I have a Accutronics spring reverb tank that hasn't got any amp, it's just the plain tank. What's the most simple way to connect it and be able to use it? For example, can I connect it to a speaker out from a hifi-amp?

Hope to hear from you!

Hi
A headphone output would 'drive' it adequately. It tends to take a little more 'power' to drive than a 'line amplifier' output (depending on model you have).
The return needs a preamp with a fair amount of 'EQ' on it to make it sound decent.
In fact the DRIVE should also have some EQ and maybe even a constant current drive, which is getting a bit technical.
A speaker level amplifier would melt the poor thing.

Matt S

This. It's the Wave Spring Reverb. Its a diy affair so break out the soldering gun.

Might I observe that the drive coils might have impedances from eight ohms to thousands, and that will be a big factor in what you can do.

I'm too lazy to look up the part number - configuration codes for you but they're up here somewhere.

Hmm, will try driving it from the headphone out then and see if I can get it to sound ok when I do the next mix! I don't have the time to build something dedicated right now.

I'll post here when I've tried

Ok, tested this: Connected the tank to the headphoneoutput of a RME Fireface800, and to the instrument input of a Focusrite ISA Two. I get a decent signal, and the tank sounds really got, but there's a severe HF-noise, sounds like something from a switching power suppy. I tried to ground the outside of the tank, but doesn't seem to help.

Probably wrong impedance. Sounds like you need a DI box. Line level DI box, not instrument level.

Thanks for the tip, will try a line level DI when I get the possibility!

I think that the impedance idea was a wild-ass guess. Not that I know what you should do but I wouldn't just throw you a wild-ass guess.

You might observe that these things do want a bit of treble cut on the output. At least that was my experience.

Not even close lol. The spring box goes after the input amplifier before the power amp section. That puts it in the line level category, not instrument level. Plugging an instrument into a line level input will cause all sorts of hum, buzz, and thin/brittle sound. Not only is it not a guess, it is a logical conclusion.

Hi
Wrong conclusions being drawn all around here.
The input to the spring is around line level VOLTAGE but as the impedance depends on individual unit you have to consider the drive CURRENT necessary.
The output is not as low as some instruments but certainly not 'line' level so it needs about 20 dB or thereabouts of gain BUT it also needs some frequency response shaping not too dissimilar to RIAA from a turntable but probably not as much.
The NOISE issues you are getting are due to bad implementation and NOT anything to do with impedances or frequency response combined with susceptibility to mains hum and anything else that aflicts low signal level mostly unbalanced audio.
To get the 'best' performance you condition the signal going into the reverb then in a different way on the way out.
Matt S

Although technically yes, you are overthinking. Simply converting the instrument level signal into a line level signal before the spring box will yield absolutely acceptable/useable results. Problem solved. In this case resistance, impedance, voltage and current are all the same thing, it's a matter of perspective. The simplest way is to convert the impedance and step up the voltage. He's trying to get it to work properly in-line, not trying to design a circuit around it.

Very cool to read your thoughts on this, so what would be the most simple way to get rid of the noise? Maybe I should try connecting it to the line in instead, but I think the signal will be too weak. I'll get back when I tried ...

He/she

Before you get too carried away, are you sure it isn't just straight up emi? You say it sounds like a switching power supply, so is there not simply just one nearby?
Have you tried moving it to a different position/orientation?

Some of my spring reverb units can't be racked up with the other gear because of this!

Now when I think about it there's actually one very close ... it's sitting on the Fireface800! Yea, I'll try some different things to try to get it work, and post back the solution.

Do you have a mixer?

It won't let me upload for some reason, but search for "****ty is pretty"

There are atlas 2 of them and the "****ty is pretty 2" has a method to hook up a spring reverb to a desk

EDIT: f-ing censorship...

Lets see if I can outsmart a bot.

Gabriel Roth wrote articles titled 5h!ttY is pretty. Look up the 2nd one

Radial Tank Driver™ -

Unfortunately not ... but the articles looks like very amusing and nice read

Yea ... took me a few seconds to understand what you were trying to spell out haha.

The articles:

www.funkydown.com/downloads/s hitty1.pdf
www.funkydown.com/downloads/s hitty2.pdf (the one with info on thank hookup)

Click the link and you will get a 404, now you're outside of Gearslutz (WTF? "Slut" isn't censored but s h i t is ) censored area and can safely remove the space between s and hitty ... sigh

Great statement. Goes straight into my signature tonight.

buy 2 and add stepped pots

I'd like to chime in and say that I just managed to do this and it blows away all my best spring plugins, with very little noise all the way up to 16kHz (probably material limitation, it should just be cut).

But it took a lot of thinking, xBBxCxB seem to be the most appropriate (because grounded input and suspended output is too hard to find). It takes at least 200mW to get creamy (80mW output headphones made them noisy and "flat" sounding), and significant EQing, lots of clipping and saturating the output before making the loopback. And, 1.800€ stereo preamps with transformer balanced DI inputs to go back with highs and no noise, a regular DI just killed all the highs and made it unusable.

So I am guessing there are cheaper parts out there that will get it to work right away, but one must definitely be creative with the DI amplification (I think that won't be cheap and good simultaneously).

Looking over this thread, at no point did I see anyone ask for or mention the model number of the spring tank. The third and fourth digits of the part number respectively indicate the input and output impedances. Once you know this you know what you're in for. Accutronics used to have a data sheet with sample circuits back in the seventies.
--scott

I did, but it's cool that you looked through the other posts. What also seems to be relevant is finding out what's available near where you live and working within those parameters, I'd say input impedance B or C, and output impedance B or C both seem to work. I also like positioning B (springs down) for the sake of simplicity. Would you ever be interested in creating a DIY kit for driving them?

I already did that in 1978 in an article for Popular Electronics, I think. 600 ohm ins and outs, input and output floated delay lines since that seemed the easiest to design for. The good part is that I put two tanks in parallel, inputs wired out of phase, so that most of the distortion and some of the boinginess cancelled out. The bad part is that I had a single-ended drive amp (because 2N3055 transistors were a buck at radio shack so why bother with elegance?) and the input amp was pretty noisy because I believed data sheets for transistors when they said "low noise" on them, not realizing that they meant low noise at high frequencies and not low 1/f noise. And also I didn't understand about limiting... the Orban spring reverb had an ingenious floating limiter circuit that greatly reduced the boinginess and I had no idea that was a thing.

If you want to build something, get the manual for the Orban and copy Bob's circuit. It's a good one (although you will find the preamp chip he used is discontinued, they are still available on ebay).

thank you for the tip! I just looked through the manual and browsed around a bit, everyone seems to stumble on their limiter circuit? do you "know" anything about it?

There's someone out there who has reverse-engineered it and is selling a replacement, but honestly it's just a gilbert cell sort of thing made with a couple jfets.

If I were doing this on the bench, I'd first build one without the limiter or eq in place, then I'd go to THAT Semiconductor design note #119 and I'd steal their sample limiter circuit, which works very well. (The one in design note #117 has an even better-shaped knee but a lot more parts). It's just a fixed threshold... adjust until you hear an abrupt reduction in boing.) Then I would do the EQ and what is inside the EQ modules are really just fast opamp boards and the hard part is in the networks.
--scott

Oh yeah, and there is the cheez-whiz limiter of two zener diodes wired back to back. This is what I would have used when I was a kid and it doesn't sound as bad as you'd think but it's very far from neutral when it limits. The THAT circuit is pretty neutral.
--scott