Homemade tape echo from scratch both hardware and circuitry

[darklife]

Started designing this around a year ago and have some experience because many of the parts came from an even older design I made back in 2004 or so when I was still in my late teens that didn't work worth crap (loved to eat tape) but I kept all the tape heads I collected and the idea never left me.

Not sure what bit me a year ago other than finding the old carcass of a long lost project I made so I scrapped the parts and went to town remaking what once barely worked as seen here from an early photo some 18 years ago...

OLD box, scroll down for new


Anyway I learned a lot about electronics since those early days and set out to design what I wished I could have back then....
Three head playback, feedback control, tape-on-tape (erase head off), VU meter, external bypass pedal jack, tilt tone control for playback heads, motor speed control from seconds of echo to slap back, dry mix that can be completely turned off for echo through only or vice verse, , large flyback wheel on the motor for the best stability I could aim for given my lack of hardware engineering, capability of both Type I and Type II tape. All using 1/8" cassette tape as the medium/loop for "easy" tape replacement.
I could go on but the video and pictures I will show speak for itself.

This is one of the cleaner shots I have with the tape head cover on..


And off..


Internals before I wrapped it all up..


Back of the unit (yes IEC plug for safety grounded to chassis internally and gain switch for both Mic and Guitar/Instrument input)..


And finally the schematic..




So here is the full imgur album of my build for more detailed pictures..
https://imgur.com/a/e3OLqCR

And for those who want to hear it and described how it works I do have it on youtube along with some other videos of the
build progress as I went along..
https://www.youtube.com/watch?v=EI8ZTQqLwwg



So a little description:

It's built into an old money storage box. I folded the lid sides upward to support a sheet of metal which I built the hardware onto. Everything was done using tin snips, drilling, and hand tooling.

Much of the hardware including the actual tape mechanisms itself like pinch roller and heads were from old tape decks that were completely trashed at some point. I always kept parts from old equipment throughout my youth for projects.

The circuitry is completely by me other than the bias oscillator which was partially copied from an old Superscope tape deck. I scavenged the erase head and bias transformer/transistors from it and rebuilt it onto perfboard with some modifications to work with my power supply voltages and heavier biasing because of the looser tape riding the heads.

It should not have took a year to build but it became such a long project from learning about tape head playback and recording along with the heavy amount of hardware fabrication from what was basically scrap metal and parts that at times I was wondering if I'd ever complete it from getting frustrated and bored with it.

Pretty glad the project came through and I think I am one of few if not the first person I see on the web to have built a tape echo from complete scratch. Only other projects I see are people modifying old tape decks or drive mechanisms.

Thanks for reading!
I'm happy to take any comments when I get to them

[darklife]

Been a while since I've been here, just in case imgur asks you folks to register again like the spring reverb project I made back in 2017 I will just repost the other images here so no need to go off site:

[darklife]

Quick schematic update, forgot to draw a ground symbol in the tone control..

Can't seem to find the edit button.

[GibsonGM]

Dude - that's *&&&*((( amazing!   

[Mick Bailey]

That's quite an achievement and something to take pride in. A nice combination of electronics, mechanics and electro-mechanical skills, and I admire anyone who can put all of these together to come up with what you have done. This is exactly the type of project that keeps me interested in music electronics.