Possible to mod H2O to get infiniterepeats/oscillations?

[MikeH]

I'm sure ("hoping") RG will chime in on this-

My effect needs are getting to be a bit much to have one board for 2 bands (which have very different fx requirements), so I'm splitting my stuff into 2 boards, that are a little  easier to manage.  Originally I had my H2O and RE-20 on the same board and I was using the RE-20 for echoing oscillations and stuff, and the H20 for clean delay.  The RE20 can satisfy my needs for Band #1 just fine, and the H2O will work for band #2, with one minor exception.  Which is, there are occasions that I still want to get those crazy oscillating echoes for the band that I use the H2O with.

Soooo... I'd like to mod my H2O to get those oscillating echoes (a la rebote, for instance).   Which I would do via remote footswitch.  Does anyone know if:

a) This is even possible, and
b) which components I would change/bypass?

My instincts say that I need to trace back the repeats pot, which is most likely a variable resistor (total guess) and either increase it's resistance by switching in a fixed resistor before or after it (most likely), or just short it out completely.

If the repeats pot is setup as some sort of voltage divider, well then I have no idea how to do it.  The schematic is a 'no-no' here, but if anyone can provide direction/background that will help, I wold be most grateful.  Thanks!

Oh, and for the record it's the older model H2O- I think it might actually be a 1st generation, I bought it in 2001.

[Mark Hammer]

In a digital delay, the encoded information is passed on, intact, from memory address to memory address, such that whatever was inserted in the first memory address is exactly what emerges from the last one.  In an analog delay, the more storage cells (teeny tiny capacitors) the information is passed on to, the more signal degradation there is.  That signal degradation is exacerbated if: a) the delay is particularly long and the caps are asked to hang onto stuff to the point where they start to leak more, and/or b) the signal is recirculated (which is tantamount to passing a signal through thousands and thousands of bucket brigade stages).

So, in principal, any attempt at "infinite repeats" is more subject to signal loss in the analog domain than in the digital domain.  You also need to add to this the fact that both sorts of delays will impose some lowpass filtering on the output of the wet path to remove artifacts, clock noise, etc.  "Filtering" involves removal of signal, such that you end up with less than you started with.

In the case of some digital devices, the point where signal is tapped for feedback purpose can be before any filtering is applied, making it possible to have infinite hold/repeat and no change in tone over repeats.  In the case of things like the various PT2399-based delays where the PT2399 effectively subs for an MN3005, more or less, the feedback path comes after the filtering, such that it will behave like an analog delay when it comes to repeats, though without the signal degradation that comes from leaving the sampled signal in a leaky storage cap too long.

When it comes to analog delay, aiming for infinite repeats is asking for trouble.  Or rather, you need to expect that the signal will sound VERY different after a dozen repeats than it did going in.

So, the short answer to your query is "If you want to have repeat and hold, you need to go digital".

[MikeH]

Well, I don't know if the H2O is analog or digital.  It's described as an analog-digital hybrid.  And that's what the current version is, which may be different than mine from 9 or so yrs ago.

And I should clarify further: I'm not looking for nice, clear, infinite repeats.  I'm just looking to get some crazy noise out of this thing. Heh heh.

I really love the sound of the H2O, and I'd rather not have to resort to using something else, so my first course of action will be to try and get something from the H2O.

[The Tone God]

And I should clarify further: I'm not looking for nice, clear, infinite repeats.  I'm just looking to get some crazy noise out of this thing. Heh heh.

Perhaps you want to look into the Dub Machine. Its an external feedback loop so you can get infinite repeats and other weird sounds but you won't have to modify your pedal.

Andrew

[MikeH]

And I should clarify further: I'm not looking for nice, clear, infinite repeats.  I'm just looking to get some crazy noise out of this thing. Heh heh.

Perhaps you want to look into the Dub Machine. Its an external feedback loop so you can get infinite repeats and other weird sounds but you won't have to modify your pedal.

Andrew

Oh yeah... I guess I could do a feedback loop.  It's a little less fun, but it would work.

[R.G.]

I  think there's a mod that the repair guy does to H2Os back at the office that does infinite repeats - but it is very much as described here; as the repeats pile up, they get muddy and noisey and almost unrecognizable from the build up of analog artifacts. It's by no means a clean loop of sound after a while.

[MikeH]

I  think there's a mod that the repair guy does to H2Os back at the office that does infinite repeats - but it is very much as described here; as the repeats pile up, they get muddy and noisey and almost unrecognizable from the build up of analog artifacts. It's by no means a clean loop of sound after a while.

That's really what I'm looking for.  So are you saying my intuitions were right? 

[MikeH]

...because they totally weren't.   

Just took a look.  Definitely not just a simple variable resistor.  Some sort of divider.  I would have to do a lot a tracing to figure out how it works.