Topic: Difference between 2.2k & 4.7k Mods?

[Cheesecadet]

Anyone know the differences between these mods?  Pros...cons?  I possibly want to get my AT 831's modded but am not sure which way to go.


I have heard the 4.7k mod raises the noise floor 3dB or so...but do not know exactly if that is bad or not???

Anyone have experience with these mods and if so would it be recommended to do a mod at all or just leave the 831's as is???

I'm clueless. 

Ryan in CA

[illconditioned]

Anyone know the differences between these mods?  Pros...cons?  I possibly want to get my AT 831's modded but am not sure which way to go.


I have heard the 4.7k mod raises the noise floor 3dB or so...but do not know exactly if that is bad or not???

Anyone have experience with these mods and if so would it be recommended to do a mod at all or just leave the 831's as is???

I'm clueless. 

Ryan in CA

Chris Church claims (and I believe him) that 4.7k has lower distortion.  I went for 2.2k in some cases so I could use my mics with plug in power.  I *have not* tested either one with plug in power, so at this point it is only a guess.  I believe either should sound fine though.

Who is doing your mod?  Just go for 4.7k and you should be fine.

  Richard

[Cheesecadet]

I have been in talk swith Chris in the past about the 4.7k mod...but he said there was a 3db noise floor increase which I was unsure if that would affect acoustic music shows in a negative way or not?

I tape a variety of shows from acoustic to high SPL show when using a stealth setup.

I just wanted some feedback about these mods before I pop for it.

i would still be running the AT 831s through a battery box into an iriver 120 or M1 DAT

So the 4.7k mod would be best I assume?

Are there any cons to doing the mod??

Ryan in CA

[Javier Cinakowski]

have you ever had distortion in your recordings at loud shows?  if not, don't worry about it. 

If you do, then a Church Audio preamp would make up for the gain you will lose with the 4.7k mod....

[rokpunk]

i waas never good at math, but the difference between the 2.2 and 4.7 mods is 2.5.         

[illconditioned]

have you ever had distortion in your recordings at loud shows?  if not, don't worry about it. 

If you do, then a Church Audio preamp would make up for the gain you will lose with the 4.7k mod....

Even at quiet shows, the mod *will* help.  You know all those people saying "AT 853 will sound best with phantom power", well, the 4.7k mod is providing a very similar driving condition that the phantom adapters do.  (I've traced the circuit.  The AT853 adapters supply about 3V and the FET has a source resistor of 5.1k.  It has a driving transistor and a transformer after that, but the mics themselves are powered in a similar way to Church's 4.7 k mod.)

Yes, it (the mod) will reduce mic sensitivity (by anywhere between 6 and 10dB people claim), but it *will not* increase the noise floor.  People that see the noise floor going up are seeing *preamp noise* and not *mic noise*.

Here is my advice:
- moderate to loud shows (anything with a PA basically): either
    1) AT853 or Church Cards with 4.7k mod > battery box > Edirol R09.  Plenty of gain, no need for extra preamp.
    2) above mics > battery box > Minidisc (line in).  Use (good and clean) gain in MD line input.
- acoustic/quiet shows: either:
    1) same mics + Church pre > Edirol R09.  Here you need lower noise of Church Pre.
    2) same mics > battery box > Minidisc (low sens mic in).  MD preamp is good and has low noise.

Oh yeah, if you want to use a poor line input, like iRiver or NJB3, you need the Church preamp.

  Richard

PS: Can someone please archive this???  Should be more widely known.  Thanks.

[Roger Gustavsson]

As you seems to be well informed about the 4.7k mod...

Is this what I should to with my Primo to end up with a 4.7k mod? Please, see below.

[Roving Sign]

As you seems to be well informed about the 4.7k mod...

Is this what I should to with my Primo to end up with a 4.7k mod? Please, see below.

I think Chris Church played around with a set of Nak 300s - He may have the answer...

[ninjadave]

if i look to get a set of U853's from sound professionals and i have them do the low sens mod, is he putting the 4.7K mod in or doing something else? i guess i could ask him directly.....thanks.

ninjadave.

