Telefunken Tape Machine Level Matching

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ruffrecords

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What tape speed and level did you do the frequency response test?

If it was 7.5ips (19cm/s) you need to do it at no higher than -10dB on the VU meter. At 15ips/38cm/s you can do it at 0dBu.

Cheers

Ian
 

Dr_J

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Hey Ian,

i did it at 19cm/s and 0dbu (1.228V) approximately. I'll check that and then try -10db.

THANKS & Cheers!
 

Dr_J

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Hey Guys,

need some help here again...
I'm struggling at one point...

The units output is unbalanced (DIN 5 pol).
As Abbey pointed to a wrong connection, I changed to a unbalanced Cable for connecting the interface (patchbay)... higher input level; fine.

Ok, according to RANE-Notes #110 unbalanced to balanced (case #14) is TIP->TIP, Shield -> RING.


ROCK-ON!
 
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Dr_J

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Hey,

the box isn't wired (properly) jet...
I try to figure out what would be the best way...
Till now I used an unbalanced TRS cable (TIP to TIP, Ground to RING) for testing.
But in the end I would like to use (if it make sense) my balanced patchbay cables, no cable mix.


Thanks!
 

Dr_J

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Hey Guys,

an afternoon later of pulling my last hair out and getting totally lost at some point...

I found out that my DIGI002 Interface outputs seems to be Pseudo-balanced (I'm only getting on tip a signal), even the manual says "balanced outputs".

Now everything seems to work fine. Sending Sinus 1k@1.228V, getting back 1k@1.228V approximately :)
Here's a quick drawing of my wiring (following RaneNotes).

Next, I'll see what I can do on the high frequency response...


THANKS &
ROCK-ON!
 

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ruffrecords

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Quite a lot of interfaces these days have impedance balanced outputs. This means the hot is connected to an op amp output (usually via a resistor) and the cold is connected to analogue 0V via a resistor of the same value. This is why you only see a signal between hot and ground.

Remember, a balanced signal exists only between hot and cold. In a balanced cable, the ground is NOT a signal carrying conductor, it is a screen. The voltage between hot and ground and between cold and ground is NOT defined so don't even expect then to exist let alone be the same.

Cheers

Ian
 

Dr_J

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I like to tell the story till the end... (is this the end...?!? ;))

A quick idea for a little box for goofing with the old tape machine... ended up in much more work than expected and opened a door to a new world (reel-to-reel)... :)

Thanks again for helping!!

ROCK-ON!



P.S.: I did some tweaking on the heads position (more or less trying around) and could improve the frequency response quit a bit. Not perfect, but I think ok for the moment... we'll see...
 

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