Zerotronics Cool Springs users - What decay time did you get

[T-rex]

I am looking for a new spring reverb and it seems the prices are pretty high for a variety of crappy looking noisy old spring units. So I have pretty much decided to get a new Zerotronics cool springs unit. The samples sound phenomenal and the reviews are all great. Anybody here have these?

They are sold out of the mini-LE version so I was just going to get the classic Cool Springs (which is more my budget anyway) but I can't decide what decay time I should get. I figured Medium time would be good, but his website says short is usually good for vocals, medium good for pads, keys etc. So now I was thinking short - medium for somewhere in between. I am really looking for a plate sounding verb without parking a giant plate in my garage. I loved my old Sound Workshops but it was could be noisy. I would have used it a lot more had it a lower noise floor and I was going to mod it but never got around to it. Now I am looking for something I can just plug in and go; but not a plug in of course. See what I did there?


I like the idea of the demeter but sometimes I want really wide stereo awesomeness for spooky vocals or sparse arrangements and the two different times in the demeter means I wouldn't be able to do that. Which also makes me think short decay is too short or limiting but I could always feed a verb into the spring to extend it. . .

Anyway, I am going to give the guy a call and pick his brain, but I thought I would see if anyone here was using these first.

Thanks!

[Marc Alan Goodman]

I have a Mini-LE and it's astoundingly plate-like. It doesn't really sound like other spring reverbs.

As far as decay time, it really is all about usage. If you're getting it to have more of an obvious effect you'll definitely want it to be longer, but if you're going to try and use it more subtly the shorter times are probably really nice. Personally I'd be attracted to the slower one. For a longer, splashier reverb the I'd rather have a cleaned up a Sound Workshop anyway.

[Jim Williams]

I used to build spring reverbs back in the 1970's as I couldn't afford a plate.

To overcome the fixed decay times I designed a one knob compressor/expander. Under compression, the reverb times increase. With expansion they shorten. An Aphex 612 Expander is perfect for shortening longer reverb times.

[Rufer]

I have the Cool Springs Classic with Short Decay. Plenty of 'verb for spooky vocals.

I am not a pro--or even close. For my unit, I needed preamps with a lot of gain. I was using a Studio Projects 828 which should have plenty to spare according to each unit's specs. I had to crank it to the second-to-last step on the 828 to get a good signal and then the pre was too noisy.

I actually purchased an AEA TRP partially to use with the 'verb. However with the TRP, I cannot increase the gain beyond +42 db without the TRP going crazy and making a horrible motorboat/motorcyle with electronic squealing noise. Eventually I can find a sweet spot and everything works right.

I asked Zerotronics and AEA about it and neither could explain it. It may just be something I am doing wrong--but after four years, I don't think so. Likely just my unit. I am sending and returning to an A&H MixWizard.

Ultimately, it works really well when dialed in perfectly. Very plate-like.

[dfuruta]

I don't want to be negative, but it seems like they're charging quite a lot for very little. Those reverb tanks are $25 each, and it'd be easy to get 4 of them and wire them up in a box?even if you want to add some transformers for balancing (and it would sound fine without), this would be a pretty straight-forward thing to diy. Maybe Zerotronics has some secret magic going on that I'm missing.

[T-rex]

I used to build spring reverbs back in the 1970's as I couldn't afford a plate.

To overcome the fixed decay times I designed a one knob compressor/expander. Under compression, the reverb times increase. With expansion they shorten. An Aphex 612 Expander is perfect for shortening longer reverb times.

Thanks for that. I have seen that trick before but never used it. I have sent a reverb or delay to a spring or vice versa to make it seem longer or different.

Well, that is true. I am a fairly capable DIY'er and it doesn't seem to be a big secret about the design but I don't mind supporting cool little companies either. Although its been a few days and I haven't heard anything back from him. So, I may end up trying something like that myself if I have too. It could be a fun experiment and these pretty much never sell used that I can see.

[Marc Alan Goodman]

I don't want to be negative, but it seems like they're charging quite a lot for very little. Those reverb tanks are $25 each, and it'd be easy to get 4 of them and wire them up in a box?even if you want to add some transformers for balancing (and it would sound fine without), this would be a pretty straight-forward thing to diy. Maybe Zerotronics has some secret magic going on that I'm missing.

You could say that about almost any audio product, especially the old school discrete stuff we all seem to like around here. A product's worth what someone is willing to pay for it.

