Reverb build question

[liagasg]

Hello there,
I ve been looking all over, trying to find a reverb/echo schematic for a reverb pedal.
Most of them use a reverb tank, or a module by accutronics.

The question is, if anybody knows a way to create the reverb effect using only transistors or ics?
I was thinking of a LFO feedback circuit like the EA tremolo schematic.

The most hard to find pedal schematic is this reverb/echo thing.

Any suggestions would be greatly appreciated.

[FSFX]

Hello there,
I ve been looking all over, trying to find a reverb/echo schematic for a reverb pedal.
Most of them use a reverb tank, or a module by accutronics.

The question is, if anybody knows a way to create the reverb effect using only transistors or ics?
I was thinking of a LFO feedback circuit like the EA tremolo schematic.

The most hard to find pedal schematic is this reverb/echo thing.

Any suggestions would be greatly appreciated.

There are loads of reverb/echo schematics on the Internet and in all of the pedal groups.

The alternatives to a spring tank are circuits based on bucket brigade devices (BBDs), chips like the PT2399 or modules like the Accutronics one that uses multiple PT2399s or things like the FV-1 based designs.

Simple ICs and transistors cannot be used as for a delay or echo you need a lot of memory to store the audio for the delay period before outputting it as well as returning some of the delayed signal back to the input to produce an echo.

Here is a PT2399 type of design:   


And here is an FV-1 type of design:

[eh la bas ma]

I just finished building a reverb and I am very pleased with the result :

https://docs.pedalpcb.com/project/Gravitation-PedalPCB.pdf

It's based on a Belton brick, and I am starting to think it's my favorite kind of reverb circuits.

I also like the 3verb : https://www.musikding.de/3verb-reverb

I built an FV-1, Spatialist from PPCB, and I was disappointed, too artificial, the decay sounds always the same, etc...

I didn't try a reverb based on PT2399, but I already know it gives poor results on longer delay settings, it's ok and perfectly effective on very short delays, but if you want to push it further, the chip will produce some background noises, impossible to remove.

[anotherjim]

To me, this one is as good as it gets without using a DSP...
http://valvewizard.co.uk/equinox.html

[italianguy63]

Rob's Chasm Reverb is awesome.. I have built about 3.

MC

[PRR]

...a way to create the reverb effect using only transistors or ics?...

No (unless you mean ten thousand transistors), but you can use a garden hose.  Cooper Time Cube

https://reverb.com/p/urei-universal-audio-cooper-time-cube-model-920-16-delay-line
Sylvia Massy video.

[Digital Larry]

I built an FV-1, Spatialist from PPCB, and I was disappointed, too artificial, the decay sounds always the same, etc...

FV-1 is capable of quite a bit more than the default programs.  It's hard to know which algo you are using, but within the limits of 3 controls you should be able to get these possibilities:
- reverb time
- high freq damping
- pre-delay

Mix can be done in the analog realm.  I'm not guaranteeing that you would like even the best FV-1 reverb, and while it certainly has its limitations, I'd imagine that it could emulate a handful of PT2399's with a little ingenuity in programming.

[Ripthorn]

I have several reverb projects that I've designed. Some use pt2399 while another one or two use a spring tank.
https://scientificguitarist.wixsite.com/home/projects

[PRR]

There's also tape, as seen in many old ECHO machines. Get the heads close and the tape speed high, recirculate, they can get to the reverb zone.

Same can be done on disk. An early spectrum analyzer wrote the audio on the edge of a platter, played back many times while a filter sweeped, and zapped some dry-ink paper wrapped around a drum extension. I had the mechanicals and was working on electronics, not so very long before BBD samples happened.

[Mark Hammer]

The basic difference between "reverb" and "echo" concerns the number of concurrent reflections.  If there is only one clearly distinguishable repeating reflection, we "hear" that as delay/echo.  The more concurrent - and non-rigidly synchronized - repeats/reflections there are, the more we hear it as reverberation.  Another aspect of reverb vs delay is that the quality of the reflections/repeats changes over time.  I've found that if I add a little bit of lowpass filtering to the repeats of a delay, such that successive repeats each get a little duller than the previous one, it begins to sound a little more like reverb, and the way that bouncing off reflective surfaces eats up more high-frequency content.

