maximum distance from Mic to Pre?

[Mike H]

I have two choices for locating my preamps in my home studio:
(1) In my rack. The cable length from mics (in another room) to preamps would be 35-40 feet.
(2) On the other side of the mix room, where the mic cables come thru the wall. In this case, the length from mics to preamps is about 12 feet.

This matters because some of the preamps have EQ's which I would like to use during mixdown. Option (1) is perfect for mixdown. Option (2) requires that I go across the room during mixdown to adjust the EQ's.

I am using DA-206 110-ohm digital cable from the mics to the preamps.

Am I OK with 35-40 ft. between mic and preamp, or will I have to go with option (2)?

Thanks.

[Jeff16years]

i want to hear what people have to say about this. my longest mic cable run at my studio is 70 feet and i have never noticed any problems or differences in sound from my shorter lengths (using mogami quad for these runs and mogami 2549 for the shorter runs)

also i have worked on TV shows where the DT12's (mic level) are run 1500 feet from the set to the truck. but i always wondered how this compared to the recording environment.

[JonCraig]

think about most major facilities. the multicore behind the racks goes into the floor, up a wall, around another wall, etc. etc. i wouldn't be surprised if 100 ft. runs were common in a big room.

i wouldn't worry about it too much (unless you've got some big sources of noise--like you live next door to a radio transmitter or something).

--jon

[opentune]

I don´t think the 35-40 feet distance will cause trouble. The first thing that came
to my mind was "how do they handle it in the big rooms?". So, like
JonCraig said, in the big rooms they don´t even have the choice to
have short cable runs...

You could do an A/B comparison with a 50 feet cable and a 3 feet cable. Then
you could see if there´s any difference...

Let us know how you decide.

[maskedman72]

125 feet here with no problems. you are fine.

[Roland]

Originally Posted by Mike H

I have two choices for locating my preamps in my home studio:
(1) In my rack. The cable length from mics (in another room) to preamps would be 35-40 feet.
(2) On the other side of the mix room, where the mic cables come thru the wall. In this case, the length from mics to preamps is about 12 feet.

This matters because some of the preamps have EQ's which I would like to use during mixdown. Option (1) is perfect for mixdown. Option (2) requires that I go across the room during mixdown to adjust the EQ's.

I am using DA-206 110-ohm digital cable from the mics to the preamps.

Am I OK with 35-40 ft. between mic and preamp, or will I have to go with option (2)?

Thanks.

The Distance isn't a problem, conventional wisdom usually states that you need to be using more than 300 m before the capacitance of the cable starts to roll off the high frequancy significantly.

Using 110-ohm digital cable between the mic and the pre-amp? If you have stated this properly this is a problem. Use proper mic cable! If you don't you are effectively nearly doubling your mics impedance (usually around 150-ohms for a pro mic) to the pre. This could potentially cause changes in sound.

If you meant that the cable running from the pre-amp to your Recorder/DAW is a digital signal and you are using 110 ohm digital cable for this, better to mount your pre-amp in the control room as long digital cable runs can (depending on the type) cause problems.

Regards



Roland

[Mike H]

I was under the impression that 110-ohm digital cable (specifically Canare DA-206) for line level analog service is not only adequate but preferable, based on comments here and elsewhere:
http://gearslutz.com/board/showthrea...=digital+cable

Is that incorrect?

In service from the mic to the preamp, I mispoke. I actually have Gotham GAC-3 mic cable. However, for my information, I would be interested in understanding a little more about why the digital cable would not work here, also. Could you please explain the problem that's created with 110-ohm cable carrying a mic level signal?

Thanks,
Mike

[JonCraig]

Originally Posted by Mike H

I was under the impression that 110-ohm digital cable (specifically Canare DA-206) for line level analog service is not only adequate but preferable,

i've also heard this many times before. if memory serves, it's capacitance specs are very good. i know one big facility close to nashvegas that's wired as such.

--jon

[Mike H]

I'll start a separate thread on the question of digital cable for mic cable service. I just want to better understand why the impedance issue prevents that; just curious.
Mike

[Roland]

Originally Posted by Mike H

I was under the impression that 110-ohm digital cable (specifically Canare DA-206) for line level analog service is not only adequate but preferable, based on comments here and elsewhere:
http://gearslutz.com/board/showthrea...=digital+cable

Is that incorrect?

In service from the mic to the preamp, I mispoke. I actually have Gotham GAC-3 mic cable. However, for my information, I would be interested in understanding a little more about why the digital cable would not work here, also. Could you please explain the problem that's created with 110-ohm cable carrying a mic level signal?

Thanks,
Mike

I'm 100% sure this is incorrect!

110-ohm digital cable, is for that, carrying signals that require 110-ohm. There is also 75-ohm digital cable for signals that require that.

The issue is that mic preamps are designed to be very at high impedence seeing a very low load. In the case of professional microphones usual impedence is normally a nominal 150-ohm load. Now here is the simple bit, you use 110-ohm cable you now have an impedence of 260-ohms. Hi impedence mics are around 600-ohms so you can see how far you have come.

One of the disadvatages is that HF roll off will happen much earlier. Usually HF roll off isn't a problem in cables up to 300 metres. The higher impedence also will affect the performance of the mic amp as it is designed to be optimum with a 150-ohm load. You need to get an electrical engineer in here to explain all the possible problems and tell you the calculations that back this up, its been several years since this was explained to me.

Long and short, you have microphones, then use decent quality microphone cable, thats what it is designed for, 110-ohm digital cable is for digital signals. There is plenty of amateur crap talked in these forums, trust that a manufacturer knows what he's doing when he describes what his product is optimized for!

Regards


Roland

[XSergeantD]

Originally Posted by Roland

The issue is that mic preamps are designed to be very at high impedence seeing a very low load. In the case of professional microphones usual impedence is normally a nominal 150-ohm load. Now here is the simple bit, you use 110-ohm cable you now have an impedence of 260-ohms. Hi impedence mics are around 600-ohms so you can see how far you have come.

110Ω cable does not mean there's a 110Ω resistor inside the cable, nor does it mean that the cable will measure 110Ω. You are not adding 110Ω resistance

[Roland]

Originally Posted by XSergeantD

110Ω cable does not mean there's a 110Ω resistor inside the cable, nor does it mean that the cable will measure 110Ω. You are not adding 110Ω resistance

You are right and I was wrong on that, however I do know that there are technical reasons for not using this cable for microphones. Unfortunately there are not a lot of elctronics experts here on this forum. I belong to another forum where there are some very well known industry designers and I will post there to get the definitive reasons and report back!

Regards


Roland

[XSergeantD]

[QUOTE=Roland].... however I do know that there are technical reasons for not using this cable for microphones. Unfortunately there are not a lot of elctronics experts here on this forum. I belong to another forum where there are some very well known industry designers and I will post there to get the definitive reasons and report back! [QUOTE]

Cool, but post it on the other thread started on that particular subject (Digital cable in mic cable service? ). I've used both with not problems. Also notice on Mogami 2983, which is used for their patchcords, ther are rated digital/analog.
Anyway, to answer the original post, at Hit Factory studio 1 we had multi-pair cable run thru the walls/ceiling to the machine room then to the patchbay to console pres at a total length of bout 150 feet (maybe 200 max) with no complaints which turned out to be caused via the mic cable length. Ya just need to have spec'd the right cable for longer distances., The general problem manufacturers will explain as using dig cables as mic cables is the strand count/guage. Dig cable tends to have less strand count but a larger guage, but that comment should go on the other thread, so I'll head over there to continue.
peace