A* börjar verkligen bli en trögubbis, blandar ihop Panasonic och Samsung till höger och vänster!
Jag hittar allt på olika siter, läser igenom trådar osv.
Ytterligare en stor tråd, med en intressant recension, jag klistrar in resultat!
Inte bara vackra ord, men jag tror att det ligger närmare sanningen än många andra som bara avgudar denna lilla maskinen.
Citerat från:
http://www.avsforum.com/avs-vb/showthre ... enumber=14
Skrivet av: ssangste
Ok.... here we go..
First things first..... Many thanks to the significant other for helping me with some blind testing (more on that below). She is too accomodating sometimes with this obsession of mine...
Caveats: there's a lot of subjective opinions below (as well as, I'm sure, a number of spelling and grammatical errors, since I doubt I will proofread this. My apologies on that and I hope it doesn't ramble too much). This is what *I* heard in *MY* system with *MY* ears. I'm just reporting what I hear. Take whatever you wish from these opinions, but I do encourage you to hear the amps for yourselves. It's a minimal investment compared to some of the other megabuck stuff that's out there and more than worth the fun of experimenting with different equipment. These will be my final comments on the amps' sonics. I've done a LOT of swapping of components and testing. It starts to run together after a while. But I felt it necessary to get a good handle on these amps. Having said all that, these comments will be limited to two channel listening, either with a digital input or analog input. I haven't done surround sound in my theater room for ~5 years because I couldn't stand the sound of receivers enough to put up with one and own it. I've always done strictly two channel with tube amplification and ribbon tweeter speakers for good horizontal dispersion... I own only redbook CDs, no SACD or DVD-A. While I own most of the "audiophile approved" CDs, I listen to a BROAD range of stuff, from poorly recorded classical to jazz, female vocals, pop, rock, classic rock, metal, punk, grunge, blues, a very little bit of country, bluegrass, and celtic. Some examples of common artists used in this test: The Tragically Hip, Metallica, U2, Sex Pistols, The Doors (their CDs sound terrible but their vinyl is surprisingly good!!), Jacintha, Diana Krall, Allison Krauss, Pink Floyd Mo-Fi, Sarah Mc, Great Big Sea, Muddy Waters, Jewel, Holly Cole, SOL, B.B. King, Midnite, Chris Isaac, and many others. A lot of recordings out there are horrendous. So it's a good test for an amp to see how it handles every day music. If it makes all CDs sound the same, that's not always such a good thing (unless you want that). If it shows all the flaws in the recording process, the crushed dynamics, etc.you may have a winner there (again, depending on your goal for your system).
Equipment: The xr45 and xr25 were in stock form. Some people are doing things with power cords, etc. I've never had a power cord tame high frequency harshness and brightness before. I have had them improve the bottom end a bit and remove a bit of a haze to the sound. Anyway, these are comments for the stock units. I will play with power cord mods and power supply mods later.
Two digital sources were tried. The first was a HTPC with ASIO out from an Audiophile 24/96 SPDIF using WAV files on hard drive and CDs played through CD-ROM. Second one was the crappy entry model Toshiba DVD player from a year or two ago with the included junk video patch cable feeding coax digital out to the panasonics.
Analog source was my own custom modded CD player with heavily modded power supply, and custom built analog stage from scratch.It began life as a Sony CDP-790 from the early '90's. But other than the transport and case, you wouldn't recognize it because all the internal boards are new, made from scratch.
Amps used for analog comparison were custom circuit and build tube designs using top quality iron. Preamp was custom circuit and build using 6sn7 dual triodes.
Cabling was home brew and commercial cabling, using either teflon coated pure silver, teflon coated silver covered copper, and teflon coated copper in various configurations.
Two pairs of speakers were used at different points. One custom design and built bookshelf used Hiquphon tweeters and Scanspeak revelator mid woofers (yes, a pair of these drivers cost more retail than the panasonic amp!). Ported box with a Qts of ~0.95 with an in room F3 of 39Hz. The second set of custom floorstanders used morel's best tweeter and an audax carbon fiber midbass (i.e. much warmer, little less detailed sound). Secret woofer on the bottom . In room F3 of 26 Hz, Qts of 0.65.
