1776 Multiplex with charge/discharge trimmers

[MAO]

05/04/2016 - Verified
05/07/2016 - Try 1M2 (or 1M) for the 2M2 if detune is shallow

I added trimmers for the charge and discharge resistors. The default setting for the 1M "charging" trimmer is 1 Meg and 47k for the 100k "discharge" trimmer.  See build doc for details.

The 2k V-Adj trimmer requires precise adjusting, see build doc and video for procedure. (Note, in the video he says probe the Anode of D3, it's actually the Cathode. The build doc shows it correctly)

Build Doc

V-adj Calibration Video 

I also added optional green LEDs to improve PT2399 noise performance (thanks Jon Patton!)

The layout should fit in a 1590BB, towards the bottom with top mounted jacks and rotary switch.  Hopefully low profile stomp switches will fit under the board. If not, a 1790N will do the trick, plus the modulation add-on board would fit easily too.  

Modulation Board

NOTE: the TL072 is upside down and there are 2 10u tantalum caps. Also, I would suggest going with 2n2 for the 1n caps.

 

[notnews]

Sorry for the dumb question.. but what is the sonic function of these charge and discharge trimmers?

[MAO]

The best way I can describe them is there is a Speed switch in the circuit which is momentary stomp switch. When you hold down the switch, it bends the pitch upwards. When you release the switch, the pitch bends back down.

The trimmers should allow some adjustment as to how fast or slow the pitch bends occur.

The charging trimmer should affect the speed of the upwards pitch, and the discharge trimmer should adjust the speed of the downwards pitch.

Maybe they also affect the range of the pitch bends, I don't know, I'll report back once I have it built.

This video shows the Speed switch in action. It's the stomp switch on the left. (It looks like he has also somehow added a "Slam" switch mod, the middle stomp switch ,which causes the controlled oscillation. I may have to look into that mod!)    

[Travis]

The "slam" or oscillation switch is easy. Just a momentary footswitch (normally off) which connects lug 3 with lug 2 of the repeats pot when you hold the switch down. To take it further, you could have a variable resistor in series with the switch to have some control over the onset of oscillation. I have pretty much worn this trick out, it's lots of fun

The repeat pot setting will also interact with the momentary switch

[MAO]

Cool, thank you Travis. I'll being giving that a try for sure.

Any suggestion on the value for the variable resistor?

[Travis]

My pleasure. Hope you enjoy that trick as much as I have. Lots of people have been adding the "slam" switch but I haven't seen anyone else adding a pot in there so maybe I should have capitalized on that before sharing lol

The value of the pot depends on your taste and the circuit in question really but most likely it will fall somewhere from 10K-50K

[cjonesplay]

Thanks for another great layout for what looks like a really interesting design.

Anybody successfully build this bad boy yet? I just ordered the H11F1 and I'm hoping someone might be able to verify before I go to making a big mess.

Also Travis; thanks for the heads up on the stomp switch for oscillation. So that's how they do it! I'll be adding this to a couple of my favorite delays now:)

[MAO]

Thank you, yeah this a great delay.

I have mine 99% done, just need to hookup the pots.

Should have it fired up tonight.

[MAO]

Can't say 100% verified yet, the mode switch and controls work.

I was able to calibrate the 0.45v, but the speed switch didn't seem to be working. The LED ramps up as it should, but the resistance on H11F1 pins 4-6 doesn't change. Will get back to it asap.

But, the delay itself sounds great.

Note: apparently the input of the PT2399 will be overdriven if the voltage at pin 7 goes above 2v. That's the reason for the added green LEDs on pin 7, to keep the voltage at pin 7 below 2 volts. I mention it because on mine, the LED on the rightmost PT2399 is lighting often. Curious if anyone else experiences the same. ( I'm using a Tone Zone humbucker)

[MAO]

Still having trouble figuring this one out.

The H11F1 appears to be working properly. When I remove the PT2399 I can measure the resistance change across pins 4 and 6. When closing the speed switch, the resistance goes from 50k to 30k and returns to 50k when releasing the switch. Seems to be working as expected. But when I plug the PT2399 back in, there is no change in sound when using the switch. Can't read the resistance across pins 4 & 6 either when it's plugged in.

From what I can tell, the delay is working fine, just the speed switch is failing.  

[cjonesplay]

Thanks for all the updates, I'm still waiting for the H11F1 to come from SmallB. I wish I could wrap my head around why the PT2399 is interfering. I'll start building this week and see if I have the same trouble.

[MAO]

Yeah, I don't get it. Still no luck.

The layout appears to follow the schematic, my board appears to follow the layout. Going to give it one more look tonight.

I have to say, I'm not crazy about this layout though. I'm not sure what I was thinking with the input, output and 9v connections all at the top of the board. I must have thought it had a buffered bypass when I started the layout.

