VU2 stereo VU buffer kit Build thread

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VU2 stereo VU buffer kit Build thread

Postby Joe Malone » Fri Sep 28, 2012 8:59 am

PLEASE READ ALL NOTES & ERRATA BEFORE STARTING ASSEMBLY
VU2 stereo VU buffer PCB
PCB can be power using the +/-DC solder pads or the IDC10 header as used on our AMP HEAD kit.
If using single rail +DC can be +12v to +36v and -DC wired to 0v.
If using dual +/-rail +DC can be +6 to +18v and -DC can be -6 to -18v. (NO 0v power rail is connected when dual rails are used)

Image

47k = Yellow Violet Black red
3k3 = Orange Orange Black Brown
100R = Brown Black Black Black

VU2 Stereo buffer kit parts list here

INPUTS
3 OPTIONS (You can also have XLR and TRS at the same time by adding a Stereo in kit.)
XLR PCB Mount (one for left and one for right channel)
TRS PCB Mount (one for left and one for right channel)
3 pin connectors (one for left and one for right channel)
IN+ = + Balanced input signal (Unbalanced + input) (Red Wire)
IN- = - Balanced input signal (Unbalanced shield) (Black Wire)
G = 0v ground shield (Not used for unbalanced input) (Yellow Wire)

OUTPUTS
4 pin connectors (one for left and one for right channel)
M+ = Meter + terminal (Yellow wire)
M- = Meter - terminal (White wire)
L+ = Lamp + terminal (Red wire)
L- = Lamp - terminal (Black wire)

Notes & Errata
Note 1. When using a meter with internal rectifiers do the mod shown below to disable the VU buffer rectifier.
Image

Note 2. If trimpot is fitted the opposite way to what the overlay shows buffer it will work fine but gain will increase counter clockwise.

Note 3. If you need more gain change R7L & R7R from 3k3 down to a minimum of 100R. It is also then worth putting a red LED or or 2 x 1N4007 in series across the meter +(Anode) /-(Cathode) terminals to limit & protect the meter in overload conditions. You can also get more gain by changing R9L & R9R from 100R down to minimum of 22R or 10R.

Note 4.Current VU2 pcb has pin 4 of the IC socket masked over so best to solder a cut off component leg form that pin to -DC as shown below.
Image


RLamp values for LED or Bulb
If you want to run a LED fit RLamp of 3k3. or use this formula to work out the resistor value for the brightest LED R = (V - 2) / 0.02. Where V is the voltage running the VU buffer.
If you want to run a Bulb fit RLamp of 10R for soft start and run the VU buffer on the same voltage as the lamp needs. Like 12v or 24v etc.

NOTE ALL PHOTOS BELOW SHOW THE TRIM POTS FITTED THE WRONG WAY AROUND.
BRASS SCREW SHOULD ON OPPOSITE SIDE

Image
Image
Image

For step by step build info the rest of the VU2 is the same as the Mono VU buffer kit build thread here
Joe :-)
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jimi
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Re: VU2 stereo VU buffer kit Build thread

Postby jimi » Tue Jan 22, 2013 6:09 pm

Quick question regarding this kit used with JLM 34mm meters, which I couldn't find an answer to by poking around the forum:

For C3L & R, should I be using the supplied extra 100uF electros for a slower response with these meters?

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Re: VU2 stereo VU buffer kit Build thread

Postby Joe Malone » Tue Jan 22, 2013 6:19 pm

jimi wrote:Quick question regarding this kit used with JLM 34mm meters, which I couldn't find an answer to by poking around the forum:

For C3L & R, should I be using the supplied extra 100uF electros for a slower response with these meters?


No C3L & R never change value. To slow any meter the 100uF is just place across the Meter +/- terminals. This will work with 34mm meters
Joe :-)

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Re: VU2 stereo VU buffer kit Build thread

Postby jimi » Tue Jan 22, 2013 6:21 pm

Awesome. Thanks Joe. So do you recommend this or will they work fine without 100uF across the terminals?

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Re: VU2 stereo VU buffer kit Build thread

Postby Joe Malone » Tue Jan 22, 2013 6:37 pm

jimi wrote:Awesome. Thanks Joe. So do you recommend this or will they work fine without 100uF across the terminals?


The 34mm with the 100uF works perfect.
Joe :-)

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Re: VU2 stereo VU buffer kit Build thread

Postby jimi » Tue Jan 22, 2013 6:43 pm

Bloody marvelous. Thanks Joe. Thanks a bunch.

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Re: VU2 stereo VU buffer kit Build thread

Postby jost » Tue Jun 10, 2014 5:21 pm

Hey Joe!

For running this kit to drive the 34mm meters, any recommendations on the specific make and model of the 100uF capacitors across the meter terminals?
Will the standard 100uF/6V electrolyte capacitors do, or should I get something fancier for best results?
(Yes, I could just dig up the oscilloscope. But you probably tried this already, so I thought I'd ask...)

Also I couldn't find the pinout for the 10-pin header at the center anywhere, is that documented?

Sweet PCB by the way. Because the packing density is so high I recommend a fine-tipped soldering iron for assembly!

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Re: VU2 stereo VU buffer kit Build thread

Postby Joe Malone » Wed Jun 11, 2014 3:43 pm

jost wrote:Hey Joe!

For running this kit to drive the 34mm meters, any recommendations on the specific make and model of the 100uF capacitors across the meter terminals?
Will the standard 100uF/6V electrolyte capacitors do, or should I get something fancier for best results?
(Yes, I could just dig up the oscilloscope. But you probably tried this already, so I thought I'd ask...)

Also I couldn't find the pinout for the 10-pin header at the center anywhere, is that documented?

