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Author Topic: BusmanR4 VS. Stock R4  (Read 18266 times)

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Offline Gutbucket

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Re: BusmanR4 VS. Stock R4
« Reply #60 on: March 15, 2007, 05:59:09 PM »
Back to comp methodology for a moment..

2 tracks, same show, same song...

source 1: Neumann AK40s>LC3>KM100 > BusmanR4
source 2: Neumann AK40s>LC3>KM100>stock R4

The mics were flown just a few inches apart on the same stand.

I read the part above about the comp and the problems with it & then skipped several pages of hooha, so forgive me if someone else suggested this already, but how about this simple procedure to effectively eliminate the variables in the comparison:

Run the test as stated above for one song (or set), then switch the cabling at the input to the recorders and record a second song (or set). 

You'd then have 4 samples total. Compare the two versions of the first song, realizing that the mics/position/cables etc. are not perfectly identical, then compare the two versions of the second (same caveat).  Between the two sets of samples you can eliminate any bias other than the recorder itself.. If you prefer the one version of the recorder both times you've eliminated the other differences.
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Offline Todd R

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Re: BusmanR4 VS. Stock R4
« Reply #61 on: March 15, 2007, 06:20:51 PM »
OK, let's get this party started!

I have been using AD8512 (fet input) opamps in the R4, both the first (instrumentation amp) and second (buffer) stages.  These run off +/-5V.  The stock unit, NJM2068 can go in the dumpster!  I'm pretty happy with these.  Perhaps I could get lower noise, but they are fine for now.  Oh yeah, I removed the series 10k resistor that is used for the line/mic attenuator.  My inputs are fixed to mic input only now.

OK, the problem I have now is that there are ADC drivers that must run off only +5V (single sided).  The stock unit has NJM2100D.  I tried OP262, which I think works pretty well, but I'm open to suggestions.  Another alternative would be a CMOS chip, like AD8656.  This is a bit noiser, though.  And I don't know how good CMOS sounds for audio.  On my TODO list...

Oh yeah, some people have suggested using very high speed "video type" opamps, but I am not comfortable with this.  In fact, I tried using these for ADC drivers, but got oscillation problems.  Not recommended IMO.

  Richard

PS: Whoever is stealing tickets.  Knock it off!  I'm providing valueable information and discussion here.  If you don't like it, go away.

Or don't listen to me.  :P  Excellent, Richard, thanks for all the info! +t as always.   I've read on other boards that the high speed amps really need good circuit design and board layout or oscillation and ringing is a strong possibility.  Maybe that means they could be good for original designs, but they appear more problematic for modding.

All this is in the wrong thread I suspect, but I don't know where it should go.  All this great info is getting buried in threads that will get lost I'm afraid.  I think it was mentioned before, but we need to bug Bri to see if he can set up a Hacker's Corner.
Mics: Microtech Gefell m20/m21 (nbob/pfa actives), Line Audio CM3, Church CA-11 cards
Preamp:  none <sniff>
Recorders:  Sound Devices MixPre-6, Sony PCM-M10, Zoom H4nPro

Offline poorlyconditioned

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Re: BusmanR4 VS. Stock R4
« Reply #62 on: March 15, 2007, 06:31:07 PM »
OK, let's get this party started!

I have been using AD8512 (fet input) opamps in the R4, both the first (instrumentation amp) and second (buffer) stages.  These run off +/-5V.  The stock unit, NJM2068 can go in the dumpster!  I'm pretty happy with these.  Perhaps I could get lower noise, but they are fine for now.  Oh yeah, I removed the series 10k resistor that is used for the line/mic attenuator.  My inputs are fixed to mic input only now.

OK, the problem I have now is that there are ADC drivers that must run off only +5V (single sided).  The stock unit has NJM2100D.  I tried OP262, which I think works pretty well, but I'm open to suggestions.  Another alternative would be a CMOS chip, like AD8656.  This is a bit noiser, though.  And I don't know how good CMOS sounds for audio.  On my TODO list...

Oh yeah, some people have suggested using very high speed "video type" opamps, but I am not comfortable with this.  In fact, I tried using these for ADC drivers, but got oscillation problems.  Not recommended IMO.

