Gain Reduction Meter - 20 Segment Bargraph

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mediatechnology
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Gain Reduction Meter - 20 Segment Bargraph

Post by mediatechnology »

I'm reintroducing, after a long absence, a 20 segment LED gain reduction meter for the Waveulator and compressor projects.


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The actual board size is 3.1" by 1.0". The mounting holes are spaced 2.3".

The new version of the GR20 has bar/dot capability and more powering options.

In a recent Waveulator build I used the 5V output of the TDK CUT-35 5FF switcher to power the GR20 and it worked out very well relieving the bipolar supply - and it's ground - from meter currents which, at 10 mA/segment, is about 200 mA FS.

The full scale input voltage is 2.4V.

I should have a small run of boards this afternoon to test.
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mediatechnology
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Re: Gain Reduction Meter - 20 Segment Bargraph

Post by mediatechnology »

The boards run great and I have just a few at the moment.

Now that I know they run I'll order more...

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GR20 Gain Reduction Bargraph. Actual size is 1.0" x 3.1"

The dot mode draws only about 20 mA; bargraph full scale about 220 mA.

The dot mode with the LTA-1000E displays has a slight minute glow at segment 1 (at the right-hand) and segment 11 (just past the middle) when those values are exceeded. This is a common LM3914 effect and although it can be resolved with two added resistors I chose to leave it because it provides a marker at 0 scale and mid scale. In a dark room, where you can't see the panel cutout, it provides a scale. One could actually ad resistors to brighten it as well.

Bargraph, which I prefer, doesn't exhibit this effect.

I put the bar/dot jumpers on the underside in this one so I could easily change it.

I'll need to fine-tune the spacer height to accommodate panel thickness but the 3/8" are pretty close. Front Panel Express can also do blind fasteners to eliminate exposed front panel mounting screws.
emrr
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Re: Gain Reduction Meter - 20 Segment Bargraph

Post by emrr »

Cool.
Best,

Doug Williams
Electromagnetic Radiation Recorders
Bill Wilson
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Re: Gain Reduction Meter - 20 Segment Bargraph

Post by Bill Wilson »

Hi Wayne: I could not find the board for the 20 db gain reduction meter on the KA page; would like to know how much they cost.
Bill Wilson
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