need help with some wiring of a paia ring mod!

Started by mikeford, December 12, 2013, 08:45:46 AM

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mikeford


Hello!
Well, i'm trying to get this paia ring mod into a stompbox case, but how to wire it up ai got me flummoxed!
(the SG for instance!)



I am using this wire diagram.



Not only the input ground and SG, but using dual, plus, ground, neg 18 volts.

(heck, I had scott over at PAIA say you can do a dual 9v dc wall warts w dual barrel jacks/ 9v batts.! thats another can o wires to open!)
Any o' you gents have some insight?
A possible wiring diagram?
THANKS!!

mikeford


PRR

Your generic fuzzz layout has "no" knobs, one power and two audio jacks.

Your ring-mod has dual power, four audio jacks, and at least two knobs.

There's too many new-ideas here.

Use the PAiA build-manual to get it working on the bench. THEN look at how to add the bypass. Then try to work it all into a box.
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dwmorrin

I believe "SG" is PAiA speak for "Star Ground."  Just consider it "ground" for now, and worry about star grounding later.
You can use two dc jacks to get your bipolar power, but two 9V batteries may be a better starting place if you're not sure what you're doing.
You mentioned "neg 18" volts... but I don't see that anywhere...

mikeford

the layout is not for a fuzz, but a generic example of true bypass wiring. that is what i am trying to do with the ring mod.
The integration of the input jack is what has me hung up. so basically, SG and ground are the same?

dwmorrin


Mark Hammer

You will need to provide some means for turning the bipolar power on and off.  That could involve either:
- a DPDT toggle or slide switch to diable the pair of batteries
- use of a charge pump to produce +/-9v from a single battery or single external supply
- using RG's circuit for disabling 2 batteries at once

The first of those is perhaps the least elegant or flexible, but it IS the simplest, and maybe even the cheapest.

My sense is that, while it was very clever for its time, there are some things that could stand improving in the design, which 1980 did not provide any means for incorporating builder feedback to do.

One of these is that feeding the 565 a broadband signal is just begging for atonal hash.  If you want something that has some chance of being relatively "pitched" at the output, you need to carve away some of the unnecessarily treble and harmonic content feeding the input of the 565.  YOU have essentially two opportunities to do that.  First, stick a 220-330pf cap in parallel with R17.  That will affect dry signal as well as RM signal so it's your choice to go more in the direction of 220 (more treble) or 330 (less).

Second, D3/D4 will not only limit the dynamics of the signal feeding the 565, but it will also generate harmonic content.  To that end, you want a second cap placed in parallel with D3/D4/R5.  The value will depend on what you choose for R12.  What is shown (33k) is the value for feeding a signal that needs a little "level help".  Split that up into 15k and 18k, in series.  Run a 3300pf cap to ground from their junction, and a 2700pf cap to ground in parallel with D3/D4/R5.  That will give you a 2-pole lowpass filter set for around 3khz-ish, to make the 565 a little less confused and overly busy.

And because you my not want or need the extended top end, and certainly don't want any hiss or sum frequencies that addharshness, consider adding a 3rd lowpass filtering cap in parallel with R14; perhaps in the 470pf range.

Finally, ring modulation is one of those effects that I think deserves a momentary engage switch, because it is rarely something you want to leave on, and more often an effect you want to engage for a riff and then turn off.  A normal stomp switch is perfectly adequate, but if you have any plans for gigging with it, you may want to consider installing a momentary/non-latching stompswitch as your bypass of choice.  Just something to mull over.

mikeford

Thanks!
It's a bugger! I have a paia phaser w/envelope follower and I will use what I learn doing this one  as a springboard!

mikeford

Mr. Hammer,
do you have a link for rgs circuit to disable the two 9volts at once?
Thanks!

mikeford

or, is there a free software somewhere that i can download, a sort of pedal diagram creator?

Mark Hammer

Quote from: mikeford on December 13, 2013, 08:45:11 AM
Mr. Hammer,
do you have a link for rgs circuit to disable the two 9volts at once?
Thanks!
Well, I know I didn't dream it, but I can't seem to find it on the GEOFEX page.  Maybe somebody else knows the link.

mikeford

I think I will try to wire this up with a dual 9volt adapters, with a true bypass/led indicator only.

Anybody have  a diagram on how that would look?
also, what miliamperage should the 9 volt adapters be?

dwmorrin

Quote from: mikeford on December 14, 2013, 08:16:43 AM
I think I will try to wire this up with a dual 9volt adapters...
Anybody have  a diagram on how that would look?
also, what miliamperage should the 9 volt adapters be?

http://www.musicfromouterspace.com/analogsynth_new/WALLWARTSUPPLY/WALLWARTSUPPLY.php
I highly recommend building yourself a bipolar power supply to power this, and whatever other bipolar devices you experiment with.
The linked DIY project is very convenient, as you can use a common 9VAC 1000mA rated wall wart.   (Instead of picking out a power transformer, which is sometimes a confusing task.)
Music From Outer Space sells the PCB and parts too, so it's easy to do.
I would recommend building this into its own enclosure, and use a 3 or more pin connector to supply the power over a single connection to the ring mod.  Use something you wouldn't use with audio.  I use 4 pin DIN connectors for my bipolar stuff.
The linked project can power several bipolar effects projects.

mikeford


Mark Hammer

Note that, if you HAVE a bipolar +/-9V supply of some kind, that doesn't mean it has to be used as one all the time.  That is, you can use the positive and negative outputs to power circuits that have been designed around 2 batteries or some other bipolar standard, but you can also use just the ground and +9v to power other pedals that only require that.  In other words, a bipolar supply covers more bases; don't think of it as a nuisance to suit only one circuit.