My zerotronics spring sounds really good. Could I have built something similar? Undoubtably. Would it have taken a lot of time and experimentation to decide what tanks to use, how best to wire them, what kind of transformers it would need, what to use for a chassis and how to cut the chassis up? Absolutely. Sometimes I like to spend the time and do things myself (actually often), but that doesn't reduce the value of something that's already been developed and built.

[dfuruta]

You could say that about almost any audio product, especially the old school discrete stuff we all seem to like around here. A product's worth what someone is willing to pay for it.

My zerotronics spring sounds really good. Could I have built something similar? Undoubtably. Would it have taken a lot of time and experimentation to decide what tanks to use, how best to wire them, what kind of transformers it would need, what to use for a chassis and how to cut the chassis up? Absolutely. Sometimes I like to spend the time and do things myself (actually often), but that doesn't reduce the value of something that's already been developed and built.

Yes, that's true. I'm probably just being cynical, and I'm sure this guy put a lot of effort into selecting the right transformers and figuring out the best way to mix the different tanks. But, it seems like with this (as opposed to a discrete preamp or whatever), the main difficulty is over once one has the components sitting on the workbench. I mean, there aren't that many ways to hook up a reverb tank.

[The Scum]

Full discolsure: Ralph at Zerotronics used to be my boss. We're still good friends. He has one of the grandparents of the SSSS model one-b, and I've got a prototype Cool Springs.

I think I've got a medium/short box at this point. The impedance matching got rethought after I got the first revision, so tanks and circuitry got swapped around a bit. The long was too long to be useful for me...but I also just worked on a tune that clocked in at 306 BPM...not much room for any reverb, so the short is more useful to me. If you're working with the Righteous Brothers (or Radar Bros), the long might suit you.

I also don't think it's overpriced. One common costing formula is that the retail price (that's what MI retailers are calling "street price" these days) should be between 4 and 6 times the cost of the parts. So at an estimated $175 for parts, that gives us a costing factor of 3.14. By that math, it's actually possibly underpriced (or being sold by someone who is very aware of keeping their overhead low).

I also wouldn't be surprised if there weren't a couple of particular tricks being used in the drive/pickup circuitry, that help make the reverb a little wetter. When I was building an experimental plate a couple of years ago, Ralph had some very particular ideas about what I should be doing regarding drive & recovery circuits.

[T-rex]

Yeah, as I said in my original post, I really just want something that works that I can plug up and go and sounds great. I looked around a bit at building one but the case, transformers, tanks and the 16 different possible combinations of wiring the tanks is waaaaay more time than I have want to spend to have an inferior sounding spring compared to a couple hundred more for a really nice sounding reverb.

So any word with Ralph? Its been several days since I emailed and I haven;t heard anything. I just want to make sure he is still building them.

Also, I have a pair of your SSSS EQ's on my short list. Just have to fill in some other holes first!

[Jim Williams]

These are pretty easy to build yourself. There are a couple of tricks that make them behave better.

I used Accutronics tanks in the 1970's/1980's. The 3 spring type 9 and smaller type 8 tanks were developed then. I found using a constant-current drive design works best. I used an opamp with a pair of discrete current transistors. The tank was placed into the opamp feedback loop.

I had Accutronics build the tanks custom for me. I used a pair for each channel, that doubles the density to 6 springs. The drive coil was wired reverse from the other. That cancelled out the fundamental frequency and eliminated the booing sounds, mostly the harmonics were passed.

The other trick was having the return coil on one tank polarized with a reversed magnet. That way the two coils are connected in series to form a hum-cancelling pickup, just like a Les Paul. That removed all the hum.

It sounded more like a plate reverb than springs. I sold it all off decades ago, I use stuff like Bricasti now days.

[T-rex]

Sounds so simple when you put it that way! Yeah, I may have a go at this sometime in the near future. But with my lowly level of DIY / electrical engineering skills, I will have to find the time to experiment with it. It will take me some time for the research and testing to get it right; whereas I am sure you could just whip one up.

It does sound like exactly what I am looking for, a poor man's, quiet plate. I would gladly take a Bricasti, but I still need the right leg I would have to sell to buy one 2 channel reverb box. Although from the nothing but glowing reviews, I am sure it's worth every penny.

[Marc Alan Goodman]

Great tips Jim! Thanks.

[T-rex]

Just an update: I have a Mini-SE on the way! It's the MINI-LE but in a plain box. That was what I was really wanting all along so I am super psyched!

There's been tons of press on the Mini-LE so I probably won't have anything new to report but I will give some impressions when I get it in a couple of weeks.