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

[Echo North]

Hi all, finally got my build completed and calibrated. Everything is sounding great.

However, I'm having some trouble with the knobs not sitting flush to the face. I have large gaps of different widths. It seems that some of the pots have a longer shaft that others, preventing the knobs from sitting closer. After spending so many hours on the internal build, I want the outside to look clean too! Any solutions?

Pics here:
http://i.imgur.com/mLtbrhN.jpg
http://i.imgur.com/RR55QDn.jpg

Thanks!

That is how they should sit. You don't want them dragging on the nut or even worse the faceplate which will leave bad marks.  Just pull the closer one out a little to match the other and lock it down.

Mike

 

[Spanzor]

Your Qbias went fine right?

Try the same test as Rubberband above.

Mike

Thanks Mike!  That's what I figured about the parallel resistors.  All these measurements are in AC voltage

-Input XLR +  = .373
-TP1=  .15
-TP15 =4.658
-TP17 =.872
-Output Transformer BRN  =13.38
-Output XLR + =13.14


Thanks dude!

 

[thecmarus]

Okay,

At a complete loss as to what might be my issue. New FET Rev A I just finished building.

Q1 shows 1db drop no problem. Null adjust is fine.

Last step involves no compression. Attack knob makes the needle twitch when engaged but that's it. Moving the release from clockwise to CCW actually makes the volume drop.

Checked all the solder connections and everything seems okay.

I've built 4 hairball Lolas, 1 FET 500, and this is my second FET rack and I've never had an issue up until now. It's driving me crazy and I'm sure I made a careless mistake somewhere. I'm gonna just start checking the resistors to start with to make sure I didn't mix up a value.

Edit: Can't find an obvious resistor error. There is some compression if I crank the input all the way, but the release knob still acts wonky.

Edit #2.

Checked every resistor using a color calculator and they all check out. Checked every solder joint. Unit passes audio and sounds great. I can even hear the compression happening it's just not showing it properly on the meter.

The release knob somehow has the most control over the VU meter. The needle follows the knob as I turn it from left to right, and there's a few DB drop in volume as a result.

 

[Echo North]

Thanks Mike!  That's what I figured about the parallel resistors.  All these measurements are in AC voltage

-Input XLR +  = .373
-TP1=  .15
-TP15 =4.658
-TP17 =.872
-Output Transformer BRN  =13.38
-Output XLR + =13.14


Thanks dude!

Seems ok.

Can you set the QBias?

 

[Echo North]

Okay,

At a complete loss as to what might be my issue. New FET Rev A I just finished building.

Q1 shows 1db drop no problem. Null adjust is fine.

Last step involves no compression. Attack knob makes the needle twitch when engaged but that's it. Moving the release from clockwise to CCW actually makes the volume drop.

Checked all the solder connections and everything seems okay.

I've built 4 hairball Lolas, 1 FET 500, and this is my second FET rack and I've never had an issue up until now. It's driving me crazy and I'm sure I made a careless mistake somewhere. I'm gonna just start checking the resistors to start with to make sure I didn't mix up a value.

Edit: Can't find an obvious resistor error. There is some compression if I crank the input all the way, but the release knob still acts wonky.

Edit #2.

Checked every resistor using a color calculator and they all check out. Checked every solder joint. Unit passes audio and sounds great. I can even hear the compression happening it's just not showing it properly on the meter.

The release knob somehow has the most control over the VU meter. The needle follows the knob as I turn it from left to right, and there's a few DB drop in volume as a result.

Is this the older build? With all the wiring?

Mike

 

[thecmarus]

Is this the older build? With all the wiring?

Mike

Nope. New model FET A build. I don't even think it's possible I wired it wrong!

 

[Spanzor]

Seems ok.

Can you set the QBias?

The Q bias I can set, and I can get through the null adjustment also. 

When I get to the bit where I need to adjust the GR meter tracking, I get stuck after switching the attack off.  My XLR output reads at .775ACV and is almost all the way down.  When I bring up the input knob, I max it out before I get the output to read +10dBu.  It maxes out at about 1.54ACV.

Thanks!

 

[Echo North]

Nope. New model FET A build. I don't even think it's possible I wired it wrong!

Maybe a side chain issue then.

Set your unit to:
Input: 12 O’Clock
Output: 12 O’Clock
Attack: GR ON (Full CW)
Release: Full CW
Ratio: 20:1
Meter: GR
Signal: Sine 1kHz @ 0dBu

1. Using chassis as your ground reference, what is your AC V at TP22 for all 4 ratio settings.
2. Using chassis as your ground reference, what is your DC V at TP21 for all 4 ratio settings.

Mike

 

[Echo North]

The Q bias I can set, and I can get through the null adjustment also. 

When I get to the bit where I need to adjust the GR meter tracking, I get stuck after switching the attack off.  My XLR output reads at .775ACV and is almost all the way down.  When I bring up the input knob, I max it out before I get the output to read +10dBu.  It maxes out at about 1.54ACV.

Thanks!

Right, because your TP22 AC is so damn high.

Has to be a short or bad R value on your ratio PCB.

What revision do you have again?  What is the rec number of the PCB? (1.11, 1.14...)

