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  #1  
Old 02-17-2017, 08:10 AM
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steerpike steerpike is offline
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Nortronics heads in an MCI JH110 mono to stereo conversion

Hi All,

I have two MCI JH-110 -inch machines, both mono, saved from dumping, so cost me nothing.

Also I have acquired Nortronics -track medium-impedance "premium" Record and Repro heads: I'd like move one electronics block across from one 110 machine to the other to create one stereo machine.

I'll retain the original full-track erase head, since I will never have a need to re-record only one track.

Are the Nortronics heads a good match for a JH110?
I have found posts that say mechanically they fit pefectly, but no comments on their audio performance or how they match the MCI amplifiers.

Any ideas, or suggestions please?
  #2  
Old 02-18-2017, 07:23 PM
goldear goldear is offline
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I purchased a pair of Notronics heads for my MCI about 10 years ago from one of the original Nortronics guys. He told me that the heads that he was selling me the should be drop-in compatible with the originals. But do you have the same heads as I purchased? Who knows...

Unfortunately this is one of many projects which I have never had time to get around to, so I can't tell you how it worked out. Unfortunately I can tell you from experience that the MCIs have hundreds of those little red devil caps which love to fail short, and fry resistors. So I recommend replacing all of those before doing anything else.
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  #3  
Old 02-21-2017, 07:26 AM
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steerpike steerpike is offline
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Thanks for the comments.
I'll try it! The mono heads are very worn (machines are from the national broadcaster), and without a head transplant they are unlikely to ever get any use at all.
Cap replacement, yes I heard that. And IC sockets too.

The way the MCI head mounts work, and the way the headblock just pulls right out, make head work on this machine such a stress-less delight!

Last edited by steerpike; 02-21-2017 at 01:52 PM.
  #4  
Old 02-26-2017, 01:10 PM
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390FE 390FE is offline
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Have you by any chance tried to measure the impedance & dc resistance of the original mono heads & the one channel of the Nortronics stereo heads to see what the diff is?

Of course you will need to demag the heads after your testing of them.
  #5  
Old 02-26-2017, 01:29 PM
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steerpike steerpike is offline
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Quote:
Originally Posted by 390FE View Post
Have you by any chance tried to measure the impedance & dc resistance of the original mono heads & the one channel of the Nortronics stereo heads to see what the diff is?

Of course you will need to demag the heads after your testing of them.
I will have to measure the Z of both sets of heads, Originals and Nortronics.
My data on the Nortronics just says 'Medium impedance", no specifics, and no info on gap width or DC resistance either :-(

The Nortronics heads lack the magnetic shielding that extends beyond the face of the head - as the originals have. But I see photos of multitrack MCIs also have heads without this type of shielding.
  #6  
Old 02-26-2017, 06:27 PM
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390FE 390FE is offline
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Quote:
Originally Posted by steerpike View Post
The Nortronics heads lack the magnetic shielding that extends beyond the face of the head - as the originals have. But I see photos of multitrack MCIs also have heads without this type of shielding.

Are the original shields removable such that you could adapt them to the Nortronics heads? Or maybe you could adapt some Teac shields?
  #7  
Old 02-27-2017, 02:23 AM
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steerpike steerpike is offline
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Quote:
Originally Posted by 390FE View Post
Are the original shields removable such that you could adapt them to the Nortronics heads? Or maybe you could adapt some Teac shields?
No space! The Nortronics heads as they are, are a very snug fit into the head mounting casting. No chance to get any sort of shield around them and still fit them into the mounting.
  #8  
Old 03-01-2017, 03:26 PM
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That is a bummer. How about something like maybe copper tape, aluminum tape or even a very thin gauge of metal/foil to make a custom shield?

Please post some pics of the head block on the deck. Would be interesting to see what you have to work with & what you are working on.
  #9  
Old 03-03-2017, 02:13 PM
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I'll do some photos.
Maybe the Nortronics heads do not need such a shield? I've seen photos like this ones below, where there is no additional magnetic screen.

There is also present the 'pop-up' screen that is not part of the headblock, in front of the tape (in the second photo, it is in the 'down' position in it's slot in front of the head).



  #10  
Old 03-03-2017, 06:47 PM
Knasty Knasty is offline
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Have you contacted Chris Mara in Nashville Kentucky? He rebuilds MCI's to new condition.
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