DrWho Posted July 16, 2005 Share Posted July 16, 2005 Well I've been searching on and off for the last few months for a free software RTA that you can install on a computer based testing rig and came across this and figured I'd share it with the rest of ya's: http://www.hitsquad.com/smm/programs/VA It's a bit clumsy to use (the price for free I suppose), but it pretty much has all the functionality you could ever want out of an RTA. It's also got a built in oscilloscope as well which is always fun to play with (and it will do D/A conversions on a streaming digital input). There is also a calibration function built into it, but I haven't figured it out yet. I'll eventually be getting a Behringer ECM8000 ($65), which should hook me up real nice for measuring some of the things I plan on building in the future. One question, does anybody know if the "signal boost" on the audigy cards is the same thing as +48V phantom power? I've got an oldschool Rauland Spectrum-Master (3516) 8 channel microphone mixer hooked up to my pc right now, but it's rather noisy, which doesn't lend itself very well to testing purposes. Does anybody know what it'd take to build my own pre-amp with phantom power...without purchasing something expensive. There's gotta be a $20 solution out there somewhere. Quote Link to comment Share on other sites More sharing options...
DrWho Posted July 16, 2005 Author Share Posted July 16, 2005 Well I found this: Rolls PB223 ($55), which is $10 cheaper than the Behringer Eurorack UB802 ($65). Since it's only $10, I'm thinking the Behringer might be the way to go because it'll give me some expandability options. Still wondering what y'all think. Quote Link to comment Share on other sites More sharing options...
BEC Posted July 16, 2005 Share Posted July 16, 2005 The UB802 Mixer and the ECM8000 mic are only $49.99 each at Musicians Friend. Bob Crites Quote Link to comment Share on other sites More sharing options...
thumperxes Posted July 16, 2005 Share Posted July 16, 2005 how can i use my comp and for rta what would i need. i have an audgity 2 zs Quote Link to comment Share on other sites More sharing options...
Deang Posted July 16, 2005 Share Posted July 16, 2005 What purpose does the mixer serve? Hey, cut me a break, I'm just a dumb audiophile. Quote Link to comment Share on other sites More sharing options...
BEC Posted July 16, 2005 Share Posted July 16, 2005 Dean, Amplification and phantom power for the mic. Bob Quote Link to comment Share on other sites More sharing options...
scriven Posted July 16, 2005 Share Posted July 16, 2005 Doc, If you are interested in DIY the ECM8000 specs list it as requiring +15V to +48V. Here are some sites that explain the phantom supply wiring: http://www.new-line.nl/default.asp?i=61 http://www.tangible-technology.com/power/Phantom_Power_connect.html and a follow up article http://www.tangible-technology.com/power/phantom_aug02.htm Quote Link to comment Share on other sites More sharing options...
scriven Posted July 16, 2005 Share Posted July 16, 2005 I just went to the RTA site and the first thing that came up was an advertisement for the BOSE Wave music system! You just can't get away from them! Quote Link to comment Share on other sites More sharing options...
DrWho Posted July 17, 2005 Author Share Posted July 17, 2005 Btw, phantom power is just sending a DC signal through the cable...it's basically a way of boosting the signal of the microphone who's diaphragm isn't moving far enough to induce enough current to send the signal down the line. The more phantom you give it, the lower your noise floor gets. Well at least that's what I've been told...I've never noticed much of any significant differences. I'm also running the Audigy2 ZS. Basically, I'm going to take advantage of the front panel mic input that also accepts a balanced 1/4" cable. My other option would be to connect the tape outs to the RCA inputs on the front panel as well. Anyways, it doesn't really matter because they all spec out to about the same (and have over a 100dB noise floor...though I measure it to be closer to 60dB right now with nothing attached)...still plenty good enough for measuring though. Quote Link to comment Share on other sites More sharing options...
johnyholiday Posted July 17, 2005 Share Posted July 17, 2005 US-122 from TASCAM ,The US-122 also provides a dedicated control for adjustable zero-latency direct monitoring http://www.tascam.com/Products/US-122.html Quote Link to comment Share on other sites More sharing options...
