Next Build: Spring Tank and Elliott Sound circuits?

[Joncaster]

Hey All,

I'm deep into the world of spring tanks and their supporting circuits, having a ball.

I'm thinking of this:

Rod Elliott's Dual Opamp Drive circuit for medium impedance tanks (150-250ohm)
Using the Unbalanced Input, Mixer and Output stages on this page as a start:
http://sound.whsites.net/articles/reverb.htm

To drive an 8DB2C1D (9" tank, 3-spring, medium decay, 310ohms)

Circuit in a separate box/pedal unit, and tank mounted in an isolating enclosure.
Or just bang it all together in a head unit ala traditional with footswitch.
Not too sure. If I can get away with a unit to mount on my pedalboard, with the tank next to it somehow, that would be cool.

Anyone have ideas on the best way to implement the Bipolar 15V supply?

Im thinking a GGG Bipolar PS board, but I can't find 24VAC wall warts yet, so might go the full hog and bring wall power into the box and step down inside.
That opens up potential for EMF and ground issues, though.

I would love to take advantage of the headroom/node impedance offered by a true Bipolar supply, but not adverse to jiggling the circuit for single ended if anyone has done this successfully (I've only found one reference in my searches of this circuit particularly).
Chips would be NE5532

I'll keep researching, but anyone feel free to chime in with thoughts or real world findings.

(Also not stuck on the Elliott verb, but as far as I can find, it's better than the Center Stage or the G.F. Cook designs?)
A FET version of the 6G15 would be another option, but can't find any info other than the SurfyBear premade PCB.

One last consideration:
Would be nice to have enough headroom in the circuit to push a bit of fuzz face through it, etc.
That's one reason the Elliott looks up to the task.
He also offers compression ideas, which might help with this (love that light bulb one!)

[antonis]

(Also not stuck on the Elliott verb, but as far as I can find, it's better than the Center Stage or the G.F. Cook designs?)

I've nothing against Rod Elliot's projects (other than his persistence of using bi-polar supply on every each audio design.. ) but I'd strongly suggest you to try TH Custom Effects Re-Verb V4.0, based on BTDR-2..



IMHO, it's a neat & tidy build with, IMHO again, excellent results in all of its possible modes (boost, tone, dry/wet mix, etc.)
You can easily modify the circuit for bi-polar supply, even on its current PC board..
(I've done it to incorporate it inside a practice amp..)

About pushing a fuzz-face-like circuit: IMHO, you might get intro trouble, 'cause both effects use op-amp input buffers before signal splitting, resulting in non-"original" Fuzz-Face-ish responce..

P.S.
For +/- 15V supply, there are several suggestions almost everywhere (ESP also deals with it..)

[Joncaster]

(Also not stuck on the Elliott verb, but as far as I can find, it's better than the Center Stage or the G.F. Cook designs?)

I've nothing against Rod Elliot's projects (other than his persistence of using bi-polar supply on every each audio design.. ) but I'd strongly suggest you to try TH Custom Effects Re-Verb V4.0, based on BTDR-2..



IMHO, it's a neat & tidy build with, IMHO again, excellent results in all of its possible modes (boost, tone, dry/wet mix, etc.)
You can easily modify the circuit for bi-polar supply, even on its current PC board..
(I've done it to incorporate it inside a practice amp..)

About pushing a fuzz-face-like circuit: IMHO, you might get intro trouble, 'cause both effects use op-amp input buffers before signal splitting, resulting in non-"original" Fuzz-Face-ish responce..

P.S.
For +/- 15V supply, there are several suggestions almost everywhere (ESP also deals with it..)

Thanks Antonis!

I've been pondering the BTDR-2 and it does look a lot easier to deal with. I suppose the romantic in me likes the idea of tanks.
I might have to do both.
Seeing as I have to ship either a tank or a chip all the way here...

And yes, i'll be wading through the Bipolar info out there tonight!
I figure it's good to learn.

[j_flanders]

Chips would be NE5532
I'll keep researching, but anyone feel free to chime in with thoughts or real world findings.

