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Here's a crude schematic of what I did.  Removing all components attached to both pin 6s on the zero point schematic.  Now for mine, for whatever reason, I need to put 3.6k resistors between the MCPs and pin 6s to get the tempo LED to sync up with the actual repeats.

I think you're going to have to remove the entire current mirror section, including the transistors and resistors you have highlighted in blue. 

The way I got the Taptation working with the Zero Point DD, was to hook each pt2399 pin 6 up to it's own MCP41100 and then running them in parallel into the Taptation.  I didn't experiment thoroughly with the modulation under this setup, but I did seem to have it working with two individual mod paths running from the MCPs in parallel to Taptation pin 6, being controlled at the same time with a dual pot.

I scored a copy of Television - Marquee Moon on vinyl the other day.  Now constantly being spun in my apartment.  So good.

Dear Captain Ahab,

I think the BYOC ping pong has something like this where you can switch between series and parallel dual PT2399s.  Not sure if that's what you're after.

Yes. I'm ahead of you. I had a 42100 arrive in the mail, and I'm getting close to having the time to do some testing.

Jacob

Great Jacob, glad someone with some smarts is looking into this. 

A heads up, I think I messed up my MCP42100 chip by letting the shutdown/reset pins float instead of hooking them up to the 5V.

-Jason

Is anyone familiar with using a MCP42100?  From the datasheet (http://www.mouser.com/ds/2/268/11195c-64695.pdf), it looked like it was a good solution for adding tap tempo to ZPDD, but I'm hitting a snag where the delay is stuck on medium delay regardless of delay pot or tap tempo setting.  Based on the tempo led, the taptation side is working correctly, but does not change the actual delay length.

The MCP42100 appeared to be basically the same as the MCP41100 except with a second digital pot section and reset shutdown pins.  Anways, I think the reset shutdown pins are where I'm going wrong, but I'm not sure what needs to be done to fix it.  Right now I both reset & shutdown pins connected to nothing. 

Any thoughts?

I''m not sure if you could feed it into the mirror, the taptation circuit is controlling resistance to ground basically, where the mirror is actually controlling the current into pin 6.

What I was going to try, to get tap on the ZPDD, was to omit the current mirror section and build up the taptation circuit using a MCP42100 digital pot instead of the MCP41000.

Just curious (anxious is probably more like it ) if anyone has had a chance to look into using the Taptation with the ZPDD?  I've got the Zero Point DD next up in my building queue.

Aw nuts.  I thought I could get away with using a dual-gang like this, but you're right, probably works much better on the switch.



Not that having the toggle switch is a bad thing, I just always want to turn knobs...

Hi,

Probably a silly noob question, but I was wondering if it would be possible to have the Grapevine Rock/Rawk modes on a pot (dual gang) instead of a switch.  Would it even work for sweeping between the Rock/Rawk modes? 

Any thoughts, comments, suggestions?

Thanks

Stecykmi, I checked all the grounds on the Input, Output, Vero and on the Gain pot and they were all good.  I made a stupid mistake while testing that amplified the hiss more than normal.  As Midwayfair mentioned, the little white noise comes out as you dial back on input signal, and when I was testing things out I didn't realize I already had my guitar volume pulled back some.  So the hiss was being brought out more than it normally would. 

Midwayfair, turns out you were right.  It's totally not a loud hiss when my guitar is at full volume.  It actually reminds me of the white noise from my fender champ...making the pedal even more Fender like.


Thank you both for your help.

I boxed everything up last night and I'm pretty happy with it.

Thanks.  After a bunch of debugging I'm chalking it up to the nature of how the pedal handles input signal.  I didn't think it was being affected by the gain pot, but it is.  As I turn up the gain pot the hiss gets quieter, even with no audio signal being played.  It does the same thing when I bypass the gain pot and turn down the volume pot on my guitar.

I forgot to mention that this was on old LV that I did on vero.  I think this image might clarify what I mentioned about the power to the LEDs.

Hi,

So I recently made some mods to a LaVache pedal, really I just put the gain pot on a foot switch so I could toggle between a cleaned up sound and full dirt.  The other thing I did was add two extra LED status indicators for the gain foot switch and for the boost foot switch.  For the two new LEDs I just ran two additional leads from the power rail to 4.7k resistors connected to each LED.  So in total, the pedal has 3 LEDs.  

Now I noticed that I'm getting a "ssss" sound when the pedal is engaged.  I probed around and I think I pinned down the root cause to power supply noise.  I get the same "ssss" where R3 (3k3) connects to the transistor as I do if the audio probe is connected directly to the power rail.  I checked the connections and the resistance of R3 and everything checks out normal.  

So I'm wondering if the addition of the two extra LEDs messed with the power filtering?  And if so, would changing the value of C4 or C5 fix it?

Thanks