[BUILD] New FET/RACK Official Help Thread - Please read first post!

[Diamondj421]

Since installing the new FETs, both compressors operate identically now! Woohoo! However, the stereo links are still not working. When I turn the links on, one of the compressor's meter just stops working. Even if I switch the send/receive on both units, the same compressor has no meter movement. Thoughts?

 

[Potato Cakes]

Swap the Active stereo link cards and see if the problem persists. If the compressor is working then that part should be fine. Also double check your soldering for the Active Link board connectors.


Thanks!

Paul

 

[Diamondj421]

Thanks Paul!
I actually went through and checked my solder points (easier than switching them) out and I feel like I'm closer to my final goal. Now however both compressors, while reacting to the same transients, seem to have a very different range of compression. Let's call them "A" and "B", While passing a drum track through the pair, "A" will compress anywhere from -1dB to -7dB. "B" on the other hand "B" stays pinned to -20dB until I increase the speed of the release to ~"6". At this point, the compression range is anywhere from -1dB to -20dB. Changing the attack and/or input on either unit has no effect. Does this sound like anything you've dealt with?

 

[Potato Cakes]

Mike has a guide on how to properly set up both units for stereo linking on the page for the Active Link cards. The controls are not going to match as linking 1176's isn't perfect. Once you do get them set they do track well with each other when using music. They don't match up nearly as well when just using tone. Both of mine work in stereo very well after I read the Active Link guide and set it up properly.

Thanks!

Paul

 

[Echo North]

XLR+ = .388 VAC
TP1 = .184
TP15 = .303

TP15 is way too low. Should be about 2.5VAC for a D and 4.00VAC for an A.

Can you easily remove Q1? If so do you get more signal?

Mike

 

[thecmarus]

TP15 is way too low. Should be about 2.5VAC for a D and 4.00VAC for an A.

Can you easily remove Q1? If so do you get more signal?

Mike

Removed Q1 and getting over 4.00 VAC plus some! I assume I should replace Q1 and Q11 with some matched 2n5457s and report back?

The release knob still has control over the GR meter but theres no volume drop going on now. Maybe I'm having more than one issue here?

Thanks for getting back to me Mike I greatly appreciate the help.

 

[Spanzor]

Sorry, Pad 16 is just ground. Ignore that.

I'll need to get back to you in a day or so.  I'm in the middle of 10 days semi-off (home project).  I need to take some measurements.

Hey Mike-

Any thoughts on what could be the issue?  No rush

Best,
Spencer

 

[Echo North]

Hey Mike-

Any thoughts on what could be the issue?  No rush

Best,
Spencer

Just getting back to the office.  Will have something for you tonight or tomorrow am.  Sorry for the delay.

 

[RobertCheek]

Hello there

I just got started yesterday on building a pair of Rev As. I completed the power supplies for both and one tested great. The other however is reading +20 VDC on CR8 and the correct -10 VDC on CR9... also the power transformer is getting super hot.

Ideas ? Thanks for your time - Robert

 

[MeesterZee]

I saw some other users added a custom power light above the meter on their builds to mimic the original Rev A cosmetics. Can I safely draw power for a 110VAC LED off the terminals of the power switch?

 

[Echo North]

Hey Mike-

Any thoughts on what could be the issue?  No rush

Best,
Spencer

Hi Spencer,

I've been off most of July so I've been unable to assist you with this deeper issue. I'll be back full time this coming monday and we'll get this banged out.

In the mean time we know your bad 22 voltage seems way too high.

With the same test set up, and in 20:1 ratio, measure your AC:

Pad 15
Both sides of R78 (confirm it's 47K)

Thanks!

Mike

 

[Echo North]

Hello there

I just got started yesterday on building a pair of Rev As. I completed the power supplies for both and one tested great. The other however is reading +20 VDC on CR8 and the correct -10 VDC on CR9... also the power transformer is getting super hot.

Ideas ? Thanks for your time - Robert

Hmmmm. The heat thing concerns me.

Try swapping the power transformers. If you have the same issue, we know it's a PCB level issue. If it works fine with the other transformer, you may have a bad transformer. In that case don't use it anymore and email me.

Mike

 

[Spanzor]

Hi Spencer,

I've been off most of July so I've been unable to assist you with this deeper issue. I'll be back full time this coming monday and we'll get this banged out.

In the mean time we know your bad 22 voltage seems way too high.

With the same test set up, and in 20:1 ratio, measure your AC:

Pad 15
Both sides of R78 (confirm it's 47K)

Thanks!

Mike

Thanks Mike!

My  pad15 measures 4.592ACV

R78 measures 43.94K ohms.  Voltage for the upper leg (towards top of unit, towards 20:1) my ACV measures 3.796v.  The lower leg (closer to the bottom of the unit and towards 4:1 ratio) measures 4.589v.

Thank you!
Spencer

 

[thecmarus]

Removed Q1 and getting over 4.00 VAC plus some! I assume I should replace Q1 and Q11 with some matched 2n5457s and report back?

The release knob still has control over the GR meter but theres no volume drop going on now. Maybe I'm having more than one issue here?

Thanks for getting back to me Mike I greatly appreciate the help.

Okay, just to follow up. I'm getting a nice strong signal now at TP15 with some tweaking. I touched up all the pads that even looked slightly off. I'm not sure which joint it was, but it's now fixed.

I'm still getting the weirdness with the release knob. When I slow the release the meter follows it to the left and the volume drops even with the attack knob off.

Any hints as to where I should look to solve this problem?

Thank you Mike. I'll keep poking at it but I'm not sure where to start with this one.

 

[Echo North]

Okay, just to follow up. I'm getting a nice strong signal now at TP15 with some tweaking. I touched up all the pads that even looked slightly off. I'm not sure which joint it was, but it's now fixed.

I'm still getting the weirdness with the release knob. When I slow the release the meter follows it to the left and the volume drops even with the attack knob off.

Any hints as to where I should look to solve this problem?

Thank you Mike. I'll keep poking at it but I'm not sure where to start with this one.

Were you able to calibrate anything?

 

[Echo North]

Spanzor,

Alright I'm back and ready to sort this for you. Poked around our Rev A just now trying to sort you.

You're voltage is high at pad 22 because you're not getting any compression.

Were you able to complete the Qbias adjustment?

Mike

 

[thecmarus]

Were you able to calibrate anything?

Yes calibration went perfectly well after clearing up my other issue, and the unit behaves in what I would perceive as a normal fashion as long as the release time is at the fastest speed.

 

[Echo North]

Yes calibration went perfectly well after clearing up my other issue, and the unit behaves in what I would perceive as a normal fashion as long as the release time is at the fastest speed.

Is the PCB clean? Does it have a lot of flux?

Mike

 

[thecmarus]

Is the PCB clean? Does it have a lot of flux?

Mike

Cleaned it with 99% alcohol and a toothbrush after I was finished and after doing my most recent touch ups. Looks pretty clean to me. Used Kester solder so hopefully nothing weird with that.

Thank you Mike!

 

[nickmorzov]

Just finished my Rev D FET rack and i'm getting an extremely quiet and distorted signal, my build didn't come with a socket for CN15 and it seems i've got a fat blue resistor for that PCB (not set up or mounted yet) i can't imagine this having an impact over the sound... any help would be greatly appreciated!!