Author Topic: VU meter problem

April 16, 2021, 04:13:01 PM
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dimitrip

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Hi! I am trying to calibrate the unit for the first time. 

My problem is the VU meter refresh rate, particularly the falling. It is extremely slow i.e., several sec to drop by one led. The higher the volume the more seconds it takes. E.g., 9-10 seconds for the yellow leds, 1-2 seconds for the lowest couple of greens. In fact, it looks like this delay gets an additional second for each led as we go up higher in volume.

Rising seems like it's working fine. It jumps instantly to the highest level and, unless there is a lasting drop in volume, it stays there.

I've looked for mistakes on the meter PCB but I couldn't find any. Any idea what I should try?

No problems with audio or controls. And I love the sound of it! :D

Thanks in advance!

April 17, 2021, 09:36:43 AM
Reply #1

JPK

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Check value and solder joints of R49 and C55. These components define the time constant of the meter.
JPK

April 17, 2021, 04:30:59 PM
Reply #2

dimitrip

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Yes, that was it! Had a bad joint on R49. Now they're dancing! :D

Thank you very much JP!

March 28, 2023, 10:51:16 PM
Reply #3

riley1990

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Hi. I built two units. The VU meter works incorrectly on both. As soon as the signal level reaches the first red LED, the yellow one goes out and only the green bar works. All parts are in their exact place. I soldered all the points, but the error still exists. Has anyone encountered this error?

March 29, 2023, 11:45:26 AM
Reply #4

JPK

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It could be a reversed red LED or a bad solder joint on U4.
JPK