[mcp6453[_2_]]

As chronicled here, I bought a Delta 1010LT audio card so that I can bridge my
direct outs in my Mackie 1402-VLZ. While I was testing a couple of mics while
using just the mixer, I noticed a dramatic lack of headroom and distortion in
the mic. It turns out that the Input 1 to the Delta 1010LT is loading the Mackie
preamp. If I remove the insert, the problem clears. The direct out is 1/4" TS,
and the 1010LT input is XLR. The tip is wired to pin 3, and the sleeve is wired
to pin 1.

Input 1 on the 1010LT is normally a mic input except that I have it jumpered as
a line input. Apparently changing the input to a line input instead of a mic
input does not change the (low) impedance. Channels 3 through 6 of the Mackie
are feeding (RCA) inputs 3 through 6 on the 1010LT, and those inputs are not
loading the preamps. Am I overlooking a setting on the 1010LT?

[hank alrich]

mcp6453 wrote:

As chronicled here, I bought a Delta 1010LT audio card so that I can bridge my
direct outs in my Mackie 1402-VLZ.

Direct output or isnerts?

While I was testing a couple of mics while using just the mixer, I noticed
a dramatic lack of headroom and distortion in the mic. It turns out that
the Input 1 to the Delta 1010LT is loading the Mackie preamp. If I remove
the insert, the problem clears. The direct out is 1/4" TS, and the 1010LT
input is XLR. The tip is wired to pin 3, and the sleeve is wired to pin 1.

Input 1 on the 1010LT is normally a mic input except that I have it
jumpered as a line input. Apparently changing the input to a line input
instead of a mic input does not change the (low) impedance. Channels 3
through 6 of the Mackie are feeding (RCA) inputs 3 through 6 on the
1010LT, and those inputs are not loading the preamps. Am I overlooking a
setting on the 1010LT?


--
shut up and play your guitar * http://hankalrich.com/
http://armadillomusicproductions.com/who'slistening.html
http://www.sonicbids.com/HankandShai...withDougHarman

[mcp6453[_2_]]

On 2/6/2011 9:06 PM, hank alrich wrote:
mcp6453 wrote:

As chronicled here, I bought a Delta 1010LT audio card so that I can bridge my
direct outs in my Mackie 1402-VLZ.

Direct output or isnerts?

Inserts

[Mike Rivers]

On 2/6/2011 8:09 PM, mcp6453 wrote:
As chronicled here, I bought a Delta 1010LT audio card so that I can bridge my
direct outs in my Mackie 1402-VLZ. While I was testing a couple of mics while
using just the mixer, I noticed a dramatic lack of headroom and distortion in
the mic. It turns out that the Input 1 to the Delta 1010LT is loading the Mackie
preamp. If I remove the insert, the problem clears. The direct out is 1/4" TS,
and the 1010LT input is XLR.

This is because Input 1 (and 2, I think) on the Delta 1010LT
is a mic input. It has too much gain for the signal level
coming from the mixer's direct output, and it also has too
low an input impedance which, indeed, will load the direct
output. This is a bad mismatch.

Input 1 on the 1010LT is normally a mic input except that I have it jumpered as
a line input. Apparently changing the input to a line input instead of a mic
input does not change the (low) impedance.

It depends on what the jumper does. But there may also be a
problem with your wiring. The direct outputs of the 1402
aren't differential, but they are balanced. While I can't
promise that it will work better, you might try a cable or
adapter that has a TRS plug on the mixer end, wired with the
tip to pin 2, right to pin 3, and sleeve to pin 1 of the
XLR. There are enough variations in how XLR-1/4" cables and
adapters are wired that you could have something wrong there.

Note, too, that there are two jumpers and therefore four
possible settings, all documented in the manual. There are
two sensitivities for the mic input, one of which has gain
in the same ballpark as a "consumer" line input. Also there
are two sensitivities for the line input, a "pro" and a
"consumer" level. However, the specs say that the input
impedance is 9.5 k ohms minimum, which shouldn't load the
direct outputs of the mixer.

Check the jumpers. The manual is a bit confused in this
section (at least the downloadable version) but I believe
they should be set like in Figure 2, both "down."

--
"Today's production equipment is IT based and cannot be
operated without a passing knowledge of computing, although
it seems that it can be operated without a passing knowledge
of audio." - John Watkinson

http://mikeriversaudio.wordpress.com - useful and
interesting audio stuff

[Mike Rivers]

On 2/7/2011 6:25 AM, mcp6453 wrote:

Inserts

Oh. Why didn't you say "inserts" instead of "direct
outputs?" I forgot that the 1402 doesn't have direct outputs.

Then you definitely have a wiring problem. I'll let someone
else talk you through it. I'm running out of patience this
morning.

