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DIY Stompboxes => Building your own stompbox => Topic started by: mattthegamer463 on April 27, 2012, 11:11:51 PM

Title: DIY Tape Looper
Post by: mattthegamer463 on April 27, 2012, 11:11:51 PM
Hey guys,

Found a broken CD/Tape/radio combo and thought I could make a tape looper, so I carved it up and am working on an enclosure, then I'll build a circuit for motor control, amplifier, etc. and footswitch controls.

At present

(http://img.photobucket.com/albums/v321/mattthegamer463/Guitar%20Pedals/th_IMAG0543Custom.jpg) (http://smg.photobucket.com/albums/v321/mattthegamer463/Guitar%20Pedals/?action=view&current=IMAG0543Custom.jpg) (http://img.photobucket.com/albums/v321/mattthegamer463/Guitar%20Pedals/th_IMAG0544Custom.jpg) (http://smg.photobucket.com/albums/v321/mattthegamer463/Guitar%20Pedals/?action=view&current=IMAG0544Custom.jpg)

I'll keep you guys updated, I'm sure someone will find this interesting.
Title: Re: DIY Tape Looper
Post by: mattthegamer463 on April 30, 2012, 07:00:39 PM
Finished up the enclosure because this is my last week of machine shop access, time to start working on the electronics.

(http://img.photobucket.com/albums/v321/mattthegamer463/Guitar%20Pedals/th_DSC08103Custom.jpg) (http://smg.photobucket.com/albums/v321/mattthegamer463/Guitar%20Pedals/?action=view&current=DSC08103Custom.jpg) (http://img.photobucket.com/albums/v321/mattthegamer463/Guitar%20Pedals/th_DSC08104Custom.jpg) (http://smg.photobucket.com/albums/v321/mattthegamer463/Guitar%20Pedals/?action=view&current=DSC08104Custom.jpg) (http://img.photobucket.com/albums/v321/mattthegamer463/Guitar%20Pedals/th_DSC08105Custom.jpg) (http://smg.photobucket.com/albums/v321/mattthegamer463/Guitar%20Pedals/?action=view&current=DSC08105Custom.jpg) (http://img.photobucket.com/albums/v321/mattthegamer463/Guitar%20Pedals/th_DSC08106Custom.jpg) (http://smg.photobucket.com/albums/v321/mattthegamer463/Guitar%20Pedals/?action=view&current=DSC08106Custom.jpg)
Title: Re: DIY Tape Looper
Post by: joelindsey on April 30, 2012, 09:46:11 PM
That certainly looks cool! I commend you for going ahead with a cassette loop/delay device. There's been a great deal of discussion about it but I've yet to see anybody build anything like it.
Title: Re: DIY Tape Looper
Post by: deadastronaut on May 01, 2012, 09:47:50 AM
excellent, can't wait to hear/see it in action.... :icon_cool:
Title: Re: DIY Tape Looper
Post by: timd on May 01, 2012, 09:54:06 AM
I have been searching many sites recently for this exact kind of thing, but there isn't much info on how to construct them.
Title: Re: DIY Tape Looper
Post by: dirtysteev on May 01, 2012, 12:17:05 PM
Sweet. I tore apart an OLD tape deck the other day, down to it's bones, and what do I find? A cute little 9V motor attached to the drive, two wires for the playback head, two wires for the recording head. Simple. I think it is a prime candidate for turning into a looper/delay as well. I already rebuilt an amplifier for it, just need to work out the input controls and I think I want variable voltage on the drive itself for speed. Stay tuned.
Title: Re: DIY Tape Looper
Post by: garcho on May 01, 2012, 12:58:13 PM
I've wanted to build a cassette tape delay for years, exciting project.
Title: Re: DIY Tape Looper
Post by: artifus on May 01, 2012, 01:07:02 PM
http://www.diystompboxes.com/smfforum/index.php?topic=80091.0 (http://www.diystompboxes.com/smfforum/index.php?topic=80091.0)

http://www.diystompboxes.com/smfforum/index.php?topic=96092.0 (http://www.diystompboxes.com/smfforum/index.php?topic=96092.0)

http://www.diystompboxes.com/smfforum/index.php?topic=93339.0 (http://www.diystompboxes.com/smfforum/index.php?topic=93339.0)

few more ideas in the forum search
Title: Re: DIY Tape Looper
Post by: Colonel Angus on May 01, 2012, 01:54:07 PM
http://hackaday.com/2010/12/20/tape-delay-made-from-recycled-cassette-decks/ (http://hackaday.com/2010/12/20/tape-delay-made-from-recycled-cassette-decks/)

This is an awesome build, a tape delay DIY. Somewhat off-topic but related.
Title: Re: DIY Tape Looper
Post by: mattthegamer463 on May 01, 2012, 05:38:21 PM
Quote from: dirtysteev on May 01, 2012, 12:17:05 PM
Sweet. I tore apart an OLD tape deck the other day, down to it's bones, and what do I find? A cute little 9V motor attached to the drive, two wires for the playback head, two wires for the recording head. Simple. I think it is a prime candidate for turning into a looper/delay as well. I already rebuilt an amplifier for it, just need to work out the input controls and I think I want variable voltage on the drive itself for speed. Stay tuned.

