Magnetron + tap + tails

[Blaise]

Hi,

I am working on a modified Magnetron delay using the electric canary bontempo daughter board https://electric-canary.com/bontempo.html to add tap tempo.
My plan is to remove R2 and C2 of the bontempo, connect R11 pin 2 from Magnetron to the G pin of Q1 in bontempo and pin7 of the bontempo MCP41100 to pin 6 of the 2399 of the magnetron.

Assuming that this all works, how would I add tails (I am fine with sacrifying true bypass if necessary)? I am looking at the schematic of the iridescent delay from electric canary but quite don't understand how the tails part works.

 

[Feral Feline]

It's my understanding that you can't have trails without it being buffered.

There are pedals that can be switchable, ie both buffered or unbuffered, but turning off the buffer for true bypass turns off the trails, too.
When you want tails, buffering is necessary.


Looking at the Iridescent Delay schematic, I'm guessing the buffer (IC2B) is only in the signal path when the delay itself is bypassed;
Q2 is part of the bypass, but I don't understand this type of bypass well enough to truly understand what's going on. Doesn't matter since you're wiring up a Magnetron.

I've got the old Magnetron, doc from 2018 — R11 is very different than the 2022 Magnetron doc.


I don't understand why you're connecting Magnetron's R11 Pin2 to Bontempo's Q1 Gate. If I understand correctly, you're retaining the Magnetron's TIME pot, but it's redundant once you connect the Bontempo to Magnetron's PT2399-Pin6.

I would think everything on the Magnetron that's connected to its Pin6 can be ditched and just the Bontempo hooked up to the Magnetron's pad1 of TIME, because the Bontempo takes over the TIME, SPEED and DEPTH controls and associated circuitry.


As for the bypass, I'd use PedalPCB's C-BUFFER.

 

[Blaise]

It's my understanding that you can't have trails without it being buffered.

There are pedals that can be switchable, ie both buffered or unbuffered, but turning off the buffer for true bypass turns off the trails, too.
When you want tails, buffering is necessary.


Looking at the Iridescent Delay schematic, I'm guessing the buffer (IC2B) is only in the signal path when the delay itself is bypassed;
Q2 is part of the bypass, but I don't understand this type of bypass well enough to truly understand what's going on. Doesn't matter since you're wiring up a Magnetron.

I've got the old Magnetron, doc from 2018 — R11 is very different than the 2022 Magnetron doc.


I don't understand why you're connecting Magnetron's R11 Pin2 to Bontempo's Q1 Gate. If I understand correctly, you're retaining the Magnetron's TIME pot, but it's redundant once you connect the Bontempo to Magnetron's PT2399-Pin6.

I would think everything on the Magnetron that's connected to its Pin6 can be ditched and just the Bontempo hooked up to the Magnetron's pad1 of TIME, because the Bontempo takes over the TIME, SPEED and DEPTH controls and associated circuitry.

What I was trying to achieve was using the magnetron's modulation circuit and the bontempo as a substitute for the TIME pot.
On the bontempo doc, pin7 of IC1 is labeled modulation PWM. My understanding of the magnetron circuit (confirmed with a sound probe) is that the section of the circuit leading to R11 also generates the modulation PWM.

As for the bypass, I'd use PedalPCB's C-BUFFER.

Once I can get modulation working the was I want it, Ill get back to tails...

 

[Feral Feline]

COOL!

I've got a friend who wants/needs a delay, so some form of delay has moved up the build queue.
Your efforts have given me an idea to maybe try the following: have a footswitch that switches between the stock Magnetron Pin6 accoutrement and the Bontempo's controls (or similar such as TapTation).

 

[Blaise]

COOL!

I've got a friend who wants/needs a delay, so some form of delay has moved up the build queue.
Your efforts have given me an idea to maybe try the following: have a footswitch that switches between the stock Magnetron Pin6 accoutrement and the Bontempo's controls (or similar such as TapTation).

Sure, but why not build 2 different delay then? You're going to end up with duplicate pots for time depth rate, a bunch of switches etc.
To make it clear, I still have not figured out how to combine the modulation of the magnetron with the tap functionality of the bontempo.

 

[Feral Feline]

Why not? It's like having a dual channel OD pedal or a tremolo with two different speeds. I'd be able to have two pre-sets but without having to spend $$$ on two PT2399 ICs, main PCBs etc; one main PCB will fit in a smaller enclosure more easily than two and take up less space on my pedalboard than if I build two completely separate delays (whether housed in one enclosure or separate enclosures).
This derailment is delaying getting to the crux of your Magnetron.

Back to your project...
I was thinking if you're retaining the Magnetron's modulation then you wouldn't need it on the Tap-Tempo controller;
I remembered uk-electronic.de has a TapTempo daughterboard for PT2399, but forgot it says specifically:
"...not for delays with modulation to pin 6 from PT2399!"

The only other Tap-Tempo controller that comes immediately to mind is the Taptation (no longer found on the TTG website!).
You can get the Taptation ICs from Musikding or DIYSB, and daughterboards from GPCB (PDF) or JMK has 3 options.
GPCB's has modulation, which IIRC you can omit the modulation.
JMK's MINI (PDF) just does the Tap-tempo, no modulation. Perhaps this option would be easier to integrate with the Magnetron?


Hmm. I mustn't forget Electric Druid. Have you looked at Electric Druid's TAPLFO (or other ED offerings)?



I'm not saying you should abandon the Electric Canary Bontempo, I'm just exploring if there are other options available to you.