Led-meter for the S S L comp...??

Hi.

does anyone have a schematic for a led-current meter..

all meter circuits I've found are measuring the voltage...


thanks,
mat

The sslclone outputs voltage Alright. 1mA at 2KOhm at 20dBGR = 2V at 20dBGR = 0.1V/dB

Jakob E.

Instead of the edgecoil GR meter i assume??


A linear LED meter will do the trick.

Based on a LM3914 (as opposed to an LM3915 or LM3916).


Can find a schem here...

http://www.electronics-tutorials.com/devices/lm3914.htm

stick ina magic eye tube they will look way cooler. :green:

that sounds good...

If I want a scale from 0-30 db... will a 3k resistor do the trick??

1db will be 0,667V ???


thanks,
mat

No. The opamp that drives the meter puts out 0.1V/dB

3V would be 30dBGR

...

The first compressor I got for my then new little studio was a dbx266XL. It was cheap and it was better than the software version in Logic. I later discovered that it sucks and that the Logic comp just suck even more. Hehehe Well, it's been sitting in my rack anyway and I've used it where I HAD to and then of course just gently touched the material with it. When you know it's limits you can use almost anything with an ok result.

However, now that my first GSSL is almost ready and I'm going to build another immediately after the 266 will be pulled out of the rack for good. I have a few RNC's and a couple of the original dbx163's and a 163x, a couple of other ones and have gotten better software ones as well.

I too am thinking about this LED meter solution and since there's 2 in the 266 plus some quite cool on/off buttons with square LEDs in them, and a back panel fully loaded with XLRs, parallel jacks and all I'm thinking about scrapping the unit and re-use as much of it as possible.

Can anyone tell me beforehand if the LED meters will be unusable for use with the GSSL or will I have to open it, post pictures, find schematics and so on before anyone can tell me what I can and can't do?

(The unit has both balanced and unbalanced inputs so I'm already considering that maybe that's all taken care of on separate PCBs in the unit and maybe I can leave it in...? We'll see...:razz

EDIT:
Ahhh, re-reading some of the posts in this thread I can see that I will have to measure my way around to find out how the LED meter cirquits will react to what they'll be fed from the cirquit in the GSSL...

yo all

ive been digging also for led meter's for ssl

the formula V=1.25*(1+R2/R1) of the LM3914 made for full scale voltage?
like as Gyraf said the meter is 0v-2V per 20 db so the V supose to be 2v?
and then set R1=3.3k R2=2k????

did i got it right?

or i need simply drive 2v to 5v ?

Just for experimental puposes, i found a opamp based audio LED vu meter, independend of special IC driver, i think a quad you have at hand would work nice. It just draws 20mA(!!!) and runs off the opamp powerrails with no critical values. Maybe this one could be easily adopted to the GSSL, you could even leave out the 12V regulator and use the 12V from the GSSL board...

http://www.4qdtec.com/avu.html

And another one using a very simple 2 quad opamp design:

http://www.zen22142.zen.co.uk/Circuits/Audio/vumeter.htm

Kind regards

Martin

Hi, Im new in DIY projects, but Im about to build my own GssL
and I really want LED indication. I found this "kit"
http://www.talkingelectronics.com/Projects/StereoVUmeter/StereoVU.html

Would this be appliable for GssL ?

Regards Johan

[quote author="sounden"]
http://www.talkingelectronics.com/Projects/StereoVUmeter/StereoVU.html
[/quote]

That's nice, an all discrete LED bar ! :wink:

Would this be appliable for GssL ?

Click to expand...

Not as it is, at least.

Jakob E.

Hi Steven:

I'm not so familiar with the GSSL, but I think that the output for the current meter is negative vs. ground. Check the output voltage on the 2k resistor. If the voltage really is negative vs. ground then you need an inverter (single opamp + 2 resistors) to shift the voltage to the first quadrant (positive 0-2V, for example).

Regards,
Milan

Hi - as others have said,

You need an inverting buffer with variable gain feeding the led driver chip in linear mode. Calculate a reasonable led current for your Vcc ( a couple of resistors) and that's about it. Kind of cheap and cheerful, but works great.

Led driver for GR on ssl. Set the range how you want it with a trimmer.

Check out other threads on this subject. Some have been cool enough
to share their efforts.

Hi
Does this kind of circuit can work with comppressor like 1176 and other with optoelement like LA-2A, LA-4A. With a little (big) help from my friend Kev I will soon finish my LA-4A but I havent VU. Maybe to make one GR Led meter and one for Audio VU.
Thanks
Duka

[quote author="dukasound"]Hi
Does this kind of circuit can work with comppressor like 1176 and other with optoelement like LA-2A, LA-4A. With a little (big) help from my friend Kev I will soon finish my LA-4A but I havent VU. Maybe to make one GR Led meter and one for Audio VU.
Thanks
Duka[/quote]


Doesn't the LA2A and LA4A use a VU meter? With a switch to change between both gain reduction and output level?

The SSL doesn't use a VU meter for gain reduction. It uses a It uses a linear LED meter based on the LM3914.

To make an LED VU meter you would need to use the LM3915 (not LM3914) which is a logarithmic version.


Here is an LED VU meter using the LM3916




Provided by our friends at ESP

http://sound.westhost.com/project60.htm



did you build the LA4 on Kev's site? how'd it go so far?

Hi
I know about VU in LA-2&4 or 1176 and similar. I built a couple with VU but I asked how to make led gain reduction meter for this kind circuit. Too I made for my preamps Led VU with 3915. Maybe to combine one board for G.R one for Level. But how?
Duka

3db/led

Can make one board that can do either VU or Linear response
easy. Just put in the corresponding chip. And switch in the rectifier.
And the variable gain amp with inverting or non inverting input
(for you pesky s&s*l@s)

One board