Walco Chord and Note Sustainer build report

[RickL]

Schematic http://users.rio.com/senorris/junk/wcns.gif and layout http://users.rio.com/senorris/junk/wsusmk.gif

I appologize for not acknowledging who first posted this, all I remember are the URLs. Identify yourself so I know who to praise.  :oops:

I bought the package of Walco effects that periodically gets offered on Ebay and when I realized I had copies of the schematic and layout I had to build it to see if it sounded like the original. It does, kinda noisey but usable.

I used common-as-dirt parts for the construction: MPF 102 for the FET. 2N3904's for the low gain transistors (2SC871's) and 2N5088 for the high gain (2SC644). I also used a 1k trimmer for the 330 ohm resistor on the emitter of the first 2SC871 since I had a notation on my paper copy that it might have to be varied (from the original post?). I also added a 100k volume pot at the end after testing it and finding it quite loud. I had to twist the legs of my transistor subs to fit the layout but I can confirm that the layout works. Oh, and I used a 1M5 resistor instead of parallel 3M3's.

Varying the  trim pot seems to change either the compression amount or the attack. All the way one way I get motorboating, the other direction gives less volume but more apparent pick attack. The lower volume can be adjusted for with the added volume pot. If you build this it might be worth making the trim a panel mount pot.

If you're looking for an easy to build compressor with some noticable squash this one is worth a try.

[Fret Wire]

Thanks for the build report Rick. Does it sound similar to Tonefrenzy's clips?
http://www.tonefrenzy.com/effects/walco_chord_note_sustainer.html

I believe that schematic is by Dan N. I have the above schem., and a revised one: 6/5/04

[petemoore]

THa's a huge input resistor...perhaps that contributes to the noise...maybe a lower % tolerance R would reduce noise?

[John Egerton]

What's the best version schematic available for this?

Listening to the tonefrenzy samples this thing sounds wicked!

Thanks

John

[RickL]

I listened to the samples and that's about what the one I bought and the one I built sound like. Both of mine are noisier as the note dies off. You can hear that a bit in some of the samples but it seems to be more noticable live. An artifact of the sampling process maybe? Or the one on tonefrenzy might just be quieter than mine.

[Fret Wire]

Here's the whole lot, you can get 5 for $45
http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&category=22669&item=3752978017&rd=1

Am I right that these are new, but packaged to look like vintage effects?
I'll have to look over the revised schematic Dan posted to see the differences.

[Fret Wire]

http://diystompboxes.com/sboxforum/viewtopic.php?t=22367&highlight=walco

http://diystompboxes.com/sboxforum/viewtopic.php?t=16727&highlight=walco

[Michael Allen]

Here's the whole lot, you can get 5 for $45
http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&category=22669&item=3752978017&rd=1

I just scooped that up...

[Fret Wire]

Cool  Of course, you'll have to peek inside those things and let us know whats in there.

BTW, How's school going? Good, I hope.

[Dan N]

I did the trace and did not realize that the 3SK30A was such a weird looking object. I thought the extra leg was just a case ground. Thanks to input from the forum, we got this:
http://users.rio.com/senorris/junk/wcnsV2.gif

Sounds like a normal FET does the job. Neat about the trim pot. Panel mounting might be cool!

In the original thread I think I likened the sound of the sustainer to the sound of the beach on a windy day.

I bought the 7 Effect pack. Everything except the fuzz.

The Feedback Eliminator uses a little RTL divider IC. Should probably put that one up on blocks to see what the hell it is...

Dan

[Fret Wire]

Hi Dan, was the Feedback Eliminator just a noise gate type of effect. I'd like to hear the Sound-Go-Round, sounds cheesy enough to be interesting.

http://www.harmony-central.com/Effects/Data/Walco/

[RickL]

The Feedback Eliminator seems to be an expander. It's one way of implimenting a noise gate but it does colour the sound a bit. Single notes seem to kind of jump out.

I don't have an original Sound-Go-Round but I built one from the schematic that showed up on the net some time ago and it works about as described in the link. The schematic called CMOS echo does the same choppy trem sound although it's a different design.

If you're planning on actually using any of the originals spray the contacts of the switches and the pots with contact cleaner. I think alot of the problems described on the link were caused by dirty switches. I had the same problems with the Walcos I got and cleaning the switches solved the problems.

[Dan N]

Hi Dan, was the Feedback Eliminator just a noise gate type of effect. I'd like to hear the Sound-Go-Round, sounds cheesy enough to be interesting.

http://www.harmony-central.com/Effects/Data/Walco/

Hi, I'm not sure what the heck the feedback eliminator is. I just got my champ howling with lovely feedback, and the eliminator seems to boost the signal more than anything else. I'll draw it up and let the good folks here decide what it is. The MFC 6040 is not an easy or cheap part to find anymore.

The sound go round is really fun. It just ticks like crazy all the time.

[jmusser]

I can't really tell that this effect is doing anything! It must be very subtle. I keep hearing him play some notes, and wait for the effect to click in. It's not like I'm trying to bash the guy or expect to hear a distorted sustain. Maybe if I heard the guitar by its self first, and then the effect to have a comparison.

[RickL]

As compressors go it's pretty in-your-face, not subtle at all. You should notice it most right at the beginning of a phrase where the attack of the note sounds kind of squashed. It has a fairly long release time you won't notice it as much on the following notes.

The other thing you're listening for is the added sustain of the note. A long held note should sound the the volume isn't dropping off the way it would on an unprocessed note. You'll also hear an apparent increase in noise as the gain is increased the try to keep the volume as loud at the end of the note as it was at the beginning.

If you want to compare it to a more subtle compressor check out the Orange Squeezer.

I agree, an unprocessed signal the compare would be helpful when listening to compressor samples.

[jmusser]

I kind of "let myself in" an office here, where I could get to some good quality speakers, and yes, I can hear it now. The guitar and amp sound wonderful to start with, and with the added compression and sustain it is outstanding! Is this the kind of set up that Country music guitar players use to get the sort of pedal steel effects they get? This pedal will be a must in my arsenal, because I don't own a compressor that's of this quality, and definitely not with this type of sustain.

[wui223]

Anyone can help me figure out what to do with the FET? I cant get 3SK30.

[jmusser]

RickL said in his notes at the top of the page that he used an MPF102 for the FET. I believe that's a standard Radio Shack part.

[Zero the hero]

Rick, did you try different fets?
I don't know if this would influence the noise, but datasheet for MPF102 says that this is a "RF amplifier disigned for electronic switching"... maybe, changing the fet would improve signal to noise ratio.

[brad]

The 3SK30 is a dual gate mosfet...check it out:

http://users.rio.com/senorris/junk/wcnsV2.gif

Is it necessary?  Beats me!   :wink:  I think it's a really cool sounding effect though.