Foona's DIY Spring reverb unit. [WARNING alot of pictures]

Moderator: interruptor

Post Reply
User avatar
Posts: 15
Joined: Sun Dec 02, 2007 7:41 pm
Location: Sweden

Foona's DIY Spring reverb unit. [WARNING alot of pictures]

Post by Foona » Thu Nov 19, 2009 10:22 am

Foona's DIY Spring reverb unit.
[HAMMOND A-100 spring tank]

WARNING! A lot of pictures!

Picture 1
PSU (power suply unit), PSU connection panel
and Pre-amp/Amp curcuit


Picture 2
I built a frame in oak wood and then i stained it with Mahogany brown
stain. In this picture I've drilled a few holes for parts that are to be
fitted onto the main panel.


Picture 3
A friend from the Swedish elctronics forum helped me with the panel.
I made the design with the help of my wife in AutoCAD and then sent
the blueprint to my friend. Using his CNC-cutter he made the panel for


Picture 4
I got this spring reverb tank of Ebay. It was taken from an old
Hammond 100 organ. I got it very cheap about 10 U$D and with
shipping totall sum was about 23 U$D.....almost.....
When the package arrived at the customs here in Sweden they refused
to send it to me. I had to send them a receipt including pictures and
a written letter describing what it was.
Then they billed me another 55 U$D's before they sent it to me....


Picture 5a and 5b
I used HiFi DLS brand cables to connect the tank to the Pre-amp/Amp


I build a combined Pre-amplifier/Amplifier circuit using this schematic.
This schematic including information on this amp project can be found at
Elliott Sound Products. Link:


Picture 6a and 6b
I built a PSU (power supply unit) in the most simplest
way using this schematic.
*The curcuit drawing shows a 9 volt curcuit, but this unit runs on 15 volts*



Picture 7


Picture 8
It may sound funny but my wife was the one screwing the feet onto
the frame, seriously no pun intended.


Picture 9

I used the original brackets that came with the frame. All I had to do
was shape them like an "L" and then attach the unit into the frame.


Picture 10

Behind the panel. As you can see I had to rework the holes to make
everything fit.

Picture 11

Here I have mounted the dual 18volt transformer, PSU and Amp cucuit
into the frame.

Picture 12

Reverb unit mounted and cables hooked up.

Picture 13
Looks like candy! :D


Picture 14
First I mounted a steel plate on the back and I didn't like the look of it.
I just didn't look ol'school enough so I grabed a piece of Masonite, cut it
and mointed in over the steel plate. Looks yummy!


Picture 15
Panel is really nice looking, especially with those sexy knobs!


Picture 16
Here we have the front of the unit. A steel plate coated two times with
"rust-away-paint", two layers of black paint and two layers of clear
coating. The camera used to take this photo ain't that good but you can
clearly see the table reflecting against the faceplate.


I named this unit the "Springa" and it can be heared and seen in this
video righ here:

8-) Foona - Bring Em Down "Im Your's" Riddim Dub LIVE session 8-)

Hope you enjoy my project!

Love an' Blessin's
/Foona - Studio 5

User avatar
Posts: 118
Joined: Thu Feb 26, 2009 9:29 am
Location: lyon/france

Post by ocoughi » Thu Nov 19, 2009 4:09 pm

hmmm...instructive...thanks for sharing...
i got few questions:
the trimmers are the drive level and reverb level?
is the drive a reverb input? the amount of sound going into the spring.
and the reverb level is the output of the amplified spring signal?
what about dry/wet signal? have you got only the sound of springs or a mix dry/wet at the output?

User avatar
Posts: 256
Joined: Thu Jan 17, 2008 12:40 pm
Location: Dortmund City


Post by JahNice » Fri Nov 20, 2009 3:14 pm

Yes Foona, good project! Give thanx for sharing and for documenting the building process with so many informing pics.. The finished "Springa" is a beauty!

Peace Yiannis

User avatar
Posts: 15
Joined: Sun Dec 02, 2007 7:41 pm
Location: Sweden

Post by Foona » Mon Nov 23, 2009 6:38 am

Thank you! :)

ocoughi: You are correct, trimmers/pots control drive and reverb level.
One can also shut the reverb off completely with the swittch. No dry wet
control, only a mixed output.

Post Reply