Sonics: All of my original observations still hold true (except the digital popping in the 25... it has since mysteriously disappeared just as quickly as it appeared in the first place)
Both the 25 and the 45 have excellent detail, both in an absolute term and especially considering the price of the units. Even after nearly a week of 24/7 burn in, the 45 and 25 both exhibit the same slight harshness, and definite brightness on the top end. The 25 is still harsh and bright in the middle, and actually got worse with burn in. The 45 is much better in the midrange, mainly because it isn't as thin sounding. So the much fuller lower midrange masks some of the brighness. Bass in the 25 is very thin, even though it goes deep. The 45 is MUCH MUCH MUCH better than the 25 in this area. It is still juuuuuust a touch thin, but overall is pretty close to having the right weight to it.
Imaging and the soundstage is very good with the two units in *two* dimensions. From left to right and top to bottom, instruments and voices are placed well. Depth of the image is where this unit comes up just a touch short. Flip on the tube rig and instantly the soundstage depth from in your lap to six feet behind the front wall instantly reappears. One note here: I haven't been able to pinpoint the reason, but the image is slightly smeared with the 45 compared to the 25. Everything is kind of smushed together more and there is less seperation of instruments and voices.
While the 25 and 45 get all the nice little details to come out of the recorded source, they still have yet to take on that "real" sound. Instruments still don't have the defined space around them I am used to, nor do they ever let me forget that I am listening to recorded music. Part of that is the lack of soundstage depth so things are sort of piled up on top of one another rather than giving the illusion of the upright bass being 6 feet behind and to the left of the lead singer... and the amp itself just doesn't make acoustic guitar sound like it's really an acoustic guitar being played in the room (or any other instrument for that matter). It sounds like a recording of a guitar being played back, whereas my tube rig sounds exactly like a guitar would if played live in my room, and exactly like an upright bass would, etc..... I can't describe it any better than that. I'm not spectacular at verbalizing what I'm hearing and I think this is another area where I fall short in my description....
As I have said before, the digital input (even with subpar digital sources) is MILES better than the analog input. It is not even close to being a subtle difference. I'd really like to do some testing with a good digital source to see if there are any improvement and if any of the things I am describing can be attributed back to the source.
Playing all types of music through these units was quite revealing, figuratively and literally. Both did an admirable job of showing all the flaws in the recording, presenting the differences in recorded ambience, compression, and dynamics. Good job of being more accurate and not trying to make things sound the same.
As it stands right now, the brightness and harshness up top can be a deal breaker for some. Matching of components becomes a critical step. If you have really bright sounding speakers to begin with, this receiver will likely exacerbate the problem even more, the X25 especially. I don't recommend silver cabling hehehe These are not tubey warm and lush sounding amps. As it is, they can be fatiguing to listen to for extended periods of time with very accurate speakers. That's why I brought in the second set of speakers to try out with them. The morel/audax combo help significantly in this department, adding a bit of warmth, a little bit less detail and masking some of the harshness. Of course, if you're like half the people I know and can't hear above 12 KHz, you may not notice a difference I also adjusted both sets of speakers' crossovers to pad down the tweeter and one other area of the frequency spectrum to adjust their sonic character. Voila! A setup that I can actually listen to without constantly grating my teeth and wanting to run screaming from the room. Again, never to be confused with a good tube setup, but a great sound nonetheless.
Overall, I am thoroughly impressed with these units, despite a lot of negative comments above. Considering I am comparing the unit to custom built tube electronics that cost SIGNIFICANTLY more than this unit (just the parts to mod my analog CDP were enough to buy 4 of these XR45s alone) is a testament to just how good it is for the money. The X45 is much better in my books than the 25 because of the fuller bass and midrange. It's worth the bucks for the sonic improvement. Will the 45 replace my tube gear as the ultimate in performance regardless of price?? Not a chance. But you get such an incredible bang for the buck, that it is hard not to recommend the unit. I haven't heard a receiver under $1500 (and I've heard a LOT of them) that I would take over it. I haven't heard many of the high dollar, bell and whistle receivers... so I can't comment on them....
the extra bonus of this whole endeavor is that not only is this thing pretty darn good for two channel listening, but you get 4 more channels of amplification and surround sound processing thrown in as well!! That's what makes this little unit an absolute steal!! Get yourself a cheap DVD player, and use the money you just saved on amplification and cabling to buy better speakers. That's how I am going to be demonstrating it to people.
