Let's Talk Reverb Tanks

admin · Post by **admin** » Mon May 28, 2007 9:54 am

Greg: From reading online I have noted that there are low impedance and high impedance reverb pans. Transformer driven reverb pans seem to be low impedance. High impedance units (at least at the input) seem more prevalent in circuits that have less power.

Is the quality of the reverb produced related to the high or low impedence, per se or does it have more to do with the physical properties of the reverb unit itself?

soundmasterg · Post by **soundmasterg** » Mon May 28, 2007 10:53 am

You know, I haven't messed around with reverb a whole lot Peter. I added a Fender reverb circuit and pan to my brother's Silvertone 1484 and it works great and sounds great. I have a stock Silvertone 1484 that the reverb works on, (very rare to have it working!) and it sounds really cheesy and is cap coupled instead of transformer coupled to the rest of the circuit like Fender's is. That doesn't mean that cap coupled setups sound bad as Ampegs used cap coupled setups and sound fantastic. I think its more about the circuit you're using, and the actual tank you choose. For the Fender style tanks, there are the regular Accutronics, and some other brands too. Theres also older ones, which tend to sound better than newer ones for some reason.

admin · Post by **admin** » Mon May 28, 2007 10:56 am

Thanks Greg. I really hope you can shed some light on the question I have about my high impedance reverb pan and my '63 Fender Reverb Reissue on the Tube Versus Digital Reverb thread.

jingle_jangle · Post by **jingle_jangle** » Mon May 28, 2007 12:38 pm

My Magnatone M10 (and all Maggies as far as I know), used cap-coupled reverbs, and although they are not as "wet" sounding as a Fender unit , they are still pretty lush and nice. Softer, I'd say.

jps · Post by **jps** » Mon May 28, 2007 4:32 pm

Maggies? I thought the tall flat thingys in my livingroom with the wires running out from the back of them were Maggies!

charlyg · Post by **charlyg** » Mon May 28, 2007 4:38 pm

Jeffrey - A fellow at work offered me his last week, but alas, no funds!

sir_andrew_of_left_coast · Mon May 28, 2007 5:57 pm

Peter,
Your query had me wondering whether the reverb on my amp was high or low impedance. (This was the amp I ended up getting when I was considering a Reverberato.) The make is "Juke" and it uses an Ampeg type C reverb with a Maggie recovery circuit. According to this Vibroworld site, mine is quite high.

https://www.vibroworld.com/parts/tech18.html

I'd have to concur with Greg. I don't think the impedance is necessarily a predictor of reverb quality. Looking at the chart, Mesa Boogie amps have low impedance like Fender... but are Mesa Boogies all that renown for their reverb? They could be... I don't know for sure... all of those that I've heard are just high-gain screamers. Ack!

jingle_jangle · Post by **jingle_jangle** » Mon May 28, 2007 6:36 pm

Notice that, though Vibroworld are the clearing house for almost all things Magnatone, they do not sell either the reverb pans (special to Maggies) or the varistors (for Magnatone's special pitch-varying vibrato) which are the Maggies' most unique parts.

When my own M10 arrived with a snapped reverb tank spring, I was forced to purchase a Fender Twin Reverb unit (identical dimensionally to the Maggie unit) and transpose the reverb impedance-matching chokes from Maggie to Fender unit. This was very fiddly work (each choke is the size of a sugar cube and must be completely disassembled and re-assembled on the new laminations) requiring magnifying goggles and tweezers.

Worth the experience, though. A fabulous-sounding amp, belying its 8" speaker and 3" tweeter. I do have two rare Maggie RS-1 12" extension speakers for it, though, to give the bottom end an SPL a boost.

ken_j · Post by **ken_j** » Tue May 29, 2007 3:27 am

"...but are Mesa Boogies all that renown for their reverb?"

My DC-5 has a somewhat soft or subtle reverb. It sounds ok but nowhere as lush or wet as my Fender.

soundmasterg · Post by **soundmasterg** » Tue May 29, 2007 3:31 pm

Zack at Vibroworld used to sell the varistors for the Maggies until I bought up the last 8 NOS ones that he had. I sent one to Ted Weber last year for him to spec out in case he might be able to find a modern equivilant. I think he was going to come out with a kit based on the Maggie vibrato circuit. Anyway, I've got 8 of the varistors, and they ain't going anywhere, because I plan to build them into an amp later on.

sir_andrew_of_left_coast · Tue May 29, 2007 3:39 pm

Agreed, Paul. The pitch-varying vibrato is quite a neat feature. The amp I mentioned above has it as well.

rick12dr · Post by **rick12dr** » Mon Jun 11, 2007 7:47 pm

Any of you guys ever replace your original tanks with upgrade Accutronics tanks?Back in the early 80s I and a couple of my buddies were really into the still mfd Music Man amps. They, like many others, used a specific Accutronics tank.One of the guys was an electronics guru, and he got hipped to replacing the std 2 spring[technically a 4 spring] with a 3 spring[6 spring] equivalent.
The original reverb was not bad, but by replacing the tank[at the time, the price was around $20, direct from Accutronics] we upped the ante quite a bit.Another friend did this to an original early 60s Fender reverb unit, and the new 3 spring just made the thing Kill!.I think you can still get these,AFAIK.Comments?

admin · Post by **admin** » Tue Jun 12, 2007 9:36 am

Don: You can still get these reverb tanks for under $30. My friend added a three spring tank to his unit and found that it was a bit too much.

johnallg · Post by **johnallg** » Fri Jun 22, 2007 3:46 pm

Ok, I just had a thought - has anyone made their own spring assembly to put the signal through? With a PVC pipe and endcaps, using an appropriately suited spring suspended through the center and attached to screws in the endcaps, wouldn't that work for a spring tank? What about a mini Slinky? Am I missing the concept totally?

bitzerguy · Post by **bitzerguy** » Tue Jun 26, 2007 6:21 am

Back in the late 80's and early 90's I helped a very fine guitarist named Roberto Aspri fine tune and develop his passion. Here is a vid I saw about installing it.

http://www.youtube.com/watch?v=I2AhHuAT4yI

The portable "clip=on" version was available in two styles, classical (nylon) and the one I helped with for the steel string acoustic with compensated bridge. We also did a couple of in-guitar versions permanently installed in a couple of Norman guitars.

I found tension of the spring, as well as consistency in the thickness of the wire used to make the spring were both critical to reverb length and depth. Too much tension and the tone depth disappears and too little tension the length of the effect drops off. We ended up allowing for quite a bit of adjustment on all versions.

While I didn't do it all, my part of the design was the springs and the "pickup", a small steel stamping that mounted one end of the three springs and slid under the strings at the bridge.

I still have two of the prototypes and still use them. Al Dimieola had endorsed it at one time.

...Dean