[BUILD] FET/500 Official Support Thread

[Echo North]

well, since it drops audio significantly it doesnt make much sense i guess - if i apply 1k sine @ .775V (measured in BYP at the output), it drops to NOTHING even with the QBias fully CCW and input and output centered, and .110V with input and output fully CW.

Under the standard test set-up:
Input: 12 O’Clock
Output: 12 O’Clock
Attack: GR OFF
Release: Full CW
Ratio: 20:1
Meter: GR
Signal: Sine 1kHz @ 0dBu (0.775 VAC across input + and -)

What is your ACV @ all 3 pins of the output pot?  YOU MUST USE THE + LEAD OF D4 AS YOU COMMON PROBE GROUND POINT.

 

[electric_underground]

Under the standard test set-up:
Input: 12 O’Clock
Output: 12 O’Clock
Attack: GR OFF
Release: Full CW
Ratio: 20:1
Meter: GR
Signal: Sine 1kHz @ 0dBu (0.775 VAC across input + and -)

What is your ACV @ all 3 pins of the output pot?  YOU MUST USE THE + LEAD OF D4 AS YOU COMMON PROBE GROUND POINT.

ground pin - 0V
middle - 0,02V
bottom - 0,12V
those with the QBias centered
(still the lunchbox output shows 0,775V between pins 2+3 with the unit in BYP mode, just to make sure i am not making a fool of myself here )
thanks a lot!!

 

[Echo North]

Something is definitely messed up around Q2/3.  Make absolutely sure all of the components in that signal amp stage are in the right place and properly soldered with no lifted pads.

If all else fails we can send you a new Q2/3,  Maybe one died.

Mike

 

[arsmusic]

I have a 1176 Fet Rev a 2018 model.  I built this a year ago and it works great.  When I finished it it did not work.  There was one cold solder joint which I fixed in 5 minutes. 

I just moved the 1176 rev a to a different rack and the output went out again.  The input works in GR mode when I hit +4 or +8 there is no movement on the vu meter.  So, I take it the output circuit is not working.  When should I look for when trouble shooting this problem?

 

[arsmusic]

I have preformed the tests on this page

https://www.hairballaudio.com/blog/resources/post/fetrack-troubleshooting-guide

From the start every tests passed until I got to

2.  Amplification Stages

Output Transformer BRN

The BRN one failed.  The TP 1, 15, 17 passed though.

Test 3 GR In All pass

Test 4 GR out All pass

Test 5 GR Th V All pass


So does that narrow the problem down a bit to what it could be?



So, the only fail was

Output Transformer BRN

Notes on that:

Low voltage at Output Transformer BRN: have issues in your Signal Line Amp section marked on the PCB. Check the DC voltage chart for this section.
Low voltage at Output XLR + and -: likely have issues with output transformer wiring.

What DC voltage should I check for this and how do I do it?

EDIT

I have tested Q 4, Q5 and Q6 DC voltage and they are all good.

I think I might have a bad solder joint on blk I will re-solder and get back to you if this fixes the issue.

It was the blk solder joint of the output transformer.  It is working now!!!

 

[Echo North]

I have preformed the tests on this page

https://www.hairballaudio.com/blog/resources/post/fetrack-troubleshooting-guide

From the start every tests passed until I got to

2.  Amplification Stages

Output Transformer BRN

The BRN one failed.  The TP 1, 15, 17 passed though.

Test 3 GR In All pass

Test 4 GR out All pass

Test 5 GR Th V All pass


So does that narrow the problem down a bit to what it could be?



So, the only fail was

Output Transformer BRN

Notes on that:

Low voltage at Output Transformer BRN: have issues in your Signal Line Amp section marked on the PCB. Check the DC voltage chart for this section.
Low voltage at Output XLR + and -: likely have issues with output transformer wiring.

What DC voltage should I check for this and how do I do it?

EDIT

I have tested Q 4, Q5 and Q6 DC voltage and they are all good.

I think I might have a bad solder joint on blk I will re-solder and get back to you if this fixes the issue.

It was the blk solder joint of the output transformer.  It is working now!!!

All fixed?  Sounds like this was a FET/RACK?

 

[arsmusic]

Yes, thanks it is all fixed.  It was a Rev A fet rack.

 

[stephan.gueguen]

Hi there, I have a couple of questions about my current Rev D build.  I have completed the unit successfully and audio is passing, and everything seems to be working correctly, however I am experiencing several oddities. 

During calibration, everything went smoothly except one thing,  VR2 adjustment.  During this process I was unable to get the VR2 to affect the metering.  However, after adjusting VR1, and setting the output control to -6dbU the meter already landed on -10.  Do I have an issue somewhere, or is it good to go? I was able to successfully calibrate otherwise.

