CLX-VU Build Thread (DBX 160VU ) UPDATE: REV 3

[AW]

Do you have the original schematic of the dbx160, you can trouble shoot it better.
https://dbxpro.com/en/products/160

 

[yvus]

Thank you for the schematic. I am currently using this one I found here (http://juggernautmusic.com/2018/04/clx-vu-build-documents/), but I can't find where the problem originates.

 

[AW]

Do you have the same problem with both boards

 

[yvus]

No, with one board only. I have no sound at all from the other one passed the second TL082, but I focus on the first one now.

 

[AW]

I would double check that you have the right value resistors and the diodes are facing correctly. Also check bottom of board for cold solder joints. 

 

[yvus]

Thank you, I will do this. In fact, I just realized there is audio  coming out the (-) output, it is just much quieter as the one coming out of the (+) output. But when I see the schematic, it seems to be normal.

 

[AW]

Hope you find the problem, the link you sent me of rev2 schematic I never seen before, I wish there was a way to download it, it's very hard to read on that site. Are you using the rev3 boards, there is a build guide, BOM I could send you if you don't have it.

 

[yvus]

I think I found the problem on the second PCB, it was a faulty solder, thank you for your feedback. The difference in volume between the (+) and (-) pins on the XLR output seems to be normal. You can download the schematic, I did it, but I can't manage to upload it here, it doesn't seem to work. I don't know why because the file format is ok, and the size is under the limit. It is the Rev 2 schematic, but there is no big changes in cicrcuit between rev 2 and 3 I guess, the changes are more about the components prints on the board from what I understood. I use rev 3 PCBs. Thank you anyway, it seems to work now !

 

[BerndVP]

don't you guys got the rev 3 pdf ?

 

[yvus]

Yes, I do, but there is not full schematic on it, unless I have not the right document, in which case I would be interested !

 

[AW]

Glad to here you got it working, I had issues with the PCB's
There was no connection on the PCB board between CR-3 cathode, and CR1 anode.
It drove me crazy because I knew everything was connected correctly, but was not getting +/-15vdc.
I had to jumper CR-3 cathode to CR-1 anode to get the power supply to work correctly.
Had to do it on both boards.

 

[AW]

I can't seem to get my VU meter needle to sit to the left properly for input, and output, GR mode is right at zero, but when I switched to input or output the needle pins to the left with no input signal. I tried adjusting all the proper trim pots, with no luck. I am using the Hairball audio meter with R107=3.3k

 

[yvus]

Hello AW,

I think this is normal, in IN mode, your meter has to be at 0dB when there is a signal at about 1.228 VRMS at the input of the unit. When there is no signal, it is normal the needle sticks to the left of the meter (because a 0V signal is equivalent to - infinity in dB). Same thing for the OUT mode, the meter should be at about 0 with the same 1.228 VRMS an the input and the gain pot on 0 db. So the meter seems normal on your unit.

 

[AW]

Thanks for the reply, but the needle is pined to the left with no signal applied. When the in, and out positions are selected the meter is not in it's natural position, it's like there is a negative DC voltage applied when no signal is present. When you turn the power off the needle goes to it's natural position.
Are you saying this is normal for this compressor?

 

[yvus]

Yes, I think this is normal for this circuit and this meter.

 

[AW]

It's working great!!
I would definitely recommend this build, it makes my electric bass pop.
Very fast response I wish I could compare it with a genuine one.

 

[BerndVP]

so you're calibration worked ?
Did you get the 4:1 without any problems ?

The problems I have are:
- BELOW and ABOVE LEDS not working correctly
- 4:1 kind of working...

 

[AW]

I think I got the 4:1 working, got the 10db change when switching from -30db to -20db
As per the calibration instruction listed here.
Did you check your led's for correct wiring? Take a look at the original schematic they show how they are wired.
Connecting the anode, and cathodes correctly.

 

[band_master]

I tried clicking on the links for the BOM and the site appears to be hacked FYI

 

[AW]

Here is mine
Missing power transformer, possible some other items.
https://www.mouser.com/ProjectManager/ProjectDetail.aspx?State=EDIT&ProjectGUID=ee77c46d-ffdd-4bbb-915a-d0d5c423980c