--
"Today's production equipment is IT based and cannot be
operated without a passing knowledge of computing, although
it seems that it can be operated without a passing knowledge
of audio." - John Watkinson

http://mikeriversaudio.wordpress.com - useful and
interesting audio stuff

[Peter Larsen[_3_]]

mcp6453 wrote:

As chronicled here, I bought a Delta 1010LT audio card so that I can
bridge my direct outs in my Mackie 1402-VLZ.

note: must mean inserts.

While I was testing a
couple of mics while using just the mixer, I noticed a dramatic lack
of headroom and distortion in the mic. It turns out that the Input 1
to the Delta 1010LT is loading the Mackie preamp. If I remove the
insert, the problem clears.

Well ...

The direct out is 1/4" TS, and the 1010LT
input is XLR. The tip is wired to pin 3, and the sleeve is wired to
pin 1.

This is wrong, tip goes to pin 2, either not connected or bridnged, and
housing goes to pin 1.

Input 1 on the 1010LT is normally a mic input except that I have it
jumpered as a line input.

Yes, and strictly speaking probably balanced also when jumpered to line
level input, with pin 2 hot and pin 3 return. So connectin to pins 1 and 3
is plain wrong.

Apparently changing the input to a line
input instead of a mic input does not change the (low) impedance.

Well, yes, lowish, aint no specs on M-audios site?

Channels 3 through 6 of the Mackie are feeding (RCA) inputs 3 through
6 on the 1010LT, and those inputs are not loading the preamps. Am I
overlooking a setting on the 1010LT?

You are overlooking the difference between bal and unbal wiring, also check
minimum load impednce on the M1202. I'd make a small snake with 4 stereo
jacks with pin and ring bridged to unbal out, and wire the required xlr with
1 and 3 bridged.

Dunno about the impedance load that inputs 1 and 2 on the 1010lt
constitutes, a 1:2 tranny may or may not be required, my recollection is
that such a tranny gives you a 1:4 impedance conversion. I will no doubt be
aware almost instantly if I got that wrong ...


Kind regards

Peter Larsen

[Mike Rivers]

On 2/7/2011 11:35 AM, Peter Larsen wrote:

You are overlooking the difference between bal and unbal wiring,

He also doesn't understand the wiring of insert jacks. He
needs to connect the tip and ring together on the Insert
(TRS plug) end of the cable, connect the center conductor
of the shielded cable to tip+ring, and the shield to the
sleeve. On the XLR end, the shield goes to pins 1 and 3, and
the tip+ring goes to pin 3. The plug goes ALL THE WAY (not
half-way, though that'll work) into the Insert jack.


--
"Today's production equipment is IT based and cannot be
operated without a passing knowledge of computing, although
it seems that it can be operated without a passing knowledge
of audio." - John Watkinson

http://mikeriversaudio.wordpress.com - useful and
interesting audio stuff

[mcp6453[_2_]]

On 2/7/2011 12:21 PM, Mike Rivers wrote:

He also doesn't understand the wiring of insert jacks. He needs to connect the
tip and ring together on the Insert (TRS plug) end of the cable, connect the
center conductor of the shielded cable to tip+ring, and the shield to the
sleeve. On the XLR end, the shield goes to pins 1 and 3, and the tip+ring goes
to pin 3. The plug goes ALL THE WAY (not half-way, though that'll work) into the
Insert jack.

Actually I do understand the wiring. The *insert* jack on the Mackie is, of
course, TRS, not TR. I apologize for the brain fart. The TRS plugs connected to
the inserts are wired correctly to bridge the outputs of the preamps. The Tip
and Ring are jumpered and connected to Pin 3 of the XLR. The Sleeve is connected
to Pin 1. I questioned whether to jumper Pins 1 and 2 on the XLR, but having
read on the GearSlutz or somewhere that the 1010LT works with an unbalanced
input with Pin 2 open, I didn't jumper it. There is no schematic and the manual
sucks.

The problem description is the same. When I connect the Mackie Channel 1 insert
to the 1010LT, the Mackie preamp is loaded excessively. The manual does not say
what the input impedance is for the mic preamps except to say that they are
"compatible" with low impedance microphones. Obviously the input impedance for
Inputs 1 and 2 is much lower than 9.5K. I'll probably throw a line to mic
transformer in there, which kills two birds with one stone.

[Mike Rivers]

On 2/7/2011 2:54 PM, mcp6453 wrote:

I apologize for the brain fart. The TRS plugs connected to
the inserts are wired correctly to bridge the outputs of the preamps. The Tip
and Ring are jumpered and connected to Pin 3 of the XLR. The Sleeve is connected
to Pin 1. I questioned whether to jumper Pins 1 and 2 on the XLR, but having
read on the GearSlutz or somewhere that the 1010LT works with an unbalanced
input with Pin 2 open, I didn't jumper it. There is no schematic and the manual
sucks.

Odd. That sounds like it's wired as "pin 3 hot." Scott
would approve, but all of Europe and most of the Americas
wouldn't. The reason why you're getting loading, if the 1010
input is wired conventionally, is that you may be nearly
grounding the Mackie output by connecting it to Pin 3 rather
than Pin 2. Just move that wire from Pin 3 to Pin 2, and for
good luck while you're in there with your soldering iron,
connect Pins 1 and 3.