Next question, my attack pot seems to not be affecting the attack time. I realize that the extreme values are something like (.04ms-.09ms) 'don't quote me on that, but Im not noticing any difference in metering, where the release definitely slows down.  should I be concerned? What can I double check?

Also, Im noticing the input and output pots are a little noisy, I built a Lola and I also notice the same 'crackling' noise on the output of that.  I am still somewhat new to DIY builds, but am very meticulous with my soldering, what do you think may be this issue there, poor solder points somewhere? Not endgame, because there is no issue when the pots are set.

Final question,  when I really push the unit into input distortion (output dialed back), it doesn't seem to have the usable crunch that I am used to with other 1176 units I have heard.  Could it be an issue with my bias calibration? I really notice it on low frequency information.  Is there a component that I should double check? The unit sounds great when Its not over pushed, so really not a huge concern.

Thanks for any help,

Stephan

 

[Echo North]

Hi there, I have a couple of questions about my current Rev D build.  I have completed the unit successfully and audio is passing, and everything seems to be working correctly, however I am experiencing several oddities. 

During calibration, everything went smoothly except one thing,  VR2 adjustment.  During this process I was unable to get the VR2 to affect the metering.  However, after adjusting VR1, and setting the output control to -6dbU the meter already landed on -10.  Do I have an issue somewhere, or is it good to go? I was able to successfully calibrate otherwise.

VR2 has a very small range, maybe 1 LED either way.  However if the meter is reading correctly, you should be good to go.

Next question, my attack pot seems to not be affecting the attack time. I realize that the extreme values are something like (.04ms-.09ms) 'don't quote me on that, but Im not noticing any difference in metering, where the release definitely slows down.  should I be concerned? What can I double check?

It's actually micro-seconds of time.  It's likely working.  If you want to see it, run some drums through the unit and look at your daw metering. Compress a drum loop and adjust the attack full CW and full CCW, you'll see a change in that DAW metering.

Also, Im noticing the input and output pots are a little noisy, I built a Lola and I also notice the same 'crackling' noise on the output of that.  I am still somewhat new to DIY builds, but am very meticulous with my soldering, what do you think may be this issue there, poor solder points somewhere? Not endgame, because there is no issue when the pots are set.

Well that sucks.  Dirt in the pots can happen though it very rare.  If you want to email us we'd be happy to send new ones.

Final question,  when I really push the unit into input distortion (output dialed back), it doesn't seem to have the usable crunch that I am used to with other 1176 units I have heard.  Could it be an issue with my bias calibration? I really notice it on low frequency information.  Is there a component that I should double check? The unit sounds great when Its not over pushed, so really not a huge concern.

This one is more difficult because it's subjective. If I had to guess, you're just hearing the difference between the proper RACK version power supply and whatever is in your 500 series rack.  The difference in the supply topology will be extreme, no matter what 500 series rack you have.  Some are better than others, obviously but none are like the full rack supply.  In the end, I'd probably say that what you're hearing and that is the one draw back between the 500 series and rack version, the power supply.

Thanks!

Mike

 

[blueberryjam]

Hi Mike,
I have a couple FET 500 rev Ds and they both have the same exact issue : the GR meter acts a bit crazy, all the leds light up as soon as there is a bit of gain reduction, some more than other (the units' meters are not in BAR mode), it doesn't make sense nor look accurate at all. The peak meter works fine. I've recalibrated a few times and thoroughly cleaned the pcb but it didn't help. Everything else seems to be working fine. Any ideas?

 

[Echo North]

Hi Mike,
I have a couple FET 500 rev Ds and they both have the same exact issue : the GR meter acts a bit crazy, all the leds light up as soon as there is a bit of gain reduction, some more than other (the units' meters are not in BAR mode), it doesn't make sense nor look accurate at all. The peak meter works fine. I've recalibrated a few times and thoroughly cleaned the pcb but it didn't help. Everything else seems to be working fine. Any ideas?

That's super weird.  Not sure where to even start with that.  Odd that they both have the same issue.  So they're in dot mode....you can calibrate it to the 0, then when you start compressing they all light up?

Mike

 

[rachansky]

I've just completed two builds of the 500 series rev. A and I'm not getting any signal through the unit. I have checked all the components and everything appears to be populated correctly.

I have also verified a supply voltage to nearly every part of the unit with the exception of pins 4 and 5 on the meter board.

I know this could be almost anything but I would appreciate it if you could provide some numbers for expected voltage/current on the pins leading to the meter board.

Please and thanks.

 

[Echo North]

I've just completed two builds of the 500 series rev. A and I'm not getting any signal through the unit. I have checked all the components and everything appears to be populated correctly.

I have also verified a supply voltage to nearly every part of the unit with the exception of pins 4 and 5 on the meter board.

I know this could be almost anything but I would appreciate it if you could provide some numbers for expected voltage/current on the pins leading to the meter board.

Please and thanks.

