GB -- "VU Meter Amplifier" PCB - Page 3

jackinnj · 23rd September 2006, 05:35 PM

Quote:

Originally posted by tommak
I'm also interested!

Does anyone know if this will work well with the Corning pH meter Model 7 meters you can buy on eBay?

I searched the EDN site and found Jon Munson's article on the above design. ( Then I saw that jackinnj also linked to this in another thread. )

http://www.edn.com/contents/images/6280030.pdf

Thanks,

Tom

I have a couple of those Corning meters -- they use tubes -- they are exactly the type I used when doing analytical and quantitative chemistry over 30 years ago.

jackinnj · 24th September 2006, 06:04 PM

Quote:

Originally posted by Nordic
I'd be interested if you can help me with a method to test VU meter rateings... I have a few sets pirated from miscelaneous pieces of amps and tapedecks...

The meter movement is driven by the current flowing in its coil -- you have to determine the amount of current which drives the meter to full scale -- as shown in the attached, choose a potentiometer whose value is twice that necessary to cause the meter to deflect to full scale. In the case of a 50uA meter and 1.5V battery a 100k potentiometer will work. The shunt potentiometer should be about 1k -- this method is described in the ARRL handbook.

Nordic · 24th September 2006, 06:36 PM

ah ok, small voltage + ohms law and observe swing on needle.... it is a DC voltage though that I need to apply?

jackinnj · 29th September 2006, 08:01 PM

ok, here's a 3D image of what the board looks like -- two channels -- 5" x 2" -- I am going to make a proto to make sure that they work. You can make your own 10mH inductors or purchase from Mouser:

Flodstroem · 29th September 2006, 11:46 PM

Only one comment to your layout: why do you have so much space/air round components ? This board could be halves the size to what it looks to be now by placing the on board components tight and closer together. This will make the board more flexible to use in amps where there is not much space to fit a board including one VU-meter (mono block amp), or worth, one board and two VU-meters (stereo amp). If using this board in a pre-amp or in a mixer, ok, there is usually space enough for this, but seldom in a power amp due to the "big" VU-meters you had to mount if visibility should be good enough. Also there should be a power supply to feed this VU-board, an extra placing issue.

Just some thoughts

Otherwise it looks great.

Regards

jackinnj · 30th September 2006, 01:38 AM

If I had "Autoplace" I could probably fit it into 3/4's the space -- bur my poor addled brain can't take the strain.

I like to site the mounting holes at least 0.200 inch from the periphery and try my best to keep everything which is defined by their centers into a tight rectangle. I allow for R0207R10 resistors which are a little big for a tiny project. My fingers aren't quite as nimble as they used to be, but I agree -- it could be perhaps 25% smaller.

Jack

Nordic · 2nd October 2006, 07:33 AM

Come on Jack, you know you want to make is smaller... small is the new black.

So how long before we can start ordering?

eapavant · 3rd October 2006, 08:43 PM

I am interested. Looks good.

ChrioN · 12th October 2006, 02:29 PM

Looks very good!

bushroot · 28th October 2006, 07:04 PM

Interested in a board as well.

29th September 2006, 11:46 PM	#25
Flodstroem diyAudio Member Join Date: Sep 2004 Location: Norway	jackinnj, Only one comment to your layout: why do you have so much space/air round components ? This board could be halves the size to what it looks to be now by placing the on board components tight and closer together. This will make the board more flexible to use in amps where there is not much space to fit a board including one VU-meter (mono block amp), or worth, one board and two VU-meters (stereo amp). If using this board in a pre-amp or in a mixer, ok, there is usually space enough for this, but seldom in a power amp due to the "big" VU-meters you had to mount if visibility should be good enough. Also there should be a power supply to feed this VU-board, an extra placing issue. Just some thoughts Otherwise it looks great. Regards __________________ Regards Flodstroem

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24th September 2006, 06:36 PM	#23
Nordic diyAudio Member Join Date: Sep 2005	ah ok, small voltage + ohms law and observe swing on needle.... it is a DC voltage though that I need to apply?

29th September 2006, 08:01 PM	#24
jackinnj diyAudio Member Join Date: Apr 2002 Location: Llanddewi Brefi, NJ	ok, here's a 3D image of what the board looks like -- two channels -- 5" x 2" -- I am going to make a proto to make sure that they work. You can make your own 10mH inductors or purchase from Mouser:

30th September 2006, 01:38 AM	#26
jackinnj diyAudio Member Join Date: Apr 2002 Location: Llanddewi Brefi, NJ	If I had "Autoplace" I could probably fit it into 3/4's the space -- bur my poor addled brain can't take the strain. I like to site the mounting holes at least 0.200 inch from the periphery and try my best to keep everything which is defined by their centers into a tight rectangle. I allow for R0207R10 resistors which are a little big for a tiny project. My fingers aren't quite as nimble as they used to be, but I agree -- it could be perhaps 25% smaller. Jack

2nd October 2006, 07:33 AM	#27
Nordic diyAudio Member Join Date: Sep 2005	Come on Jack, you know you want to make is smaller... small is the new black. So how long before we can start ordering?

3rd October 2006, 08:43 PM	#28
eapavant diyAudio Member Join Date: Aug 2005	I am interested. Looks good.

12th October 2006, 02:29 PM	#29
ChrioN diyAudio Member Join Date: Oct 2004	Looks very good!

28th October 2006, 07:04 PM	#30
bushroot diyAudio Member Join Date: Oct 2004 Location: The high-five state	Interested in a board as well.