Silly question about P&G 8120

Just hooking up some of these faders & I want to check that I'm getting the connections right.

See attached data sheet.  When you look at the wiring diagram for the 8120 the ends of the fader are labelled 0dB & infinity dB.

Which one of these should be the top of the fader i.e where the signal is fed in ?    I'm think that infinity dB should be where the signal is fed in  & 0dB should be the 0v connection.  But then a lot of faders are labelled - infinity when the signal is turned down.  Just checking because i don't want to wire up a whole desks worth of them wrong .....

Attenuation 0dB to infinite (as shown in the panel garduation/slots section on the data sheet), so feed to 0V...
Also "pin 2 (infinty)&3 should joined to obtain cutoff"...
I DON´T KNOW IT but everything else would be highly misleading!

Rob Flinn said:

Just hooking up some of these faders & I want to check that I'm getting the connections right.

See attached data sheet.  When you look at the wiring diagram for the 8120 the ends of the fader are labelled 0dB & infinity dB.

Which one of these should be the top of the fader i.e where the signal is fed in ?    I'm think that infinity dB should be where the signal is fed in  & 0dB should be the 0v connection.

Click to expand...

Try the opposite...  0dB is unity gain or the top of the fader. Minus infinity is full attenuation or the bottom.

  But then a lot of faders are labelled - infinity when the signal is turned down.  Just checking because i don't want to wire up a whole desks worth of them wrong .....

Click to expand...

You can wire up just one and check...

JR

L´Andratté said:

Attenuation 0dB to infinite (as shown in the panel garduation/slots section on the data sheet), so feed to 0V...
Also "pin 2 (infinty)&3 should joined to obtain cutoff"...
I DON´T KNOW IT but everything else would be highly misleading!

Click to expand...

That makes sense comparing to the graduation for the faceplate, but really it's -infintity no infinity, so the sheet is a bit misleading....

Rob Flinn said:

That makes sense comparing to the graduation for the faceplate, but really it's -infintity no infinity, so the sheet is a bit misleading....

Click to expand...

Not really. The designations refer to attenuation.
So 0dB indicates no attenuation ( unity 'gain' ie 0dB)
'infinity' indicates infinite attenuation

Of course mixing desks are often configured to have, say, 10dB gain at the top of the fader but that is realised electronically (obvs).
The 'infinite'  end of the fader is still infinite attenuation (ideally).

For transparency : ex- P&G employee

btw - and apologies if pointing out the obvious - but the 8000 series have carbon loaded plastic bodies (assuming they are same as when I was there). To get proper screening you must 'earth' (ground) them at the insert as indicated in the datasheet figure.
I recall we had complaints where a customer had neglected this (maybe used nylon screws - it's a long time ago now !)

Newmarket said:

Not really. The designations refer to attenuation.
So 0dB indicates no attenuation ( unity 'gain' ie 0dB)
'infinity' indicates infinite attenuation

Of course mixing desks are often configured to have, say, 10dB gain at the top of the fader but that is realised electronically (obvs).
The 'infinite'  end of the fader is still infinite attenuation (ideally).

For transparency : ex- P&G employee

Click to expand...

I think the confusion came into because I had to design some fader plates for them.  I was looking at some incompatible fader plates I had for some inspiration & all the figures on the plates had a "-" before the figure.  i.e -5, -10 etc  Whereas the P&G data sheet panel graduation chart just has the numerals.