Ampex repro playback head details

Hi

First post here, so hope Ive got it right. I couldnt find a match for this in the groupediy search engine so Ive opened a new subject.

Ive have a old Ampex repro playback head labelled "Ampex 7680023-03 with a 7- underneath"  Does anybody know anything about it ? ie what was it used in, pinouts, loading etc the DCR measures 55 ohms.

I have goon through lots of Ampex manuals and have never found any 768 series cat numbers, most of the heads are 404xxxx etc

thanks in advance if anybody reads this.

...DCR measures 55 ohms.

Click to expand...

I hope you didn't measure the resistance with a multimeter! This will magnetize the head!

No big problem, should be defluxed regularily anyway..

Jakob E.

Picture please!

Good question for the Ampex mailing list.

Join up..  I'ts full of old time Ampex Guys with
lots of Ampex knowledge.

http://www.recordist.com/ampex/

GARY

Wow Thanks for quick response.

Ive added some pictures, tricky little things to photograph. I got it from a bloke at a ham swap it had 55 ohm the bag. I was a bit wary about hooking it up directly to the LCR meter anyway.

Thanks for the ampex list hint Ill head over there and join.

I was hoping this was a half decent head so I could play with building a simple playback system for it.

Ops new to this here is the back view ie terminals

and the front gap view.

1/4" 1/4 track head

time period (way its made) looks to be 60s and may be either a HiZ or Lo Z, but my guess is a Hi Z head.
could be a F-Line series or something similar

definitely consumer gear not pro, which does not mean its not a good head, mostly that the mounting arrangement is not as high quality as a pro head.

Alan

looks like the reproduce head from my F44. I think the heads in the 1200 series machines also looked like this. Definitely Hi-Z. They were decent heads. Wish I could say that for the transports they were mounted on. I believe the heads on the z-deck machines looked like this too. Wish he had photo'd the top of the head.

--rick

thanks

Im asking on Ampex list as well so Ill post any info I find out on both. Looks like I posted 2 pics of the front. So here is the top view.

I just found a link to them on the bay ( they look the same anyway ). Someone was selling a set. But no real info in the listing.

I will go and look at the service manual for the z-series deck (those were SS autoreverse decks sold around 1967. They were notorious for always needing belts)

I am looking at the Z deck service manual.  The head numbers are different,  7xxx numbers,  but no match.


Play 7040160-01
Play Rev 7040161-01
Rec  7040224-01
Erase 7040218-02


Closer.  Still no cigar.

Ive measured the heads for inductance as follows

top channel
@ 1000 hz parallel mode = 142.7 mH
@ 1000 hz series mode = 140.3 mH
@ 100 hz parallel mode = 199.0 mH
@ 100 hz series mode = 123.0 mH

bottom  channel
@ 1000 hz parallel mode = 146.0 mH
@ 1000 hz series mode = 143.9 mH
@ 100 hz parallel mode = 200.0 mH
@ 100 hz series mode = 121.0 mH

With a 55 ohm DCR this puts the head impedance in the 56 Ohm territory. Lowish I believe. ( hence high gain pb stages ? )

Its beginning to look like this is for one of the consumer series decks from the sixties although we have not yet found which model.