Aria ADT-1 Distortion

blackboarcult · Post by **blackboarcult** » 31 Jul 2022, 19:29

And the last for Today. Boy, what an ugly-sounding one this is.
Fortunately it bears enough resemblance to, let's say, a Roland Bee Gee to be able to do some overhauling and turning it into something else than a paperweight or door stopper.
As us', unverified, checked two times but not three, etc etc.
Can't for the life of me find the bloody pics of the innards, but if anybody needs/wants 'em, I can reopen the thing and take a few shots.

Enjoy!

CheapPedalCollector · Post by **CheapPedalCollector** » 31 Jul 2022, 22:26

The clipping circuit is weird, does that even work? Seems like those would be zener diodes.

blackboarcult · Post by **blackboarcult** » 01 Aug 2022, 03:14

A similar arrangement can be seen in the Randall amps of the 80s (Rg80 etc). And they use zeners indeed. Won't be long before I gut this thing again to mod it, will have a closer look to determine diode type then

Manfred · Post by **Manfred** » 01 Aug 2022, 08:21

I found this detail photo of the PCB where you can see the clipping diodes.
My guess is that these are 2.4V or 2.7V Zeners.

: ADT-1 Detail Shot.jpg (56.83 KiB) Viewed 740 times

blackboarcult · Post by **blackboarcult** » 01 Aug 2022, 12:03

According to LtSpice, at max gain the output of the first opamp half shows around 4V for a signal input of 0.6V. Since the circuit starts clipping WAAY before cranking to max gain, your guess would make perfect sense