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

[Echo North]

Ok awesome. Is it possible to switch the off position on the attack knob to a slow attack time? I only ask because I find myself using the AE version of the plugin most between the 3 available through UAD.  Thanks as always!!!

Not off the top of my head no.

 

[matt_weber]

Hey there,

Just finished my first Rev A build and I'm having two issues....

1. the 8:1 ratio isn't working.
2. the release function is not working great either.

I first noticed the 270k resistor for the release circuit was bad so I replaced that but I'm still having the same issue. I have a second release pot from a second Rev A ill be building and can try swapping that. However, when i tested the resistance of the pot, (in circuit) i got a reading of 240k ohms full CCW and 147k ohms fully CW.

For the 8:1 circuit resistors, Im getting a reading of the follow at each resistor...
R22: 46k ohms
R21: 55k ohms
R62: 430 ohms

Everything else with the build works as it should.

Thanks in advance!

 

[matt_weber]

Update: 8:1 ration began working after a fresh power cycle

 

[Echo North]

Update: 8:1 ration began working after a fresh power cycle

I'd re-flow the solder on that switch.

 

[Echo North]

Hey there,

Just finished my first Rev A build and I'm having two issues....

1. the 8:1 ratio isn't working.
2. the release function is not working great either.

I first noticed the 270k resistor for the release circuit was bad so I replaced that but I'm still having the same issue. I have a second release pot from a second Rev A ill be building and can try swapping that. However, when i tested the resistance of the pot, (in circuit) i got a reading of 240k ohms full CCW and 147k ohms fully CW.

For the 8:1 circuit resistors, Im getting a reading of the follow at each resistor...
R22: 46k ohms
R21: 55k ohms
R62: 430 ohms

Everything else with the build works as it should.

Thanks in advance!

What do you mean by "not working great".  Is there no noticeable change in release time when turning the control?

 

[Echo North]

-----moved from another post------
Hey Guys / Hairball Audio-
I built an 1176 Blue Stripe and couldn't get Calibration Step 3 to work.  I ran the calibration 6 times and it won't let me adjust to -10 on the meter.  After running the troubleshooting Guide my results are as follows:
Power: +30 VDC and -9.6VDC
1)Bias Voltage: -1.008 to -1.760
2)Amplification Stages
TP1: 57mV unbiased 57mV biased
TP15 2.384V Unbiased 2.107 biased
TP17 593.5mV unbiased 149.1mV
Output XLR: 10.76 V
3)GR Control Amp Input
20:1 ---388mV
12:1---- 1.89.5mV
8:1 ---126.5mV
4:1 ---- 64.1mV
4)Gain Control Amp Output
20:1 ---3.476 V
12:1---- 1.702 V
8:1 ---1.137 V
4:1 ---- .578 V
5) Gain Control Amp Threshold Voltages
20:1 ---  - 5.854 V
12:1----    -3.296  V
8:1 ---        -2.493 V
4:1 ----      -1.69 V

Any help on how to get step three to work would be great
Thanks,
Sweep
----------------

 

[Echo North]

-----moved from another post------
Hey Guys / Hairball Audio-
I built an 1176 Blue Stripe and couldn't get Calibration Step 3 to work.  I ran the calibration 6 times and it won't let me adjust to -10 on the meter.  After running the troubleshooting Guide my results are as follows:
Power: +30 VDC and -9.6VDC
1)Bias Voltage: -1.008 to -1.760
2)Amplification Stages
TP1: 57mV unbiased 57mV biased
TP15 2.384V Unbiased 2.107 biased
TP17 593.5mV unbiased 149.1mV
Output XLR: 10.76 V
3)GR Control Amp Input
20:1 ---388mV
12:1---- 1.89.5mV
8:1 ---126.5mV
4:1 ---- 64.1mV
4)Gain Control Amp Output
20:1 ---3.476 V
12:1---- 1.702 V
8:1 ---1.137 V
4:1 ---- .578 V
5) Gain Control Amp Threshold Voltages
20:1 ---  - 5.854 V
12:1----    -3.296  V
8:1 ---        -2.493 V
4:1 ----      -1.69 V

Any help on how to get step three to work would be great
Thanks,
Sweep
----------------

Are you getting the 10dB drop on the output?

 

[matt_weber]

I notice the slightest bit of difference when turning the release knob but it’s extremely minimal. I’d say maybe a %5 difference if that. 

 

[Echo North]

I notice the slightest bit of difference when turning the release knob but it’s extremely minimal. I’d say maybe a %5 difference if that.

The release can be pretty subtle if you're only compressing a couple dB on a source like guitar.  If you're compressing say a snare by 10dB that should sound pretty drastic.  have you tried that?