Blind testing: I wanted to make sure I was not imagining the differences between the 45 and 25. So I setup some blind testing. Absolutely every component and cable was kept exactly the same. The two receivers were stacked on the rack and covered over from the front so that I could not see which unit was on, or which unit had the speaker wire connected, etc. Digital input was fed from the Toshiba DVD player through the included video patch cable to the coax input on the panasonics. Cardas banana plugs were used to make switching speaker cables easy for her.
Trials of 10 were run. 10 times, I would leave the room and the significant other would either switch the inputs or leave them the same, and record which unit was connected (she always disconnected the connections so that in case I could hear rustling in the room I wouldn't be able to use that to my advantage. She would then just rehook the same connection or connect to the other receiver). With only one RCA interconnect and two banana plugs to change it never took her more than 10 seconds (or so she claimed). I would be led back into the room, eyes closed and not allowed to look at the equipment rack, take a seat and listen to a selection of music. I then wrote down which receiver I believed was connected. Before testing began, both units were level matched running a frequency sweep and measuring with an SPL meter, as well as having the mic at the listening position and taking readings with my audio software... (the 25 needed slightly more volume on the volume knob to level with the 45 (i.e. -23 on the 25 to achieve the same volume at -25 on the 45. Don't know why they were different, but it was there nonetheless). Once level matched, the volume controls were then not touched. This makes this test much easier than using just power amps and trying to level match each time to a single preamp!! The original intent was to run 10 trials, take a break, run 10 more, etc. until I got to 100 and then review the results. Since I was so confident of my results, we reviewed after each 10 trials and used that as our break period. I often only listened for 10 seconds or less on the music before making my choice of which unit was playing. After 2 rounds of 10 trials with the Hiquphon/SS speaker, I was 20 for 20. So we switched to the morel/audax combo. Because the Qts of the H/SS combo was 0.95, the bass was just too much of a giveaway between the two units. The M/A combo had a lower Qts, which I thought would make it harder to pick out the lax bass and lower midrange in the 25. Well, I was wrong. After 20 trials with the M/A speakers, I was 20 for 20 again. Again, it was waaaay too easy to tell the difference. We stopped the test there. I could have tested 1000 times and probably gotten the same results.
In an absolute SPL sense, both the 25 and the 45 had *exactly* the same SPL response in the bottom end. I didn't do any waterfall tests to see if there were differences there. But just listening to the two, it was very very very easy to tell a difference. I found out what I needed to know. I could tell the difference between the two and the differences I was hearing were not in my head. Was the test scientifically significant, or were there flaws in the test? I could give a flying rat's arse either way.... I'll just go on my merry way believing what I want to believe and leave it up to others to argue endlessly about that subject......
Conclusion: I think the 45 is much better than the 25 and worth the little bit of extra money. I've always been a tube guy because I couldn't put up with the harsh and bright sound of solid state. While this 45 is still bright and harsh, I was able to tame it enough with speaker selection and design, as well as cabling, to make the resulting sound tolerable and enjoyable to listen to. That's somethign I've never been able to do with solid state amps or every other receiver I've tried. For someone starting at scratch and building a two channel system, you get exceptional bang for the buck by adding a cheap DVD player. That leaves lots of room in the budget to build or buy a good to great set of speakers. Less cables to buy, again, more money for speakers. Finally, because it also does surround sound, I may actually get to watch a movie in surround sound instead of a two channel tube setup!
Is the Panasonic 45 the be all and end all of amplification? No. If you still want truly high end reproduction, there is better out there. But you're not going to find it for $300... I encourage everyone to give a 45 a spin.... It might just surprise you... I'm off to start learning more about switching power supplies... I can't wait to break out the soldering iron and try some things....
!
!
!? (A* börjar bli gammal trögubbis? 
!?
! Jaha mer o läsa då 