DrWho Posted July 17, 2005 Author Share Posted July 17, 2005 ---------------- On 7/16/2005 6:15:48 PM scriven wrote: Doc, If you are interested in DIY the ECM8000 specs list it as requiring +15V to +48V. Here are some sites that explain the phantom supply wiring: http://www.new-line.nl/default.asp?i=61 http://www.tangible-technology.com/power/Phantom_Power_connect.html and a follow up article http://www.tangible-technology.com/power/phantom_aug02.htm ---------------- What would be the downside if any of introducing a DC adapter to those designs instead of using batteries? Does the amperage rating matter or should I be more concerned about the voltage output? That Tascam looks really nice, but I think I would purchase a better mic before dropping that kind of cash on the AD stage. Quote Link to comment Share on other sites More sharing options...
Marvel Posted July 17, 2005 Share Posted July 17, 2005 Try Elliot Sound Products. Nice spec projects you can build. http://sound.westhost.com/index.html Quote Link to comment Share on other sites More sharing options...
DrWho Posted July 17, 2005 Author Share Posted July 17, 2005 Hey great, I was looking all over for that westhost link! I had it in my favorites on my old computer that got stolen a while back and I haven't found the site since. They don't seem to have a good plan for a phantom supply though...or maybe I'm overlooking something. Quote Link to comment Share on other sites More sharing options...
scriven Posted July 17, 2005 Share Posted July 17, 2005 ---------------- On 7/17/2005 3:31:35 AM DrWho wrote: ... What would be the downside if any of introducing a DC adapter to those designs instead of using batteries? Does the amperage rating matter or should I be more concerned about the voltage output? ---------------- The only problem I see is that some of those wall warts have some serious 60 Hz ripple in the dc output. I don't know how sensitive the mic is to ripple. The batteries may be a pain but they do produce clean power. As far as the current draw goes it is not listed on the spec sheet but I doubt the mike will suck up very much. Contact me first if you decide to build something - I am also interested one and we might be able to save a couple of pesos on shipping if we buy the parts for two on one order. BTW, I have an ECM8000 and you are welcome to borrow it if you like. Quote Link to comment Share on other sites More sharing options...
DrWho Posted July 17, 2005 Author Share Posted July 17, 2005 Hey cool, sounds like a plan. What about an AC adapter instead and then using one of those fancy diode tricks to convert it to DC? Or perhaps throwing in a transformer somewhere...there's gotta be a way to get rid of the ripple. In two years I should probably have an answer for this, but I dont' wanna wait that long Quote Link to comment Share on other sites More sharing options...
Marvel Posted July 17, 2005 Share Posted July 17, 2005 ---------------- On 7/17/2005 2:29:44 PM DrWho wrote: Hey cool, sounds like a plan. What about an AC adapter instead and then using one of those fancy diode tricks to convert it to DC? Or perhaps throwing in a transformer somewhere...there's gotta be a way to get rid of the ripple. In two years I should probably have an answer for this, but I dont' wanna wait that long ---------------- Uh.. that.s what a D.C. adapter does. Depending on the D.C. voltage required, you need a voltqge regulator and filter caps to smooth out the D.C. ripple on the line. For low current, like the phantom power, it wouldn't be too hard. Here is his phom power schematic: http://sound.westhost.com/project96.htm Quote Link to comment Share on other sites More sharing options...
DrWho Posted July 17, 2005 Author Share Posted July 17, 2005 lol i worded that bad...I know that's what they normally do; I was just trying to consider expanding on the idea and throwing in stuff in between the diodes, I dunno. The whole ripple thing doesn't make any sense to me to begin with. Quote Link to comment Share on other sites More sharing options...
scriven Posted July 17, 2005 Share Posted July 17, 2005 Filter caps are the answer - even if I am not quite sure what your question was. Quote Link to comment Share on other sites More sharing options...
scriven Posted July 17, 2005 Share Posted July 17, 2005 Doc, what do you have against using batteries? Quote Link to comment Share on other sites More sharing options...
DrWho Posted July 17, 2005 Author Share Posted July 17, 2005 you gotta replace them when they wear out and I've got a buttload of AC and DC adapters laying around (nope, no ACDC music). I would like to borrow your mic sometime and see if the "mic boost" built into my sound card acts enough like a phantom power source. It says +20dB boost next to it on the menu...not sure if I can translate that to voltage or not. Quote Link to comment Share on other sites More sharing options...
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