Dr ZEE
Anti-Pro Circles Insider
evm1024 said:
me waiting for the show
pls
me waiting for the show
pls
SteveMac
New member
cjacek said:
Jeez, the price.
evm1024
New member
All buffed up
Here are some photos of the heads buffed up and the tool used. I still need to do a full recalibration but as it stands it now is -3 db at 20kHz. Not bad.
Long as I had it apart I replaced the 4558/4559 opamps with OPA2132. I also noticed that it would be easy to switch it over to IEC-1 eq if one wanted.
I'll post a full response curve when I get a chance to cal it up again. Work has me tied up for the next week or so. Time will be short.
--Ethan
PS I suspect that a few hours tape motion will add to the polish....
Dr ZEE said:me waiting for the show
Here are some photos of the heads buffed up and the tool used. I still need to do a full recalibration but as it stands it now is -3 db at 20kHz. Not bad.
Long as I had it apart I replaced the 4558/4559 opamps with OPA2132. I also noticed that it would be easy to switch it over to IEC-1 eq if one wanted.
I'll post a full response curve when I get a chance to cal it up again. Work has me tied up for the next week or so. Time will be short.
--Ethan
PS I suspect that a few hours tape motion will add to the polish....
Attachments
B
Beck
Guest
SteveMac said:Jeez, the price.
The prices at USR are a bit high, but they were among the highest when they sold Quantegy tape, before and after the tape scare.
I look for prices to come down as more vendors pick up the RMGI line. It was just a few years ago that most tape houses gave us the choice of Quantegy or EMTEC. Hopefully they will all stock both again.
RMGI is way behind predictions... they are just now barely rolling out 1/2" tape and wider. The place we’re in right now is “so close but yet so far away.” Still some more waiting to go before we’re settled in.
T
Tim Gillett
Banned
Ethan,
I was just confused reading your initial post that you actually had the answer to the problem right in your hand and nobody really needed to tell you anything more.
Re photos of heads, they really need to be much more magnified to be of any use for diagnosis. The working faces of tape heads need to be viewed at least with some kind of magnifying lupe. I mean when looking at them with your eye. The most important area is the part where the tape actually touches the head, ie: the small area around the gap.
I seem to have spent much of the last 20 years staring at tape head faces through magnifying lupes, both before and after relapping. Since I'm not a youngster any more I need more magnification than I used to but even so, some sort of magnification (close up lens) would be necessary even for the younger folk.
Sometimes sticky shed muck can be very hard to remove and, if left on there for a long time, can corrode the surface because it seems to hold moisture.
Sometimes the head needs relapping because of this even though it's not worn in a mechanical sense.
You're right that recording tape itself can do an excellent final job of polishing the head face to perfection.
With good reel machines running at say 15ips it should be dead easy to get flat 20hz to 20khz specs. (In my area of high speed cassette duplication, running cassettes at 15ips, the aim is to get it flat to 80khz!) There should be no need to crank up play or record eq. If you are having to set trim pots anywhere near their extremes there is something amiss and checking the heads themselves is always a good place to start.
Best wishes, Tim
I was just confused reading your initial post that you actually had the answer to the problem right in your hand and nobody really needed to tell you anything more.
Re photos of heads, they really need to be much more magnified to be of any use for diagnosis. The working faces of tape heads need to be viewed at least with some kind of magnifying lupe. I mean when looking at them with your eye. The most important area is the part where the tape actually touches the head, ie: the small area around the gap.
I seem to have spent much of the last 20 years staring at tape head faces through magnifying lupes, both before and after relapping. Since I'm not a youngster any more I need more magnification than I used to but even so, some sort of magnification (close up lens) would be necessary even for the younger folk.
Sometimes sticky shed muck can be very hard to remove and, if left on there for a long time, can corrode the surface because it seems to hold moisture.
Sometimes the head needs relapping because of this even though it's not worn in a mechanical sense.
You're right that recording tape itself can do an excellent final job of polishing the head face to perfection.
With good reel machines running at say 15ips it should be dead easy to get flat 20hz to 20khz specs. (In my area of high speed cassette duplication, running cassettes at 15ips, the aim is to get it flat to 80khz!) There should be no need to crank up play or record eq. If you are having to set trim pots anywhere near their extremes there is something amiss and checking the heads themselves is always a good place to start.
Best wishes, Tim
SteveMac
New member
Couple questions about this
I have a couple questions
Is it always safe to buffer the heads?
Are all heads supposed to be "mirror like"?
What exactly is "the gap"
I have a couple questions
Is it always safe to buffer the heads?
Are all heads supposed to be "mirror like"?
What exactly is "the gap"
SteveMac
New member
Well, I tried downloading it but this computer just doesn't have the wherewithall for a file that large I guess. Think I need a new computer.
EDIT: I did get to that page. Pretty interesting. I'll have to find a way to download that somehow.
EDIT: I did get to that page. Pretty interesting. I'll have to find a way to download that somehow.
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Dr ZEE
Anti-Pro Circles Insider
Dr ZEE
Anti-Pro Circles Insider
Dr ZEE
Anti-Pro Circles Insider
Steve, it's kind of pain in the neck reading large pdf files if the file is not on your computer but on the server... well, it's still possible.
anyhow, ... this document contains some interesting information and illustrations as well... not all related to audio recording... but I'd say it does not hurt to have some general idea about all that stuff .. if you've got time to waste , of course
anyhow, ... this document contains some interesting information and illustrations as well... not all related to audio recording... but I'd say it does not hurt to have some general idea about all that stuff .. if you've got time to waste , of course
jpmorris
Tape Wolf
Well it was a little on the chunky side. It might have been an idea to have given the file size. Now the B67 service manual is just evil. I'd never seen a 225MB PDF file before.Dr ZEE said: