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Re: Stereo VU meter kit BUILD THREAD

Posted: Tue Mar 17, 2015 6:29 am
by navehgrofi
Hey Jo

So i've managed to do everything good and working, so please don't pay attention to my previous message

i do have 1 issue now

after everything worked my computer has restarted since that my meters stop working

could it be a power Skype fired them or something?

Re: Stereo VU meter kit BUILD THREAD

Posted: Wed Mar 18, 2015 2:17 pm
by Joe Malone
2 more questions please:

1. im successfully having meters read, but even with the highest gain position i cannot bring the needles over -3 dB (I'm sending high volume 1 kHz sine wave)

What dBM input level are you sending to the meters? What rectifier diode types and arrangement are you using? And what series resistor do you have with the meter? Or are you using one of our buffer kits?

2. is this setup recommended:

Audio Device outputs (UnBalanced) through TRS Line (Sleeve not connected?) to VU STEREO Inputs, then Pseudo Balanced at ten wiring to XLR outputs (lines to speakers are only 1 meters or less long)

The 0v shield should be connected from the Sleeve of the TRS should connect to XLR pin 1 so shield connects all audio products together. (Not needed for meters)

or should i use Fully balanced lines to the inputs?

Short run so should be ok.

Re: Stereo VU meter kit BUILD THREAD

Posted: Wed Mar 18, 2015 3:59 pm
by navehgrofi
i am using your stereo VU Audio buffer ...

as i said meters stopped working after pc restart...

Re: Stereo VU meter kit BUILD THREAD

Posted: Wed Mar 18, 2015 4:25 pm
by Joe Malone
navehgrofi wrote:i am using your stereo VU Audio buffer ...

as i said meters stopped working after pc restart...


OK did see that last post

To get more level to the meter simply turn up the 25 turn trim pots on the VU Buffer PCB. Make sure you have fitted the trim pots the correct way because if reversed they will need to be turned anticlockwise

Is the computer supplying the audio correctly? Almost impossible for a spike to blow this up. Do you have correct DC power to running in the VU buffer?

If still having problems send me some photos of the top and bottom of the PCB and the whole wiring and your setup to my email.

Re: Stereo VU meter kit BUILD THREAD

Posted: Wed Mar 18, 2015 9:38 pm
by navehgrofi
the power supply is correct.
i do have audio inputs and output (through the attenuator)
the thing is it worked...

it might be related to the attenuator wiring i changed to your recommendations (pseudo blenched wiring)

with the TRS sockets supplied with the VU Buffer, it has 6 wiring points to the VU board (2 for Sleeve, 2 for Ring, 2 for Tip)

does it matter from which of the two i wire to the attenuator?

Re: Stereo VU meter kit BUILD THREAD

Posted: Thu Mar 19, 2015 9:34 am
by Joe Malone
navehgrofi wrote:the power supply is correct.
i do have audio inputs and output (through the attenuator)
the thing is it worked...

it might be related to the attenuator wiring i changed to your recommendations (pseudo blenched wiring)

with the TRS sockets supplied with the VU Buffer, it has 6 wiring points to the VU board (2 for Sleeve, 2 for Ring, 2 for Tip)

does it matter from which of the two i wire to the attenuator?


But are you getting audio to the monitors and is the attenuator working?

Is only the VU meters not working??

Like I said in the last reply some photos of the top and bottom of the VU buffer PCB and your wiring and total setup to my email would answer a lot.

Re: Stereo VU meter kit BUILD THREAD

Posted: Mon Mar 26, 2018 10:07 pm
by ralphonz
Hi,

I've had my kit sitting around for a while and finally got a round to building it! Everything seems to be working great 8)

My question is about calibration. This may be a stupid question but, whats the best way to send +4dBm, or 1.23V AC? I am using a MIDAS Venice firewire console, I've currently set everything to unity and calibrated the meters to read 0VU at -14dBFS 1K sine, but this doesn't seem right, most music I play goes into the red on the VU.

Seems daft that I can build the thing but can't manage the calibration! Any help would be greatly appreciated :oops:

Re: Stereo VU meter kit BUILD THREAD

Posted: Mon Mar 26, 2018 10:13 pm
by Joe Malone
ralphonz wrote:Hi,

I've had my kit sitting around for a while and finally got a round to building it! Everything seems to be working great 8)

My question is about calibration. This may be a stupid question but, whats the best way to send +4dBm, or 1.23V AC? I am using a MIDAS Venice firewire console, I've currently set everything to unity and calibrated the meters to read 0VU at -14dBFS 1K sine, but this doesn't seem right, most music I play goes into the red on the VU.

