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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

Showing 7 responses by evergrey

evergrey OP
15 posts
 
Almarg,
The positioning of the switch is on 'balanced'. But, this does not make a difference in sound level/quality if i were to put it on 'unbalanced' as long as both connection types are in.
The ground switch is currently on 'lift'. I have not tried to change that. What about phasing?
~EG
evergrey OP
15 posts
 
Milpai,
At this point, i would have definitely said good quality RCA's are the way to go in my system if i could only run one type. The XLR's just did not have the the same sonic vibrancy/detail/depth. The initial increase in gain, actually seemed to deteriorate the sound, so i lowered the gains on the amp.
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.
evergrey OP
15 posts
 
Well, this investigation has taken a turn for the worse. I decided to remove the Synergistic RCA's from te amp and turn the ground switch to 'normal'. After i turned my equipment back on from the cable change, i lost sound out of the left chennel. I've tried every scenario to see if it wasn't my source, preamp, speakers or different cables. I've deduced that my amp blew a channel. The 4 buss fuses inside, although taped uo to hide the filament, seemed to still work because the 2 blue lights on te front panel were lit up, the 'Hi Temp' light was off, and te right channel worked.
This is a total bummer and now i have contacted Parasound to see what my options are.
Thanks to everyone for all your input.
Mlenn, are you going to leave both IC's sets connected? didn't know that it would have a similar result for others or not.
evergrey OP
15 posts
 
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.
evergrey OP
15 posts
 
Hey Milpai, I have been enjoying the amp now for a few months. Parasound took care of the problem and actually brought it up to current standards. I am very pleased with the sound and the current setup. The combination of the Sonic Frontiers preamp with the Parasound A21 amp works very well. I am considering some tube rolling in the near future.
evergrey OP
15 posts
 
Sorry for the delayed response. Milpai, i share the same thoughts as you do about this amp. Running through my Sonic Frontiers tube preamp, I feel like i have a great combination of both detail and warmth. The soundstage is very plentiful as well. I gotta say that this combination of BOTH xlr and rca connections really makes that combination wake up. Insofar as tube rolling goes, i was referring to the stock sovtek 6922 tubes that came with the preamp. I'd like to change (roll) these 6 to the recommended Amperex or Phillips equivalent.
My speakers are the next thing to be upgraded, but i really am not sure what to go for. Considering my appetite for prog rock, jazz and tech metal, I am keeping my eye on B&W 803's, Tyler Acoustics, Von Schweikert VR4jrs, Dali Ikon/Euphonia's.....but i am not sure if these are the right combination. I have no ability to audition these locally. What is the speaker choices that other A21 users enjoy?
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