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Author Topic: PRINT THRU  (Read 5196 times)

QUEEF BAG

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Re: PRINT THRU
« Reply #15 on: February 26, 2011, 04:02:39 am »

yup level will exasorbate print thru,

and the offending program material was very transient in nature,
though it wasn't slammin' loud.

the other machine does not have any print thru problems with the same
project at all.

at the moment i'm convinced it's the machine.
tho i could be wrong.  the next thing to swap is the audio cards.
if that yeilds no results, it's time to look at the bias signal.


as far as i know tape machine operating level is ALWAYS referenced to 185 nW/m
that IS zero vu on repro

there is always that thing of setting up a machine for +6 with a +3 tape,
then during repro set-up you would make the meters read -3...
but you know about that.
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slothus

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Re: PRINT THRU
« Reply #16 on: February 26, 2011, 08:22:47 am »

QUEEF BAG wrote on Sat, 26 February 2011 20:02

yup level will exasorbate print thru,


And shuttling the tape can reduce it somewhat. Thermal Idiots can be manipulated to a small degree that way.
Quote:


the other machine does not have any print thru problems with the same project at all.


Exact same reel of tape on the different machine calibrated exactly the same and same level to tape?

Quote:


as far as i know tape machine operating level is ALWAYS referenced to 185 nW/m
that IS zero vu on repro

there is always that thing of setting up a machine for +6 with a +3 tape,
then during repro set-up you would make the meters read -3...
but you know about that.



You're right but I maintain it should be notated as over 180nWb/m (ref/1Khz) these days. This equates to the old Ampex operating level of 185nWb/m at 700hz. +6 with a 700hz reference tone is a different fluxivity than with a 1K tone. Using 185nWb/m assumes a reference frequency of 700hz but then calling +6 355 nWb/m assumes a 1K reference tone.

I've had a few disagreements with assistants when I've asked for a particular cal on a machine over this. They've usually been wielding one of those old Ampex slide chart things as absolute proof that "+6" is 370 nWb/m, and could never be 355nWb/m.


Brent Punshon
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radardoug

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Re: PRINT THRU
« Reply #17 on: February 26, 2011, 02:25:14 pm »

250 nWB is now a common reference level, probably more than 185 or 180.
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QUEEF BAG

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Re: PRINT THRU
« Reply #18 on: February 26, 2011, 04:22:56 pm »

yeah i don't know anyone with a 185 or 180 nW/m tape.
they are all probably sticky by now.

i have seen 355 to 370nW/m on the side of +6 calibration tapes.
that has always bugged me.

different companies seem to have different ideas?

yeah same exact set up on the other machine.
no print thru. same reel of tape.

it is now just a puzzle, not a desparate issue now that
the other machine is in there and working fine, but
it will have to be fixed.  now i will have the time to find it.

i'll let ya know wuzzup

and thanks to eveyone!
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Greg Reierson

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Re: PRINT THRU
« Reply #19 on: February 26, 2011, 08:27:27 pm »

Try swapping transport parts like rollers and heads between decks. You might also look for a stray magnetic field from a motor or solenoid. Do you have a Gauss meter?


GR
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QUEEF BAG

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Re: PRINT THRU
« Reply #20 on: February 27, 2011, 01:55:55 am »

i do have a gauss meter, haven't used it yet.
good idea though.
degaussed everything in the tape path, including pinch roller
(old scully 2" story about that one)

the guys in studio B don't wanna give up that machine yet,
they loved the sound of it, except the print thru
and in spite if the fact we got the next machine tweakd to sound just
the same.

who am i to mess with the bond that that can develop between
man and machine ?
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radardoug

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Re: PRINT THRU
« Reply #21 on: February 27, 2011, 02:32:57 pm »

Are you sure its not audio getting from output back to input while its in record, and therefore adding an echo to the signal? You could prove this by recording at the front of a reel, and then at the back. Print through is the adjacent layer of tape printing, so at the front of the reel the print will be short delay, and at the end it will be long. If it doesn't vary, then its feedthrough, possibly in the in/out assembly. Use a burst of tone, easy to hear the starts and ends then.
Does the in/out assembly have its transformers fitted? Any funny loading on the outputs? Missing or dodgy ground to the in/out assembly?
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