UK Vintage Radio Repair and Restoration Powered By Google Custom Search Vintage Radio and TV Service Data

Go Back   UK Vintage Radio Repair and Restoration Discussion Forum > Specific Vintage Equipment > Vintage Tape (Audio), Cassette, Wire and Magnetic Disc Recorders and Players

Notices

Vintage Tape (Audio), Cassette, Wire and Magnetic Disc Recorders and Players Open-reel tape recorders, cassette recorders, 8-track players etc.

Closed Thread
 
Thread Tools
Old 6th Apr 2017, 3:55 pm   #21
TIMTAPE
Octode
 
Join Date: Jul 2006
Location: Perth, Western Australia
Posts: 1,965
Default Re: 8 track cartridge looping gaps in audio

Since the erase head is always a little "ahead" of the record head it will erase a small section of the old recording even beyond where you stopped recording. The only way to prevent that would be to shut off the erase head current fractionally before stopping recording.
How to arrange that?

Really, if you like "the sound of tape" why not have the best of both worlds? Record via a decent 3 head open reel tape machine to a digital recorder. You will have the tape sound - and at much better quality than a consumer 8 track machine could provide - and you will have the vastly superior editing capabilities of digital audio.
Many have also found that the sound of a suitably overdriven transformer such as in some guitarists' distortion pedals, is similar if not identical to overdriven analog tape, but without the noise and all the hassles of maintaining and operating an analog tape machine.

Last edited by TIMTAPE; 6th Apr 2017 at 4:12 pm.
TIMTAPE is offline  
Old 6th Apr 2017, 4:06 pm   #22
vapidleopard
Retired Dormant Member
 
Join Date: Sep 2015
Location: Wigan, Greater Manchester, UK.
Posts: 20
Default Re: 8 track cartridge looping gaps in audio

Quote:
Originally Posted by TIMTAPE View Post
Since the erase head is always a little "ahead" of the record head it will erase a small section of the old recording even beyond where you stopped recording. The only way to prevent that would be to shut off the erase head current fractionally before stopping recording.
How to arrange that?
Yes, this is what I'm leaning towards being the problem.
I've tried to put a switch on the only wire I can see coming from the erase head to the circuit board but I get pops in the audio. I must have done it wrong somehow. Someone on another forum suggests the pops may be 'bias spikes from other current shift through record head winding when you switch out'
No, me neither.
vapidleopard is offline  
Old 6th Apr 2017, 4:16 pm   #23
llama
Octode
 
llama's Avatar
 
Join Date: Jun 2006
Location: St Osyth, Nr Clacton, Essex, UK.
Posts: 1,482
Default Re: 8 track cartridge looping gaps in audio

Quote:
Originally Posted by vapidleopard View Post

Also, I'm guessing with it being for studio and not home use they will be quite expensive.
I've just looked at my old auction purchases and I paid £28 for a recordable ITC back in 2013. So not too expensive but pretty much the only one I've seen in the past few years!
Graham
__________________
Half my stuff is junk - trouble is, I don't know which half!
llama is offline  
Old 6th Apr 2017, 5:37 pm   #24
TIMTAPE
Octode
 
Join Date: Jul 2006
Location: Perth, Western Australia
Posts: 1,965
Default Re: 8 track cartridge looping gaps in audio

Quote:
Originally Posted by vapidleopard View Post
Quote:
Originally Posted by TIMTAPE View Post
Since the erase head is always a little "ahead" of the record head it will erase a small section of the old recording even beyond where you stopped recording. The only way to prevent that would be to shut off the erase head current fractionally before stopping recording.
How to arrange that?
Yes, this is what I'm leaning towards being the problem.
I've tried to put a switch on the only wire I can see coming from the erase head to the circuit board but I get pops in the audio. I must have done it wrong somehow. Someone on another forum suggests the pops may be 'bias spikes from other current shift through record head winding when you switch out'
No, me neither.
Yes they're right.

Both the erase head and the record head are fed from the same oscillator source. Most of the power goes to the erase head. When the erase head is disconnected, the oscillator's operating conditions are upset and it can no longer power the record head as it did. The quality of the recorded sound may change.

Also, any sharp disconnection or connection like that can magnetise the head, creating bumps and noises in the recording, and partially erasing previously recorded programme - even when just playing back - until the heads are properly demagnetised with the correct tool. Another problem best avoided.

Well designed machines ensure the oscillator current is controlled, both when "ramped up" and "ramped down".

In machines designed to disconnect the erase head, or both erase and record heads, a special circuit loads the oscillator with the same load as would have been provided by those heads, ensuring consistency of performance for the other heads still connected.

