Balanced/unbalanced dilemma - Gear advice needed!

Posted: Fri Sep 05, 2008 5:34 am

I am going crazy trying to work out my home DJ setup. I have the following components.

Technics 1210 turntable (RCA)
Integrated hi-fi amp (RCA)
Native Instruments Audio Kontrol USB soundcard (Balanced)
Channel Islands Audio Phono pre + dedicated power supply (RCA)
Aego M 2.1 speakers (RCA )

My soundcard has 1/4" balanced ins and outs. However, I played my first digital set recently and it was a disaster. The sound on the floor was muffled and quiet with audio drop-outs (not to mention no monitor headphone output). RCAs on the mixer were used. I'm guessing their was a mismatch and the soundcard didn't have enough juice.

I want to do the following:

1. Archive all my vinyl for digital use
2. Use my soundcard with the Aego M system for general computer audio
3. Avoid the same problem with DJ mixers if I ever get booked again

I understand that I need a DI Box. Ideally, I would like one box but that may not be possible. Their is something called a Matchbox HD that is bidirectional or I could get something like a Radial J33 (phono pre-amp and DI box) or a stereo DI Box and connect it to my home hi-fi amp then into the soundcard.

The last two solutions will require another box to use when I play out, though whereas the Matchbox could be used for everything. Am I right in my thinking? It all seems so complicated.

Any advice greatly appreciated.

Posted: Fri Sep 05, 2008 6:32 am

I'm not sure exactly how you are connecting everything, but keep in mind that phono RCA's are different than line level RCA's. If you connect the phono out of your turn table to the CD/Tape RCA line in, it will sound like junk. Likewise, if you connect your line out RCA of your pre to the phono in RCA on your hi-fi, it will sound like junk.

If you care to detail your connections, I'm sure someone could point to the problem.

[edit]
another way to make your audio sound like junk: connect the headphone out to a balanced line in with a TRS cable!

Are you DJing with 90Watt computer speakers? That could also make your audio sound like...
[/edit]

Posted: Sun Sep 07, 2008 9:00 am

Thanks for the reply. Don't worry, the 90w system is for my ears only. As I am short on deskspace, the Aego speakers are only used for iTunes and making mix tapes.

The hi-fi amp has a dedicated phono input but I am removing it from the equation as it is the weakest link. Goodbye.

I only mentioned the Aego M speakers because they will be connected to the balanced Audio Kontrol outs. The Matchbox HD could double as a transformer here. Maybe balanced to unbalanced here will be unproblematic.

That leaves me with the following:

Audio Kontrol interface (balanced ins & outs)
Technics 1210 (RCA outs & ground wire)
Channel Islands Audio VPP1 & VAC1 Phono Pre + Power Supply (RCA outs)

Basically, what I need to know is which of the following two setups would I be better off using.

1. Technics to Radial to Audio Kontrol
2. Technics to Channel Islands to Matchbox HD to Audio Kontrol

If the Matchbox HD was vaguely comparable, it would be useful (I presume) to avoid the problems I had when DJing on a club system as it is bidirectional. I could also use it once all my vinyl has been archived for connecting other unbalanced equipment to my AK1.

What to do?

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