Thats what I've got here, we should swap notes.  Does the deck still work or is it fully apart now?  I would be interested in seeing voltages into the heads when in play and record modes, to see if there is a DC bias (I think there is) and what the record amplitude is. 
Title: Re: DIY Tape Looper
Post by: Earthscum on May 01, 2012, 09:06:56 PM
Quote from: Colonel Angus on May 01, 2012, 01:54:07 PM
http://hackaday.com/2010/12/20/tape-delay-made-from-recycled-cassette-decks/ (http://hackaday.com/2010/12/20/tape-delay-made-from-recycled-cassette-decks/)

This is an awesome build, a tape delay DIY. Somewhat off-topic but related.

HA! That's awesome... I have one head, but it's single sided (not auto-reverse). I was going to hack apart a couple auto-reverse cassette decks, one for write and one for record (use the full width of the tape). I see new (probably considered "NOS" :lol: ) tapes at the flea markets, or new cheapy tapes at the dollar stores. I'd much rather just buy a couple of the heads, but my searches have revealed no source for tape heads.  :icon_cry:
Title: Re: DIY Tape Looper
Post by: ashcat_lt on May 02, 2012, 06:38:42 AM
^^^You know those cassette things you plug into your ipod for cars without an Aux input?  ;)
Title: Re: DIY Tape Looper
Post by: mattthegamer463 on May 04, 2012, 09:51:16 PM
I've done some experimenting, and it looks like playing tapes back is way easier than recording them, but both can likely be done without too much trouble.  Investigating my tape deck, I found that when recording the head was receiving a 32V p-p 106kHz sine wave.  I had a 1kHz source hooked to the input and I wasn't seeing anything but pure wave so I'm not sure what was going on there but it could have been a channel mixup so I'll look into it further this weekend, and try to find more parameters to work with.

I was initially under the impression that the 2nd head in the unit is for recording, and the main one was playback but in fact that is an erase head, play/rec is all done on the center head.  This is disappointing since the device can't be used as a delay without heavy modification.   Looks like a looper will be the only function.

My homemade loop tape seems to be working so I'll hopefully be able to do some more tinkering soon.  My tape deck is malfunctioning and won't even record on unmodified tapes, so I need to find another one so I can make some sweep signal test tapes for developing and tuning the playback EQ.
Title: Re: DIY Tape Looper
Post by: bassesofdeath on May 04, 2012, 10:19:50 PM
http://www.mysterycircuits.com/drumssette/drumssette.html
Title: Re: DIY Tape Looper
Post by: mattthegamer463 on May 04, 2012, 10:48:30 PM
Quote from: bassesofdeath on May 04, 2012, 10:19:50 PM
http://www.mysterycircuits.com/drumssette/drumssette.html

That is super cool, what a great way to do it.  You could even swap tapes for different samples, so genius.
Title: Re: DIY Tape Looper
Post by: joelindsey on May 05, 2012, 01:21:14 AM
Quote from: bassesofdeath on May 04, 2012, 10:19:50 PM
http://www.mysterycircuits.com/drumssette/drumssette.html

I love Mike Walters' work. Not only are his pieces polished and useful, they look great too. The Melloman cassette keyboard is amazing, my sister used it on her second EP. She had it at her house for a while so I had a chance to play it. Fun stuff!
Title: Re: DIY Tape Looper
Post by: mattthegamer463 on May 09, 2012, 08:03:01 PM
After much poking around with a partly-broken cassette deck, I have learned it uses a 32V p-p sine wave at 106kHz as a carrier frequency when recording.  My circuitry plan is:

Recording circuit:

Sine generator-------
                              mixing amp stage -------- magnetic head
Buffered input-------

Playback:

magnetic head-------  amplifier -------- demodulator (low pass filter or possible cancellation circuit) -------- 5 band EQ ------ amplifier --------- output to amp

It'll be lots of work to figure out how the heck to do all this.  I have a feeling it will work, if it sounds good is another story.
Title: Re: DIY Tape Looper
Post by: joegagan on May 09, 2012, 09:49:24 PM
Mike walters, my new hero.

Mattgamer, kudos for taking on such an ambitious project. Will be watching this thread for sure.