Hairball Audio

Re: [BUILD] New FET/RACK Official Help Thread - Please read first post!
« Reply #1680 on: June 11, 2019, 04:03:52 PM »
Yes un-linked.

I'm really not sure which one is working correctly they both calibrate the way they should and compress.

The one you built is focusing on the top end on the signal.

The one I built has hotter output and is focusing on the low end on the signal.

The one we built should be working correctly.  Compression is definitely going to have an EQ like effect on your program material. My guess is the newer one has an error somewhere in the build.

Go through the troubleshooting test with both units and see what you get:
https://www.hairballaudio.com/blog/resources/post/fetrack-troubleshooting-guide

You can do a simple freq response check by doing step to with say a 200hz, 1K, and 10K signal. Should be flat.

Mike
 
Hairball Audio, LLC
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Ricardus

Re: [BUILD] New FET/RACK Official Help Thread - Please read first post!
« Reply #1681 on: June 14, 2019, 01:00:54 AM »
OK. I think I'm psychologically ready to tackle these beasts.   
Audio mastering for hire..

Hairball Audio

Re: [BUILD] New FET/RACK Official Help Thread - Please read first post!
« Reply #1682 on: June 14, 2019, 05:14:19 PM »
OK. I think I'm psychologically ready to tackle these beasts.

Do it!
Hairball Audio, LLC
DIY Parts and Kits
https://hairballaudio.com

Top secret stuff and upcoming releases:
http://instagram.com/Hairballaudio
http://facebook.com/hairballaudio

Ricardus

Re: [BUILD] New FET/RACK Official Help Thread - Please read first post!
« Reply #1683 on: June 14, 2019, 09:57:19 PM »
Do it!

It's on my bench and in my vise!
Audio mastering for hire..

Matgre

Re: [BUILD] New FET/RACK Official Help Thread - Please read first post!
« Reply #1684 on: June 15, 2019, 10:39:02 AM »
Hi all,

might have overlooked it..
On Rev A, is it a problem if the input transformer (T1) touches the big orange drop (C10) on its coating sitting just beside it?

Thanks for help!
Mat



Matgre

Re: [BUILD] New FET/RACK Official Help Thread - Please read first post!
« Reply #1685 on: June 18, 2019, 12:41:22 PM »
Low voltage between OUT + OUT -.

Hi everyone,

please keep ignoring my post above, no components are touching... exept Q12 and Q13 of course.

Just finished assembly of an 1176 RevA v1.15 and could need some advise now and hope someone is willing to give.  :)
In the calibration process i cant calibrate QBias because of not getting proper voltage between OUT + OUT -.

All solders look good and tripple checked for misplaced components.

Did the troubleshooting procedure on the Hairball site.

PSU reads as it should, GND 0,3Ohm, CR8 cathode 30,73VDC , CR9 anode -9,69VDC

1. QBias Voltage:  as supposed to, highest reading (fullCW) 1,775VDC and lowest (fullCCW) 1,019VDC

2. Amp Stages:  low voltage at all testpoints: TP1 (0,074VAC), TP15 (0,005VAC), TP17(0,0008VAC), Transformer BRN(0,002VAC) and of course between OUT+ - (0,005VAC).

For TP1 issue:
TPad and T1: With 0,775VAC at input, i get VAC readings of (386,3 mVAC) on  Inputtransformer lead1  and the Tpad input. 255mVAC on Tpad out and inputtransformer lead4. Looks like nothing gets past the transformer exept the 74mVAC.
Is there a way to test Q1 exept swapping with Q11?

For TP15 issue:
All VDC are  around the ones in the RevA DC Voltage Chart in the signal amp section.

For TP17 issue:
Sorry but not sure if i test R23 right, pot goes from 0,6Ohm at infinite to around 100K at 24, then back to 34k at 0.  Shouldtn it go from 0Ohm to 250k or is it just a range?
17,15 VDC at C7 + side coming from Q3 and around the ones in the RevA DC Voltage Chart.

Outputtransformer BRN issue: all VDC are around the RevA DC Voltage Chart in the line amp section.
Checked continuity for the wiring, all seems good.

Thank you for any suggestions.
Mat


Hairball Audio

Re: [BUILD] New FET/RACK Official Help Thread - Please read first post!
« Reply #1686 on: June 18, 2019, 05:34:47 PM »
Your issue is that your signal dies in the Signal Preamp section.  75 mV is normal after the transformer (TP1). I would look closely in that section.

On the output pot, there are some parallel resistance things that are going to throw off your readings in circuit.  If you want to test it, you can remove it and test it.

Mike


Low voltage between OUT + OUT -.

Hi everyone,

please keep ignoring my post above, no components are touching... exept Q12 and Q13 of course.

Just finished assembly of an 1176 RevA v1.15 and could need some advise now and hope someone is willing to give.  :)
In the calibration process i cant calibrate QBias because of not getting proper voltage between OUT + OUT -.

All solders look good and tripple checked for misplaced components.

Did the troubleshooting procedure on the Hairball site.

PSU reads as it should, GND 0,3Ohm, CR8 cathode 30,73VDC , CR9 anode -9,69VDC

1. QBias Voltage:  as supposed to, highest reading (fullCW) 1,775VDC and lowest (fullCCW) 1,019VDC

2. Amp Stages:  low voltage at all testpoints: TP1 (0,074VAC), TP15 (0,005VAC), TP17(0,0008VAC), Transformer BRN(0,002VAC) and of course between OUT+ - (0,005VAC).

For TP1 issue:
TPad and T1: With 0,775VAC at input, i get VAC readings of (386,3 mVAC) on  Inputtransformer lead1  and the Tpad input. 255mVAC on Tpad out and inputtransformer lead4. Looks like nothing gets past the transformer exept the 74mVAC.
Is there a way to test Q1 exept swapping with Q11?

For TP15 issue:
All VDC are  around the ones in the RevA DC Voltage Chart in the signal amp section.

For TP17 issue:
Sorry but not sure if i test R23 right, pot goes from 0,6Ohm at infinite to around 100K at 24, then back to 34k at 0.  Shouldtn it go from 0Ohm to 250k or is it just a range?
17,15 VDC at C7 + side coming from Q3 and around the ones in the RevA DC Voltage Chart.

Outputtransformer BRN issue: all VDC are around the RevA DC Voltage Chart in the line amp section.
Checked continuity for the wiring, all seems good.

Thank you for any suggestions.
Mat
Hairball Audio, LLC
DIY Parts and Kits
https://hairballaudio.com

Top secret stuff and upcoming releases:
http://instagram.com/Hairballaudio
http://facebook.com/hairballaudio