I've built the version in Figure 5A in my Marshall MG10CD. (which is heavily modded, used as a head, through a Celestion Greenback, and it sounds like a proper amp, just lacked reverb.)
The amp runs on -15/15V.
I did not have the right pan.
I had an 4EB pan lying around but as he said: " it's marginal". I could not get a good reverb out of it. It was also a medium decay pan.
I also had a 4AB, long decay, the opposite side of the spectrum, but as he said: "if you're willing to sacrifice some output".
I also had an 8AB, long decay, although the same input impedance, it has 3 springs, 3 output transducers and thereby quite a lot more output than the long 2spring 4AB. I quite like the 8AB pan, it can get surfy when turned up high. But I will try an 150 Ohm pan in the future.

If you build it, don't be afraid to experiment with the R1, C2 and R2 values of the recovery circuit (Figure 9 - Generalised Recovery Amplifier Circuit)
You can voice the reverb output transducers, just like you can voice a guitar pickup:
higher/lower resistive load to increase/decrease the Q/amplitude of the frequency peak
higher/lower capacitive load to increase/decrease the frequency of the peak.

If it weren't for the -15/15 supply I had already built this in a pedal. Still looking for a good solution there, just like you.

A FET version of the 6G15 would be another option, but can't find any info other than the SurfyBear premade PCB.

I built the Surfy Bear and bought the premade PCB. The pedal is way too expensive, but the kit is very affordable.
It sounds incredible! I have it hooked up to 2 pans (long and short) and switch between them with a 4pdt switch. I do prefer an active mixer instead of the passive mixer on the pcb, as it sucks highs from the dry signal when turning up the mix for more wetness.

The schematic of the SB is online, both the early version as the newer ones.

[samhay]

>I've been pondering the BTDR-2 and it does look a lot easier to deal with.

If you go down the digital route, I can highly recomend the BTDR-3 as the extra depth control is very useful. Either will give a good approximation of a spring reverb.

[Joncaster]

But I will try an 150 Ohm pan in the future.

Thank for this info!

After some more reading, I think that's the tank type I'de want...8BB2C1B

I built the Surfy Bear ... It sounds incredible!

Is it the better of the two, for you?

[Joncaster]

>I've been pondering the BTDR-2 and it does look a lot easier to deal with.

If you go down the digital route, I can highly recomend the BTDR-3 as the extra depth control is very useful. Either will give a good approximation of a spring reverb.

Ah yes, the first circuits I checked out was the BYOC, which had the 3H in it...
A part of me wanted to just order that and be done with it!
But now i'm swimming in options haha

[anotherjim]

I think springs are great & wonderful things. If you already have a tank, I don't see why you wouldn't want to use it.

Getting a strong enough drive seems to be the problem most people face when used to working with 9v single rail supply. However, a BTL (push-pull) chip amp solution probably can drive the tank well enough. The problem is that many tanks have single end terminations for only signal and ground and that ground is common to the tank chassis, but a BTL amp cannot drive a grounded load. So you might have to mod the tank input wiring to isolate the input transducers "cold" wire from the chassis. If the input is already isolated from chassis, you're good to go.

[Joncaster]

The 8 series tanks I'm looking at have insulated input, thankfully:)

I do feel that a decent supply voltage and hefty current is needed for shaking springs around properly.
After my Neovibe build, I'm a believer in headroom and the larger suppliers.

[mth5044]

I built the Surfy Bear and bought the premade PCB. The pedal is way too expensive, but the kit is very affordable.
It sounds incredible! I have it hooked up to 2 pans (long and short) and switch between them with a 4pdt switch. I do prefer an active mixer instead of the passive mixer on the pcb, as it sucks highs from the dry signal when turning up the mix for more wetness.

The schematic of the SB is online, both the early version as the newer ones.

I have the PDF marked R3 - 20140828, presumably revision 3 from august 28 2014 - do have have access to a later revision?

Also, do you mind posting a schematic of the active mixer you used? I'd love to try it out. Thanks!