Author Topic: Yet another Aion L5 Preamp!  (Read 633 times)


  • Transistor Tickler
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Yet another Aion L5 Preamp!
« on: March 19, 2019, 11:02:28 PM »
So I'm a little late to this party, but I've been working on my Aion L5 Preamp since early January and finally finished it up last week, so here it is! This was a bear of a build, and is easily the most challenging project I've tackled to date, but I'm rather impressed by the way it turned out (which is to say, working and sounding good). That said, it's still a little temperamental- the bypass LED stayed on permanently when it was wired to the channel select switch, so I ended up going with the "always on" wiring scheme. This solved the problem, but also introduced a loud popping when the bypass is engaged or disengaged, which I can only assume is due to the LED current now being switched on and off. I also had some issues getting correct readings when it came time to calibrate it, which was probably due to my cheapo signal generator more than anything else, so I just kinda adjusted the distortion and compressor trimmers to where they sounded the best. In any case, I love the way this thing sounds! Channel 1 gives a great Fender-ish clean that takes pedals really well and livens up my rather flat-sounding Gibson G40, and Channel 2 has a great overdrive that really nails the Ty Tabor sound. The compressor is really nice as well, and the limit LED is a nice touch. Overall I'm pretty happy with it, warts and all.

Here's the guts. Not my cleanest wiring job ever, but it works and isn't overly noisy, so I'm counting this as a success. I'd definitely recommend doing what wiring you can before boxing it all up though, as the space is rather tight and trying to maneuver the wires through the holes on the underside of the board with it all in place feels rather akin to performing some delicate surgery.

Here's the board from the front with the pots installed. The 2.5kA pots I ordered from Germany never arrived after 2 months of waiting, so I improvised by adding resistors to a 5kB pot in order to fake them. It works, but the taper is a little off, so I may end up ordering a couple of 5kA dual pots and just paralleling up the sections instead.


  • Electron Doctor
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Re: Yet another Aion L5 Preamp!
« Reply #1 on: March 20, 2019, 12:08:48 AM »
This is a super sweet job! I couldn't tell that you found it a bear, going by the photographs :)

And I also love how you worked up equivalent 2.5kA pots!
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  • Electron Doctor
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Re: Yet another Aion L5 Preamp!
« Reply #2 on: March 20, 2019, 11:03:43 AM »
Looks fantastic.  Great job! 

I think if you go with a higher value on the pot you would get more of an audio taper.  I had this idea awhile back, but the circuit I tried it on had other problems and I never verified it. I'd be interested to know if you get it to work.  You could try a 10kB with a 3.3k resistor across lug 1 and 3, or a 25kB with a 2.8k resistor. 


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  • Stephan Nelson / New Zealand / Aotearoa
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Re: Yet another Aion L5 Preamp!
« Reply #3 on: March 20, 2019, 03:11:30 PM »
Excellent build, all around stunner!
BigNoise Amplification


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Re: Yet another Aion L5 Preamp!
« Reply #4 on: March 22, 2019, 03:53:53 PM »
Looks great, I had trouble calibrating the distortion myself with my phone so I adjusted it by ear.

Looks great. I wish I had used shielded cable as it does make a little noise.

Best clean sound I have heard from a preamp.

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