[Arni99]

if i look to get a set of U853's from sound professionals and i have them do the low sens mod, is he putting the 4.7K mod in or doing something else? i guess i could ask him directly.....thanks.

ninjadave.

It´s just the "Church-4.7k mod"...i bought the sp-cmc-4u with the low-sens-mod some month ago.
Chris Carfagno confirmed it´s nothing else than the 4.7k mod.

[Alchemy]

I have been in talk swith Chris in the past about the 4.7k mod...but he said there was a 3db noise floor increase which I was unsure if that would affect acoustic music shows in a negative way or not?

I tape a variety of shows from acoustic to high SPL show when using a stealth setup.

I just wanted some feedback about these mods before I pop for it.

i would still be running the AT 831s through a battery box into an iriver 120 or M1 DAT

So the 4.7k mod would be best I assume?

Are there any cons to doing the mod??

Ryan in CA

Are you really getting a lot of distortion with your 831s? I find my 831s hold up quite nicely to high SPLs, even on 2 wire.

[Will_S]

Sorry to beat this topic to death but I can't seem to find an answer to this question anywhere:

Is there some reason to think 2.2k would be better when running off low-voltage plug in power (from an R09 or iRiver) than 4.7k?  I'll be using a pair of Sennheiser MKE-2-5s.

And while I have everyone's attention:

I can find 1% resistors online but the best my local shop offers is 2%.  If I sort through a bunch of the 2% resistors to find a perfect match, is there anything else inherently superior about 1% resistors that would make them worth using?

I was thinking about doing the mod by soldering the ends of the MKE2 cables (w/ resistors inserted at the right place) onto about 8" of cable from a pair of *cheap* headhones.  I want to do this because there will be more room to play with than inside a miniplug, and also because the headphone cable is very flexible and terminates in a nice low profile right angle plug that I think will really minimize stress on the R09 input.  Is there any reason to think such a short leangth of cheapo cable would have a detrimental effect on the sound?

[illconditioned]

Sorry to beat this topic to death but I can't seem to find an answer to this question anywhere:

Is there some reason to think 2.2k would be better when running off low-voltage plug in power (from an R09 or iRiver) than 4.7k?  I'll be using a pair of Sennheiser MKE-2-5s.

And while I have everyone's attention:

I can find 1% resistors online but the best my local shop offers is 2%.  If I sort through a bunch of the 2% resistors to find a perfect match, is there anything else inherently superior about 1% resistors that would make them worth using?

I was thinking about doing the mod by soldering the ends of the MKE2 cables (w/ resistors inserted at the right place) onto about 8" of cable from a pair of *cheap* headhones.  I want to do this because there will be more room to play with than inside a miniplug, and also because the headphone cable is very flexible and terminates in a nice low profile right angle plug that I think will really minimize stress on the R09 input.  Is there any reason to think such a short leangth of cheapo cable would have a detrimental effect on the sound?

I recommend 2.2k for Sennheiser MKE2 type mics.  If you put 4.7k there, you will drop a bit more voltage on the resistor and may risk "starving" the FET of the necessary volts to operate.  I would recommend 2.2k for Sennheiser caps and 4.7k for other caps (Church Audio, AT853, etc).  Those all seem to work great on the R09 plug-in power.  I just got a pair of DPA4060 and there is *not* enough volts for these.  Apparently these need 9v supplied with a 3.3k load resistor.  I built a homemade battery box for this.

By the way, the R09 supplies 2.5v through a 2.2k resistor (approx).  Minidisc supplies less, something like 2.2v through a 6.8k resistor, so it is harder to get enough volts from the minidisc.  Yes, I have measured these values...

Oh yeah, 2% tolerance is fine.  You can fuss and get really close resistors, but it does not matter that much.  I mean a 2% change is voltage is not many dB at all.

 Richard

[Will_S]

+T and another in 12, thanks a bunch!  Any thoughts on splicing in a bit of cheap headphone cable?

[illconditioned]

+T and another in 12, thanks a bunch!  Any thoughts on splicing in a bit of cheap headphone cable?

Go ahead and splice.  However you have to do it.  These "mechanical" issues are always the hardest for me.  But things have improved since I acquired some black colored hot melt glue.  It matches my gaffers tape!

  Richard