Seems daft that I can build the thing but can't manage the calibration! Any help would be greatly appreciated :oops:


HI There is no right or wrong cal point. Only one that works for you. Use your loudest reference music so the meters are pushed just fully red on the meters. Usually something like -10dBFS will work. -14dBFS is good as it leaves some headroom but if the music you make or play is more compressed then you will just pin the meters.

Re: Stereo VU meter kit BUILD THREAD

Posted: Thu Mar 29, 2018 4:08 am
by ralphonz
Thanks Joe, I suppose I've been doing it right then :D I'm still curious is there an easy, convenient way to send 1.23vac to a device such as the VU meter?

Re: Stereo VU meter kit BUILD THREAD

Posted: Tue Oct 30, 2018 6:22 am
by timbroberg
Hi!

Maybe I'm in over my head? I put this kit together but the lights wont come on and I can't get the meters to react to incoming signal. Thought I post some pictures of my kit and maybe get some tips. I tried it with an 150 mA power supply. Since the thread says that it only draws about 40mA total I figured thats enough?

Maybe I already blew it but if not I'm thankful for any help I can get!

Re: Stereo VU meter kit BUILD THREAD

Posted: Tue Oct 30, 2018 11:05 am
by Joe Malone
timbroberg wrote:Hi!

Maybe I'm in over my head? I put this kit together but the lights wont come on and I can't get the meters to react to incoming signal. Thought I post some pictures of my kit and maybe get some tips. I tried it with an 150 mA power supply. Since the thread says that it only draws about 40mA total I figured thats enough?

Maybe I already blew it but if not I'm thankful for any help I can get!


You have fitted the TL072 opamp backwards to the pcb so it will be shorting out the power supply completely.

I cannot see the supplied IC socket fitted? So unplugging and turned around will now be difficult as it will need to be unsoldered instead of just unplugged. The TL072 may also be dead but since the power supply is only 150mA you maybe ok.

But the power supply will need to be checked to be working after this as well.

Re: Stereo VU meter kit BUILD THREAD

Posted: Wed Oct 31, 2018 8:13 am
by timbroberg
Thanks for the fast reply!

I desoldered the opamp, soldered the IC socket and turned the opamp around but still nothing. The power supply is giving me 17 Volts. Is this normal? Should I get a "better" one?
To proceed with the troubleshooting I figured I replace the opamp. Can I replace it with this one?

https://www.elfa.se/en/operational-amplifier-dual-mhz-dil-tl072-texas-instruments-tl072cp/p/17311715?queryFromSuggest=true

Re: Stereo VU meter kit BUILD THREAD

Posted: Wed Oct 31, 2018 11:04 am
by Joe Malone
timbroberg wrote:Thanks for the fast reply!

I desoldered the opamp, soldered the IC socket and turned the opamp around but still nothing. The power supply is giving me 17 Volts. Is this normal? Should I get a "better" one?

It means the power supply isn't regulated so may input some noise into the circuit but ok to test with it first and if you have noise problems change power supply.

To proceed with the troubleshooting I figured I replace the opamp. Can I replace it with this one?
https://www.elfa.se/en/operational-amplifier-dual-mhz-dil-tl072-texas-instruments-tl072cp/p/17311715?queryFromSuggest=true


First check with the dead IC removed that you have +17V between pin 8 and pin 4 of the IC socket encase the BAT85 D9 has gone open circuit from the reverse IC. The meter lights should light. Yes that IC will work fine.

Re: Stereo VU meter kit BUILD THREAD

Posted: Thu Nov 01, 2018 4:44 pm
by timbroberg
With the power supply connected I get 6 Volts between pin 8 and pin 4 and its slowly going down. Also the VU meters go up to around zero but still no light. I also checked the lamps and I get 17 Volts there as well. A bit to much right? Any thoughts on this?

Re: Stereo VU meter kit BUILD THREAD

Posted: Thu Nov 01, 2018 8:59 pm
by Joe Malone
timbroberg wrote:With the power supply connected I get 6 Volts between pin 8 and pin 4 and its slowly going down. Also the VU meters go up to around zero but still no light. I also checked the lamps and I get 17 Volts there as well. A bit to much right? Any thoughts on this?


Are you sure you have the 12v wired the correct way around? red is +12v and black is 0v?

As you should have 6v at the leds on the meters and they should be lighting up and 17v between pin 8 + and pin 4 0v with no opamp fitted?