When you simply disconnected the erase head, all this carefully calibrated balance was upset.
TIMTAPE is offline  
Old 6th Apr 2017, 5:42 pm   #25
julie_m
Dekatron
 
Join Date: May 2008
Location: Derby, UK.
Posts: 7,735
Default Re: 8 track cartridge looping gaps in audio

Why not loop the audio digitally, which avoids the issue with a length of tape between the erase and record heads necessarliy being blank; but then recreate the "tape sound" by recording it onto tape using a three-head machine with the monitor switch set to "T" so you are listening to the signal from the tape? This will give you a slight delay, depending on the separation between the record and play heads.
__________________
If I have seen further than others, it is because I was standing on a pile of failed experiments.
julie_m is offline  
Old 6th Apr 2017, 6:47 pm   #26
vapidleopard
Retired Dormant Member
 
Join Date: Sep 2015
Location: Wigan, Greater Manchester, UK.
Posts: 20
Default Re: 8 track cartridge looping gaps in audio

I do exactly this with my akai 4000DS. Well, the latter. Using the reel to reel as the looper. With varying degrees of success.
I want to be able to do similar with the 8 track. I'm not looking for high quality at all. Quite the opposite in fact.
vapidleopard is offline  
Old 6th Apr 2017, 6:54 pm   #27
vapidleopard
Retired Dormant Member
 
Join Date: Sep 2015
Location: Wigan, Greater Manchester, UK.
Posts: 20
Default Re: 8 track cartridge looping gaps in audio

Quote:
Originally Posted by TIMTAPE View Post
Yes they're right.

Both the erase head and the record head are fed from the same oscillator source. Most of the power goes to the erase head. When the erase head is disconnected, the oscillator's operating conditions are upset and it can no longer power the record head as it did. The quality of the recorded sound may change.

Also, any sharp disconnection or connection like that can magnetise the head, creating bumps and noises in the recording, and partially erasing previously recorded programme - even when just playing back - until the heads are properly demagnetised with the correct tool. Another problem best avoided
This is what I was afraid of. So switching is definitely off the agenda.
So I need to be looking for either a newer model 8 track that has a delay/relay between the erase and rec/play heads or I look for a NAB recorder to go with my NAB carts. Or lastly, I settle for splicing pre-recorded audio as a compromise.

Thanks for the continued help and support people. I'm learning a lot here!
vapidleopard is offline  
Old 7th Apr 2017, 7:44 am   #28
radiotechnician
Pentode
 
Join Date: Jan 2013
Location: Powell River, British Columbia, Canada.
Posts: 217
Default Re: 8 track cartridge looping gaps in audio

Tape recorders in the past (my past) sometimes were furnished with
dubbing keys.

These were plastic devices shaped like a key that slid down to a slot
at the front bottom of the erase head. The key spaced the tape away from the
erase head pole , making overdubbing possible.

I don't recall the make of machine. Someone in forum surely will.
__________________
Steve Dow
VE7ASO
radiotechnician is offline  
Old 7th Apr 2017, 9:26 am   #29
ricard
Octode
 
ricard's Avatar
 
Join Date: Mar 2006
Location: Lund, Sweden
Posts: 1,631
Default Re: 8 track cartridge looping gaps in audio

In lieu of disconnecting the erase head, putting something in front of it to inhibit the magnetic flux from reaching the tape should be adequate. I remember doing that in my youth on a cassette recorder so I could do blind overdubs by re-recording over the same section of tape. You don't need something very thick, a piece of ordinary paper should be enough. I remember just taking a 1 cm wide strip of paper, and holding it in front of the erase head while closing the cassette door, leaving the top of the strip sticking out through the crack between the door and the bezel.
ricard is offline  
Old 7th Apr 2017, 11:44 am   #30
vapidleopard
Retired Dormant Member
 
Join Date: Sep 2015
Location: Wigan, Greater Manchester, UK.
Posts: 20
Default Re: 8 track cartridge looping gaps in audio

This would be ideal but the heads are hard to get at on my Akai CR81D. They are on the bottom of the machine, under all the electronics.
vapidleopard is offline  
Closed Thread

Thread Tools



All times are GMT +1. The time now is 3:21 pm.


All information and advice on this forum is subject to the WARNING AND DISCLAIMER located at https://www.vintage-radio.net/rules.html.
Failure to heed this warning may result in death or serious injury to yourself and/or others.


Powered by vBulletin®
Copyright ©2000 - 2024, vBulletin Solutions, Inc.
Copyright ©2002 - 2023, Paul Stenning.