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Redfoxfur 8th May 2008 05:53 PM

building spring reverb
i'm looking to build a spring rever unit cab and all and was wondering if anyone had any usefull links on a step by step or a how to. i can get the reverb tank and i have a small 1 watt amp. I'm not realy sure whats involved any help would be apreciated thank you

gni 8th May 2008 06:02 PM

Google it. . .

unclejed613 10th May 2008 05:56 AM

mount the reverb spring in whatever position it was originally. they are made with the suspension springs in various positions to keep the tank suspended properly in one position only. i could explain how to modify the suspensions for various mounting positions, but i'd need one in front of me, and i don't have one in my parts collection. if you have good-to-excellent mechanical skills, it's not too hard to figure out.

Nordic 10th May 2008 08:26 AM

Yes my friend google.... have seen variants, from tube to chip to transistors handleing the tank...

You can also follow that link and find many schematics to pirate off...

Geek 10th May 2008 08:30 AM

Here's the test jig I use for spring tanks:

You can lose the 5751 and adapt it in :)


unclejed613 10th May 2008 01:55 PM

here's a breakdown of the part nimber system for reverb tanks:

Accutronics Reverb Tanks

Almost all the reverb tanks that one sees for sale are the Accutronics brand. They are made by:

Sound Enhancements, Inc.
185 Detroit St.
Cary, IL 60013
Although they make many models, the three types that are readily available are a limited number of their types 4, 8, and 9. The type 4 is 17" long and uses 2 long springs, each of which consists of two springs joined in the middle. Thus, Accutronics considers this model a 4-spring unit. This type was the original style selected by Leo Fender. The type 8 is 9" long and uses 3 springs. This type is most famous for its use by Marshall. The type 9 is 17" long and uses 3 long springs, each of which consists of two springs joined in the middle. Analogously, Accutronics considers this unit a 6-spring device. All Accutronics' part numbers consist of 7 characters as described below.

1st character: type 4, 8, or 9

2nd character: Input impedance @ 1kHz
Type | A B C D E F
4 | 8 ohms 150 ohms 200 ohms 250 ohms 600 ohms 1475 ohms
8 and 9 | 10 ohms 190 ohms 240 ohms 310 ohms 800 ohms 1925 ohms

3rd character: Output impedance @ 1 kHz
Type | A B C
4 | 500 ohms 2250 ohms 10000 ohms
8 and 9 | 600 ohms 2575 ohms 12000 ohms

4th character: Decay time
1 = short (1.2 to 2 sec)
2 = medium (1.75 to 3.0 sec)
3 = long (2.75 to 4 sec)

5th character: Connector arrangement
A = input grounded, output grounded
B = input grounded, output insulated
C = input insulated, output grounded
D = input insulated, output insulated

6th character: Locking device 1 = no lock

7th character: Mounting plane
A = horizontal,open side up
B = horizontal, open side down
C = vertical wall,long axis horizontal, connectors up
D = vertical wall, long axis horizontal, connectors down
E = vertical wall, long axis vertical, input up
F = vertical wall, long axis vertical, output up

The following table summarizes the above data for the most commonly available units:


4AB3C1B Fender 17" 4 8ohms/.81ohms 2,250ohms/200ohms
4BB2C1B Acoustic/SLM/Ampeg 17" 4 150ohms/26ohms 2,250ohms/200ohms
4EB2C1B Peavey 17" 4 600ohms/58ohms 2,250ohms/200ohms
4FB3D1B Music Man General 17" 4 1475ohms/200ohms 2,250ohms/200ohms
9AB2C1B Fender/ Boogie 17" 6 10ohms/.81ohms 2575ohms/200ohms
9EB2C1B Peavey/General 17" 6 800/58ohms 2575ohms/200ohms
9FB2A1C General 17" 6 1,925/200ohms 2575ohms/200ohms
8AB2A1B Boogie 9" 3 10ohms/.81ohms 2575ohms/200ohms
8BB2A1B SLM 9" 3 190ohms/26ohms 2575ohms/200ohms
8DB2C1B Marshall 9" 3 310ohms/36ohms 2575ohms/200ohms
8EB2C1B Fender 9" 3 800ohms/58ohms 2575ohms/200ohms

if you know where the isolating springs go for each mounting position, you can change the mounting type (mounting plane). all you have to do is move the outside ends of the springs to the proper holes in the case.

Key 17th June 2009 01:28 AM

More questions
Okay some more newbish questions since I was thinking of doing this as well and buying a line level reverb tank or two for my bedroom recording studio.

Are reverb tanks passive devices? That need to be followed by a pre-amp? And if so what would be the best way to do the impedance flow?

For instance my soundcard which I plan on bussing tracks to the reverb unit is the Mackie Onyx 400f. Output impedance is like this.

Mic Input:
2.4 kΩ balanced
Inst Input:
1 MΩ
20 kΩ balanced, 10 kΩ unbalanced

Output Impedance
100 Ω balanced

Now if it is passive should I have the input impeadance come as close as possible to the output impeadance of the line outs on the Onyx (150ohm or 200ohm)? And do the same for the output of the reverb tank and the inputs of the card (10k for line or 2.25k for mic input pre-amp).

unclejed613 17th June 2009 03:18 AM

a "line level" reverb tank should have the driver and preamp circuits included. the reverb tanks in previous posts are the basic spring units themselves with no drivers/preamps, just the metal box with springs and magnetics.

just running the outputs of the soundcard into a spring unit won't work well, as there's a huge amount of loss in the transducers and springs.

usually with a spring unit, you have a preamp and spring driver. at the input to the spring driver, the audio path splits int two paths "dry" (original signal) and "wet" (the reverb signal). the "dry" signal then goes directly to the output mixer/buffer. the "wet" signal is amplified to get the required drive current to the spring's input transducer. the transducer is like a small electromagnet that drives the steel spring with audio. the steel spring vibrates mechanically and acts as a delay line. that's why there are more than one spring with different coil pitches, one spring has more delay than the one next to it so the echoes from each spring arrive at different times. also, being springs, the signal echoes back and forth many times along the springs. at the output end, a second transducer magnetically picks up the vibration of the springs and turns it back into an audio signal, which is amplified by a high gain preamp stage and fed into the mixer/buffer to be mixed with the "dry" signal.

actually using a soundcard, i'm surprised you don't have a spring "emulator". some of the better modeled ones sound quite convincing, until you bump the side of the computer and no spring "crash" comes out......

Key 17th June 2009 03:20 AM

Yeah, I guess I am wondering if I can get around that by selecting the proper impedance and just using one of my mic pre-amps.

And realize this is for a multitrack so I don't need onboard blending or any of that. Just full reverb to be tracked and blended. No frills as little circuitry as possible.

unclejed613 17th June 2009 03:39 AM

sorry, i was editing my post while you were posting.... see the rest of my last post.....

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