Urei 1178 compressor setup issue

[blindboybenton]

Hi All

Ive posted here about this item a few months ago. This unit came in for being noisy and not right. I went though the whole thing and changed all op amps and caps. It left me working. I checked the output and all seemed ok

anyway the owner is a busy studio and didnt have time to but it back in. when he did he stated the it was quite but both channels were different

I have it back to do a full Qbais and meter tracking as per the manual, ( i didnt touch the presets when last in )

There is one bit that i can't work out
UREI-1178 manual.pdf

on about page 23-24 its gives you the set up procedure .. its stating about test the output in dbm on a voltage meter.
How do i do that ??

Please explain using simple terms as my electronic knowledge is limited

bassman

[mhuss]

"dBm" is a relative logarithmic measurement, where (for our purposes) "0dB" corresponds to .775 volts across a 600 ohm impedance.
Since balanced audio has been 600 ohms for quite a while (at least in the US), you can use that as a constant.

Now you have to do some calculating.
Here is an online calculator that will help:
Voltage to dBm Calculator
Enter 600 ohms and the db you want (1, -2, etc.) and it will tell you the AC voltage. For example, 1dbm corresponds to 0.87 VAC

So when the manual says "adjust the output to 1dBm," adjust it so 0.87 volts appears across the + and - output terminals.

[g1]

And as long as you can get the 2 channels to agree, the owner will be happy.
So you shouldn't have to make any big changes, just little tweaks where the 2 channels are different. Or if you find a major difference, you may be looking for another fault, rather than an adjustment issue.

[blindboybenton]

many thanks.. I will check this out later. hopefully get rid of it today

Bassman