UA1176 Rev F alignment procedure

Can anyone help me out with a setup procedure for this limiter (OEM, not clone)?.
Also, is it necessary to match the main and meter fets, and is the 2n5457 a good device to use.
Cheers
M

mobyd said:

Can anyone help me out with a setup procedure for this limiter (OEM, not clone)?.
Also, is it necessary to match the main and meter fets, and is the 2n5457 a good device to use.
Cheers
M

Click to expand...

Set up procedure is given in the manual which is available on line.

It is necessary to match the main and meter FETs for the same pinch off voltage,

I think the original uses a BF245A FET which is still available (Mouser). I see no reason to change it.

Cheers

Ian

ruffrecords said:

Set up procedure is given in the manual which is available on line.
Ian

Click to expand...

The online manual I have found makes no sense.
The "Q" bias bit works as expected but the "Gain Reduction & meter tracking" bit requires you to start with the Output
pot at full clockwise then "turn the output level clockwise until meter reads 0 VU"
Well you can't get any clockwiser than full clockwise so I'm assuming these instructions are bogus.
In any case I never get the required drop in output when I turn on the attack control so I'm looking for better/more information.
cheers
M

on line is the  'UREI-1176LNfullmanual.pdf'  version...a huge version with much to wade thru... look for that.

a good source of 1176 info


as far as the GR and meter tracking...

start with the output level fully  counter clockwise, turn level control clockwise until meter reads 0VU.

(start will level all the way down. turn up til zero)

ahhh...

this one  http://www.jblproservice.com/pdf/vintage%20jbl-urei%20electronics/urei-1176lnmanual.pdf

Lining up an 1176 is a demonic, evil task. I'm pretty sure I worked on a rev F once - not fun. The 'Q trimpot' is ridiculously sensitive and has enough backlash to bounce through the right setting for a good 3-5 minutes. Tapping the pot with a screwdriver to fine tune it seemed to be more predictable. This makes me think that any adjustments are going to warp with time and temperature anyway, so why are we bothering here. The instructions I read were very circular and sort of wrong, so maybe I found the wrong manual too? I cobbled a procedure together that seemed to work, but I chased my tail for a couple of hours, and I'm not sure why. Finally, the meters are garbage, and shouldn't be relied on for anything except providing GR induced wiggle to the operator. Do not trust zero or any levels that you read from them. Use an AP or a quality RMS voltmeter instead.

Best of luck! It is possible to make the machine do something somewhat consistently, but home dental surgery would be more pleasant.