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Post by kilroyrock on May 20, 2016 8:10:29 GMT -6
So I'm looking into making a VU meter box, and considering a larger scale diy kit build if I can source a good vu meter.
It would be a desk top box like the size of a good DI, but would have a single or stereo pair of meters. The goal wouldn't be to effect the sound (high impedance?), but allow for a meter balancing option for DAW/500 series setups, which would be handier than pulling up a plugin, and would allow for a good 2 bus meter.
Do any of you guys have a suggestion what would potentially be a good meter to buy and WHERE, that could also keep this project in a respectable price spec? I'd hope for a bigger meter than some, is 3 inch too small/big? What would be a good price point for a DIY project vu meter? I'm here in the U.S., so U.S. sources would be king. Perhaps Mouser or digikey?
Thanks!
Rob
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Post by jfoc on May 20, 2016 8:21:24 GMT -6
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Post by kilroyrock on May 20, 2016 8:56:47 GMT -6
Yeah, I saw JLM's, and Aussie makes thinks complicated. Jeff's meters are awesome, but that's a pretty costly item, I was hoping for more of a 30-40 range maybe?
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Post by kilroyrock on May 20, 2016 8:59:45 GMT -6
Jeff mentions a stereo 500 series unit he was making with that meter..did it ever come to fruition? Did I miss that ball by 6 years?
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Post by EmRR on May 20, 2016 9:12:10 GMT -6
I'd honestly look for a small format Dorrough meter on the cheap. I got one around $200, sometimes they show up even less. You buy a cheap analog meter, it's not really anything but eye candy. And the Dorrough is much better eye candy! You want real VU eye candy, it's gonna be expensive. Best you'll get is an old used radio station (big) rack panel for around the price of a raw Weston meter, and they can be $100 apiece used these days. And it'll still need a buffer amp added to it. There are also some Wohler rack mount monitor amps with big Dorrough sized high resolution meters, double service in one package.
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Post by mdmitch2 on May 20, 2016 12:01:57 GMT -6
I have the JLM stereo VU meter. I don't use it anymore since I'm working on a console now. It works great, and transparent. PM if you're interested.
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ericn
Temp
Balance Engineer
Posts: 16,107
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Post by ericn on May 20, 2016 21:04:58 GMT -6
I'd honestly look for a small format Dorrough meter on the cheap. I got one around $200, sometimes they show up even less. You buy a cheap analog meter, it's not really anything but eye candy. And the Dorrough is much better eye candy! You want real VU eye candy, it's gonna be expensive. Best you'll get is an old used radio station (big) rack panel for around the price of a raw Weston meter, and they can be $100 apiece used these days. And it'll still need a buffer amp added to it. There are also some Wohler rack mount monitor amps with big Dorrough sized high resolution meters, double service in one package. Dorrough or watch for used Logitech analog bridges on eBay.
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Post by kilroyrock on May 23, 2016 6:19:29 GMT -6
So I'm looking at all these meters and they range in UA values, 500ua,650ua,660ua . I'm having trouble finding information on what that actually means. Any of you guys know?
EmRR - I read in the latest tape op, and have read and seen videos on balancing levels for kick drums using a vu meter, which sounds like a fun thing to do, plus having a pair of meters on the desk is GREAT eye candy, as you said.
I ordered a couple cheapo's, to really understand the circuit and see what I can build out on a breadboard using known circuits, like JLM's and check a cost out on my own. the whole fun of it!
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Post by EmRR on May 23, 2016 6:40:16 GMT -6
I think a 'real' VU meter is based around a 200uA meter with very specific ballistics. You don't get those ballistics with any of the cheaper meters.
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Deleted
Deleted Member
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Post by Deleted on May 26, 2016 7:57:40 GMT -6
Real VUs are moving coil instruments with full wave rectifier, and they are kinda slow. AFAIK the ballistics should be in the range of 300ms settling time to 99% of the value, and roughly the same to swing out, to be kind of standard VU. Measured with a 1kHz sine signal at constant 0dB... Since they are slow, european AEs soon preferred PPM instruments, which help to detect overshoots much, much better.
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Post by kilroyrock on Aug 4, 2016 6:06:39 GMT -6
So I have been putting together the vu meter box, and finally got to the stage to test it, and everything works. The only problem, is the line input is looking at -17db as the MAX db's I can get out of it on the vu meter. I am plugging it into the line level out of my big knob, which shows the led metering reaching ~0db while playing a modern pop record (with modern pop mastering). The kit was supposed to have some 200k resistors in it, on the pcb, however they sent it with 10k resistors instead of 200k, and 220 ohm instead of 100 ohm. I asked them about this and they said it will work and it does...sorta. Could this be the reason for the drop in meter levels? I tried 2 separate vu meters as well, same results. I am using a 9v ac power supply, but it can take up to 20v.. Could that also be a reason? They are to the point where they will give me my money back, but if anyone can throw me a bone, maybe I can be happy with my vu meter, and they can be happy with my 6 dollars. This is the vu meter pcb kit I bought: www.ebay.com/itm/272085960573?euid=8c643d640ef942afab75d0f6a350f39d&bu=43206033932&cp=1&sojTags=bu=bu
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Post by EmRR on Aug 4, 2016 15:15:17 GMT -6
Do you mean -17dBFS is the max the meter can take? Or -17 VU is the highest meter reading?
