Balanced Pre-Amp

[CIGARBUM]

Present equipment; McIntosh MC275 - C-29 - Klipsch Belles.

Several folks have told me that I should be running a balanced interconnect between the amp and pre. The C-29 does not have the ability to be balanced, but the MC275 does. What are the options to replace the C-29 with a pre-amp that will accept the balanced connections? I know the MC2200 will accept, but I'm not sure I want to spend$$$$ right now. Are there any as good, cheaper options?

They say the sound will be "better" I just gots to know.

CB

[Coytee]

There are some that will tell you that balanced connections are not needed, as long as you do not currently have any noise being introduced into your system by your connections. Also, that they are not needed unless you are making some LONG runs.

There are others that might suggest balanced connections have other benefits. I happen to fit in that group since my Dx38 has balanced inputs/outputs and I'm forced to have some XLR connections in my system.

I once asked my local McIntosh dealer why their amps were across the room, next to the speakers. His basic answer as I recall was, it was better to have the speaker wire as short as possible. I seem to recall other comments on this (probably on this forum) where you want the low level signals as short as possible and use longer speaker wires. Go figure.

You can always try a RCA/XLR transformer. I have one that you can try if you want. What I found it did for me was to reduce some humming I had in my system and it made my input signal into my amps a bit hotter (I think 6 db??). Though it helped a specific issue I was having, that issue has since been corrected and I really wanted to yank the Cleanbox out of there for the simple sake of reducing clutter.

If you'd like to try it for a while as you play around with this, you are more than welcome to. I can have it shipped out in a day.

Enjoy your journey!!

[JL Sargent]

If you don't have any noise in your present setup then I don't think you need balanced stuff. Like Coytee said, if your running long cables and seem to be getting noise then the balanced can certainly cut down on that. I've tried all kinds of unbalanced stuff here lately and still no noise, but I use short cables. Let your ears be the judge!

[Guest " "]

The c-2200 is not a balanced pre-amp. It just has connections for XLR. I'm not sure since it's been a while since I sold mine as to the architecture used to provide the xlr connnection.....examples are...a transformer that internally converts non balanced to balalced....differential amplifers...resistors, etc.

The C-1000 is an end to end truely balanced pre-amp. The C-1000 will blow the doors of the c-2200 for numerous reasons.

I wouldn't loose too much sleep over wondering how the c-29 would sound if it were connected to the MC-275 via an xlr connection.

[CIGARBUM]

I presently have no noise in that system, as it was explained to me that the balanced type of connection actually takes some amount to circuitry out of the signal loop?? Don't know that's way over my head anyway. The lengths are relatively short (speakers are 12 feet apart and equipment rack is in the middle).

I like the idea of not loosing any sleep about it and not having to spend a bunch of $$$$ for no reason.

Thanks guys

CB

[philipbarrett]

They say the sound will be "better" I just gots to know.

"They" would be wrong. Now you know.

:-)

[CIGARBUM]

Ya, I know but, just think, if we all just stayed with the equipment we presently have, we would miss out on a whole bunch of fun. Buying, selling, and trading, you never know what may be lurking around the next corner, it's not the designation, but the journey. Besides, I can always blame "them"

[philipbarrett]

Balancing involves using a 3-conductor signal cable with + and - conductors wrapped in a 3rd "shield" conductor. Without getting too heavily into common mode rejection, the balancing circuitry removes noise introduced in the cable resulting in a theoretically cleaner signal. The professional world of long cable runs (we have snake cables of over 500' carrying mic level signals) and lots of big A/C power hanging around would not be possible without balanced lines. As you can see though, just because a circuit uses an XLR it does not have to be balanced.

Pros

As above, the CMR between the signal & ground gives a signal which cancels out electromagnetic interference and is therefore quieter. Notice no increase in the actual performance of the signal path is possible though.

Cons

The balancing circuits themselves cause all kinds of problems. Traditionally balancing was only possible with transformers and these varied in quality & frequency response depending on the need (a telephone call requires less bandwidth than high quality audio). The best audio balancing circuits still use transformers and to achieve the performance needed these are highly expensive units which is OK if you're at home and need 4 but gets pricey on an audio console with 60 or more.

To solve this problem most equipment uses "active" balancing which is basically a circuit that replicates the transformer. However, as with all active circuits they vary vastly in quality & price and even the best will introduce noice, distortion & phase anomolies into the signal path. Pro engineers have a love/hate relationship with these circuits, yes they fix one problem but create some others.

So, a necsercerry evil in a live/studio environment but without much real application for home where signal cables can be kept extremely short.

And to answer the speaker cable length vs. signal cable length debate; the lower the signal level the shorter the cable should be. If you imagine any induced noise to be of a fixed level which increases with cable length then the cable that gives the highest ratio of signal to noise should be the longest. In other words the 10s of volts of speaker level are much less sensitive to noise than the milivolts of line levels (or microvolts from a TT).

Secondly, a speaker has no gain stage (quite the reverse, they are incredibly inefficient), therefore no ability to amplify any noise introduced into the signal and is therefore the best place to be at the end of a long cable run.