Muff's Modules & More

Tombola · Last edited by Tombola on Tue Jan 03, 2012 7:04 pm; edited 1 time in total

I was just about to buy an A199 spring reverb when I decided to save 4hp of space and build my own.

The circuit is based on Roy Mallory's tech note and tone control, which is useful - a symmetrical cut/boost of bass and treble. The drive, recovery, tone and blend buffer take the four amps in a TL074.

The gain on the drive circuit is reduced quite a bit - R10 is 660R rather than 62R (it's R1 in Mallory's article), and the recovery circuit has a variable drive.

I put a couple of phono jacks on the back of my Doepfer case, so it's easy to plug in an external tank - a nice rich 6-spring 9EB2C1B (mainly because I built the circuit with the 8EB2C1B from a fender amp)

[s]http://soundcloud.com/musicthing/diy-spring-reverb-module[/s]

UPDATE: See revised schematic

limpmeat · Posted: Mon May 30, 2011 6:51 pm Post subject:

looks great, love the front panel

Neutron7 · Posted: Mon May 30, 2011 10:01 pm Post subject:

that tank sounds really nice. great job!

mikecameron · Posted: Mon May 30, 2011 11:17 pm Post subject:

I have been thinking of doing this very thing! Thanks for sharing your work, I'll be building it soon. applause

jimmyambulance · Posted: Tue May 31, 2011 8:09 am Post subject:

can't wait to try this out!

Dego · Posted: Tue May 31, 2011 8:51 am Post subject:

Very nice

BugBrand · Posted: Tue May 31, 2011 9:05 am Post subject:

Nice work.
And especially thanks for the links to Roy Mallory's interesting articles.

mig27 · Posted: Tue May 31, 2011 9:55 am Post subject:

Nice one!

And I also dig the plexi front plate.
Looks a bit like my OSC303.

Care to share how you built these?
I'm currently looking cheaper front plate alternatives than the usual Schaeffer job

Thanks!

Michael

Tombola · Posted: Tue May 31, 2011 10:21 am Post subject:

Some notes about the laser panel process here:

http://www.muffwiggler.com/forum/viewtopic.php?t=35668

mig27 · Posted: Tue May 31, 2011 10:37 am Post subject:

Thanks, appreciated.
Must look into this closer--

M

KNYST · Posted: Tue May 31, 2011 11:27 am Post subject:

sound, panel, photos, work, are all: SlayerBadger!

Jarno · Posted: Tue May 31, 2011 3:54 pm Post subject:

Thought you needed something with a bit more oomph to drive a reverb tank. Nice n small this, superb!
thumbs up

fluxmonkey · Posted: Tue May 31, 2011 9:12 pm Post subject:

nice to hear a demo comparison between the 2 springs.

boothnavy · Posted: Tue May 31, 2011 10:49 pm Post subject:

If you made R10 in your circuit variable with a pot, could you then control the input amount?

Also, would any modification be necessary if using 15v?

Tombola · Posted: Wed Jun 01, 2011 2:28 am Post subject:

Boothnavy: I did try that on the breadboard with a 1k pot, because I assumed I'd build it with variable drive and fixed recovery. It didn't work well for me - very limited useful range, quick to distort in a nasty way, but then I didn't test it with a huge range of input signals.

Re: 15v - sorry, I have no idea - I guess the TL074 datasheet would give you the max voltage. The other values don't seem that critical so you'll probably be fine.

Tombola · Posted: Wed Jun 01, 2011 2:35 am Post subject:

R9 is another interesting one - it's a kind of damping/stabilising on the recovery circuit - worth experimenting with - or removing - on breadboard

Tombola · Posted: Wed Jun 01, 2011 4:47 am Post subject:

Glitch Militia · Posted: Wed Jun 01, 2011 10:21 am Post subject:

What input / output impedance is this designed for ? I do not know that tank that you got.

I currently got this one on breadboard, tweaking some values etc. I like the sound of yours, so I'll try that next. applause

Tombola · Posted: Wed Jun 01, 2011 10:25 am Post subject:

Both my tanks are 800 Ohm / 58 Ohm (input impedance / DC). 2575 Ohm / 200 Ohm (output impedance / DC).

Tombola · Posted: Sat Jun 11, 2011 7:07 am Post subject:

This shows off the sound of the big six spring tank quite well. (

Disappointingly, the six springs are actually mounted as three springs with joints between the separate springs... )

[s]http://soundcloud.com/musicthing/maths-qmmg-anti-oscillator-diy[/s]