Tandberg tape recorders

[hum-bucket]

anyone have experience of modifying the tape recorder "Tandberg 15" to a tape delay???

or maybe you have a Circuit Diagram???

(the playback and record-head is the same)

/h

[sreten]

Hmmm......

very difficult to mod a tape recorder for delay unless it has
two seperate heads and seperate record and replay circuits.

/sreten.

[AuroraB]

There must be a misunderstnding somewhere.....
as far as I know, all Tendbergs of this age had 3 heads...
Check this link for Tandberg recorder history
http://www.nrhf.no/nrhf-TB.html

[dnsey]

The Tandberg Series 15 isn't really a very good candidate for this mod, as (IIRC) it has a synchronous capstan motor. Assuming you want the delay for creative purposes, you really need to have a continuously variable speed drive so that the delay can be varied. Other than that, you're into moving the replay head (very doifficult whilst maintaining azumith etc.) or introducing a variable loop between the heads (do-able - was used in the early days of 'skying').
The electronic side is easy enough if you have a machine with A-B monitoring - no real modification needed. Haven't we all at some time played the game of trying to speak fluently whilst monitoring the sound off-tape with headphones

[hum-bucket]

Hi!

"unless it has
two seperate heads and seperate record and replay circuits"

-I´m planning to put one head from another tandberg 15 recorder as a playbackhead and put a swich for which head to listen to.
I think it has seperate circuits becouse of the different frequency responce of the two heads recorder normally have.
The azimuth is not realy the biggist problem (I hope... ) though it would be a lo-fi ecco effect.


"all Tendbergs of this age had 3 heads..."

-check the picture!


"Assuming you want the delay for creative purposes, you really need to have a continuously variable speed drive so that the delay can be varied"

-well, just the sound and distortion of the tape is a reason do this. And if i want to **** with the sound I can just put my thomb on the tape and slow it down, if I change speed while running I will probably get some interesting effects.


so what do you think...?
What is the 4 cables for? check picture!
A circ.diagram is what I need anyway...

(It´s a model 15-22 mono 2 track.)

/h

[hum-bucket]

backside of the head:

[EC8010]

Welcome to the forum, hum-bucket. As sreten says, you need a three-headed machine for tape delay. I remember modifying a pair of Tandberg Series 15 whilst at school to give stereo. We had one that was ours for stage sound effects etc, and we managed to borrow the one that the French department had (and didn't use). I opened up the French dept's machine and disconnected the wires from the head and took them to a socket round the back, made up a lead, and connected the spare section of the head on "our" machine to another socket so that the two could be plugged together. I'd have been in all sorts of trouble if I had been found out...

Looking back, it's surprising that we didn't have trouble from the two bias oscillators beating, but it seemed to work.

[hum-bucket]

"Welcome to the forum, hum-bucket. "

-thanks!

"As sreten says, you need a three-headed machine for tape delay."

-I know the princip, I´ve played around making sound with a studer...
I´m trying to modify my 2 head machine to a 3 head....
just need to know if it´s realy possible and the control functions.

here are the pix:

http://www.oplen.com/tandberg1.jpg

http://www.oplen.com/tandberg2backside.jpg

/h

[EC8010]

You can pick up second-hand professional three-headed machines very cheaply nowadays, so unless you want to learn about tape machine design, I'd give modifying the Tandberg a miss. You see, a three-headed machine has a set of record electronics and a set of replay electronics. Now, you could modify a phono stage to be a tape replay amplifier, but it all seems a lot of work...

[dnsey]

I think it has seperate circuits becouse of the different frequency responce of the two heads recorder normally have

Most domestic machines have one set of amps, with fairly comlex switching to cater for record / replay requirements.
I don't have Series 15 ccts to hand, but certainly even some of the more 'professional' Tandbergs had shared amps.
If you want to use 'mechanical' methods to vary delay, try a cam between the heads, running on the tape, which will vary loop length. for worthwhile effects, you will also want to feed back the output of the replay head to the record side (with variable gain).