Popular PT2399 Reverb Circuits

[mimmotronics]

Just bought a tube of 10-15 PT2399s and I'm looking to build and play around with a basic reverb circuit for a blog post I'm working on. I'm wondering what are some popular schems to follow? Is it possible to get a Hall-type verb out of these chips?

[Plexi]

I guess a simple Reverb, spring like, is possible whitout some Belton brick.
I don't know some deep/dark hall.

But, take a look at:
- Ersatz Verben
- Valve Wizard Equinox II: twin PT2399, I definitely would go for this one.
- Sewer Pipes Ring-Verb

[anotherjim]

Valve Wizard Equinox II: twin PT2399

That is probably as simple as it can get and properly sound like a reverb.
Single chip ones can certainly be "reverby", but not defused enough.

[Mark Hammer]

One of the things that not many of us have tinkered with is the bandwidth of the different 2399s used in a multi-chip reverb simulation.

In the real world, when stuff takes a long time to bounce off a reflecting surface and reach us a little later, it has a different bandwidth than those first reflections.  Digital models of reverb will include such shifts in spectral content across reflections.  I haven't seen very much in 2399-based circuits that does the same.

That's not a criticism.  I am certainly very grateful for the diligent work of those who have designed the circuits and/or layouts.  But maybe we could tailor them to achieve different kinds of sound by playing with the bandwidth of earlier and later reflections, in addition to whatever level adjustment is employed.

[anotherjim]

I've ended up putting bandwidth control in my own 2399 projects. Bass cut for sure to stop mud. High end cut to reduce hiss on longer delays as much as anything. Equinox does have band control, but mostly it's cunningly applied in the RC networks that would be there anyway.
For guitar, we're lucky we only have 5KHz top anyway, but the hiss that's left is right where hearings most sensitive to it. Keep meaning to try a dual gang delay control with the extra pot working a low pass so it only gets duller when the delay is longer.

[patrick398]

I built the Rub-a-dub reverb with medium belton which i love!

[amz-fx]

I bought a handful of PT2399 chips a couple of years ago for some projects, one of which is to take 4 or 5 of them and make a simple reverb, like a basic Schroeder or Moorer verb.

I think it takes at least 4 of them to get enough reflections for a dense reverb.

regards, Jack

[Mark Hammer]

If outputs of later delay outputs are fed back to the inputs of early reflections, the two delays sum, and a third delay/reflection is created.  Ideally the shortest delay is such that it is not harmonically related to any subsequent ones.

Of course, given how cheap and compact 2399s are, I guess it is a judgment call as to whether it is simply cheaper and easier to use fewer 2399s and plan out an elaborate  set of mixing and routing nodes, or to run a fistful of 2399s like they were the digital equivalent of an MN3011 chip with multiple taps and non-harmonic clock rates.

Literally six of one and a half-dozen of the other!