Impedance Matching for Morons [me]

[twitme]

Questions questions questions...

Ok so I'm running a Groove Tubes Brick into a TC Electronics M-One. The output of the brick specs out at 600 ohms max. the input of the M-One is looking for an unbalanced 13k 1/4" input. I have an audio technica microphone transformer that takes my 600 ohm XLR from the brick and converts it [the audio technica actually reads: 250 ohm to 50k ohm transformer] to 50k ohm.

Now I realize that 50k ohm is a much bigger number than 13k ohm. And I am getting REALLY hot levels out of the brick, as in I have to turn my guitar amp way down so the brick doesn't blow the meter on the M-One into ultra-violet light spectrums [although if I turn down the gain all the way I avoid clipping the M-One]. Is what I'm doing harmful to the M-One at all? Or just not the best possible way to link my equipment up? The only other real options I have, seeing as the brick only outputs to balanced XLR, is to run that XLR into my dbx286a's mic input (XLR) or a really mediocre low end Yamaha mixer. neither of those seem like a good idea if I want to maintain the quality for which I bought the brick to produce in the first place.

Is there any easy way to explain audio interconnects and impedance? Am I destined to destroy everything with my ignorance?

thanks much!

I don't think you will destroy anything except your sound quality. I would turn the Brick's level down so that it works properly with the M One's level input at around 9 or ten oclock. See how that works - and have you tried it without the transformer? That would probably help, as a cheap xformer will be the weakest link. It ought to be better for the brick to see the higher input impedance that a lower (250) one.

By the way, the brick has an output transformer already so putting another one in series is not neccesary at all! And the specs say it is already terminated with 600 Ohms, so you can easily send it into a high impedance input with absolutely no problem. I won't attempt to try to explain the theory behind it all...

It is reallly too bad the brick doesn't have any metering. Just use the next device's metering to see what you are doing - if you don't boost anything at all with the brick it will still help a lot. Don't turn it up any more than you need to to feed the M-One. I'd run the M-One around straight up (12 oclock) or lower, and adjust the brick for good level without overs - the red lights on the M-One mean it is too loud!

Why are you going directly to the M One? Is this for recording or performance? Wouldn't it be better to take the brick into the recording device or mixer and use the M One on an aux or even on an insert? You might be degrading the quality of the brick by running it thru the M One. Since you say it has a quarter inch input it must be the original M-One, not the XL version.

And what is the source? Microphone or guitar? studio or live? You don't mention what you are trying to do - more details are always easier to reply to than less.

<L>

[twitme]

Originally Posted by Lou Judson

Why are you going directly to the M One? Is this for recording or performance? Wouldn't it be better to take the brick into the recording device or mixer and use the M One on an aux or even on an insert? You might be degrading the quality of the brick by running it thru the M One. Since you say it has a quarter inch input it must be the original M-One, not the XL version.

And what is the source? Microphone or guitar? studio or live? You don't mention what you are trying to do - more details are always easier to reply to than less.

<L>

ok so I'll fill in the information a bit more here. My setup is strictly for recording. I'm using the M-One for its A/D converters at the moment, and yes it is the original M-One so I can't plug an XLR cable into it. I lack a quality mixer, so my only other option for connectivity is going straight into my soundcard (or into the mic input on my dbx286a, but that sounds like a great way to degrade the quality quick), although I'd prefer to use the M-One for its converters. The only mixers I have are a behringer and yamaha, both low end stuff.

here's my chain: guitar amp > Rode NT1 > Brick > TC M-One > S/PDIF to Echo Mia. Substitute vox for guitar, and those are basically the only uses I'm taking advantage of here.

so would you recommend simply using an XLR to 1/4" cable/adapter sans a transformer? The brick with it's low impedance (terminated at 600 ohm) into a much higher impedance (13k ohm unbalanced, 21k ohm balanced) is just fine?

[twitme]

something like this perhaps?

http://www.musiciansfriend.com/srs7/...se_pid/335209/

or:

http://www.musiciansfriend.com/srs7/...se_pid/333074/

Yup, just try it and see! By the way, I got my M-One for it's A/D too a long time ago before i got new input devices...

<L>

Originally Posted by twitme

something like this perhaps?

http://www.musiciansfriend.com/srs7/...se_pid/335209/

or:

http://www.musiciansfriend.com/srs7/...se_pid/333074/

Either of those might work, but I think the M-One is unbalanced in so you might want one with TS instead of TRS:

http://www.sweetwater.com/store/detail/PXF105/ might work better.

Lou

[twitme]

Yup, just try it and see! By the way, I got my M-One for it's A/D too a long time ago before i got new input devices...

I've heard that people buy TC stuff just for the converters oddly enough. what are you using now? was your current upgrade worth the $$? how did you feel about the TC converters?

Either of those might work, but I think the M-One is unbalanced in so you might want one with TS instead of TRS:

The M-One can accept either balanced or unbalanced 1/4" inputs.