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

Showing 3 responses by mglenn

I have a Parasound C2 preamp processor normally connected to a Parasound A23 amp using balanced cables. My ground switch was and is in the normal position and the cable switch set for balanced cables. I decided to try adding a set of unbalanced cables between the C2 and A23 based on Evergrey's post. The sound seemed fuller and more detailed through my Salk SongTower Speakers with both balanced and unbalanced cables connected whether the amp was switched to the balanced or unbalanced cable position. The unbalanced position sounded slightly better to me when the sound level was matched.
I do not believe the position of the ground switch is the explanation since mine is set to normal (not lifted). I have noted that even when the switch on the amp is in the wrong position for the type of cables used (that is unbalanced if only balanced cables are used or balanced if only unbalanced cables are used) there is some sound output albeit at a lower level. It may be that the amp is being input by both sets of cables although one at a much lower level that for reasons unknown to me gives a richer sound at the same volume. Then again this may be a placebo effect. In any case it was worth trying as I had the spare cables available. YMMV.
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.
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.