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

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Old 28th Nov 2018, 10:25 pm   #1
Tom williams
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Default What is this for??

I have a Technics hi-fi (my dads) and inside the tape drive theres the normal tape head but next to it (left) there's this black thing I don't know what it's for, it looks like a tape head but it certainly isn't, anyone that could help would be great!
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Old 28th Nov 2018, 10:29 pm   #2
Techman
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Default Re: What is this for??

Must be the erase head.
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Old 28th Nov 2018, 10:41 pm   #3
Tom williams
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Default Re: What is this for??

The HiFi has two decks, one plays and the other is play / record, there are no wires coming out of the "head" however it is possible that part of it may be magnetised but that would be unusual because the deck that the "head" is in does not record it is only a playing deck
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Old 28th Nov 2018, 10:43 pm   #4
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Default Re: What is this for??

It's a dummy head then.
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Old 29th Nov 2018, 12:26 am   #5
RojDW48
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Default Re: What is this for??

Maybe a dummy head to keep the tension correct and allow for substitution of a second record head for SOS operation?
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Old 29th Nov 2018, 12:41 am   #6
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Default Re: What is this for??

The erase head works as a guide in playback mode on the recorder deck so a plastic guide is obviously going to be present the player deck.
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Old 29th Nov 2018, 2:23 am   #7
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Default Re: What is this for??

I have two 1980's music centres with twin cassette decks, a Sony and a Philips. In both, there is a dummy plastic head, with integral tape guides, in the playback-only deck in the position of the erase head of the record/playback deck.
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Old 29th Nov 2018, 7:46 am   #8
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Default Re: What is this for??

Some years back, there was a trend in lower budget portable recorders and stack
systems to use a small permanent magnet erase head, a technique not seen since the
1960's. This could lead to the tape and the record/playback head becoming permanently magnetised.

Such heads were ferrite and mounted on a spindle, in all modes except record
the head was held away from the tape path by a spring.
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Old 29th Nov 2018, 8:48 am   #9
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Default Re: What is this for??

Quote:
Originally Posted by RojDW48 View Post
Maybe a dummy head to keep the tension correct
That is correct. The playback only deck will have one of these dummy heads in place of the erase head. The dummy head also has tape guides so the tension is maintained and also the tape path.
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Old 29th Nov 2018, 11:07 am   #10
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Default Re: What is this for??

Restoration73

Quote:
Some years back, there was a trend in lower budget portable recorders and stack systems to use a small permanent magnet erase head, a technique not seen since the 1960's.
They were still being used in Roberts's C9950 premium cassette recorder in the mid 90's and, when recording, it caused an underlying hash on the recording. When I raised the problem with Roberts, their response was: "The recorder wasn't designed nor built by them" he went on to suggest a cure: "It's easy to remove the erase head by pulling it away from the mounting peg"

So, I have two same machines, one with the erase head removed, which I use for recording (later I erase recordings for re-use). The other machine for playback only.
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Old 29th Nov 2018, 11:13 am   #11
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Default Re: What is this for??

I once had a cheap shoe box cassette recorder that applied DC to a head for erase.
The recordings were horrid due to the DC bias.
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Old 29th Nov 2018, 11:24 am   #12
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Default Re: What is this for??

I bought my Philips music centre as it was the only one I could find that did not have a permanent magnet erase head.
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Old 30th Nov 2018, 12:56 am   #13
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Default Re: What is this for??

Yes it's a tape guide to keep the tape in the centre, height wise. Without this, the tape height could change or wander and affect the azimuth angle on the record/play head downstream.

Most cassette erase heads contain a thin hardened metal height guide, glued or clamped to the entry side of the erase head. In that case it maintains the tape height for the erase head as well as for the record/play head.

These guides can wear over time because the thin oxide covered tape can act like a fine saw or knife. A deep cut in the metal or plastic guide can develop which can only be seen with a good eye or under magnification.
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