Question for tape delay design - Page 1
Forum section: electronics / projects

author: sahko123
author_rank: Frequent Contributor
timestamp: October 06, 2019, 09:34:48 pm
content: thanks for reading this,I'm designing a tape delay for an fx rack and i have two questions i have a tape player that ive mostly dismantled. Can cassette erase heads work as mono recording heads if re-wired with the appropriate circuitry installed. and what voltages for the signal and bias would be appropriate for the use.

author: Le_Bassiste
author_rank: Frequent Contributor
timestamp: October 06, 2019, 10:46:57 pm
content: nice project idea and simple answer: no. tape erasure is accomplished with high frequency magnetic fields generated by the erase head. thus, the erase head is simply too small to deliver a useful frequency response in the audio range. so, in practice, you need at least a 3-head tape deck for your project. with that setup, you will of course have to make the tape speed variable in order to get different "room sizes", i.e., different delay times.in the good old analog times, there were also designs that used multiple playback heads for even fancier delay effects. irc, the WEM copicat had quite a fan base with fender rhodes piano players, albeit utterly noisy.http://www.vintagehofner.co.uk/britamps/watkins/copicat/copi8.htmledit: on the "spectrum" album by billy cobham, the track "snoopy's search" has a guitar solo by marc bolan, where he uses slapback echoes, causing a huge "hiss" on the recording. that's how the copicats sounded.hth!

author: dmills
author_rank: Super Contributor
timestamp: October 06, 2019, 11:40:15 pm
content: Also replay heads have a really small gap, where record heads, not so much (the recording is defined by the tape passing under the trailing edge of the gap, while the playback is in effect integrating the flux in the gap hence different designs)...Regards, Dan.

author: sahko123
author_rank: Frequent Contributor
timestamp: October 07, 2019, 08:49:50 am
content: So in other words I'd need a different tape head. Which means I'd probably have to frankenstein one in

author: Le_Bassiste
author_rank: Frequent Contributor
timestamp: October 07, 2019, 12:31:11 pm
content: here's a picture of a 3-head arrangement in a stereo cassette player. note that record- and playback-head are combined into a single head unit that has two prominent "bulges".

author: sahko123
author_rank: Frequent Contributor
timestamp: October 07, 2019, 02:21:48 pm
content: If I manage to mod a record / play head in place of the erase head to get the first recording and the next playing. And I'm not really looking for high fidelity a bit of distortion is welcome

author: jonovid
author_rank: Super Contributor
timestamp: October 07, 2019, 02:55:58 pm
content: when looking at the classic Roland RE-201, or the Space Echo.I see what your trying to do with a cassette tape drive,ben there done that, as a kid., why reinvent the wheel.the Space Echo schematics are out there.take the time to see why cassette tape maybe problematic limiting you to only 3 tape headswhy 6.4 mm reel-to-reel audio tape loop is best tape echo you can imitate.that best echo IMO is a empty room, following that is a classic plate echo - see videothe classic Roland RE-201, or the Space Echo will work as a tape delay

author: jbeng
author_rank: Regular Contributor
timestamp: October 08, 2019, 12:17:20 am
content: You can also Google "Echoplex EP-3 schematic".That will yield schematics of the actual tape delay units used by "many notable guitarists of the 1970's", according to WikiPedia.