  Richard

PS: Whoever is stealing tickets.  Knock it off!  I'm providing valueable information and discussion here.  If you don't like it, go away.

Or don't listen to me.  :P  Excellent, Richard, thanks for all the info! +t as always.   I've read on other boards that the high speed amps really need good circuit design and board layout or oscillation and ringing is a strong possibility.  Maybe that means they could be good for original designs, but they appear more problematic for modding.

All this is in the wrong thread I suspect, but I don't know where it should go.  All this great info is getting buried in threads that will get lost I'm afraid.  I think it was mentioned before, but we need to bug Bri to see if he can set up a Hacker's Corner.

Yeah, there should be a hackers' corner!  Great idea.

  Richard
Mics: Sennheiser MKE2002 (dummy head), Studio Projects C4, AT825 (unmodded), AT822 franken mic (x2), AT853(hc,c,sc,o), Senn. MKE2, Senn MKE40, Shure MX183/5, CA Cards, homebrew Panasonic and Transsound capsules.
Pre/ADC: Presonus Firepod & Firebox, DMIC20(x2), UA5(poorly-modded, AD8620+AD8512opamps), VX440
Recorders: Edirol R4, R09, IBM X24 laptop, NJB3(x2), HiMD(x2), MD(1).
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Offline Brian

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Re: BusmanR4 VS. Stock R4
« Reply #63 on: March 15, 2007, 06:32:12 PM »
can we request a mod to move all the valuable info to a thread in the archive?  maybe a member with a little more time can create thread with quotes attached?

Offline mmmatt

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Re: BusmanR4 VS. Stock R4
« Reply #64 on: March 17, 2007, 10:58:11 AM »
wow!  quite the pissing match we have going on here!   Here is my opinion on comps.  2pr same brand mics are not close enough for a comp.  mics sent through a consumer grade splitter not good enough.  2 pr identical mic cables not good enough.  Setting levels by eye or via software to peak not good enough, living room taping not nearly good enough unless you plan on taping in your living room.
     Here is what would make the test with all of these variables completely scientific and valid.  Switch the variables!  Run a couple of songs with mic a, and cable a into preamp a, and mic b cable b into preamp b, then after a couple of songs switch mic and cable a to pre b, then after a couple of songs mic a cable b into pre a and so on.  There are 3 variables (4 if you include positioning which could never be repeated exactly, but could more easily be lumped into the mic variable)
    If what you like about the comp is consistent across the board it is a completely valid and scientific comp IMO.  If your favorite changes with the cable/mic switches then we know that the comp is tainted.  It would be my guess that only thoes with very nice playback systems and impressive ears would hear much difference between the mic cable switches but it would be proof positive of the difference between the pre's.
    Switching mic cables could potentially reposition the mics so I would say forgo that step as long as the cables were the same length and type.  Another good wrinkle would be to use another brand of mic during the same show so that we could see the difference with different flavors of mics.  Radical differences like ld's vs sd's, or the Neumans vs a very flat mic for example, or maybe just a very popular mic like the c-4's or whatever Chris feels is a common mic for his sales demographic.  Using a single pair of mics and a splitter would be even better but I say still switch the outputs because the splitter or a cable in the chain could have some impact.  As for setting levels, IMO one of the biggest differences between quality and average preamps is the transient response.  One pre may record a far greater dynamic range than the other and it will show a peak far higher over the "meat" of the music than a lesser pre.  When listening, each person would have to be able to make the determination between the two even though one seemed louder (this would probably be the lesser pre... in this regard anyway) and one would have to be able to make determinations despite this difference.  Maybe two sets should be made for people to listen to... one with both sources normalized to a set rms level so they sound the same, and one set untouched.
    Doing all of this would provide a comp that is real world, scientific, and easy to compare because they will seem at similar volume and utilize the gain settings representing the meat of the pre.
    Take good notes, and snap pictures of the setup and IMO nobody could bitch about validity.

my .02


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Offline rokpunk

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Re: BusmanR4 VS. Stock R4
« Reply #65 on: March 19, 2007, 09:53:23 AM »
ahhhh, an argument with Mr. Church that doesn't involve me.

/how refreshing
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