2. amps-preamps
  3. 1308332214

Using both the Balanced and Unblanced inputs

Would there be any issue if I used both the Balanced and Unbalanced inputs on a MC275V amp to run EITHER video (RCA) and Audio (Balanced) and use the switch to select which format I wanted to use at the time, to avoid the need to plug in and out every time I wanted to change between CD and TV?
128x128signhere
martykl
3,563 posts
 
Call the manufacturer.

I have run parallel SE + BAL systems in the past, coverging at the POWER AMP. (CDP and PHONO AMP each go se to one PREAMP and bal to a 2nd PREAMP, the first PRE goes se to my POWER AMP and the other PRE goes bal to the same POWER AMP.) I always checked in first. Some said "no sweat", others said "no way". IIRC, it's a dicier move on outputs than on inputs, but I'd spend the dime on a call to be safe.

Good Luck

Marty
elizabeth
6,726 posts
 
It all depends on how those inputs are arranged inside the amp. IF they are connected in some way all the time (ground? or negative leg?) then the power from the one that is on can go back up the line some to the one that is off and possibley cause problems. Transistors don't like current coming in backwards. (simplistic concept but just the idea
So it can be risky (cause damage) to the other source output, even if that source is turned off.
theo's avatar
theo
2,331 posts
 
To be sure e-mail or call Mcintosh.
nsgarch's avatar
nsgarch
2,517 posts
 
Or if you can read schematics, it's very easy to see if they are "connected in some way" as E. puts it. In the older Gordon Gow Commemorative Edition (the first MC275 with BAL inputs) the inputs were connected. So are the BAL and UNBAL inputs of the new (mono) 50th Anniversary MC75's.

However, I KNOW, both from the schematics and from actual operation, that the MC275 Mk IV has separated inputs. I also KNOW that the Mk V has the same circuit as the Mk IV (except no level controls on the UNBAL inputs.) However, since I haven't actually seen the Mk V scehmatics, or used one, I'm not going to guess ;--)

It won't hurt anything to try. A friend with a pair of the new MC75's tried it, and simply got crosstalk, which is how we found out that ITS input circuits ARE connected.

Neil
.
xti16
1,495 posts
 
I tried that with my Octave V70SE and with the SE everything sounded right but the balanced was distorted. I was connecting a Meridian G08 to the Octave. I was trying to compare se to xlr without having to touch the cables and having both cables connected to the same source didn't work well in my case.
More to discover