Low impedance for a long guitar lead

[JoeMeek]

Dear Forum Users

Like most of you I'm a bit of a DIY'er and would like to build a device to allow the use of long leads to allow separation between the guitar and head. It is for use in a studio where the guitarist is in the control room maybe 50 metres from the amp room.

I'm guessing the only way to do this is make use of the low impedance balanced cabling that is available all through the studio but understand that it is not that simple as just plugging it in.

Have any of you guys seen a circuit that might allow me to do this? I'm guessing a pair of High-low and low-high transformers, some sort of unity gain buffer or similar. Having multiple outputs to drive several amps would be an added bonus.

I want to be sure not to effect the tone some I'm interested to hear how this might be solved DIY style.

Thanks in advance

JoeMeek

[flemingmras]

Here's a simple unity gain non-inverting buffer for ya. This should work. And it's direct coupled so it shouldn't compromise tone.

Jon

[JoeMeek]

Thanks flemingmras

I'll give it a try.

Would 150ft of unbalanced cable introduce a capacitive effect or reduce sound quality? Also I'm wondering of the low output impedance of an OP Amp (compared with a pickup) would change the way the input stage of a tube amp behaves?

I've noticed a few schematics from Jensen Transformers http://www.jensen-transformers.com/apps_sc.html that seem to apply - the AS092 and AS097. As an audio transformer will cost about $150 here in Aus I'd be interested to hear your opinions on them before I shell out for one.

Thanks for your time

JoeMeek

[NY Chief]

I have always brought the head into the control room and ran a long cable to the cabs. That seemed to work OK.

[JoeMeek]

For all that might be interested in this post I asked the question of the Jensen tech department. Here is their response.

"The AS092 is meant to take a line level console output and send it back into a guitar amp to be recorded from the amp itself. The controls on the schematic are to set the level and tonal quality of the signal going into the amp.

In your case, you should use a direct box at the guitar and send the signal at mic level to the amp then use the second part of AS097 to bring the level back up for the amp input. If you are using guitars with very high impedance passive outputs then you would be better off with an active DI because it will not load the guitar as much and can drive the cable better. As far as driving multiple amps goes, you might be able to "Y" cable them together for 2 or 3 units but you might need a distribution amp if there are too many or they load the signal down too much."

Cheers

JoeMeek

[Dai H.]

I have always brought the head into the control room and ran a long cable to the cabs. That seemed to work OK.

makes sense. So you can just keep the high impedance run short and extend the low impedance out (i.e. 4/8/16 ohm spk. out).

[Billy Batz]

I have always brought the head into the control room and ran a long cable to the cabs. That seemed to work OK.

Thats the way to do it

[JoeMeek]

I have always brought the head into the control room and ran a long cable to the cabs. That seemed to work OK.

Thanks for the replies guys.

A long speaker lead works OK but is not always an option. Many Studios do not have speaker wire from the control room to isolation rooms and running wire under doors can be a hassle (as most doors seal around all edges for sound isolation).

Also combo amps make this a challenge!!

[Billy Batz]

I have always brought the head into the control room and ran a long cable to the cabs. That seemed to work OK.

Thanks for the replies guys.

A long speaker lead works OK but is not always an option. Many Studios do not have speaker wire from the control room to isolation rooms and running wire under doors can be a hassle (as most doors seal around all edges for sound isolation).

Also combo amps make this a challenge!!

If a studio wasnt built with that basic idea in mind Id probably not record there. Its your cash and time but Id worry about that if and when it would somehow come up because Ive never seen a studio that wouldnt accomidate an amp head in the control room or at least another room to listen for the guitar player. Id be worried about that lack of proffessionalism considering the rate at studios these days. Engineers can be real know-it-all assholes sometimes (I lived with one) but your the one forkin out all the dough. Theres a million things people fuss about in their signal chain that I dont get but one thing I do is buffers. They kill dynamics. I really wanted to own a splitter to be able to run a multi amp rig, mostly for fun (or in case David or Sammy call to be their fill in for their next stadium tour ) so I got a buffer splitter from Axess which I sold then I bought that expensive friggin Framptone splitter which wasnt any better.

[Steve]

Wireless??