VUPPM 500 Meter Calibration ?

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Arnow
Posts: 2
Joined: Tue Nov 12, 2019 7:08 am

VUPPM 500 Meter Calibration ?

Post by Arnow »

Hello Joe,

I just received your wonderful VUPPM 500 Meter, thank you very much !

I have tried to calibrate the VUPPM as describe :
Send in 1k tone at 0dFS or +18dBu to 500 Input for left and Output for right.
Set mode to VUPPM mode RED PPM with GREEN VU over the top.
Adjust Left and Right level trimpots so left and right 40th red led just light.
Adjust Left and Right VU/PPM trimpots so left and right green led just light. (40th led may make yellow depending on peak mode)


I have no problem to adjust the Left and Right input trimpots !
But Left and Right VU/PPM have no response. Anything is changing when I turn both of this trimpots.
I verified the VUPPM mode (PPM in red, VU in green)

I can't find where I'm wrong !

Do you have an idea ?

Best regards
Arnaud VIALA

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Joe Malone
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Posts: 1643
Joined: Wed Jan 24, 2007 11:35 pm
Location: Brisbane, Australia
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Re: VUPPM 500 Meter Calibration ?

Post by Joe Malone »

Arnow wrote:Hello Joe,

I just received your wonderful VUPPM 500 Meter, thank you very much !

I have tried to calibrate the VUPPM as describe :
Send in 1k tone at 0dFS or +18dBu to 500 Input for left and Output for right.
Set mode to VUPPM mode RED PPM with GREEN VU over the top.
Adjust Left and Right level trimpots so left and right 40th red led just light.
Adjust Left and Right VU/PPM trimpots so left and right green led just light. (40th led may make yellow depending on peak mode)


I have no problem to adjust the Left and Right input trimpots !
But Left and Right VU/PPM have no response. Anything is changing when I turn both of this trimpots.
I verified the VUPPM mode (PPM in red, VU in green)

I can't find where I'm wrong !

Do you have an idea ?

Best regards
Arnaud VIALA
HI Arnaud
I just checked your order and you bought a built and tested VUPPM500 meter so it is calibrated already. If you want to change input level you only should ever adjust the Input Left and Right trimpots as the VU/PPM balance is already set so should not be changed. If you have moved the 25 turn VU/PPM balance trimpots then turn them down several turns until the green VU level is a few leds less than the PPM red level. Adjust your PPM level so the top red led just lights then turn the VU/PPM BAL trim up until the 40th Green led just lights for both channels. Once balance it set is doesn't need to be adjusted again. You can change input level without having to redo the balance.
Joe :-)
JLM Audio
Capturing Audio without Injury

Arnow
Posts: 2
Joined: Tue Nov 12, 2019 7:08 am

Re: VUPPM 500 Meter Calibration ?

Post by Arnow »

Hello Joe,

Oh ! Then I have decalibrate my new VUPPM :oops:

I'm not in my studio this week so I can't recalibrate it now but when I try the first time, my problem was that the VU/PPM trimpots had no action.
(The green VU level didn't move)
Is it possible ?

I will try again ASAP and tell you !

Thank you for your answer !

Best regards
Arnaud VIALA

User avatar
Joe Malone
Site Admin
Posts: 1643
Joined: Wed Jan 24, 2007 11:35 pm
Location: Brisbane, Australia
Contact:

Re: VUPPM 500 Meter Calibration ?

Post by Joe Malone »

Arnow wrote:Hello Joe,

Oh ! Then I have decalibrate my new VUPPM :oops:

I'm not in my studio this week so I can't recalibrate it now but when I try the first time, my problem was that the VU/PPM trimpots had no action.
(The green VU level didn't move)
Is it possible ?

I will try again ASAP and tell you !

Thank you for your answer !

Best regards
Arnaud VIALA
We would not have been able to calibrate it if the trimpots didn’t work. They are 25 full turn trim pots so take a lot of turns to adjust so you probably haven’t moved the alignment out by much. Use a 1khz tone to do the alignment.
Joe :-)
JLM Audio
Capturing Audio without Injury

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