Mike

 

[Spanzor]

Right, because your TP22 AC is so damn high.

Has to be a short or bad R value on your ratio PCB.

What revision do you have again?  What is the rec number of the PCB? (1.11, 1.14...)

Mike

I'll double double check for anything weird on the board.  All the resistors measure pretty close to what they're spec'd at aside from being in parallel with others.  Looks like my PCB is v1.14.

Spencer

 

[Spanzor]

Right, because your TP22 AC is so damn high.

Has to be a short or bad R value on your ratio PCB.

What revision do you have again?  What is the rec number of the PCB? (1.11, 1.14...)

Mike

Meant to add this too, I'm building the newest revision of the Rev A, only ordered it around 1 month ago. 

 

[thecmarus]

Maybe a side chain issue then.

Set your unit to:
Input: 12 O’Clock
Output: 12 O’Clock
Attack: GR ON (Full CW)
Release: Full CW
Ratio: 20:1
Meter: GR
Signal: Sine 1kHz @ 0dBu

1. Using chassis as your ground reference, what is your AC V at TP22 for all 4 ratio settings.
2. Using chassis as your ground reference, what is your DC V at TP21 for all 4 ratio settings.

Mike

Okay so TP22 AC volts;

20:1 = .200
12:1 = .110
8:1 = .072
4:1 = .042

TP21 DC volts;

20:1 = -6.027
12:1 = -3.49
8:1 = -2.69
4:1 = -1.90

Thanks for getting back to me Mike!

 

[Echo North]

I'll double double check for anything weird on the board.  All the resistors measure pretty close to what they're spec'd at aside from being in parallel with others.  Looks like my PCB is v1.14.

Spencer

With the same set-up as above, what is your AC at PAD 15, 16, 17.

Just do them all at 20:1...GR off.

 

[Echo North]

Okay so TP22 AC volts;

20:1 = .200
12:1 = .110
8:1 = .072
4:1 = .042

TP21 DC volts;

20:1 = -6.027
12:1 = -3.49
8:1 = -2.69
4:1 = -1.90

Thanks for getting back to me Mike!

Does the unit sound right? Compressing ok?

The voltages seem ok, wondering if it's just a GR Meter Driver issue. Meaning the unit works, just not the GR metering.

 

[thecmarus]

Does the unit sound right? Compressing ok?

The voltages seem ok, wondering if it's just a GR Meter Driver issue. Meaning the unit works, just not the GR metering.

Unit sounds great. Seems like the threshold is a little high after poking around more and experimenting.  Setting the q bias works fine but when trying to set the metering I can't get the 10db drop when attack is engaged. I don't know how to convert VAC to DB offhand, but it's probably only a few db from in to out if I had to guess.

However if I pass sound through it it sounds great and I can hear some compression happening with vocal and guitar tracks. When I slow the release the Vu Meter drops and the volume drops as well. 

 

[Echo North]

Unit sounds great. Seems like the threshold is a little high after poking around more and experimenting.  Setting the q bias works fine but when trying to set the metering I can't get the 10db drop when attack is engaged. I don't know how to convert VAC to DB offhand, but it's probably only a few db from in to out if I had to guess.

However if I pass sound through it it sounds great and I can hear some compression happening with vocal and guitar tracks. When I slow the release the Vu Meter drops and the volume drops as well.

Hmmm that seems wrong. You should be able to get a 10dB drop.

Set your unit to:
Input: 12 O’Clock
Output: 12 O’Clock
Attack: GR OFF
Release: Full CW
Ratio: 20:1
Meter: GR
Signal: Sine 1kHz @ 0dBu

With your DMM measure your AC at the following test points using the chassis as you reference (black probe).

-Input XLR +
-TP1
-TP15

Mike

 

[Spanzor]

With the same set-up as above, what is your AC at PAD 15, 16, 17.

Just do them all at 20:1...GR off.

Okay so:

15:  4.639v
17:  .869v

For the life of me, I couldn't find a test pad 16 after looking for about 20 minutes.  I'm building the Blue Stripe Rev A 2017 v1.14- maybe I'm missing it?

Here's a few other pads:

1:  .149v
7:  0v (bad?)
18:  0v
21:  0v
22:  2.257v

Thanks man

 

[Echo North]

Okay so:

15:  4.639v
17:  .869v

For the life of me, I couldn't find a test pad 16 after looking for about 20 minutes.  I'm building the Blue Stripe Rev A 2017 v1.14- maybe I'm missing it?

Here's a few other pads:

1:  .149v
7:  0v (bad?)
18:  0v
21:  0v
22:  2.257v

Thanks man

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.

 

[thecmarus]

Hmmm that seems wrong. You should be able to get a 10dB drop.

Set your unit to:
Input: 12 O’Clock
Output: 12 O’Clock
Attack: GR OFF
Release: Full CW
Ratio: 20:1
Meter: GR
Signal: Sine 1kHz @ 0dBu

With your DMM measure your AC at the following test points using the chassis as you reference (black probe).

-Input XLR +
-TP1
-TP15

Mike

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

 

[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.

Right on man, no rush!  Really appreciate your help on this stuff- I'm sure I speak for many of us.