Aion Amethyst #2 (Boss DM-2)

[MattG]

Build Rating

5.00 star(s)

This is my second Aion Amethyst build. Here's my first.

My wife got me the MN3005 and the CT3101 from @Cabintech for Xmas. My previous build used the (much cheaper) 3205 BBD. The main reason I was interested in the more spendy 3005 BBD chip is that it can run at a higher voltage, and I wanted to see if that made any audible difference.

The build itself was unremarkable, and everything worked on first power-up. I actually had to modify my custom CMOS-based relay bypass board for this build in anticipation of running it at >9V. Since the previous build used a BBD chip that cannot run above 9V, I made my relay bypass simple, and used a 9V relay. This new build might run at higher voltages, so I had to add a 5V regulator to the design (and use a 5V relay). This is a custom bypass PCB just for the Aion Amethyst, as there are a couple circuit-level components on Aion's stock 3PDT board.

If you read my previous build report, I had some trouble getting the bias just right. Anticipating similar issues on this build, I again installed a multi-turn pot for the BIAS control. But I don't think that was necessary. I didn't attach the scope to this build, but I quickly tuned it by ear and in my opinion, sounds great. The previous build seemed to have a very small range on the BIAS pot (even the multi-turn pot) where it sounded good. This new build seems to have a pretty broad area where I sounds just fine.

I don't know what the reason is, but I'm taking it as a win. Can I hear a difference running it at 12v? Maybe? It definitely sounds absolutely great, and I might even give it the edge over my good old Boss DM-2w. I haven't yet compared it side-by-side against my original Amethyst build. But it sounded so good, I put the back cover on, added velcro, slapped it to my board, and rocked out for a while.

The finish is AliExpress mandala stickers and Envirotex resin.

Edit: See below, upon trying this pedal on another amp, I once again did encounter the noise issues I had with my previous build.

 

[Feral Feline]

Another very cool build, made all the more cooler with the custom bypass-board and associated kajiggery.

Could the easier biasing be because this one's 3005 instead of the 3205?

 

[MattG]

Another very cool build, made all the more cooler with the custom bypass-board and associated kajiggery.

Thanks! It's such a luxury to be able to have a small, custom PCB fabricated and shipped for $5 or so.

Could the easier biasing be because this one's 3005 instead of the 3205?

I honestly don't know, but that's certainly a reasonable guess. That's the only deliberate change from the previous Amethyst I built. But there were other random changes that shouldn't make a difference, primarily in capacitor chemistry.

Either way, I'm happy I didn't have to fight it to sound good!

 

[MattG]

So... turns out build #2 wasn't a simple "plug and play" calibration like I initially thought.

Tonight I plugged into my Hiwatt DR504 clone, and in the process of quick-checking my pedals, I immediately noticed Amethyst #2 sounding pretty bad. Not only was the "distortion" I described here present, but there was also an extra "beat" or "thump" present in the repeats. This is the first time I've played this pedal through that amp. previously I was playing through my Trinity Triwatt, and also a Peavey Classic 30.

My first Amethyst build was tested and calibrated through the DR504 clone from the start.

I've often heard people refer to Hiwatts as "Hi-Fi", and this experience makes me think maybe there's something to that.

I didn't have time to go through the whole calibration process again, so I'll have to circle back another time.