SolidGold FX - Electroman delay

culturejam · Post by **culturejam** » 07 Mar 2011, 20:49

Here's the marketing blurb:
http://solidgoldfx.com/pedals/electroman.php

Basically, it's a digital delay with a momentary switch that cranks the feedback, a tone control for the repeats, and it also has an effects loop on the wet signal. The loop is why I picked this one up.

I dig the sound of it. They did a good job making the repeats sound analog-ish. And of course, the loop is pretty awesome (even though it requires one of those "Y" cables to

Okay, so despite the goop, I can see two ICs, which I assume are a dual op amp for buffers and the PT2399. Do you guys think it's worth degooping and tracing this one? I think we might be able to guess exactly how it's set up.

sinner · Post by **sinner** » 07 Mar 2011, 21:00

IMO yes. Deep Blue Delay is probably also build around of this delay IC and sounds fabulous

culturejam · Post by **culturejam** » 07 Mar 2011, 21:04

sinner wrote:IMO yes. Deep Blue Delay is probably also build around of this delay IC and sounds fabulous

Damn every boutique digital delay is built around this IC. Wamper, Skreddy, Subdecay, etc.

Alright, I guess I'll fire up my goop buster and get to work. Any suggestions? It seems like the goop is slightly flexible. I have a couple old soldering irons that might help loosen up the poop.

Hides-His-Eyes · Post by **Hides-His-Eyes** » 07 Mar 2011, 21:09

Goop seems more likely to be hiding the fact it's using datasheet values than any novelty

culturejam · Post by **culturejam** » 07 Mar 2011, 21:14

Hides-His-Eyes wrote:Goop seems more likely to be hiding the fact it's using datasheet values than any novelty

Yeah, I can't imagine the actual core delay implementation is anything mind-blowing. It's the add-ons that make it a cool pedal.

The "warp" footswitch could be done on any 2399 delay, but it's cool. The tone control is worth looking at, probably.

Jack Deville · Post by **Jack Deville** » 07 Mar 2011, 22:53

culturejam wrote:
sinner wrote:IMO yes. Deep Blue Delay is probably also build around of this delay IC and sounds fabulous
Damn every boutique digital delay is built around this IC. Wamper, Skreddy, Subdecay, etc.

Alright, I guess I'll fire up my goop buster and get to work. Any suggestions? It seems like the goop is slightly flexible. I have a couple old soldering irons that might help loosen up the poop.

FWIW, the PT2399 is a nice little IC which does not require a whole hell of a lot of additional circuitry.
The datasheet gives a minimal description of the workings of the IC, there's a fair amount of data which is not detailed.
The magic of the IC lies in the designer's hands/mind. You can follow the application note, or you can get dirty.

culturejam · Post by **culturejam** » 07 Mar 2011, 23:10

Jack Deville wrote:FWIW, the PT2399 is a nice little IC which does not require a whole hell of a lot of additional circuitry.
The datasheet gives a minimal description of the workings of the IC, there's a fair amount of data which is not detailed.
The magic of the IC lies in the designer's hands/mind. You can follow the application note, or you can get dirty.

Yeah, there are a couple of in-depth threads at DIYstomp and even one or two at Circuit Workshop where people get nuts-deep in the 2399 inner workings.

Also, check out the Subdecay Echobox for a fantastic 2399.

And of course, who could forget the amazing and bedazzling Dark Echo.

culturejam · Post by **culturejam** » 14 Mar 2011, 14:35

Here's a shot of the back of the PCB

Degooping of the top side has commenced!!

///

teej212 · Post by **teej212** » 14 Mar 2011, 19:08

im interested in the effects loop. id love to be able to put a loop in one of my existing pedals.

culturejam · Post by **culturejam** » 14 Mar 2011, 19:43

Degooped!!

I only destroyed two components during the degooping: a ceramic cap and the 5v regulator. Luckily those are cheap and easy to replace.

The dual op amp is TL072. Delay IC is 2399, as expected.

There are only two op amps total (just the one dual package), so that means the loop isn't buffered or otherwise active.

///

lolbou · Post by **lolbou** » 14 Mar 2011, 19:57

I have problems seeing the traced on component side CJ. Any better lighted shot?

The caps alignment and resistors on the right of the PT2399, as well as the caps on the left and electros and regulators rings this bell : [url=http://www.tonepad.com/project.asp?id=51[/url]... A datasheet application indeed as mentionned above.