The Belton bricks use a trio of PT2399 chips, internally, to simulate multiple unsynchronized reflections.  They come much closer to portraying "reverb" than a single PT2399 would, but generally don't sound exactly like a spring pan or "natural" room reverberation.  I have not seen any units or plans that employ a pair of Belton bricks, or any means to unsync two such units.  But I imagine two unsynced modules would yield something that sounds even more like reverb.

The old and "hen's-tooth rare" MN3011 was a 6-tap bucket brigade chip that was intended to provide solid-state reverb.  Heck, there were construction projects in Electronics Today magazine (ETI), and elsewhere, using the MN3011, that literally called the project that.  The 6 taps were not mathematically related, yielding the unsynchronized characteristic.  But at the time the chip came out, I don't think many had deeply understood what makes reverb sound like reverb, beyond the multiple unsynced-repeats aspect.  Nearly all the designs I've seen simply mixed the repeats together, down to mono, with later taps from the chip being mixed at a slightly lower level.  And as noted earlier, there's more to reverb than simply repeats.

[liagasg]

Thanks to all of you for the replies.

All I need is to add depth to the sound, as if we are playing in a hall or something like that.
I don't need repeats or slap back tones.

I've seen most of the echo/delay schematics based on PT2399, also check video of sound checks, but most of them are not what i am after.

I need something like the depth knob of a PA mixer.

From the above replies the Equinox II sounds pretty close to my needs, so I am giving it a shot.

[liagasg]

I have several reverb projects that I've designed. Some use pt2399 while another one or two use a spring tank.
https://scientificguitarist.wixsite.com/home/projects

Definitely checking that circuit out too!! Thanks!!!

[bluebunny]

From the above replies the Equinox II sounds pretty close to my needs, so I am giving it a shot.

I've used the Equinox II live.  It's not going to kid anyone that it's a "real" reverb, but it's quite effective in a live band mix and adds the depth you're looking for.

[anotherjim]

I detect confusion between reverb and delay. Many projects are purely simple delays with repeats that might be called reverberation, but it is only a single reverberation time which doesn't fool anyone. With only 2 different delay times, carefully mixing the repeats can simulate a more satisfying reverb. A better one can be done with 3 different delays and so on...
The original Belton Bricks contain x3 PT2399 ICs.

[printer2]

This is the best sounding reverb using the PT2399, it does use four chips though.

https://scientificguitarist.wixsite.com/home/t60-reverberator

[ElectricDruid]

So no love for the FV-1 then? 

It's simple to use and does a much better job than the PT2399. There are plenty of commercial reverb pedals out there using it, and there's some fancy shimmer reverbs and such like too. The circuit required is hardly more complicated than a single PT2399, especially if you're happy with the factory reverb programs. Even if you're not, add one more 8-pin chip. PedalPCB lists a load:

https://www.pedalpcb.com/product-category/reverb/

[Ripthorn]

This is the best sounding reverb using the PT2399, it does use four chips though.

https://scientificguitarist.wixsite.com/home/t60-reverberator

Thanks for the shout out! The 4 chips does make it a little on the larger side, and it's a fairly complex circuit, but I am happy with the way it sounds.

[Ripthorn]

So no love for the FV-1 then? 

It's simple to use and does a much better job than the PT2399. There are plenty of commercial reverb pedals out there using it, and there's some fancy shimmer reverbs and such like too. The circuit required is hardly more complicated than a single PT2399, especially if you're happy with the factory reverb programs. Even if you're not, add one more 8-pin chip. PedalPCB lists a load:

https://www.pedalpcb.com/product-category/reverb/

My biggest beef with the FV-1 is just the cost of the chip. Yup, I can be cheap at times. Same reason I avoid the Belton brick...

[ElectricDruid]

My biggest beef with the FV-1 is just the cost of the chip. Yup, I can be cheap at times. Same reason I avoid the Belton brick...

I agree it's far from the cheapest chip in the marketplace, but it compares pretty favourably with the price of a reverb tank!

[Ripthorn]

My biggest beef with the FV-1 is just the cost of the chip. Yup, I can be cheap at times. Same reason I avoid the Belton brick...

I agree it's far from the cheapest chip in the marketplace, but it compares pretty favourably with the price of a reverb tank!

Very true! Then again, I bought a whole sleeve of pt2399's and need to use them on something...