Rob Danielson wrote
| Hi John--
| I saw the very extensive <sursound%40music.vt.edu>sursound
| string on the R-44 lately. Are you referring to the Matchamp XTX131?
Actually the XTX129, I bought quite a lot of them in 1984, to build a pair
of high quality & very portable 8-4 mixers with active splits etc. I have
used them a lot & am very happy with the results.
I think the 131 is basically the same bar on the 129 one had to add 4
protection Zeners that are now included inside the package.
The power consumption is a rather heavy 1.5 watts each if using the
recommended +/-15 to18volt supply, but this goes down to .3w with +/- 3.6v.
Only gives a max of +8dBu out but the noise CMRR etc are all fine.
The "| >Alice Matchamp +R44 (2) -128.5dB" may be a bit cryptic but that the
performance I am getting on the R44 2dB switch position.
I'm investigating Switched Regulators at the moment but for test purposes am
using 6 AA batteries, and yes I need to add 48v too.
Any suggestions welcome
| http://www.aliceshop.com/acatalog/AliceShop_Spares_7.html Are you
| ganging together 4 Matchamps (mic -> line pres) for the R44?
Yes, using switched gains to get the <0.1dB matching I need for Ambisonic
work.
| Impressive noise performance for an under $100USD pre. How are you
| powering the modules? Are you also providing phantom power? At one
| time, folks were reporting that the line inputs on the R4 were
| disappointingly noisy. Do you feel that has been resolved with the
| R44? Rob D.
Well they could be better but in effect they only degrade the performance of
the XTX by <2dB so are very workable IMO.
John L
|
|
| >The EIN Equivalent Input Noise of in my case a 219Ohm dummy load resistor
| >and without the typically used A weighting network are:--
| >
| >R44 -111.25dB (at max gain, the most favourable EIN)
| >Fostex FR2 -124dB
| >Yamaha O2R -126dB
| >Alice Matchamp +R44 (2) -128.5dB
| >
| >Note the input gain was such that a -45dBu signal (4.4mVolts) gives a 0dB
| >Full Scale recording.
| >This being max gain for the R44 & less than max for the other 3, so the
R44
| >fig is flattering compared to the rest.
| >Re the difference A weighting may make
| >The R44 has less LF noise but it also has less LF response than the other
| >mic amps
| >Simple filtering to get a 200Hz-24k passband improves the FR2 fig by a
| >little over 1dB, I imagine the same would be true of the Yamaha & match
amp
| >figs.
| >
| >John L
|
|
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