VU2 stereo VU buffer kit Build thread

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acidfarmer
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Re: VU2 stereo VU buffer kit Build thread

Postby acidfarmer » Tue Apr 09, 2019 3:23 pm

Hello, have the following problem: at high frequencies I have full rash, at low frequencies only very low rash on the VU-meter. At the same outputlevel. Is that so normal? I have 500 uA VU-meters...

Alex

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Re: VU2 stereo VU buffer kit Build thread

Postby Joe Malone » Tue Apr 09, 2019 3:28 pm

acidfarmer wrote:Hello, have the following problem: at high frequencies I have full rash, at low frequencies only very low rash on the VU-meter. At the same outputlevel. Is that so normal? I have 500 uA VU-meters...

Alex


No not normal.

What meters are you using?

Do they have diode bridge in the meter?

Have you fitted the diode bridge on the VU2 pcb?

Photos would help check the pcb build and wiring.
Joe :-)
JLM Audio
Capturing Audio without Injury

acidfarmer
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Re: VU2 stereo VU buffer kit Build thread

Postby acidfarmer » Tue Apr 09, 2019 3:34 pm

I have this VU-meters:
https://flashstar.en.taiwantrade.com/product/vu-meter-292601.html

I have fitted the diode bridge.

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Re: VU2 stereo VU buffer kit Build thread

Postby Joe Malone » Tue Apr 09, 2019 4:26 pm

acidfarmer wrote:I have this VU-meters:
https://flashstar.en.taiwantrade.com/product/vu-meter-292601.html

I have fitted the diode bridge.


That should work fine. Need some photos of the VU2 pcb top and bottom and wiring as it is at the moment.

Are you driving balanced input signal in ?
Joe :-)

JLM Audio

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acidfarmer
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Re: VU2 stereo VU buffer kit Build thread

Postby acidfarmer » Tue Apr 09, 2019 4:49 pm

Joe Malone wrote:
That should work fine. Need some photos of the VU2 pcb top and bottom and wiring as it is at the moment.

Are you driving balanced input signal in ?


Yes, i drive it with balanced input signal. Here the Photos:
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Re: VU2 stereo VU buffer kit Build thread

Postby Joe Malone » Tue Apr 09, 2019 6:24 pm

acidfarmer wrote:
Joe Malone wrote:
That should work fine. Need some photos of the VU2 pcb top and bottom and wiring as it is at the moment.

Are you driving balanced input signal in ?


Yes, i drive it with balanced input signal. Here the Photos:


So the balanced audio output this is wired across sounds like full audio range when you listen music?

As your description sounds like when transformer output is open one leg so only high frequency bleed comes out.
Joe :-)

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acidfarmer
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Re: VU2 stereo VU buffer kit Build thread

Postby acidfarmer » Tue Apr 09, 2019 6:31 pm

Joe Malone wrote:
So the balanced audio output this is wired across sounds like full audio range when you listen music?

As your description sounds like when transformer output is open one leg so only high frequency bleed comes out.


Yes, the Audiosignal is full range. I have testet the VU-meter with another bufferboard from China at the same audio ports. With the china bufferboard i don´t have the frequency problem.

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Re: VU2 stereo VU buffer kit Build thread

Postby Joe Malone » Tue Apr 09, 2019 7:15 pm

acidfarmer wrote:
Joe Malone wrote:
So the balanced audio output this is wired across sounds like full audio range when you listen music?

As your description sounds like when transformer output is open one leg so only high frequency bleed comes out.


Yes, the Audiosignal is full range. I have testet the VU-meter with another bufferboard from China at the same audio ports. With the china bufferboard i don´t have the frequency problem.


What frequency does it roughly roll off at?

Do the blue caps have 105 or 104 written on them?

Does the china board have balanced in?
Joe :-)

JLM Audio

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acidfarmer
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Re: VU2 stereo VU buffer kit Build thread

Postby acidfarmer » Tue Apr 09, 2019 7:29 pm

Joe Malone wrote:
What frequency does it roughly roll off at?

Do the blue caps have 105 or 104 written on them?

Does the china board have balanced in?