I'll probably redo the layout with better off-board connections. Hopefully in the process the speed switch will work.  

To salvage this build, I'm about to box it up without the speed switch, going to use an oscillation switch instead. The delay modes all seem to be working fine.

My apologies up front if you have the same results, but please let me know if yours works. I'd like to compare readings as what I'm seeing just doesn't make sense.  

Mike

[cjonesplay]

A new layout? Hmm... Maybe it is better to wait for this, I think. The speed switch is a really cool feature and I've never seen another vero pedal implement this before. Darn! I wish I was better at all this stuff so I could verify, but I can barely get the effects like this working as it is. This is a head-scratcher:)

On Mon, May 2, 2016 at 11:51 AM, MAO Pedals [via Guitar FX Layouts] <[hidden email]> wrote:

Yeah, I don't get it. Still no luck.

The layout appears to follow the schematic, my board appears to follow the layout. Going to giv it one more look tonight.

I have to say, I'm not crazy about this layout though. I'm not sure what I was thinking with the input, output and 9v connections all at the top of the board. I must have thought is had a buffered bypass.

I'll probably redo the layout with better off-board connections. Hopefully in the process the speed switch will work.  

To salvage this build, I'm about to box it up without the speed switch, going to use an oscillation switch instead. The delay modes all seem to be working fine.

My apologies up front if you have the same results, but please let me know if yours works. I'd like to compare readings as what I'm seeing just doesn't make sense.  

Mike

1978 Gibson Les Paul Standard, Cherry Sunburst, Nickel Tone Zone & Air Zone Pickups, Russian Oil Filled Caps, 50s Style Modified Jimmy Page Wiring.

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NAML

[MAO]

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[MAO]

Verified!

I was lucky enough to borrow a pcb version I had made for a guy. Turns out the voltage and resistance readings were nearly identical.

I then swapped out the H11F1s, and the speed switch on my vero started working and the pcb version stopped working.

I had purchased 10 of the H11F1s from 1776 effects, not sure why they won't work in either build.

I sent a note to Josh, I'll report back on the response.

But go ahead and build it, it works as long as you have a good H11F1.

[cjonesplay]

Wow, that is really strange. I will remark that SmallBear's H11F1's are white in color and that's the ones I have so I'll give it a try this weekend. Thanks so much for the follow-ups, I can't wait to build this one!

On Wed, May 4, 2016 at 9:02 PM, MAO Pedals [via Guitar FX Layouts] <[hidden email]> wrote:

Verified!

I was lucky enough to borrow a pcb version I had made for a guy. Turns out the voltage and resistance readings were nearly identical.

I then swapped out the H11F1s, and the speed switch on my vero started working and the pcb version stopped working.

I had purchased 10 of the H11F1s from 1776 effects, not sure why they won't work in either build.

I send a note to Josh, I'll report back on the response.

But go ahead and build it, it works as long as you have a good H11F1.

1978 Gibson Les Paul Standard, Cherry Sunburst, Nickel Tone Zone & Air Zone Pickups, Russian Oil Filled Caps, 50s Style Modified Jimmy Page Wiring.

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NAML

[MAO]

Cool, let me know.

The white one worked for me, the blacks did not.

[cjonesplay]

Got the rest of the parts yesterday and I can verify that this build works properly. Here are my notes:

I may switch out the 2.2n caps for 1.5n as this went a little dark for my tastes and the feedback pot goes into oscillation a little too quickly. Sacrilege, I know, but I am adding Travis's oscillation switch so that's gonna cover it.

The white H11F1's from Smallbear worked great. The counterclockwise positions on the ramp up/down pots seems to get the fastest/longest sweeps, but I'm still playing w those. Combined with the instant oscillation switch this gets new sounds that I've not heard before!

I'm going to build up the modulation daughterboard ASAP and turn this thing into a deluxe Millenium Falcon Delay! Seriously one of the coolest vero builds I've done in a while and super easy to build thanks to your great layout! I think this belongs on the official site - it's that good!

Thanks for the layout, MAO. It will fit into a 1590BB as-is but since I'm going deluxe I'll save myself the headache and use the larger box you described. Bravo!!!

[MAO]

Nice!

Josh as 1776 was able to reproduce the same issue I was having with the black H11F1. For whatever reason, this batch of Black H11F1s have a slower response than the original White ones.

The solution is easy, dial back the 100k trimmer to 33k ish. Replace the 2M2 with a 1M2 (or 1M) and dial back the 1M trimmer to 500k ish. (This simulates 33k for R33 and 1M5 for R31)

Mine is now working as the original pcb version. Thanks Josh!!!

I would suggest replacing the 2M2 with a 1M2 or 1M even if you have the white H11F1, this may allow for better tweaking.  

[MAO]

Hang on before you box it, I have a few ideas for a 1590BB.

Stay tuned....