TPA3118 60W Power Amp Module

chromeheart said:
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 riffs
Click to expand...
Same supply to both but I have an RC filter on the preamp boards. Here's a schematic snippet of the power supply. J1 is the power coming in from the power jack and that is sent directly over to J6 to feed the power amp. R16 and C1 are the RC filter to provide clean power to the preamp circuit. About 1V is lost across R16, which doesn't matter at all.
1714004694404.png
 
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ThePanda said:
Can you modify the old board with the XLR leads?
Click to expand...
Nope. The new board has a THAT1646 chip to do the XLR driving. It's a significant circuit addition. But, there might be room to add a stand-alone balanced send using the same circuit. I've since added a ground lift switch as well. The above picture shows no ground connection to pin 1 of the XLR but had some BUZZ. Some situations need the ground and some don't. I also made a significant error in the circuit which is unsafe against phantom power. Had to add some flying bi-polar caps and 1M resistors to ground to the XLR pins. 1714003031615.png
 
Paul.Ruby said:
Nope. The new board has a THAT1646 chip to do the XLR driving. It's a significant circuit addition. But, there might be room to add a stand-alone balanced send using the same circuit. I've since added a ground lift switch as well. The above picture shows no ground connection to pin 1 of the XLR but had some BUZZ. Some situations need the ground and some don't. I also made a significant error in the circuit which is unsafe against phantom power. Had to add some flying bi-polar caps and 1M resistors to ground to the XLR pins. View attachment 73800
Click to expand...
By the way, the reason I can combine the power amp and XLR send is that I have a cab sim ahead of this built into my all-in-one preamp, which is over here:
https://forum.pedalpcb.com/threads/...absim-noise-gate-post-boost.21199/post-268081
Gotta have a cab sim ahead of any form of DI. I've found that the cab sim signal is fine for driving the power amp and real cab. Can't tell the difference with our without the cabsim ahead of the power amp, so that enabled some considerable simplification.
 
Paul.Ruby said:
By the way, the reason I can combine the power amp and XLR send is that I have a cab sim ahead of this built into my all-in-one preamp, which is over here:
https://forum.pedalpcb.com/threads/...absim-noise-gate-post-boost.21199/post-268081
Gotta have a cab sim ahead of any form of DI. I've found that the cab sim signal is fine for driving the power amp and real cab. Can't tell the difference with our without the cabsim ahead of the power amp, so that enabled some considerable simplification.
Click to expand...
This would be the schematic to make an add-on board for DI installed in an existing Volume-Only power amp build using the old board. The signal is grabbed after the first gain stage on the TL072 and then divided down to get the right level into the 1646. But, it's probably safe to go directly from the input jack to C22 without R18 and R19. This schematic is fixed to be safe if phantom power is applied. If there is interest, I might have a PCB made since I have... Many... older power amps I could stuff this in. The GND lift is not shown here. That's wired in without needing anything on the PCB.
1714066807611.png
 
Paul.Ruby said:
This would be the schematic to make an add-on board for DI installed in an existing Volume-Only power amp build using the old board. The signal is grabbed after the first gain stage on the TL072 and then divided down to get the right level into the 1646. But, it's probably safe to go directly from the input jack to C22 without R18 and R19. This schematic is fixed to be safe if phantom power is applied. If there is interest, I might have a PCB made since I have... Many... older power amps I could stuff this in. The GND lift is not shown here. That's wired in without needing anything on the PCB.
View attachment 73838
Click to expand...
Designed a PCB for an add-on DI using this schematic... 1"x1.5" Have not ordered any as yet. The annotations don't align with the above schematic. I started from scratch to do the PCB.
1714073632961.png
 
Willybomb said:
I'll grab a couple of those boards too please (shipped to Australia, if you will).
Click to expand...
Would be cheaper for you to order direct from PCBway than for me to ship to Australia. Once I've tested them, I can share the project for others to order. I'm making 2 types: single ended power supply for this add-in board and one that takes +/-15V.
 
PCBs for the small DI boards arrived. I built one of each to test and they are working fine. Two versions: Single ended power supply as an add-on to the power amps (24V); Dual supply (+/-15V). Shoot me a PM if you want one.
 
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I've shared the two versions of DI at PCBWay...

www.pcbway.com

THAT1646 Balanced XLR using singled-ended power supply (20 to 30VDC) - Share Project - PCBWay

I used this to add an XLR balanced output to my pedal-board power amp.Interactive BOM: https://paulamps.com/boms/DI%20Add-on.html
www.pcbway.com

www.pcbway.com

THAT1646 Balanced XLR using dual-ended power supply (+/-15VDC) - Share Project - PCBWay

Small balanced XLR driver that can be embedded in any project that has dual-ended power available (+/-15VDC).Interactive BOM: https://paulamps.com/boms/DI%20+-15V.html
www.pcbway.com
 
chromeheart said:
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 riffs
Click to expand...
Sorry it took so long to reply - 18v for everything. I purposely chose a preamp that could handle the higher voltage.
 
Greetings! Long time lurker first time poster here. I've been spending time on this topic for a long time. I'm ordering volume only and add-on di pcbs from PCBWay(I'm from Turkey and yeah sadly shipping rates are .. ) tomorrow. I wanted to thank you for sharing such a project @Paul.Ruby .
 
tlgcvlk said:
Greetings! Long time lurker first time poster here. I've been spending time on this topic for a long time. I'm ordering volume only and add-on di pcbs from PCBWay(I'm from Turkey and yeah sadly shipping rates are .. ) tomorrow. I wanted to thank you for sharing such a project @Paul.Ruby .
Click to expand...
You're welcome. I was in Turkey with the family last year. We stayed at a resort on the beach in Antalya.
 
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