You have to have your QBias set properly to even get output.  Rotating the Qbias doesn't change the signal at all?

Mike

 

[blueberryjam]

That's super weird.  Not sure where to even start with that.  Odd that they both have the same issue.  So they're in dot mode....you can calibrate it to the 0, then when you start compressing they all light up?

Mike

Hi Mike, thanks for your reply.
I've ran some more tests. Actually I was wrong as it looks like the GR meters might be accurate in showing the level of gain reduction, however :

1) They're in what looks more like bar mode when they should be in dot mode
2) The leds in the GR meters look a bit faint, some more than others. The led in the peak meters shines much brighter. Something looks off.
3) When pushing /saturating the inputs the GR meter bars kind of "moves down", if that makes any sense, so that 0 is not lit up anymore. The more I push  the more it "moves down". I don't think it would be a problem in real world usage because I wouldn't saturate the input like that but may be a clue as to what is going on ?

 

[rachansky]

Misaligned the fricking meter board and blew a fuse on my power supply. I wont have a chance to get another one until Friday unfortunately. Thanks so much for the quick reply!

 

[Echo North]

Hi Mike, thanks for your reply.
I've ran some more tests. Actually I was wrong as it looks like the GR meters might be accurate in showing the level of gain reduction, however :

1) They're in what looks more like bar mode when they should be in dot mode
2) The leds in the GR meters look a bit faint, some more than others. The led in the peak meters shines much brighter. Something looks off.
3) When pushing /saturating the inputs the GR meter bars kind of "moves down", if that makes any sense, so that 0 is not lit up anymore. The more I push  the more it "moves down". I don't think it would be a problem in real world usage because I wouldn't saturate the input like that but may be a clue as to what is going on ?

For the GR part oft he meter, it sits at 0 and moves down as you apply gain reduction. It's a digital version of the original analog meter.  The other meter that shows output level moves up.

The bar mode and dim light is an issue.  If actually had a few of these do exactly what you are describing in repair, but I can exactly remember the fixes.

Definitely confirm your IC on the main PCB is correct and should be a 071.  Make sure you have the 072 on the meter board and everything is oriented correctly.  See if you see any damaged diodes up there and make sure you're PCB is cleaned of any flux.

Mike

 

[rachansky]

You have to have your QBias set properly to even get output.  Rotating the Qbias doesn't change the signal at all?

Mike

Hi Mike,

Back up and running this morning. Ive made every adjustment to every pot I can think of to no avail. The top LEDs respond on both units to the qbias adjustment but I still have no output signal. The bottom LEDs only light up when I power on my rack. There is also no signal passing when the unit is in bypass.


I have confirmed the orientation of the two relays in both units as correct and reflowed the solder around them but I cant help but think this has something to do with the bypass circuit. If you have any ideas it would be much appreciated.

Thanks,

James

 

[blueberryjam]

Definitely confirm your IC on the main PCB is correct and should be a 071.  Make sure you have the 072 on the meter board and everything is oriented correctly.  See if you see any damaged diodes up there and make sure you're PCB is cleaned of any flux.

Mike

Mike,
Yes the ICs are correct, 71 on the main PCB and two 72s on the meter board. Everything looks like it's oriented correctly and I'm not seeing damaged diodes. When I got them there was a lot of flux on the PCB (bought them already assembled), so I thoroughly cleaned them up when I noticed something wasn't right with the GR meter. What's weird is that before cleaning them up, only 1 unit of the 2 had the bar meter issue, after cleaning they now both have it.

 

[rachansky]

Hi Mike,

Back up and running this morning. Ive made every adjustment to every pot I can think of to no avail. The top LEDs respond on both units to the qbias adjustment but I still have no output signal. The bottom LEDs only light up when I power on my rack. There is also no signal passing when the unit is in bypass.


I have confirmed the orientation of the two relays in both units as correct and reflowed the solder around them but I cant help but think this has something to do with the bypass circuit. If you have any ideas it would be much appreciated.

Thanks,

James

Ok I have one of the units figured out and calibrated. Big relief! The second one I am having issues with sensitivity on the output. Notable discrepancies between the two are that the max. Voltage when adjusting the bias is 17.4V, and when moving through the calibration of the output the voltage jumps through the meter range in about 1/8 of the pot travel. Double checked parts orientation/placement and have reflowed solder.

Any ideas?

 

[Echo North]

Ok I have one of the units figured out and calibrated. Big relief! The second one I am having issues with sensitivity on the output. Notable discrepancies between the two are that the max. Voltage when adjusting the bias is 17.4V, and when moving through the calibration of the output the voltage jumps through the meter range in about 1/8 of the pot travel. Double checked parts orientation/placement and have reflowed solder.

Any ideas?

You're saying the output get's super hot?  Sure you don't have the output and attack pots swapped?

Mike