Extremely high output on an Aion preamp

[hereonmars]

Hi everyone,

I've lurked a bit and this forum seems great. I'm about to build the EMU amp sim, and have built the pedalPCB rectifier distortion, very stoked.

My question is about a build I just completed - the Aion FX L5 Drive channel preamp. It sounds awesome, but the output is so loud it clips the input of my tonex, which is set to zero. This happens even at 10 o'clock on the pedals master volume. Granted, I had to use a linear taper 25k pot bc I couldn't source the audio taper. I know that would help, but it still seems odd that it would be so loud with the knob this low, even on the linear pot.

Before I go into trouble shooting mode to figure this out (which I'm still VERY green at), would a possible solution be to change the value of the pot, or to wire a resistor in series on the output jack to lower it? Hopefully this falls under 'no stupid questions.'

Thanks for your time
Mars

 

[pricklyrobot]

As the chart illustrates, you need a Log (A) pot. The human ear perceives changes in volume in a very non-linear fashion. And the taper of the A-pot is designed with that in mind.

If you can’t find an A25k anywhere, a different value A-pot would probably work better than B25k or any other value B-pot.

There might be something else going on, but I’d definitely start with a pot swap

 

[Bio77]

That pre-amp is loud by design. You can plug it into the effects loop of your amp and only use the power section.

 

[jwin615]

Reread the last line of the Compressor/limiter trimmer setup in the build doc and see if that helps.

 

[hereonmars]

Reread the last line of the Compressor/limiter trimmer setup in the build doc and see if that helps.

I did see that and if I engage the limiter it seems to keep it at a reasonable volume, not sure how it impacts the tone just get. Gonna play more with it.

 

[hereonmars]

That pre-amp is loud by design. You can plug it into the effects loop of your amp and only use the power section.

I think I will definitely do this and at least make a capture for the tonex using my JCM800.

 

[hereonmars]

View attachment 76801
As the chart illustrates, you need a Log (A) pot. The human ear perceives changes in volume in a very non-linear fashion. And the taper of the A-pot is designed with that in mind.

If you can’t find an A25k anywhere, a different value A-pot would probably work better than B25k or any other value B-pot.

There might be something else going on, but I’d definitely start with a pot swap

Thanks so much. even tho I'd looked at those curves before, seeing them again does make me realize what a huge difference it is.

I found a couple 25kA from Small Bear.