Good job on the degooping,

Did you heat the goop somehow to remove it?

Dirk_Hendrik · Post by **Dirk_Hendrik** » 14 Mar 2011, 20:02

Good job! Makes the build look a lot prettier than with all that black vomit.

culturejam · Post by **culturejam** » 14 Mar 2011, 20:06

lolbou wrote:I have problems seeing the traced on component side CJ. Any better lighted shot?

It's hard to see at almost every angle. The solder mask is very opaque. I will try some additional shots, however.

lolbou wrote:A datasheet application indeed as mentionned above.

I believe any implementation of the 2399 is going to have a similar arrangement. It's just how it works. But this one sounds really good, so something must be different about it.

lolbou wrote:Did you heat the goop somehow to remove it?

Actually, no. I used a utility knife blade (thin like a razor) to get up under the edges, and then a small pair of pliers to pull it free.

Dirk_Hendrik wrote:Good job! Makes the build look a lot prettier than with all that black vomit.

I couldn't agree more.

culturejam · Post by **culturejam** » 14 Mar 2011, 20:17

I cranked the contrast and levels in photoshop. Hopefully this makes most of the traces easier to identify.

lolbou · Post by **lolbou** » 14 Mar 2011, 21:55

Thanks for the picture CJ. Though it's still pretty difficult to see indeed... I wish I had the time to put up a multilayer file for starters...

Still I believe this is close to the Rebote 2.5 for many reasons:

- I have the Rebote and it does sound good (nothing to be impressed by when looking at the PGS video).
- The warp switch (it just shorts lug 2 and 3 of the repeat pot, am I right?) is a passive add-on and could be a mod that Francisco at tonepad could suggest.
- Part count is roughly the same. Extra parts for the electroman could be for the inserted tonestack (tweaking of the input LPF that would explain that a darker tone setting gives a later self-oscillatiion when warp is engaged?), and apart from the jack, what would you use for FX loop?

I don't know if the opamp is used for the same operations as in the Rebote (buffer and mixer if I get it right). But this would mean that the Electroman relies on CMOS output impedance for driving the FX loop (which is clever but the datasheet I have doesn't mention any value).

Now values may differ, I reckon.

ps: I tested the warp on my rebote (quick turn of the pot CW) : same stuff. Though I cannot change the tone, thus "enabling more repeats before total oscillation" as in the PGS video...

culturejam · Post by **culturejam** » 14 Mar 2011, 23:29

Hare are the values. The only one I don't know for sure is the ceramic that was wiped out during the degoop. I'm going to assume that it is between 100p and about 680p (almost definitely less than 1nF).

...

lolbou · Post by **lolbou** » 15 Mar 2011, 06:16

+1 for resistor values = a real help to me!

Have to go to work, but will check these tonight, or at lunchbreak... Sounds like these are close to the delay application of the datasheet.

culturejam · Post by **culturejam** » 15 Mar 2011, 13:20

lolbou wrote: Sounds like these are close to the delay application of the datasheet.

Yeah, I think we should be able to come up with a quick-and-dirty schematic without doing a full standard trace.

It just so happens that I had a Rebote 2 on my breadboard when I opened up the Electroman. I'm slowly changing the values over to see if I can get it close.

I think the real keys to this one, though, is the add-on features. The loop is cool as hell, tone control is nice to have, and the footswitch is handy for noise-rock guys who gig a lot.

I think the ultimate add-on for a 2399 delay, however, is some form of heavy-duty filtering or compression on the wet signal. Like a compander, or the filtering on the Echo Box.

Hides-His-Eyes · Post by **Hides-His-Eyes** » 15 Mar 2011, 14:13

Does companding a PT2399 do good things for the clock noise like an analogue delay, or is it only done for the tone it gives?

culturejam · Post by **culturejam** » 15 Mar 2011, 16:11

Hides-His-Eyes wrote:Does companding a PT2399 do good things for the clock noise like an analogue delay, or is it only done for the tone it gives?

To be honest, I'm not totally sure how much it will help overall hissy noise. I've never heard clock noise, per se, with a 2399.

I would imagine if you set up the "traditional" way (compress the signal going into the delay line, then expand it coming out) it would increase the headroom of the repeats. I'm thinking that will make it possible to get more clean delay time out of the old girl. The Echobox gets about 800ms of really clean, usable delay time. Granted, it doesn't use a compander, but I'm not sophisticated enough to set up filtering like Brian does.