Topic: Making an external meter for a DMIC-20?

[Swampy]

So Im thinking of doing a gain mod to my DMIC, but it would almost be useless without an extrnal meter. The stupid meters on the DMIC go from like -20 to -3... Is there any way I could meter the DMIC? It only has BNC or coax out... Or would there be some way to monitor levels off of one of the JB3's outputs? Id appricate any help! THANKS!

[JackoRoses]

Best thing I came up with from reading here and scouring ebay
is a external SVU-1 or 2 from ebay
or a DIY vu meter you hack that will take a line in..
http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&category=3319&item=3849480727&rd=1&ssPageName=WD1V
or http://www.hobbytron.net/audiosub.html from nickspicks .
I still am trying to figure out what to do myself. Hack/mod one or be lazy and buy one..

[Swampy]

Would it be possible to hook this http://www.hobbytron.com/vk4305.html up to the line out on the JB3, or not? that seems far too simple!

[JackoRoses]

Yes it is possible and what I was thinking of doing myself.
The only drawback is it requires 10v +
But I was wondering if you could just snip the first 2 leds and cut some power draw..

Edit:
I should add it mentions cailbration from a trim potentiometer,
does it come with one though? "If nescessary, the unit can be calibrated by means of a trim potentiometer."
I did not see one in the kit and would it be necessary, or could you just calibrate it via whatever source you are using by watching clip levels?

[fozzy]

i would skip the kit and get a SVU-1, they are very rugged and easy to calibrate. 

[JackoRoses]

I hear you fozzy, just makes me fleshy that they want 75$ (on ebay and more elsewhere)
for that thing.
There is nothing to it. You seen the kits! they are a third of the price.
Makes me want to buy a bunch and just assemble them, place them in a container
and start selling them.  Or mod the UA5 to accept one

[Swampy]

i would skip the kit and get a SVU-1, they are very rugged and easy to calibrate. 

the day I speand over 100 bucks on meters, please kill me

[JackoRoses]

glad to see I am not alone
75$ is a lot of money still, at least to me it is...

[Swampy]

glad to see I am not alone
75$ is a lot of money still, at least to me it is...

no joke!

[ChrisV]

I have some DIY meters.   They were kind of a pain in the ass to build, if I had to do it over again I'd probably just buy the SVU-1. 

But one advantages I really like my meters for is they have much more smaller incriments for the leds...the SVU is in incriments of 3 db I believe but mine are 1 db or maybe even less.   I prefer that.
Disadvantages of my DIY:  I can't get it to work off of 9 V batteries or 9.6 V battery packs so I am lugging a big old 12 V Ni-MH battery just for my meters.    And for some reason the 2 exact same kits I bought to make it stereo are different...one side will go up quicker than the other so they are unequal slightly.    I just know at what point they are equal and made that my value.

Just make sure you do get(or build) a stereo version and not just mono.  I originally had a mono one with a switch and that didn't work well at all trying to get the left and right levels equal.

[Todd R]

It might be worth a call to G-P to see if there is an easy way to recalibrate the meters.  Maybe if the calibration is fine-tuned with a cal-pot you might be able to get the meters to be more like -20, -6, -3, 0.   Seems like an outside chance, but might be worth a shot.

[Swampy]

I just sent them and email... We'll see what they have to say...

[jk labs]

It might be worth a call to G-P to see if there is an easy way to recalibrate the meters.  Maybe if the calibration is fine-tuned with a cal-pot you might be able to get the meters to be more like -20, -6, -3, 0.   Seems like an outside chance, but might be worth a shot.

Typically these devices are built around a "preprogrammed" IC to do the actual measurement. Specifically that is the LM3914 (linear),
LM3915 (dB) and LM3916 (VU).

But from pictures it looks like there is another IC (SIP) being used in some ("SU-?") devices. This one
I do not know about.

There is also a BA chip capable of stereo but it is a VU meter: -20, -10, -6, -3, -2, -1, 0, +3, +6, +10 or something like
that. A bit awkward for digital level use. But it seems suitable if one collapsed the three topmost levels into one LED: 
-20, -10, -6, -3, -2, -1, 0, OVER 

(First time i play with colors, remains to be seen if it somes out well..)

J

   

[jkoch]

I have some DIY meters.   They were kind of a pain in the ass to build, if I had to do it over again I'd probably just buy the SVU-1. 

But one advantages I really like my meters for is they have much more smaller incriments for the leds...the SVU is in incriments of 3 db I believe but mine are 1 db or maybe even less.   I prefer that.
Disadvantages of my DIY:  I can't get it to work off of 9 V batteries or 9.6 V battery packs so I am lugging a big old 12 V Ni-MH battery just for my meters.    And for some reason the 2 exact same kits I bought to make it stereo are different...one side will go up quicker than the other so they are unequal slightly.    I just know at what point they are equal and made that my value.

Just make sure you do get(or build) a stereo version and not just mono.  I originally had a mono one with a switch and that didn't work well at all trying to get the left and right levels equal.

your setup did seem to work pretty well though...well, until you lost the connector or whatever it was wish i had something like that instead of the level indicators from hell (ua5 & jb3) lol

[mattb]

Alex, it's possible to make an effective SVU on the cheap.  CanaKit UK106 is only $15 assembled and has been the basis of many threads.  Runs on standard 9v batts.  I added a switch to the mix to prevent drain... which may or may not be an issue, I just did it.  You may find that having only 5 leds will not give you the degree of  sensitivity you desire, in which case a build based on a pair of UK134 might be the ticket.  I don't see any trim pots on this unit but the product blurb says that "the input sensitivity can be adjusted." and it runs with 6-18v.  May require further investigation, YMMV   www.canakit.com

This worked pretty well for me using the JB3 line out for signal, but I did end up choaking down some pride and picked up a SVU-2 primarily to get the headphone amp... probably not the smartest money I've spent, but the unit sure works well.
 

I had one of those and could only get the JB3 output to light the bottom one or two LEDs with the calibration pots all the way up with somehting peaking at or above -3 dB. I hear it works well with the UA-5. I'd love to know a of a good meter kit that would work well with the JB3. Could I have just had one that wasn't very sensitive?