Cable conundrum: Parasound A21 with RCA AND XLR


Ok, hope someone can give me a lesson. I recently aquired a Sonic Frontiers Line 2 preamp with both unbalanced and balanced outputs. First I hooked up my Audio Metallurgy GA-0 XLR's to my A21 amp, and I was not pleased with the sound. No depth, soundstage was choked. (gain was adjusted) I then connected my Synergistic Res RCA's to the outputs after disconnecting the XLR's. still not that pleased with what I thought was an upgrade.

In an accidental discovery, I reconnected the XLR's to the preamp WITHOUT ever disconnecting the RCA's. BLAMMO!! What sound I got! almost 5.1-like wide soundstage, reach-in depth, and the detail...let's just say i heard things from my CD's I never heard before.

So...how can this be? Both outputs from the preamp go to both inputs at the amp (balanced and unbalanced). Parasound tells me this is not a detriment to the amp. But I thought you could only use one or the other. Not both at the same time.
Any explanation?
evergrey
Evergrey, sorry to hear about the problem with your amp. I do not know why this problem would be related to your cable change if the system was off when the change occurred as you indicated. Thanks for the warning and please keep us updated on what you hear from Parasound.

Yes, I plan to leave both sets of cables connected to my A23 for the present, but will continue to avoid any changes in switches or cables unless the equipment is off. I blew the external fuse on my A21 (used in separate HT system) once when thoughtlessly switching from ground to lift with the system on. Fortunately, a simple replacement of the fuse fixed my problem. Lesson learned.

My C2 will sometimes switch into a silent protection mode if I touch the unit or connected equipment and get a static spark. Switching to another source or turning mute on and off returns the unit to normal operation. I appreciate this is likely unrelated to your A21 problem.

Hope you get your amp problem resolved soon.
Mglenn, thanks for the support. I'd like to open the discussion back to this cable discovery. I wonder why this is not discussed more frequently amongst users, in utilizing both XLR and RCA at the same time, if results like this can be achieved. I suspect that the approach of good quality cables in both categories can help achieve some terrific results.
EG, sorry to hear of the left channel problem, which I can't shed any light on.

Re your and MGlenn's observations of improved sound with both sets of cables connected, I suspect that the reason it is not discussed more frequently is that it is specific to your equipment.

I think that MGlenn's observation that significant sound comes through even when unconnected inputs are selected is key. That indicates crosstalk between inputs within the A21, and is most likely an unintended (and non-ideal) characteristic of the design. For whatever reason, though, it apparently happens to be synergistic with the A21's overall sonic characteristics and/or the characteristics of the rest of your systems.

Best regards,
-- Al
Evergrey,
Was your issue resolved? What reply did you get from Parasound?

Mglenn,
I believe that the A21 is not a "true" balanced design and so you are able to listen to some music when the switch (balanced/unbalanced) is in wrong position. But some manufacturers are of the opinion that RCA is more musical than Balanced.
Milpai,

In my home theater system, I use a Parasound C2 controller (yes, I have 2 of these) with Parasound A21 and A51 amps connected with balanced cables. In my opinion this sounds very musical driving three Von Schweikert VR4JR speakers and four TS150 speakers whether used as a 7.1 system or where only the left and right speakers are driven. For some reason, the C2 and A23 combination driving my Salk SongTowers sounded somewhat thin and veiled in my 2 channel system when connected with balanced cables alone.