DIY Cassette Tape Delay Pedal

[FcKw]

Hi,

it's been a while since my last post and effects build in general, but I recently got bitten by the DIY bug again and just wanted to share my newest build with you and the 3D designs I made, to give this build a proper home.

First of all it is a cassette tape delay pedal based on the Echo-Matic tape delay project and parts of a Marantz PMD-221 tape recorder. To make the PMDs parts footprint as small as possible, I removed most of the hardware, like potentiometers and switches, that were protruding from the mainboard and tape unit. I also designed and 3D-printed some smaller tape control buttons to help the tape unit to be as small as possible. The less important controls were removed or hardwired and the important ones included in the pedals control panel (rec level, limiter settings, speed control, speed switch). I also kept and relocated the record level meter for record level control and for looks, of course. ;-)

The Echo-Matic circuit also got some slight modifications:
In my opinion this circuit desperately needed an input buffer, without it, it was just insanely dampening the high frequencies of the guitars signal. I used a simple input buffer circuit like it is used in a tube screamer for example and the dampening was completely gone. I also added the "Stupidly Wonderful Tone Control 2" from amzfx before the input of the tape recorder circuit to be able to control the delays tonal characteristic, which is also a "must have" for more flexibility in my opinion.

The result is a wonderful sounding tape delay, that gets more and more pitch modulated with slower tape speeds/longer delays and leads to chorus-like effects when overlaying the guitars original signal, but it can also do very pristine shorter delays.

The cassette I am currently using is a TDK EC6M endless cassette that I modified to be see-through.

I uploaded my 3D models of the enclosure to Thingiverse if someone might be interested, the frame is printed with PLA filament and the top and bottom plates are cut out of carbon fiber: https://www.thingiverse.com/thing:4807390



I also made a first short demo video:

Next up would be designing a cassette that incorporates a second play head for longer pristine delays, that could perhaps also be moved by a slider, like it is done in other tape delay units...

Best,
Patrick

[garcho]

outstanding work, bravo!

[Marcos - Munky]

Amazing! One of my goals is to build a cassette delay, but it'll take lots of time until I can do it . Congrats on your build, it looks and sounds great.

[FcKw]

Thanks, I am also very happy with the outcome! But the actual tape delay isn't that much to build, just building the simple Echo-Matic circuit and connecting it to a 3-head tape recorder. Perhaps modifing the recorders speed control and adding a buffer to the Echo-Matics input and a tone control and you are done. I just made it harder for me, by having the idea to put everything together into a pedal-like enclosure.

But that is how I started, too:

[lv1s]

Amazing! Could you put schematic with your modifications, or PCB

[iainpunk]

that could perhaps also be moved by a slider, like it is done in other tape delay units

or by a motor for some vibrato/chorus type modulation on the delay.
or maybe a treadle?

cheers

[FcKw]

Amazing! Could you put schematic with your modifications, or PCB

OK, I will see if I can come up with a way to illustrate the modifications to the original Echo-Matic schematic... I only used a perfboard, so there is no PCB. I mainly followed the Echo-Matics original PCB layout.

that could perhaps also be moved by a slider, like it is done in other tape delay units

or by a motor for some vibrato/chorus type modulation on the delay.
or maybe a treadle? ...

Interesting ideas. The motor speed adjustment already introduces a nice pitch shift on slower speeds. With a movable play head I might already be able to dial in some modulation with an additionally adjustable delay time. The idea at the moment is to use the spare knob position I left me for modifications and perhaps design a mechanical system that moves the additional play head by turning the knob instead of hacking the nice top panel for a slider.