Unbalanced to Balanced

I ordered an ART Clean Box Converter (cost just over £40) not really expecting much. I like to site my power amps as close as possible to my speakers. This means that in practice you have to use fairly long lengths of signal cable from the Pre Amp. SWMO is always commenting on the spaghetti that spews out of my Hifi system and urges me to hide it from the vacuum cleaner. The result of this is a less than ideal routing of cable. My power amps are Monarchy Audio SM 70 Pros and most reviewers have remarked on how well the work as balanced differential amps. My preamp however a TagMcLaren PA10 only has RCA phono unbalanced outputs. To cut a story short £40 came my way for participating in an ICT interview so I decided that, "nothing ventured etc" and I got the converter. Fortunately I had several balanced interconnects as used with microphones. I connected it all up according to the diagrams on the manual (no very clear) and hey presto - my speakers were making music. The lowering of the noise floor was impressive and the silences on Damien Rice 9 album were awesome. Imaging etc was better but really the spaces between the music was remarkable. The downside is I have noticed that there is a quiet but audibly annoying "hum" from my sub that I will investigate tomorrow and music to listen to has to be played with the computer, most definitely off!

After this initial installation I am delighted with the product. Tomorrow I will try connecting my sources direct to the converter and use its gain controls for the volume. That should be interesting!

Initially I was concerned that adding a couple of OP amps into the signal path would not be wise but in practice it has been well worthwhile.

 

In that case you might like to look in to transformer based devices for doing the job. Don't know of any off hand though.

 

Balanced to unbalanced

Hi

I've been lurking for a while, but this is my first post- please be gentle!

It will be obvious that I'm not that technically literate, but couldn't one get from unbalanced to balanced simply by using a TVC and disconnecting the outlet windings from the earth? The earth of teh balanced output would then be made at the power amp.

This would be easy if the TVC was installed a wooden case (eg Promitheus). Since I recently bought Larkrise's Ref 4 and have a power amp that has balanced inputs, this might be of interest.

 

not sure you need to disconnect the earth - as far as i know the promitheus outputs are balanced whatever you feed it with.

 

With the transformer outputs one end of the secondary winding will be connected to ground and the other to the hot pin of the output. This will give you a single ended output. If you took the grounded end of the winding and connected it to the minus phase of the XLR and the other to the positive you will have a floating balanced output. You can then connect the ground pin of the XLR to the ground going in to the pre-am.

Hope that makes sense.

 

Thanks Tenson

That's what I was thinking.

 

What was wrong with just making an RCA to XLR lead ?

 

I tried that using adapter plugs! Didn't do anything for the sound!

However, my sub bass is connect via adapter plugs and works a treat. I found that it was much, much better to connect one output from the pre amp to the sub bass and the other to the left and right amps than using the sub bass filtering and pass through.

 

because the signal will still be unbalanced,you either need a few bits of electronics or a transformer to make it balanced