Sweet PCB by the way. Because the packing density is so high I recommend a fine-tipped soldering iron for assembly!


The 100uF cap to slow the attack and release of the meter can be any 100uF 6v or more.

THE VU2 10pin Header STEREO PORT is the same on our AMP HEAD & STEREO IN PCBs

STEREO PORT
Pin 1 Left Audio +
Pin 2 Left Audio -
Pin 3&4 V+ = DC +
Pin 5&6 0v = GND
Pin 7&8 V- = DC -
Pin 9 Right Audio -
Pin 10 Right Audio +
Joe :-)

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Re: VU2 stereo VU buffer kit Build thread

Postby jost » Mon Jul 07, 2014 5:32 pm

Thanks! Works great!

One other thing:
I need to power this off a single +5Vdc rail via a DC-DC converter.

Since that gives me the choice of input voltages, what would be the "ideal" setup? (symmetric/unsymmetric, 12V/36V...)

Can you give an estimate on the peak power consumption of the board itself?
I assume the 34mm VU meter's power consumption is negligible, plus max 20mA each for the LEDs?

DC-DC converters don't have the highest efficiency to begin with, and it gets even worse on partial load, so I'd like to avoid massive over dimensioning if I can, but of course it needs to be strong enough to power everything in all situations.

Thank you again!

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Re: VU2 stereo VU buffer kit Build thread

Postby Joe Malone » Tue Jul 08, 2014 11:47 am

jost wrote:Thanks! Works great!

One other thing:
I need to power this off a single +5Vdc rail via a DC-DC converter.

Since that gives me the choice of input voltages, what would be the "ideal" setup? (symmetric/unsymmetric, 12V/36V...)

Can you give an estimate on the peak power consumption of the board itself?
I assume the 34mm VU meter's power consumption is negligible, plus max 20mA each for the LEDs?

DC-DC converters don't have the highest efficiency to begin with, and it gets even worse on partial load, so I'd like to avoid massive over dimensioning if I can, but of course it needs to be strong enough to power everything in all situations.

Thank you again!


OK first I would try running the VU2 on the 5v as some TL072 can run on that low voltage. Otherwise just a small 1W 5v to 12vdc should be fine.
Joe :-)

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Re: VU2 stereo VU buffer kit Build thread

Postby Niki » Thu Jul 24, 2014 9:44 pm

Hi Joe,

How to adjust the time/memory response to display the peak level on my analog Vu-meter.
I have a stereo analog VU connected to the VU2 (with a bridge rectifier). This VU2 is connected to a preamp which has it's own led VU. When I use this preamp, and when the musical peak lit on the 0dB led level, the VU2 shows only -15dB.
I precise that I have calibrated both the VU led and VU2 + analog VU: I sent a 1kHz 0db level on the preamp input and set the led VU for turning ON the 0dB led and also set the 0dB level on the VU2 for a 0dB indication on the analog VU.

Is it possible to increase the "memory" effect of the VU2 ? by increasing a capacitor or something other ?
(I have made the recommended modifications on the board components)

Nicholas

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Re: VU2 stereo VU buffer kit Build thread

Postby Joe Malone » Mon Jul 28, 2014 12:31 pm

Niki wrote:Hi Joe,

How to adjust the time/memory response to display the peak level on my analog Vu-meter.
I have a stereo analog VU connected to the VU2 (with a bridge rectifier). This VU2 is connected to a preamp which has it's own led VU. When I use this preamp, and when the musical peak lit on the 0dB led level, the VU2 shows only -15dB.
I precise that I have calibrated both the VU led and VU2 + analog VU: I sent a 1kHz 0db level on the preamp input and set the led VU for turning ON the 0dB led and also set the 0dB level on the VU2 for a 0dB indication on the analog VU.

Is it possible to increase the "memory" effect of the VU2 ? by increasing a capacitor or something other ?
(I have made the recommended modifications on the board components)

Nicholas


Your reading are correct as the peak and average should be about 10 to 15dB different. You do NOT set the peak led and 0VU to be the same level.

The slowness is mechanically built into the VU meter movement. The VU2 buffer is only a amp buffer so does effect the response time at all.

You need to set VU meter usually to +4dBM = 0VU and the peak led to about 10dB to 15dB more (usually -2dBFS) depending on your A/D input level or D/A output level.
Joe :-)

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steenhart
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Re: VU2 stereo VU buffer kit Build thread

Postby steenhart » Thu Sep 25, 2014 3:19 pm

Hi All,

I have bought some old Siemens Lichtzeiger http://commons.wikimedia.org/wiki/File:Lichtzeiger_Instrument_Siemens_%26_Halske.jpg
Can I use this board to drive the meters??

Regrads Ronald

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Re: VU2 stereo VU buffer kit Build thread

Postby Joe Malone » Thu Sep 25, 2014 3:38 pm

steenhart wrote:Hi All,

I have bought some old Siemens Lichtzeiger http://commons.wikimedia.org/wiki/File:Lichtzeiger_Instrument_Siemens_%26_Halske.jpg
Can I use this board to drive the meters??

Regrads Ronald


I have no idea about those besides they look great. Are they just a moving coil with needle ? As I cannot see any actual needle?

Do you have move info
Joe :-)

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steenhart
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Re: VU2 stereo VU buffer kit Build thread

Postby steenhart » Fri Sep 26, 2014 4:13 pm

Hi Joe,

on the coil there is a little mirror and it will reflect the light beam to the front.
Because there is no needle this is a very quick system fasten than every normal Vu-meter.
Normally you need the vintage TAB U70 amplifier.
Have lot of these meters so will try your board once.

regards Ronald

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