Gates Sta Level Super Dark Sonically

[Hamburg58]

Hi guys
So I have 2 old Sta Levels. One is the earlier dark grey version and the other is the light grey later revision with the different VU. I bought them used from the same guy a few years ago. They both have always sounded different. The lighter grey sounds pretty good. It's a bit noisy but working on that right now. And also replacing the output with a 600 ohm Tpad instead of the stock pot that doesn't Goto 0.

The issue is with the darker grey unit. We changed out all of the bad tubes, replaced the filter caps on the back with some CE repros, fixed anything that was wrong with connections etc to revert the unit back to the original schematic.

It's less noisy. But it's still super dark. It's like the high end cuts off around 6k and the more you compress the more you get 200hz or so. My lighter grey unit isn't like that. It has beautiful top end and still some nice bumps down low but very low. Not like 200hz.

Any advice ? Is it a transformer? Does it need a total recap? I'm super bummed! Other Sta Levels I've used from this era sounded great and didnt have this issue with the bandwidth being so shelved off..

Cheers !

 

[emrr]

take a real response measurement of both, impossible to say without that.

 

[Kingston]

And when that fails you should start probing specific parts of the signal path with an oscilloscope and a signal (sine) generator to find out where the response dips.

Hint: most audio interfaces have low enough output impedance to act as decent signal generators, but you still need a basic (high impedance input) oscilloscope to see where you are.

 

[Pip]

And when that fails you should start probing specific parts of the signal path with an oscilloscope and a signal (sine) generator to find out where the response dips.

Hint: most audio interfaces have low enough output impedance to act as decent signal generators, but you still need a basic (high impedance input) oscilloscope to see where you are.

Based on your ears I would say it will and yes you should send signal through and probe for the failure. I am assuming you have schematic. Make sure that the primary of the output transformer is not gapped or shorted in any way as this would be my first guess as where to look. Check also R24, 31 and 39 for there values.

You have something of an asset in you have a working unit to measure values on and compare.

 

[Hamburg58]

Based on your ears I would say it will and yes you should send signal through and probe for the failure. I am assuming you have schematic. Make sure that the primary of the output transformer is not gapped or shorted in any way as this would be my first guess as where to look. Check also R24, 31 and 39 for there values.

You have something of an asset in you have a working unit to measure values on and compare.

I am not well versed in using a scope. I own a studio in Hollywood. Have built a few things. Have basic troubleshooting and repair knowledge for my console and tape machine etc. I will see if I can borrow a scope and figure out how to correctly do this and see how things measure up. It would be cheaper than paying my tech 125 an hour to do it!

Are there any good DIY instruction threads on the forum on this sort of thing? I'll do some research. I'll start with the transformer though. My tech just replaced the choke as well. It was done.