3. Meter works as expected except on 2:1 ratio, where it stays on 4dB GR minimum
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Author Topic: Meter works as expected except on 2:1 ratio, where it stays on 4dB GR minimum

October 25, 2022, 02:50:19 AM
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mjc7900

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Meter works as expected except on 2:1 ratio, where it stays on 4dB GR minimum
So the whole setup process went really well until I was passing audio through the unit and checking the sound (and liking it a lot) with some drum loops.  At this point I switched off of the 10:1 ratio down to 2:1.  At 2:1 and 2:1 only the dB Compression meter jumps up to 4dB of compression and stays there as a new baseline.  What is the likely culprit here?  Everything else works as expected, sounds completely clean, and functions normally.  Only the meter in 2:1 mode doesn't work as expected.
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October 25, 2022, 09:37:14 AM
Reply #1

JPK

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Re: Meter works as expected except on 2:1 ratio, where it stays on 4dB GR minimum
Is it only the display with the sound being compressed normally in 2:1?
Does the meter needle move from the +4 position when audio is sent?

You could check that diodes D1 and D2 are in the correct direction.
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JPK
October 25, 2022, 03:28:28 PM
Reply #2

mjc7900

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Re: Meter works as expected except on 2:1 ratio, where it stays on 4dB GR minimum
The meter does move in 2:1.  Its like the meter sees 4dB as the new "zero" when in 2:1 mode.  The meter will respond to input signal though.  I will check the diode position again.
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October 26, 2022, 04:48:31 PM
Reply #3

mjc7900

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Re: Meter works as expected except on 2:1 ratio, where it stays on 4dB GR minimum
just checked D1 & D2 and they are oriented correctly.
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October 26, 2022, 05:45:54 PM
Reply #4

mjc7900

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Re: Meter works as expected except on 2:1 ratio, where it stays on 4dB GR minimum
Is it time for an isopropyl bath - and if so:


  • Would that be for all three PCBs?
  • Do I need to remove ICs prior to submerging?
  • What strength isopropyl is recommended?

Thank you!

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October 27, 2022, 11:02:37 AM
Reply #5

JPK

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Re: Meter works as expected except on 2:1 ratio, where it stays on 4dB GR minimum
Not sure for the isopropyl. The issue would be there for the 3 ratios.
Do you get the same meter shift without the channel 2 installed?
Do installing channel 2 modifies the shift level?
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JPK
October 27, 2022, 07:45:22 PM
Reply #6

mjc7900

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Re: Meter works as expected except on 2:1 ratio, where it stays on 4dB GR minimum
I'll have to check.  Just pull the second channel, keep JP1 in place, and do the same test?
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October 28, 2022, 11:22:31 AM
Reply #7

JPK

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Re: Meter works as expected except on 2:1 ratio, where it stays on 4dB GR minimum
Yes exactly.
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JPK
October 31, 2022, 03:50:20 AM
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ReadyToRockAudio

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Re: Meter works as expected except on 2:1 ratio, where it stays on 4dB GR minimum
I'm having the EXACT same issue. Everything seems to work perfectly, except On 2:1 my meter rests at about 3db.  4:1 and 10:1 rest at zero.
I'll be watching this thread.

Chris
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November 02, 2022, 02:44:49 AM
Reply #9

ReadyToRockAudio

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Re: Meter works as expected except on 2:1 ratio, where it stays on 4dB GR minimum
JPK,
    I went back and checked D1 and D2.   I did have them in backwards!   It was the one part of the instructions I glossed over.  Oops.  K means Cathode (aka black ring, negative).
Mine is working perfectly now.  Sounds great!   I hope MJC7900 can get his figured out.

Thanks so much!
Chris
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November 03, 2022, 02:29:01 AM
Reply #10

mjc7900

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Re: Meter works as expected except on 2:1 ratio, where it stays on 4dB GR minimum
Well my diodes are correctly oriented and the unit behaves in the same way whether there is one or two channels installed...

Glad to hear you got yours working though, Chris!
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November 04, 2022, 06:34:59 PM
Reply #11

JPK

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Re: Meter works as expected except on 2:1 ratio, where it stays on 4dB GR minimum
What is the DC voltage on TP5 and TP11 (only channel 1 installed)?
Check that the resistors R5 to R9 are in the correct position.
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JPK
November 09, 2022, 11:32:00 PM
Reply #12

mjc7900

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Re: Meter works as expected except on 2:1 ratio, where it stays on 4dB GR minimum
TP5 @ .367vdc
TP11 @ .006vdc

I just confirmed also that R5-R9 are correctly placed as well.

Thank you!
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November 10, 2022, 12:57:02 PM
Reply #13

JPK

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Re: Meter works as expected except on 2:1 ratio, where it stays on 4dB GR minimum
Try removing Q1, it might be damaged (Its function is to stop the meter moving when the compressor is bypassed).
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JPK
November 21, 2022, 04:18:12 PM
Reply #14

mjc7900

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Re: Meter works as expected except on 2:1 ratio, where it stays on 4dB GR minimum
Should I just remove it and plug the compressor back in to check?
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November 22, 2022, 07:36:20 AM
Reply #15

JPK

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Re: Meter works as expected except on 2:1 ratio, where it stays on 4dB GR minimum
Yes.
Heat the 3 pins together with a big blob of solder.
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JPK
December 02, 2022, 06:23:51 PM
Reply #16

mjc7900

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Re: Meter works as expected except on 2:1 ratio, where it stays on 4dB GR minimum
Replaced the 2N7000 (I had some available), still behaving the same way.  Where the meter hovers is dependent on the release time as well.  Another interesting development - the release potentiometer housing now spins freely on the soldered pins and the detents are now essentially useless and the potentiometer is likely not functioning correctly.  Pretty inexplicably too.  I didn't do anything to prompt that behavior.  
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December 06, 2022, 09:22:40 AM
Reply #17

JPK

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Re: Meter works as expected except on 2:1 ratio, where it stays on 4dB GR minimum
Please check again this value: TP11 @ .006vdc. It seems too low.

The release rotary switch needs to be replaced. Please contact me at jpk(a)soundskulptor.com.
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JPK
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