Audio Delay Circuit

[Rich Grise]

I read in sci.electronics.design that martin griffith


That's far too sophisticated.

Well, who was it that suggested un-pinching the pinch roller on one
of the decks? And tying them together shouldn't be that hard - if
the two decks have the heads at the same height off the baseplate,
just a piece of scrap metal could keep them aligned. Sounds like it
should be a walk in the park.

(I used to do the alignment on 8-track players in the Radio Shack
repair shop. It was surprisingly easy to get them good enough to
get out the door. ;-) )

Cheers!
Rich

 

[Rich Grise]

I read in sci.electronics.design that John Fields


Yes, even 20 ft or so apart. You need intermediate support for the tape,
of course.

At 3.75 IPS, 10 seconds is only 37.5 inches, just under a 'metre'. ;-)

Mr. Woodgate, I suspect you're pulling our chain yet again. ;-P

Cheers!
Rich

 

[Rich Grise]

Yep, broadcast "profanity delays" for phone-ins, before ITC came out
with the swapped head NAB cartridge nightmare. Thats one thing
digitised audio did solve

You could do it on one stereo deck. Just use a Moebius tape loop. ;-D

Cheers!
Rich

 

[John Woodgate]

I read in sci.electronics.design that Rich Grise <[email protected]>

Well, who was it that suggested un-pinching the pinch roller on one of
the decks?

You can do that on el-cheapo machines that don't have things like
capstan servos.

 

[martin griffith]

You could do it on one stereo deck. Just use a Moebius tape loop. ;-D

Cheers!
Rich

bias, erase would be a significant challenge. Nice idea though


martin

 

[Pooh Bear]

---
Pretty close!-)

The CODEC - RAM - counter scheme is the right way to go, IMO.

In another life I used to work for an outfit named "2-Tel
Interconnect Systems" and we built an audio delay based on that
scheme for use with phone patches. Jumper selectable delays, as I
recall, up to about a half a second or so, but nothing inherently
limiting the delay other than depth of RAM. Also, as I recall, we
used 64k X 1 bit of dynamic RAM.

I've searched through my old stuff and couldn't find the schematics,
but the circuit at:

http://www.eetchina.com/ARTICLES/2003AUG/PDF/2003AUG29_AMD_AN02.PDF

(which link someone posted earlier) seems to be pretty close to what
we used.

The trick is to slacken off the pinch wheel pressure on one machine ( or
indeed completely disable it )

Graham

 

[John Fields]

This was for disc cutters in the old days
http://sphl.audiogon.com/cgi-bin/buy_auc.pl?anlgtabl&1128995648

But it can be done with 2 tape decks, you just have a tape tension
sensor between the decks that controls the capstan servo on one of the
decks,

 

[John Woodgate]

I read in sci.electronics.design that John Fields

_And_ the transports have to be aligned properly so that the tape won't
try to run off the capstans, and on and on, I think. Seems to me like
the long way 'round when it can be easily done with probably
substantially less than $10 worth of parts the other way(s).

Yes, it can NOW; those techniques were used when it couldn't be done
digitally.

 

[John Fields]

I read in sci.electronics.design that John Fields


Yes, even 20 ft or so apart. You need intermediate support for the tape,
of course.

---
And adequate tensioning mechanisms on both machines and God knows
what-all else, including a reason why to do it that way.

Seems a little bizarre for the OP's needs when for less than $10
worth of parts he can easily build it out of silicon.

 

[John Fields]

The trick is to slacken off the pinch wheel pressure on one machine ( or
indeed completely disable it )

 

[John Fields]

You could do it on one stereo deck. Just use a Moebius tape loop. ;-D

 

[John Fields]

Yeah, but you're John Fields.

 

[Rich Grise]

Ergo it _is_ goofy?

Yeah, that must be it.

Thanks,
Rich

 

[Rich Grise]

And adequate tensioning mechanisms on both machines and God knows
what-all else, including a reason why to do it that way.

Seems a little bizarre for the OP's needs when for less than $10
worth of parts he can easily build it out of silicon.

I'd be interested in seeing this circuit.

Thanks!
Rich

 

[Jim Thompson]

Doom and Gloom

Glue the tape to a drum ;-)

...Jim Thompson

 

[John Fields]

I'd be interested in seeing this circuit.

 

[Rich Grise]

Glue the tape to a drum ;-)

...Jim Thompson

Heaven sakes, Jim! I had to go back and check the thread to see what
in the world you were talking about!

But, yes, a drum would work too - see "G-15 drum memory":
http://www.computermuseum.li/Testpage/DRUM-Memory-BendixG15computer.htm

Obviously, it would have to spin verrrrry sloooooowwwwwly...

Cheers!
Rich

 

[Rich Grise]

The link to it's been posted twice already. Get off your lazy ass
and find it if you're interested.

This one?
http://www.eetchina.com/ARTICLES/2003AUG/PDF/2003AUG29_AMD_AN02.PDF

Thanks, but Mouser, Digi-key, and Newark come up 0, and the one source
that lists the chip (MX609P) is one of those "Register and give us your
personal information before we'll tell you how much it is" sites.

Where do you buy yours?

Thanks,
Rich

 

[Jim Thompson]

Heaven sakes, Jim! I had to go back and check the thread to see what
in the world you were talking about!

But, yes, a drum would work too - see "G-15 drum memory":
http://www.computermuseum.li/Testpage/DRUM-Memory-BendixG15computer.htm

Obviously, it would have to spin verrrrry sloooooowwwwwly...

Cheers!
Rich

3.75ips, for 5 second delay, would only be ~6 inches in diameter,
rotating at 12rpm ;-)

Maybe you could slow down a hard-drive ?

...Jim Thompson

 

[Pooh Bear]

Glue the tape to a drum ;-)

There were indeed proper drum based echo units.

http://www.binson.com/History/history.html


Graham