The problem description is the same. When I connect the Mackie Channel 1 insert
to the 1010LT, the Mackie preamp is loaded excessively. The manual does not say
what the input impedance is for the mic preamps except to say that they are
"compatible" with low impedance microphones. Obviously the input impedance for
Inputs 1 and 2 is much lower than 9.5K.

The spec sheet is kind of fuzzy about that, and 9.5K is
certainly compatible with low impedance microphones. In
fact, some might sound brighter into 9K than into 2K, but
who's bragging? g

Just put the signal on the right pin of the XLR and see if
that doesn't fix your problem. It's easy and a lot cheaper
and less destructive to the signal than using a transformer.



--
"Today's production equipment is IT based and cannot be
operated without a passing knowledge of computing, although
it seems that it can be operated without a passing knowledge
of audio." - John Watkinson

http://mikeriversaudio.wordpress.com - useful and
interesting audio stuff

[mcp6453[_2_]]

On 2/7/2011 4:49 PM, Mike Rivers wrote:
On 2/7/2011 2:54 PM, mcp6453 wrote:

I apologize for the brain fart. The TRS plugs connected to
the inserts are wired correctly to bridge the outputs of the preamps. The Tip
and Ring are jumpered and connected to Pin 3 of the XLR. The Sleeve is connected
to Pin 1. I questioned whether to jumper Pins 1 and 2 on the XLR, but having
read on the GearSlutz or somewhere that the 1010LT works with an unbalanced
input with Pin 2 open, I didn't jumper it. There is no schematic and the manual
sucks.

Odd. That sounds like it's wired as "pin 3 hot." Scott would approve, but all
of Europe and most of the Americas wouldn't. The reason why you're getting
loading, if the 1010 input is wired conventionally, is that you may be nearly
grounding the Mackie output by connecting it to Pin 3 rather than Pin 2. Just
move that wire from Pin 3 to Pin 2, and for good luck while you're in there with
your soldering iron, connect Pins 1 and 3.

The problem description is the same. When I connect the Mackie Channel 1 insert
to the 1010LT, the Mackie preamp is loaded excessively. The manual does not say
what the input impedance is for the mic preamps except to say that they are
"compatible" with low impedance microphones. Obviously the input impedance for
Inputs 1 and 2 is much lower than 9.5K.

The spec sheet is kind of fuzzy about that, and 9.5K is certainly compatible
with low impedance microphones. In fact, some might sound brighter into 9K than
into 2K, but who's bragging? g

Just put the signal on the right pin of the XLR and see if that doesn't fix your
problem. It's easy and a lot cheaper and less destructive to the signal than
using a transformer.

I ran Tip/Ring of the plug connected to the insert on channel 1 to Pin 2 and
Sleeve to Pins 1 and 3. For some reason that I don't understand, the loading
problem appears to have been solved. The mic preamp is not loaded such that it
distorts.

The exercise has uncovered another issue. The Delta card and my M-Audio
Audiophile 2496 in a different computer have a lot of digital noise in the
playback. Record is fine, but the S/N ratio on playback is unacceptable. The
noise is clearly audible when the playback level is set for a normal level. The
Delta card is in the last slot (farthest from the other cards) and the
Audiophile is in the slot next to the video card.

Has anyone here had any experience getting rid of the noise? If I cannot get rid
of it, it's a deal breaker.

[Mike Rivers]

On 2/8/2011 8:29 PM, mcp6453 wrote:

I ran Tip/Ring of the plug connected to the insert on channel 1 to Pin 2 and
Sleeve to Pins 1 and 3. For some reason that I don't understand, the loading
problem appears to have been solved. The mic preamp is not loaded such that it
distorts.

I can understand that. You removed Pin 3 from the signal
source, and apparently Pin 3 on the Delta 1010LT is nearly
ground.

The exercise has uncovered another issue. The Delta card and my M-Audio
Audiophile 2496 in a different computer have a lot of digital noise in the
playback.

Both computers, each with its own, different, sound card
have the same kind of noise? Is that "digital noise"
crackles, pops, and skips/mutes? Or is it hums and buzzes?
Is the noise in playback no matter what the source, or
only when you play back a recording that you made? Do you
get the same kind of noise when you play back a downloaded
or streaming audio file?

If you could post a short example of something you've
recorded where it could be downloaded, someone could check
your recording and see if that's where the problem lies.

Do you have something connected to the computer that might
be causing a problem with noise on the ground? This may not
be obvious. For example, if you have a TV set which is
connected to cable also connected to the computer so you can
play the computer into the TV set? TV cable is, or at least
used to be, a well known noise source.


--
"Today's production equipment is IT based and cannot be
operated without a passing knowledge of computing, although
it seems that it can be operated without a passing knowledge
of audio." - John Watkinson

http://mikeriversaudio.wordpress.com - useful and
interesting audio stuff