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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
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almarg
9,670 posts
 
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
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milpai
2,326 posts
 
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.
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mglenn
21 posts
 
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.
evergrey OP
15 posts
 
Milpai,
I shipped my amp out to Parasound since it is still under warranty. They are standing behind they product and will resolve this for me.
As for your assessment, this cable arrangement worked with each CD i tried. Perhaps Mgleen is correct in stating that there is crosstalk between the RCA/XLR connections. But to make such an impact doesn't seem to be accidental to me. Again, i wonder if this configuration would work with different amplifiers. The sonic quality improvements in the combined configuration mode of having both RCA and XLR inputs hooked up to my preamplifier from my A21 cannot be downplayed.
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milpai
2,326 posts
 
Everygrey,
Hope you have got the amp back by now. How do you like the sound now?
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