[sdiy] [AH] Custom ARP Avatar

[Tim Parkhurst]

Okay, one more and I'll let this thread rest.

Double up on input/mixer pots:
1. Remove the stock slider. They face upwards and are not sealed, so even
new ones will eventually get dirty and scratchy and fail.
2. Use a punch or a reamer to put two holes in the existing slider slot.
Put a nice, sealed rotary pot into each of those holes. I don't recommend
using a drill here because it will get caught in the slot too easily. Leave
enough room for knobs, and the other nearby panel controls.
3. Remove the selection switch below each slider and replace it with a 1/8"
switching phone jack.
4. Wire the upper pot to the existing input mix resistor. Wire the
switching jack and the lower pot to a new input mix resistor.

In this setup, the upper pot controls the signal that would normally be
routed from the upper position of the (now removed) selection switch. The
output from this pot goes into the existing resistor on the input mixer.
The signal that used to come from the lower position of the selection
switch goes through the switching jack, to the lower pot, and then to a new
input mixing resistor. The switching jack allows you to patch in something
else besides what would normally be the second selection switch input. Now
you've got a much wider range of modulation and audio inputs. For example,
on the VCF input mixer, you can now add a variable amount of the saw AND
pulse waves from each VCO. The same thing applies to the VCO FM, S/H input,
and VCF FM inputs. You might want to use a piece of perf board under each
set of pots to make the wiring for the new pots and input resistors a
little neater. You'll want to stagger the positions of the pots, or use
smaller pots so that they fit properly next to each other on the panel.

Oh, and one other easy mod would be some range switches for the internal
LFO and envelope gens.

Okay, I'm done now.

Tim (so many inputs, so little time) Servo
---
"Imagination is more important than knowledge." - Albert Einstein





On Sat, Mar 22, 2025 at 11:17 PM Rob Secret <rob at secret-secret.com> wrote:

> The Avatar was my second synth. I only had it and the Xpander. No
> keyboards! I did auto players and controlled the avatar with an electric
> mandolin (I didn’t have a guitar). With this set up I think I was the first
> to do a midi mandolin. :P
>
> The Avatars are very interesting synths to be sure, even though they are
> basically just an Odyssey.
>
> To me the coolest thing about the Avatar was its Hex Fuzz. Nothing sounds
> like that, well maybe the Rolands did, but that sound is really cool. You
> can play more than just 5ths with a very warm tone.
>
> Synth wise I no longer have the Avatar thanks to a very aggressive evil
> landlord, but like you Ben I’m going down the bARP rabbit hole. I have some
> of the 2500 modules, with a bunch more on order (waiting for them to make
> it through the backorder experience). I also got two of the bARP 2600’s
> (Brown and Blue). But in addition to this I picked up the Korg 2600m and
> Korg Odyssey desktop module. The thought process being that the desktop
> could replace the Avatar. It sort of does, but of course without the Hex
> fuzz.
>
> Back when I had the Avatar I seriously considered doing mods like these.
> Today though I don’t know if I would. Now that there are bARP modules, and
> Odyssey clones I don’t think I would do it. But every time I see a modded
> one, even with poor mods, I get excited by the possibilities! It does look
> like a lot of fun!
>
> -Rob-
>
>
>
> On Mar 22, 2025, at 2:39 PM, Ben Stuyts <ben at stuyts.nl> wrote:
>
>
> On 22 Mar 2025, at 20:39, Michael E Caloroso <mec.forumreader at gmail.com>
> wrote:
>
> > I have a stock (working) Avatar here. Can you tell me more about the
> mods you are doing?
>
> Preliminary plans here
> http://www.analoguediehard.com/studio/keyboards/arp_avatar/index.html
>
>
> Ooh, that’s a nice writeup. Thanks for that!
>
> Some years ago I wanted to do lots of mods too but never got around to it.
> I recently acquired a bunch of Barp 2500 modules. These are quite nice
> reproductions (although Eurorack is not my fav. format, too small).
> Together with the Barp 2600 already here, it’s a bit of a mini 2500. This
> renewed my interest in modding the Avatar, but probably less extensive. It
> definitely needs additional patch points, so that is probably going to be
> my main focus.
>
> Ben
>
>
>
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