Topic: Modded ATs » PM-4 » no gain Phantom » D7

[blu666z]

This is a question that Jon at JK Labs asked me that I was not able to test before I sent him my ATs for some work.  Can anyone shed some light?

How much gain is necessary in order to "lift" the signal
out from the PM-4(+ no gain P48 supply) up to line level?
If you go AT943 -> PM4 (P48 wo gain like the PS-2 I assume)
do you have sufficient signal to go line in on say a D8/D100/M1?

-Kevin

[Sean Gallemore]

I usually turn my MP-2 most of the way down anyway.

if I didn't have the MP-2, I would feel fine running mic > BB w/ no gain > DAT

[caymanreview]

what kinda work you havin done?

[ashevillain]

do you have sufficient signal to go line in on say a D8/D100/M1?

I ran mine into line-in on the SBM-1 and didn't come close to 0db. The shows I did like this were outdoors though...that might make a difference. If you are indoors @ a loud show you might have enough. I ran with some line transformers indoors and had plenty of gain(dial on SBM about 6-7)...those give 6dB I believe. I estimate somewhere between +3 to +6dB would be sufficient. A few times I enjoyed not being able to come close to 0dB...i.e. crank the level all the way to 10 and forget about it....raise to desired level later in Wavelab.

[blu666z]

what kinda work you havin done?

A box similar to the one built for the ck6x caps.  Phantom power for modded ATs that will incorporate the circiutry in the PM4 power adapters. 

-Kevin

[caymanreview]

nice

[jk labs]

what kinda work you havin done?

A box similar to the one built for the ck6x caps.  Phantom power for modded ATs that will incorporate the circiutry in the PM4 power adapters. 

-Kevin

Well, "incorporate" and "incorporate" :-)  Nothing so far indicates that the PM-4 in any way provides any special or optimized interface for the FET within the AT943. We'll see what kind of interface we end up with...

My issue is that I have been unable to establish the dB difference in signal level between the std. battery box method of powering and the PM-4/48V method. Comparing official AT specs with SP specs for the battery box
version just don't make sense.

My gut feeling is that we must be talking more than 26 dB lower output from the PM-4 (and -20 dB with the 8533 or one of it's sieblings?). This could mean that for connection to line inputs there could be a need for a gain stage  within a "one box P48 powering solution". 

Kevin's mics are soon to arrive and then we'll know. I just like to prepare mentally and think through the options in advance.

Posted by: SchwillRIOT 
I usually turn my MP-2 most of the way down anyway.
if I didn't have the MP-2, I would feel fine running mic > BB w/ no gain > DAT

This is what I was looking for. Thanks!
At this stage I take this to mean that with the MP-2 (miniumum gain of +16 dB), the P48 method of powering requires some 20 dB of gain. And that the battery box method provides a line level signal.   

[jk labs]

do you have sufficient signal to go line in on say a D8/D100/M1?

I ran mine into line-in on the SBM-1 and didn't come close to 0db. The shows I did like this were outdoors though...that might make a difference. If you are indoors @ a loud show you might have enough. I ran with some line transformers indoors and had plenty of gain(dial on SBM about 6-7)...those give 6dB I believe. I estimate somewhere between +3 to +6dB would be sufficient. A few times I enjoyed not being able to come close to 0dB...i.e. crank the level all the way to 10 and forget about it....raise to desired level later in Wavelab.

Interesting! Thanks! And there is a slight noise advantage in hitting "10" on the record dial on the
sbm-1.   

But just so there is no doubt: was this with the ATs connected to the PM-4? Or were you using one of the
AT solutions for interfacing to the phantom power?

Jon

[Sean Gallemore]

Posted by: SchwillRIOT 
I usually turn my MP-2 most of the way down anyway.
if I didn't have the MP-2, I would feel fine running mic > BB w/ no gain > DAT

This is what I was looking for. Thanks!
At this stage I take this to mean that with the MP-2 (miniumum gain of +16 dB), the P48 method of powering requires some 20 dB of gain. And that the battery box method provides a line level signal.   

take what I said with a grain of salt.  In fact I take back the statement.  What I mean is that when using the AT8533s with the AT853s, I run the mp-2 @ 7-8 o/clock and the PCM-M1 @ 7-9 on the dial.  I realize the mp-2 has a minimum gain value, so that might be a good starting place.

[Sean Gallemore]

do you have sufficient signal to go line in on say a D8/D100/M1?

I ran mine into line-in on the SBM-1 and didn't come close to 0db. The shows I did like this were outdoors though...that might make a difference. If you are indoors @ a loud show you might have enough. I ran with some line transformers indoors and had plenty of gain(dial on SBM about 6-7)...those give 6dB I believe. I estimate somewhere between +3 to +6dB would be sufficient. A few times I enjoyed not being able to come close to 0dB...i.e. crank the level all the way to 10 and forget about it....raise to desired level later in Wavelab.

Interesting! Thanks! And there is a slight noise advantage in hitting "10" on the record dial on the
sbm-1.   

But just so there is no doubt: was this with the ATs connected to the PM-4? Or were you using one of the
AT solutions for interfacing to the phantom power?

Jon

his signature says PM4, but he also good have been running a battery box or ATs before-hand.  Good question.

[ashevillain]

Interesting! Thanks! And there is a slight noise advantage in hitting "10" on the record dial on the
sbm-1.

Youre welcome! I seem to be able to do the same thing with the current setup I'm using(in my sig.) w/ the SBM-1 on 10 and the MP-2(1/8" output) knobs all the way counterclockwise. The MP-2 is sending +6dB of gain at this setting.

But just so there is no doubt: was this with the ATs connected to the PM-4? Or were you using one of the
AT solutions for interfacing to the phantom power?

Yes. AT 853 > PM4 > PS-2 > SBM-1. When I used the line transformers(Hosa MIT-435*) they were between the PS-2 and SBM, of course.

I had a set of 8533's but never ran them in the field...

* = edit

[caymanreview]

When I used the line transformers(Hosa, dont remember the model #)

odl-176?

when i ran ps2 > mod-sbm1 i ran some modd'd odl-276's that were mod'd w/ rca output to go directly into the sbm1

[ashevillain]

i ran some modd'd odl-276's

huh?? that's the optical > coax converter....you had it modded?

see previous post for edit.