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

[noiro]

between S & D of Q1 , nothing at all 0.000VDC, I think I will replace that 2n5457, I have plenty of those here

 

[Echo North]

DC Resistance, not voltage.

 

[noiro]

oups sorry misread you, it's 27k

 

[Echo North]

Doesn't seem bad.

I'd remove Q1. If your signal is back, you have a bad Q1. If not it's something else.

The unit will not compress with Q1 removed, but it'll pass signal fine. Basically it's a mic pre.

Mike

 

[noiro]

oh I see I will try that in the meantime I'm testing the connector between the main pcb and the attack/release and ratio, those also were force out of their place, man those postal services can be very hard on packages, that one was return from Australia, refunded the person of course. So now I'm just keeping it for me here in my little humble studio. ;-)

 

[noiro]

Hi Mike, just figure out the problem, it's all good now. It was R8 1K resistor that was dead, actually it was broke in half. Thank you for helping my out! Peace! -jy

 

[Lakewood]

Hey! I just finished a 1176 Rev. A build and got some problems with the calibration.. The unit is passing audio and is compressing, but it seems that my QBIAS pot (R59) does not affect the Meter / Output voltage like in the 1st calibration step of the calibration guide so i started troubleshooting via the FET/RACK troubleshooting guide..

1) I measured -15.57VDC at CR9 ... Before populating the PCB the Voltage was fine at about -10VDC...
Could this be the first problem?


2) My resistance across S and D of Q1 is about 300Ω with the unit powered OFF.. I read that it should be around 27kΩ.. Is my Q1 faulty?

1. [BUILD] New FET/RACK Official Help Thread - Please read first post!
   
   Set your trimmer so you have the highest DC you can get at TP18 (I get -1.603VDC), then test the DC resistance (Ω) across the S and D of Q1.

Further i measured the QBIAS voltage with the following settings:

Input: 12 O’Clock
Output: 12 O’Clock
Attack: GR OFF
Release: Full CW
Ratio: 20:1
Meter: GR
Signal: None

With your DMM measure DC at TP18 using the chassis as reference . Rotate the Qbias pot (Rev A/D:R59) and note the DCV at each extreme of the pot. Expected negative DC voltages are noted:

Test Point TP18	Rev A
EXPECTED	-1 VDC to -1.78 VDC
MEASURED	-1.603VDC to -2.837VDC

The guide recommends to contact the forum if the measurements are off.. So here I am

PS: I Measured Voltages between -1.24VDC and -2.18VDC at the Q1 GATE when turning the QBIAS pot (R59) fully CCW/CW!

Every kind of help is much appreciated! Kind regards,

Leo

 

[EarthTone]

Just finished and calibrated mine last night! SO stoked! Sounds awesome!!! Destroys the UAD plugin.

I have some questions!!

First- I noticed when I touch the output knob I hear a little click sometimes. Not loud, not mechanical, like an electrical click. In operation after you find your setting and stop touching it it’s fine. Seems like a grounding issue? Thoughts?

Then! Very important- How is everyone setting their knobs’ pointers on the faceplate markers? The pointers do not have full travel from start to finish of any of the markings. I currently have my knob pointers installed as per Hairball’s guide. But I’m really confused about the attack and release markings especially. How do you use it like a classic unit from 1~7 if you don’t have full travel of the pots from “OFF” to 7 on each knob? Confused…

Also! I used the Orange Drop caps mod in my build. I installed the mod already and I didn’t listen to it with the original caps that were sent before installing them. Should I have used the Orange Drops? Right now I love how it sounds! So big and crispy. What would change if I installed the stock capacitors in the 4 audio coupling spots? Would the action of the compression change, or would it be more that the tonality would change? Do I have to recalibrate it if I wanted to try the stock caps?

One last thing! One of the #6 screws for the case was missing. What thread pitch should I order if I want to replace it? Also one of the holes for the IEC inlet was not drilled which was annoying but I was able to drill one out by hand without ruining anything.

Overall I LOVE this compressor and had a ball putting it together. The wiring being pre-done is such a great perk! Made it so much easier. The only thing I ever hate doing on builds is crimping connectors. It was a super fun build! I may do another pair around Thanksgiving when they go on sale again!

Thank you Hairball!

 

[Echo North]

Hi,

Make sure you start here...

https://help.hairballaudio.com/hc/en-us/articles/360049490733-FET-RACK-Operational-FAQ

Knobs:
All the modern clones (that I know) have the same issue. Back in the UREI days pots commonly rotated 320 degrees. That is not true anymore. 290-295 is more standard. You can set it how you like. Set to the max rotation to the beginning/end or line up the middle. It's up to you, I usually set max rotation to the high setting. For the smalls I set the attack to line up to 6 o'clock in the off pos. Withe the release you can do whatever.Again I generally set everything to the max...except the attack because of the off Switch.

Caps:
It's really subtle, nothing that is going to knock you socks off. If you like it stick with it.

IEC Hole,
That is super weird. Sorry about that! I've never seen that before.

Screws:
The are 6-32 and 1/4" long but can be longer. The head is undercut.

Mike

 

[EarthTone]

Hi,

Make sure you start here...

https://help.hairballaudio.com/hc/en-us/articles/360049490733-FET-RACK-Operational-FAQ

Knobs:
All the modern clones (that I know) have the same issue. Back in the UREI days pots commonly rotated 320 degrees. That is not true anymore. 290-295 is more standard. You can set it how you like. Set to the max rotation to the beginning/end or line up the middle. It's up to you, I usually set max rotation to the high setting. For the smalls I set the attack to line up to 6 o'clock in the off pos. Withe the release you can do whatever.Again I generally set everything to the max...except the attack because of the off Switch.

Caps:
It's really subtle, nothing that is going to knock you socks off. If you like it stick with it.

IEC Hole,
That is super weird. Sorry about that! I've never seen that before.

Screws:
The are 6-32 and 1/4" long but can be longer. The head is undercut.

Mike

Hey @Echo North thank you so much for the personal attention Mike! Gotta hand it to you- The quality of everything from the build guide to the parts to the sound and packaging- Rockin'! So fun to build and now to use.

Thank you so much for the rundown about all this! Yes I did read the operational FAQ page and that was helpful.

Thanks for the knob placement guide. OK sounds good. I'll just set it up like you mentioned, that all seems to make good sense to me.

I think I'll stick with these caps! I love the sound as it is now with the Orange Drops. Maybe if I do another, will try the stock caps.

Thanks for the verification on the screw size and threading. Great- I will order some of those. There is a chance I dropped one when installing the case top and bottom but I haven't been able to locate it yet so wouldn't hurt to have a few spares anyway.

Cheers man looking forward to building the next one sometime down the line! Now that I have heard this one I think I'll end up with at least one more, if not two!

Cheers,
Matt

 

[EarthTone]

Guys I just gotta say... My RevD rack version with orange drop mod is just incredible. Sounds so f'ing sick I love it! Thank you Hairball!