Hi, I need advice before I try to use PCBs/VU buffer PCBs with VUs from Calrad
In the specs of that VU , it is mentioned "DiodeBr" - does it mean it has already internal rectifiers ?
Has anybody already used these VUs and know any specific tip for them ?
see at : http://www.calradstore.com/60-133.html
( 60-133, VU Meter, DC resistance: 600W+DiodeBr.+3.9kW/120W )
thanks a lot , Joe !
PCB/VU buffer and Calrad VUs
Moderator: Joe Malone
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Re: PCB/VU buffer and Calrad VUs
Yes Diode bridge means internal rectifier so do both Note 1 and Note 2 from the VU Buffer build thread. See below.guilhermea wrote:Hi, I need advice before I try to use PCBs/VU buffer PCBs with VUs from Calrad
In the specs of that VU , it is mentioned "DiodeBr" - does it mean it has already internal rectifiers ?
Has anybody already used these VUs and know any specific tip for them ?
see at : http://www.calradstore.com/60-133.html
( 60-133, VU Meter, DC resistance: 600W+DiodeBr.+3.9kW/120W )
thanks a lot , Joe !
Note 1. When using a meter with internal rectifiers like our Nissei AL29 do the mod shown below to disable the VU buffer rectifier.
Note 2. Since the VU buffer runs on a single power rail it will have a power on voltage jump which will show as a large deflection on the meters pointer.
The size of the pointer deflection varies depending on meter type, voltage used, gain setting. This can be greatly reduced by slowing the rise of the half rail voltage on the VU buffer PCB.
This can be done by either changing the two 3k3 resistors shown below both to 47k or 100k. Or change the 10uF cap shown below to 100uF to 220uF 16v. Or doing Both changes. (VU buffer kits will have 2 extra 47k from Feb 2012)
//www
Joe
JLM Audio
Capturing Audio without Injury
JLM Audio
Capturing Audio without Injury
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Re: PCB/VU buffer and Calrad VUs
OK, thanks Joe for valuable information !
I ve alredy mounted the kit , but didnt turn it on because I´m traveling on tour...
I´ll replace the resistors first and experiment .
Any trouble if I use just one 12 V DC source to power 2 circuits in parallel (for both L/R channels)
or I should use 2 separate DC sources, one for each ?
thanks
guilherme.
I ve alredy mounted the kit , but didnt turn it on because I´m traveling on tour...
I´ll replace the resistors first and experiment .
Any trouble if I use just one 12 V DC source to power 2 circuits in parallel (for both L/R channels)
or I should use 2 separate DC sources, one for each ?
thanks
guilherme.
- Joe Malone
- Site Admin
- Posts: 2078
- Joined: Wed Jan 24, 2007 11:35 pm
- Location: Brisbane, Australia
- Contact:
Re: PCB/VU buffer and Calrad VUs
One 12v source can run multiple VU Buffers fine as they only draw about 20mA each. It is VU lamps that draw usually 100mA each so add up current wise quickly.guilhermea wrote:OK, thanks Joe for valuable information !
I ve alredy mounted the kit , but didnt turn it on because I´m traveling on tour...
I´ll replace the resistors first and experiment .
Any trouble if I use just one 12 V DC source to power 2 circuits in parallel (for both L/R channels)
or I should use 2 separate DC sources, one for each ?
thanks
guilherme.
Joe
JLM Audio
Capturing Audio without Injury
JLM Audio
Capturing Audio without Injury
-
- Posts: 3
- Joined: Thu May 24, 2012 12:59 am
Re: PCB/VU buffer and Calrad VUs
thanks again for quick responses !
good to have such a follow-up !
have a nice weekend.
good to have such a follow-up !
have a nice weekend.