Pros: Transparent, well built, fun to use
Cons: Ummm... it doesn't clean my dishes? Can't really complain at this price point
I bought the Corda Jazz as a gift for a family member. I am trying it out with my own equipment for a few days before I gift it.
Overall Sound Impressions:
Long story short: Excellent sound quality. Beats anything I've heard in the same price range (although admittedly limited to a few other head amps). No noise, no overtones, no drama, no artificial adjustments. This can always be debated, but it was transparent enough for me to notice significantly changes between different settings on my source, different headphones, well recorded vs. poorly recorded media, et cetera.
I could not listen loud enough to cause any audible distortion with my headphones. Although I was physically at my limit so didn't try the knob all the way while listening to music. If anyone were so inclined to send me some headphones for review I would be happy to test with more demanding headphones and report back here.
Cross Feed Impressions:
Yes it works. I have a Corda Classic in the mail so I will be comparing the more comprehensive crossfeed of the Classic vs the Jazz at a later date.
As others have mentioned I noticed is does not always make a big difference. It works best on acoustic music from what I've been able to gather. This probably has to do with the way the music is recorded; such as real instruments being played versus synthesized.
Overall, I find that I'm able to listen longer without hearing fatigue (especially a large difference with my closed phones used in testing). The crossfeed presents a more balanced and natural soundstage, instead of the annoying two mirror images that are easily distinguishable without using the crossfeed. Unlike non-Meier versions of crossfeed I've used I didn't notice any detriments to the sound quality while the crossfeed is active.
Sources + Headphones pairing Impressions:
I would be remiss if I didn't mention some cautions here: for sources with relatively high output (mine is 2 V RMS w/ unbalanced - I haven't tried the balanced but we can imagine what the effect would be), in combination with dynamic low impedance headphones with relatively high sensitivity this amp is not a good match - especially with almost anything recorded on CD past the year 2000 (notable exceptions from a few labels aside). Lookup loudness wars.
With well recorded (non-bricked) source material it's not a problem, but for most mass-produced modern CDs even with the gain at 0 db and volume set to minimum the listening volume can get uncomfortably loud. I guess you could try to compensate with different RCA cables (but that would surely introduce other undesirable elements - I would rather have the cable be as transparent as reasonably possible without high capacitance).
This is not a problem with the AKG K701's. It is a problem with Ultrasone headphones. The Corda Classic with - db gain setting would be more appropriate for Ultrasone headphones. From the other reviews I've seen I don't foresee this volume issue with high impedance or relatively insensitive headphones (maybe efficiency is the more correct term here) due to the SS design of the Jazz.
Disclaimer: my hearing is a bit weird so maybe others may not have this problem at all. I've been tested by a doctor in an anechoic chamber to have an abnormally wide hearing range (beyond normal). This may contribute slightly to my experiences above.
Packaging & Build Q Impressions:
Packed well, double boxed, suspended internally with tight fitting blue foam. Build quality is perfect - especially for the price. It would be nice if the outer panels were a bit thicker like my Onkyo CDP (that thing is a tank), but this is a non-functional nit. Meaning... there is no vibration or any other issues and the panels are very sturdy.
I was expecting the Jazz to get hot, but even after 5 hours straight of use it is merely warm to the touch. This might be because my headphones aren't pushing it hard enough. :)
The gain button provides non-ambiguous spring-loaded action. The toggle switches which control the power and crossfeed functions provide a positive 'clunking' report.
The volume knob feels analogue because it is (partially at least). No physical stepping clicks. With no music playing but power on, a soft electronic clicking can be heard when increasing volume past the 12/24 hour position. When music is playing at normal volume it is not audible.
The Neutrik headphone socket provides a satisfying grip on the headphone jack. The RCA terminals are just like most others in terms of function. I haven't used the equipment enough to comment on the thickness of the gold plating. I am using a non-aggressive RCA connector...
Source: Onkyo C-7000R with filter slope set to sharp & slow alternately (sharp = ruler flat FR, slow sacrifices this a bit for better precision in the soundstage for locating instruments and positioning. It is easy to tell the difference on live music). This is an amazing component in it's own right, even better considering I got it for significantly less than list price). Not easy to find on the market however. This is a statement product, and statement they have made. More info: http://www.onkyousa.com/Reference_hifi/hi-fi/index.html
Cables: Stock power cables, BJC LC-1 RCA cables
Surge Protection: Brickwall 8 Outlet (isolated outlets)
Headphones: Ultrasone PRO 750, PRO 900, PRO 2900, AKG K701's
Music: A bit of many things: Fabrizio De Andre, Pink Floyd (Gold CDs), Gorillaz, Massive Attack, Courtney Tidwell, Dead Can Dance, Daft Punk, Juno Reactor, Kraftwerk, Morcheeba, Thievery Corporation, Deep Forest, Gustav Mahler (Deutsche Grammophon), Tube Roehre (tube recorded Symphony), Roger Waters, Talking Heads, Chant (real acoustic from some monks), Korn, et cetera...