Audio Delay Circuit

Well..... 3.75 ips was a standard tape speed but dedicated echo units like Wem's Copycat didn't bother about that.

One of the nicer echo units actually used a magentic drum. No tape splices to pop-click !

Graham

--
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.

--
You\'d still have to screw around with the take-up lever/tension
adjustments and make sure the tape tracked over both sets of heads.

Sounds kind of goofy to me.

I read in sci.electronics.design that John Fields wrote (in ) about 'Audio Delay Circuit', on Thu, 13 Oct 2005:

You lift off the pinch roller on one machine.

--
Regards, John Woodgate, OOO - Own Opinions Only.
If everything has been designed, a god designed evolution by natural selection.
http://www.jmwa.demon.co.uk Also see http://www.isce.org.uk

When I was in college I worked at the student radio station (WPGU). They used this method for call-in shows. IIRC, they used both heads on the same machine (echos were done by feeding the read head directly back to the write) and had the tape loop around other machines just because they were handy.

Goofy perhaps, but it worked.

--
  Keith

Yeah, but you're John Fields.

--
Flap!
The Pig Bladder from Uranus, still waiting for that
hot babe to ask what my favorite planet is. ;-j

--
The way I read the suggestion was that the read head was going to be
on one machine, the write head on another, and that the tape was
going to strung between the two machines; one doing the reading and
the other doing the writing.

Two sets of heads on a _single_ machine, easy!  Two sets of heads on
different machines, not-so-easy to goofy.  Is that kind of a rig
what you\'re talking about?

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

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

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

Cheers! Rich

I read in sci.electronics.design that John Fields wrote (in ) about 'Audio Delay Circuit', on Thu, 13 Oct 2005:

Nevertheless, a lot of non-goofy people have done it successfully.

--
Regards, John Woodgate, OOO - Own Opinions Only.
If everything has been designed, a god designed evolution by natural selection.
http://www.jmwa.demon.co.uk Also see http://www.isce.org.uk

I read in sci.electronics.design that John Fields wrote (in ) about 'Audio Delay Circuit', on Thu, 13 Oct 2005:

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

--
Regards, John Woodgate, OOO - Own Opinions Only.
If everything has been designed, a god designed evolution by natural selection.
http://www.jmwa.demon.co.uk Also see http://www.isce.org.uk

This was for disc cutters in the old days

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,

martin

I read in sci.electronics.design that martin griffith wrote (in ) about 'Audio Delay Circuit', on Thu, 13 Oct 2005:

That's far too sophisticated.

--
Regards, John Woodgate, OOO - Own Opinions Only.
If everything has been designed, a god designed evolution by natural selection.
http://www.jmwa.demon.co.uk Also see http://www.isce.org.uk

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

--
Regards, John Woodgate, OOO - Own Opinions Only.
If everything has been designed, a god designed evolution by natural selection.
http://www.jmwa.demon.co.uk Also see http://www.isce.org.uk

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

martin

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

martin

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

Graham

Glue the tape to a drum ;-)

...Jim Thompson

-- | James E.Thompson, P.E. | mens | | Analog Innovations, Inc. | et | | Analog/Mixed-Signal ASIC's and Discrete Systems | manus | | Phoenix, Arizona Voice:(480)460-2350 | | | E-mail Address at Website Fax:(480)460-2142 | Brass Rat | |

| 1962 | I love to cook with wine. Sometimes I even put it in the food.