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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...

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...

By the way, In using LA2 pedals now for years live and recording, something learned is that it's fine to have the cab sim right after the dirt and prior to all the wet effects. Cab sim does not need to be at the end of the chain. I've been trying to explain this to some guitar players and they...

If I were doing this again from scratch, I would have done the frequency analysis ahead of time and probably made the cabsim a separate PCB. Although I did compare drive and clean channels behavior and tone, I didn't study the cabsim enough before doing the full builds. Then had to figure out...

Another tweak. RB16 controls the mid scoop. The original value of 51k has too much scoop. Changed to 100k. This is the full frequency comparison of real versus mine with the tweaks. Ignore the noise. Takes way too long to get the full spectrum. The real curves would be smooth. Red is real, Blue...

I've been doing a lot of ear testing and found the low end was lacking. Spent some time hacking at it but finally decided to do direct comparison of frequency response between a real LA2 pedal and mine. Lots of work comparing sub-circuits. Finally found the primary culprit. The cab sim had the...

I would strongly recommend a Picoscope. DIY scopes are very lacking and usually terrible displays, with lots of lag and poor features. Stand-alone scopes with their own screens are not needed. And really need a decent signal generator that is controlled from within the scope. For example, using...

Since I already typed this out for someone asking how to use my soft-touch code, figured I could post it public. This is for Arduino and ATtiny (or Digispark, Olimexino, etc...). Download and install Arduino from here: https://www.arduino.cc/en/software Run Arduino IDE. Go to File |...

I don't have the components to prove it but I would be surprised if below unity. It's probably higher. The signal at the FET gate is 1/3rd of the incoming signal when all the way down and I would be surprised if the gain stage is less than 3X to recover that.

Not unity gain. But might not matter if close enough? If you turn the volume all the way down, does everything work that way you want? If so, good enough. Alternatively, a tiny jfet or BJT (source or emitter follower) buffer would be very easy to add in the bypass path. I think I've seen little...

Latest version of the Volume-only Preamp adds an integrated DI. It pairs with the combo pedal posted here: https://forum.pedalpcb.com/threads/combo-build-for-pedal-board-core-pre-boost-clean-drive-channel-cabsim-noise-gate-post-boost.21199/post-268081

A couple TPA3118 Power Amps with my Volume-Only preamp and integrated DI are finished today... The combo pedal, this power amp plus a tuner and some wet effects are a complete system on a pedal board.

Yep! Modular but still custom and compact. This is what my buddy wants for his rig, right down to the satin finish instead of gloss.... He has a Fortin NATAS that might be his external drive option.

By the way, I should say... The AMT LA2 series of pedals sound great. I've compared the M2 to recent modeling pedals like the TC Ampworx 800 and V550. These old AMT analog pedals sound better compared side by side. My favorites are the M2, E2, C2 and K2, which are similar in tone but still...

FYI, I have PCB that uses an ATtiny84 to control three latching relays, has 3 inputs (for switches), 2 open collector transistor outputs (for two LEDs) and 3 latching relays. It's for a specific application but is generic enough that it can do this job. It's used in this combo build I posted...

With the bottom switch in the down position, the only option is bypass. The upper switch doesn't matter but shorts input to output in the down position.

FYI, this is the diode-lift switch to remove Octave. I wanted to see a schematic of it... https://fuzzcentral.ssguitar.com/octavia.php Looking at the wiring in post 6, this is what it does: Both switches up: FUZZ, no Octave. FS up Toggle down: FUZZ, With octave. FS down Toggle Up: Bypass. Both...

I've spent an inordinate amount of time creating a combo build with 3 footswitches in a 1590DD case. The picture tells most of the story. I'm happy to share info about it if anyone is interested... I'm wondering if anyone else has any interest in such a thing.... To make this all fit, I had to...

More info needed. Got a schematic of what you have built? I don't know how the present switching is wired, which is the starting point.