 

[matt_weber]

I have tried many different input amounts and ratios. Also tried slamming a room mic and getting it to pump but still just a fast release only.

A side note on the ratio switch, the 8:1 is In fact working now. I Can’t quite explain why it stopped for a minute there.

 

[Echo North]

I have tried many different input amounts and ratios. Also tried slamming a room mic and getting it to pump but still just a fast release only.

A side note on the ratio switch, the 8:1 is In fact working now. I Can’t quite explain why it stopped for a minute there.

All 3 release legs are still intact?  They are a bit fragile.  The resistor across it on the PCB is the correct value and fully soldered?

Mike

 

[matt_weber]

All 3 legs are intact. I removed the release pot to test its resistance against a second release pot from a still in box build and they match. I went further and installed the other release pot and still no luck.

 

[Echo North]

All 3 legs are intact. I removed the release pot to test its resistance against a second release pot from a still in box build and they match. I went further and installed the other release pot and still no luck.

Triple check the values and solder joints on there guys. Make sure C22 is 0.22 and not 0.022 or something.

 

[matt_weber]

Confirmed C22 on my build is .22

 

[Echo North]

Confirmed C22 on my build is .22

Hmmm that's a weird one.  Is there a lot of flux on the PCB?

That 8:1 issue makes me worry that you may have a cold joint or loose connection somewhere that maybe causing both issues.  Those obviously are super hard to find.

All the tiny blue caps are the correct value?

Mike

 

[matt_weber]

yup the blue caps are correct as well

 

[Echo North]

yup the blue caps are correct as well

Ya that's a weird one.  I've seen this before when the PCB is super dirty and full of flux.  Make sure it's clean and all the joints are good.

You could always send it in....I'm a little stumped on it. 

 

[controlvoltage]

So, I have a question.

I've built two FET Rack Rev D units and they were ordered not too long apart from each other, though not at the same time.

They both sound great and work correctly as far as I can tell. However, it seems like the taper on the output control is quite different between the two units. I have them set up so that 24 is exactly the same on both units, however if I were to set one to 18, the other would have to be set significantly higher to match the same output. If I go the opposite direction they also don't line up anymore.

Was there a taper change at some point?

The inputs seem to be a lot more closely matched, though I do have to tweak just a little to get exactly the same gain reduction with the same 1k test signal.

 

[Potato Cakes]

Have you measured the resistance between wiper and CW and then CCW on the output pot in those positions? Those pots have 20% tolerance, so if you happen to have one with lower resistance and the other with higher resistance still within the tolerance range that would explain that. Even when stereo linking them you will have to adjust the outputs independently to get them to match.

Also, 1k tone is not a good test for matching with the 1176's. I've had similar issues you have doing the same thing, but when I did the same test with a stereo drum stem the knob position were much closer to being at the same positions. There is a bit of a write up on the Hairball Audio site that deals with linking 1176's. I think it's still there. If both units are working properly and sounding good with no hums or buzzes then I wouldn't put too much stock in the knob positions.

If your OCD won't let you look past this knob position discrepancy like I experience sometimes, then you can do these things to see if you can get them more closely matched:

- Turn in and out knobs all the way down and make sure the indicator line starts at the same position.

- Recalibrate them side by side

- Replace the pots with ones that are more closely matched.

Report back and let us know.


Thanks!

Paul

 

[controlvoltage]

Have you measured the resistance between wiper and CW and then CCW on the output pot in those positions? Those pots have 20% tolerance, so if you happen to have one with lower resistance and the other with higher resistance still within the tolerance range that would explain that. Even when stereo linking them you will have to adjust the outputs independently to get them to match.

Also, 1k tone is not a good test for matching with the 1176's. I've had similar issues you have doing the same thing, but when I did the same test with a stereo drum stem the knob position were much closer to being at the same positions. There is a bit of a write up on the Hairball Audio site that deals with linking 1176's. I think it's still there. If both units are working properly and sounding good with no hums or buzzes then I wouldn't put too much stock in the knob positions.

If your OCD won't let you look past this knob position discrepancy like I experience sometimes, then you can do these things to see if you can get them more closely matched:

- Turn in and out knobs all the way down and make sure the indicator line starts at the same position.

- Recalibrate them side by side

- Replace the pots with ones that are more closely matched.

Report back and let us know.


Thanks!

Paul

Ah, yeah the tolerance could be the reason. I haven't tried measuring the pots, actually. It's not really a big deal, honestly, as I use the very nice metering on my Dangerous AD+ Converter to match if I need to. Though I do actually have a bit of OCD, it's not so much this kind of thing that bothers me unbearably.

Why would it be that a test tone wouldn't work well with these, though? I'm not sure I follow that.