Power supply should have little/no effect.
Sensitivity adjusted?
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Post by kilroyrock on Aug 5, 2016 7:17:33 GMT -6
I mean that I can't get the meters to show a signal higher than ~-17. The led meter on the big knob shows 0, and I've got it on full line level output, but with the +10db boost, I can get it to -17, else it's at -20.
There are two pots (L and R), but there isn't any real difference when I spin them on the signal. I think that's a much smaller error correction for matching, right?
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Post by rocinante on Aug 6, 2016 11:34:17 GMT -6
What meters are you using? Those meter driver aren't all that great. They're okay but you gotta play with what kind of meter you're using to what driver board. I'm beginning to build a meter bridge for my summing line mixer. I already have implemented two of the smaller 8027 meters that hairball carries as the Master stereo LR out on the mixer. *On a side note Hairball meters are actually more affordable than the ones off ebay. Sometimes you'll find a deal but generally Mike's are $5-20 cheaper. Not all meters are the same. I have a ton of Hairball meters as well as a few unknowns and teac's and some of the tn stuff Athough the Hairball meters do work they are more like signal indicators. Honestly Durroughs or digital is the way to go. But its spendy. I'm still experimenting but ideally I want 8 meters on a 2u that I can connect via cat cable to the mixer.
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Post by rocinante on Aug 6, 2016 11:38:27 GMT -6
It sounds like the resistors they sent you were a modification they thought was better. Try the resistors it calls for.
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Post by EmRR on Aug 6, 2016 12:18:36 GMT -6
is there a schematic? I don't see one.
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Post by rocinante on Aug 6, 2016 12:25:16 GMT -6
Sometimes there is a schematic but it depends on which company you buy it from if its posted. The one I got had the schematic on the ebay site. I think 'Jim's Audio' sends it to you with the 'kit'. A few of them do anyway. Expect no help though (did we ever?) as they are a business not a designer.
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Post by rocinante on Aug 6, 2016 12:26:40 GMT -6
Has anyone successfully converted an amp meter to be usuable?
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Post by kilroyrock on Aug 11, 2016 6:51:25 GMT -6
There's no schematic, just the board and parts. I agree with rocinante and I am going to buy the parts. In learning more about electronics, a lower resistor value will pull my juice but have less noise, where a higher resistor value (what it called for originally) pulled less power but as the potential for higher line noise? Do I have that right? If anything, this whole thing is forcing me to get out of "build the diy kit" mode into "find out what the hell all this stuff does" mode. Btw, my jim Williams THAT 1512 replacement pip is in the mail, and i'll do a test with the sequencer on my synth between the two chips in my colour pre for S's and G's. I know that's a different thread, but it's my other project going from "BTDIYK" mode to "FOWTHATSD" mode!
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Deleted
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Post by Deleted on Aug 11, 2016 16:16:12 GMT -6
Yepp, you are on the right track with the resistors, i guess. Leaving the paint-by-numbers kit path and actually understanding how stuff works can be a really rewarding experience.
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Post by EmRR on Aug 12, 2016 10:06:33 GMT -6
Are they active op amp gain set resistors or passive in line pad resistors? Totally different, if you don't know you are just guessing.
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Post by kilroyrock on Aug 12, 2016 10:56:13 GMT -6
Are they active op amp gain set resistors or passive in line pad resistors? Totally different, if you don't know you are just guessing. Well I'd be guessing, so I'm trying to understand the difference.
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Post by EmRR on Aug 12, 2016 11:07:44 GMT -6
If they are a voltage divider network into the card, they are a passive pad. If they are gain set resistors around the op amp, they are entirely different. Either could need to be changed.
Personally I won't buy any kit ever again from anyone not providing a complete schematic; it's a great way to hobble the user and be indemnity free on all levels. If I gotta figure it out, I'm building from scratch as the designer, rather than doing their homework for them. But that's a personal rant, carry on....
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Post by kilroyrock on Aug 12, 2016 12:54:39 GMT -6
But I mean, $6!
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Post by svart on Aug 12, 2016 13:15:32 GMT -6
Are they active op amp gain set resistors or passive in line pad resistors? Totally different, if you don't know you are just guessing. Well I'd be guessing, so I'm trying to understand the difference.
Looks like a ton of other VU drivers. An opamp buffer, with a rectifier on the output. I'd bet those resistors are gain-set, not attenuation.
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