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Author Topic: Pedal into TPA3116, impedance problems?  (Read 727 times)

syndromet

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Pedal into TPA3116, impedance problems?
« on: August 14, 2019, 02:40:56 AM »
Hi guys, long time no see!

I've been playing around with tube stuff for the last few years, but I figured it was time to have some fun with SS again. I'm planning a pedal sized amp based on the TPA3116 driven by a MI Crunchbox. I'm using one of these boards for the power amp:
https://www.aliexpress.com/item/32811325655.html?spm=a2g0s.9042311.0.0.27424c4dHDFca6

When I hook the pedal straight into the power amp board I get sound, and it's nice and loud. I can hear the potensial, but the sound gets way to bassy. The crunchbox is usually a pretty trbley pedal, but when hooked up to the TPA3116 I need to turn the tone controll all the way up, and I still feel I miss a little too much treble.

The pedal has an output impedance at around 1 Kohm, and the amp board has an input imedance of 10 Kohm. Ofcource, the pedal is made to see impedances a lot higher than this, and I suspect that is why I get a lot of treble loss. What is the best way to fix this? I can't change the input impedance on the power amp without affecting the gain of the amplifier, right? And since the output of the pedal is 1 Kohm, I don't really see how a buffer can make things better?

Any Ideas to how I can make this combo work? I can already hear that it has a lot of potential..

phatt

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Re: Pedal into TPA3116, impedance problems?
« Reply #1 on: August 14, 2019, 07:56:55 PM »
It's a digital power module and most will have way tooooo much bass for guitar use.
Just insert a capacitor between the pedal and power amp to roll off some bass.
At a guess start at 22nF and then go down to 10nF,, keep trying different values until you find a balance. :tu:
Phil.