in this way I can supply the parts individually without power/voltage issue.
Later, who knows, I could build a dual channel preamps + amp, all in one. It's a thing I tried to do in the past with a about 5w amp DIY, but I'm stuck because the PSU.

 

[Willybomb]

Well, I've hit a roadbump. My 9v regulator is getting blown when I swap in the 24v PS. Not sure what's going on there. Not an issue on a straight amp build as the buffer circuit can take 24v, but I'm not sure the other circuits in my 60watt build can (the cabsim and xlr driver). Certainly, when I hooked everything up to the straight 24v it started smelling a bit bad...

 

[Elijah-Baley]

Is the 7809 was hot? Maybe it need an heatsink at higher voltage?
Not sure, but... what about the current consumption? At 24v you need too much ampere for the 7809?

 

[zgrav]

Thanks for your reply.

I have two question: one about the speaker, seen the higher wattage I could get with this amp than my 1w - 2w amps I built until now; and another one about a good and right PSU to use with it, being laptop PSU are not made for audio application, though volts and amperes are often more than good.

Maybe it's something I still don't know, but I thought that if I use a 60w amp with a 15w speaker, the speaker can't resist to the power of the amp and I will damage it. Am I wrong? I have a pair of tv speaker 8 Ohm 30w, and my amp is a 120w with two 12" speaker 8 Ohm (individually), I can't read anything about the wattage, but the amp is 120w, and those works in parallel and are ok, of course.

About the headroom, I think it depends from the voltage of the PSU. The laptop type PSU are the better thing we could use with this amp, I assume. At least 2.5A, better 3A or over. And 18v at least, but often it has around 19v, that is good enough. I guess with a 24v I'll get even more headroom, I mean more watt, so more volume and less distortion. If I have to replace the plug and/or invert the polarity I can do it, I'd buy the PSU for that, so no problem with it, I guess.

About the preamp I'm not too much worried about it. I want to make some experiment and I think I'll build this amp stand alone to try it with the pedals I can use as preamp, in this way I can supply the parts individually without power/voltage issue.
Later, who knows, I could build a dual channel preamps + amp, all in one. It's a thing I tried to do in the past with a about 5w amp DIY, but I'm stuck because the PSU.

The amp works fine with a lower voltage power supply -- even 9 volts. It just puts out less power, which may not be a problem if you are planning to use it with a speaker rated at 15 watts. 12 volt power supplies that run at up to 2 amps would be worth considering. cheaper, less strain on the amp, and less likely to damage your speaker.

 

[zgrav]

Well, I've hit a roadbump. My 9v regulator is getting blown when I swap in the 24v PS. Not sure what's going on there. Not an issue on a straight amp build as the buffer circuit can take 24v, but I'm not sure the other circuits in my 60watt build can (the cabsim and xlr driver). Certainly, when I hooked everything up to the straight 24v it started smelling a bit bad...

A heat sink is required when you are pushing the regulator near its maximum limit. The datasheet suggests it can take 35V but the electrical characteristics list 25V as the max. A 24V I would recommend a heat sink and thermal paste between the regulator and heat sink. Maybe consider running the voltage to the regulator through a couple of diodes first to lower the voltage.

 

[Willybomb]

A heat sink is required when you are pushing the regulator near its maximum limit. The datasheet suggests it can take 35V but the electrical characteristics list 25V as the max. A 24V I would recommend a heat sink and thermal paste between the regulator and heat sink. Maybe consider running the voltage to the regulator through a couple of diodes first to lower the voltage.

Good points. I'll try that.

 

[Elijah-Baley]

The amp works fine with a lower voltage power supply -- even 9 volts. It just puts out less power, which may not be a problem if you are planning to use it with a speaker rated at 15 watts. 12 volt power supplies that run at up to 2 amps would be worth considering. cheaper, less strain on the amp, and less likely to damage your speaker.

My only 9v PSU is an old Boss red label, but it's only 300mA. Is the TPA3118 max current draw 50mA? I'm not sure.
To get 12v I should use extra circuits or I have to buy a 12v PSU, but in this case I prefer to buy a 19v laptop PSU. I prefer higher wattage to benefit better the amp.

My speakers:
Cheap Speaker 8" - 8 Ohm - 15w into a wood box.
Marshall Speaker 8" - 4 Ohm - 30w in a small guitar amp.
Crate Speaker 12" - 8 Ohm - ?w (the amp is 120w solid state, so I think it's over 50-60w).
or
two Crate Speaker 12" - 8 Ohm - ?w in parallel 4 Ohm.

With 8 Ohm speaker I can get:
At 9v about 5w.
At 12 about 8w.
At 19v over 20w. (Not for Cheap Speaker).

With 4 Ohm speaker I can get:
At 9v about 8w.
At 12 over 15w.
At 19v over 35w. (Not for Marshall Speaker).

Conclusion, the 19v PSU it will be ok just with the Crate Speaker.