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Connect balanced audio interface to unbalanced power amp
Old 22nd December 2013
Gear Head

Connect balanced audio interface to unbalanced power amp

Hi all, I'm hoping you can give me some advice on how to interface my audio interface with an old Quad 303 power amp.

The audio interface is a Multiface II, which claims to cope with either balanced or unbalanced output. The Quad obviously wants a lower-level unbalanced input.

I want to put an attenuator in between the two, to control monitoring level.

So, I've come up with two options: either run everything unbalanced out of the Multiface, and use something like a Radial MC3 for level control:

Radial MC3 Monitor Controller

The other option would be to take balanced outs through an attenuator like the ATTY:

or this:

Connect balanced audio interface to unbalanced power ampSLC-1 Studio Level Controller /HQ Stepped Attenuator f. Active Monitors/Speakers | eBay

And then convert from balanced to unbalanced before the amp. I'm not sure what the best way to do that would be, but I've found this:


and these inline Lundah transformers:

Problem Solvers | Product Categories | Lundahl Transformers

Would something like this work -- in particular would the transformers color the sound? I'm trying to get the least alteration possible on the signal path.

I suppose the last option is to ditch the Quad, but I recently had it serviced and it does sound sweet.

Many thanks for any advice.

Old 23rd December 2013
Gear Head

No one got any views? Is there a sub-forum I should be in?
Old 23rd December 2013
Gear Addict
emeline-rec's Avatar

plug em together and see what happens, if it sounds good don't worry about it. You'll want some kind of volume control though so you could interface the two with a monitor controller.
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