PT2399 delay with modulation - PCBs for sale

rosch · Joined: Oct 03, 2009 Posts: 165 Location: germany

thanks guys!

Taylor · Joined: Jul 13, 2006 Posts: 170 Location: us

I've received a few emails asking if these were available again.

Yes, I have Echo Base boards. They are still $14 plus shipping. I've set up a little website to make ordering really easy:

http://musicpcb.com

I'd prefer orders to be made through the site from now on, to make things easy for everybody and so I can get your boards shipped out faster.

Skrog Productions · Posted: Sun Oct 24, 2010 3:39 am Post subject:

Just ordered 2 for shipping to Scotland , yay Smile

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Dave.

inlifeindeath · Joined: Apr 02, 2010 Posts: 316 Location: Albuquerque, NM

great website! how's the octave down coming along? Sounds awesome!

Taylor · Joined: Jul 13, 2006 Posts: 170 Location: us

Thanks!

I have some prototype boards of the octave down right now; there was a tiny bit of bleed from the logic part of the board (rail to rail square waves) to the audio part of the board (that delecate guitar signal) which makes it not quite as clean as I'd like. So I'm working on a revision which decouples power and ground between the 2 sections.

But it sounds really nice and it will have several fun and useful mod options.

inlifeindeath · Joined: Apr 02, 2010 Posts: 316 Location: Albuquerque, NM

excellent, really looking forward to it! any suggestions to improve tracking on my blue box (aside from compressor / compander ideas i've found) that you may have to discovered while working on this?

Taylor · Joined: Jul 13, 2006 Posts: 170 Location: us

Uh, well mine is based on the OC-2, and it uses a special front end that basically tracks the positive and negative halves of the wave separately - this seems to help the tracking.

As far as the Blue box goes, I always figured that the funky tracking was part of the attraction. Smile

furio · Posted: Sat Apr 30, 2011 3:19 am Post subject:

Thank you so much! Yesterday I have received the PCBs. I'm missing to complete it only the transistors and one 15n capacitor.

I had only this MKT 1uF 10%: http://www.elcomp.at/shopexd.asp?id=19905

Which transistor is it better to buy and install, BC560B or BC560C?

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Taylor · Joined: Jul 13, 2006 Posts: 170 Location: us

furio · Posted: Sat Apr 30, 2011 1:06 pm Post subject:

Thanx Taylor! My little girl of eight also thank you, for the first time she has assembled a board (on the right side).

Taylor · Joined: Jul 13, 2006 Posts: 170 Location: us

Wow! I guess we can't see the solder side, but your daughter's work is cleaner than that of many adults I've seen. Very Happy

Tell her I said, "great job!"

clarke68 · Joined: Sep 10, 2009 Posts: 28 Location: Bay Area, CA

Does this project need any mods to work with synth output levels? I saw in your build document that "some builders found that the EB was distorting when using guitars with humbuckers or other hot signals".

I don't know a thing about humbuckers, but I assume that their output is next to nothing compared to a modular synth. Would your diode-lift/Humbucker-friendly mods do the trick?

Also...the Dub Madness mod looks awesome!

slacker · Posted: Thu May 05, 2011 12:56 pm Post subject:

In order to use it with synth levels you'll need to attenuate the signal down to the same sort of level as guitar. A simple voltage divider in front of the circuit will do the job, the 22k/1k values from Ken Stone's Stompbox adapter are a good starting point. http://www.cgs.synth.net/modules/cgs60_sba.html

The humbucker friendly mod is probably worth doing as well. The diode lift mod is more a matter of taste, I personally like the sound of the clipping you get from the diodes at higher feedback levels some people prefer it without.

The other thing is that the output won't be at synth levels. If the delay is the last thing in your chain and you're then going to an amp or recording device or whatever then that's probably not a problem because you can just adjust the levels to suit. If you do want to get the output back up to synth levels, then you could try increasing the 10k resistor in the feedback loop of the output stage to 220k, in theory that will boost the signal back up to the right level. Sorry I don't know which resistor that is on the layout, Taylor will know
The only problem you might have doing this is because the circuit is only running on a single supply you might run out of headroom and the opamp will clip. If this happens then try a lower resistor value. Or just build it stock and use the Stompbox adapter circuit to boost it back up.
Hope that helps Smile

clarke68 · Joined: Sep 10, 2009 Posts: 28 Location: Bay Area, CA

That does, thanks. It almost didn't occur to me to ask, since this is a synth forum and I tend to assume everything here is for synths, but I realized that the Echo Base has another family over at diystompboxes.

I actually have a couple of the CGS Stompbox Adapter boards laying around...shouldn't be hard to squeeze one in behind the panel.