The frequency goes from 10hz to 22khz at the delta 1072 output. The vu-meter shows at 100 hz only -15db, at 10khz it indicates + 4db for example. When i use a fullrange signal (music), displays the meter accordingly. So at low frequencies, low levels, high frequencies come at a correspondingly higher level. I have tested the JLM board unbalanced...it´s the same result.

The cinaboard have only unbalanced input.

The blue caps have 105...

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Re: VU2 stereo VU buffer kit Build thread

Postby Joe Malone » Tue Apr 09, 2019 8:38 pm

acidfarmer wrote:
Joe Malone wrote:
What frequency does it roughly roll off at?

Do the blue caps have 105 or 104 written on them?

Does the china board have balanced in?


The frequency goes from 10hz to 22khz at the delta 1072 output. The vu-meter shows at 100 hz only -15db, at 10khz it indicates + 4db for example. When i use a fullrange signal (music), displays the meter accordingly. So at low frequencies, low levels, high frequencies come at a correspondingly higher level. I have tested the JLM board unbalanced...it´s the same result.

The cinaboard have only unbalanced input.

The blue caps have 105...


OK makes no sense at all then.

If you connect the VU buffer across the balanced out of D/A etc does it still have the same problem?

Where did you connect the unbalanced board to as this is transformer floating out by the looks? So should not have worked on the output?
Joe :-)

JLM Audio

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acidfarmer
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Re: VU2 stereo VU buffer kit Build thread

Postby acidfarmer » Tue Apr 09, 2019 9:12 pm

Joe Malone wrote:
OK makes no sense at all then.

If you connect the VU buffer across the balanced out of D/A etc does it still have the same problem?

Where did you connect the unbalanced board to as this is transformer floating out by the looks? So should not have worked on the output?


I just tested it directly on the audio interface. Same result in behavior ...with balanced and unbalanced in. Strange... :?

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Re: VU2 stereo VU buffer kit Build thread

Postby Joe Malone » Tue Apr 09, 2019 9:14 pm

acidfarmer wrote:
Joe Malone wrote:
OK makes no sense at all then.

If you connect the VU buffer across the balanced out of D/A etc does it still have the same problem?

Where did you connect the unbalanced board to as this is transformer floating out by the looks? So should not have worked on the output?


I just tested it directly on the audio interface. Same result in behavior ...with balanced and unbalanced in. Strange... :?


Do both left and right do exactly the same thing?
Joe :-)

JLM Audio

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acidfarmer
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Joined: Tue Apr 09, 2019 4:46 am

Re: VU2 stereo VU buffer kit Build thread

Postby acidfarmer » Tue Apr 09, 2019 9:20 pm

Joe Malone wrote:Do both left and right do exactly the same thing?


Yes...

acidfarmer
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Re: VU2 stereo VU buffer kit Build thread

Postby acidfarmer » Wed Apr 10, 2019 3:14 am

I found the mistake ... that's almost embarrassing for me ... :roll:
The construction manual states:
input cable red = +
yellow = -
black = ground
But the supplied plugs have the assignment red = - and yellow = +, if the plugs are mounted as on the pictures.

My mistake was to orient myself to the cable colors, instead of making sure that the connector assignment is the right way around.

Big Thanks for your support Joe! :)

Shame on me...

Alex

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Joe Malone
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Re: VU2 stereo VU buffer kit Build thread

Postby Joe Malone » Wed Apr 10, 2019 2:46 pm

acidfarmer wrote:I found the mistake ... that's almost embarrassing for me ... :roll:
The construction manual states:
input cable red = +
yellow = -
black = ground
But the supplied plugs have the assignment red = - and yellow = +, if the plugs are mounted as on the pictures.

My mistake was to orient myself to the cable colors, instead of making sure that the connector assignment is the right way around.

Big Thanks for your support Joe! :)

Shame on me...

Alex


HI Alex
Sorry for the stuff up. Great to hear you worked it out. Strange the wrong colour code. Are the 3 pin cables in the kit short wire (150mm to 200mm) or ones with locks and 300mm wire? Photo would be great as the colour code shouldn't be changing if the right cables are being packed in the kit. Thanks for spotting the problem I will have to get this worked out ASAP as I don't want colour changes causing confusion.
Joe :-)

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