Je n'ai pas parlé d'inepties, je parle d'enthousiasme que vous tentez de nous faire partager
Pages 140 à 149 les deux comparaisons portent sur un ampli pro et un A21 (sur Adcom aussi mais vu ce que j'en pense inutile d'en parler
) ... ils ne s'enflamment pas... sans le pourrir pour autant.
Je calme juste ce qui risque d'être une fable : l'ampli à 300 euros qui écrase tout sur son passage,
Sur le CDA 254S qui avait suscité le même enthousiasme :
"I just tried the CDA-254S in my reference system with my Magnepan 1.6's and Van Alstine hybrid preamp and DAC. Compared to my Parasound A21 amp the 254S lacked the deep bass, dynamics and treble resolution that the A21 has. Bass was tighter and better controlled. There 254 has a darker background, no grain and more air, transparency and wider sound stage. But the midrange was thinner and it needed more slam and power. I think that it may have better dynamics and bass with the 400va power transformer that the 254L has.
So now the question is, do I take a chance on an SDS-470? How do the SDS amps compare to the CDA amps in sound, bass, treble ?"
L'A21 n'est pas mauvais, c'est vrai
Sur le SDS470
"I finally completed my SDS-470 kit build this past weekend. I thought I'd post my initial impressions.
First: on the first test, I powered it on, but got no sound. I noticed the on-board LEDs indicated "Left Off" and "Right Off". The power supply lights were on. I used my DMM, and verified that I had DC going to the amp board. Nothing changed on the preamp side, and the music was playing. I was about to come here to ask for help when I noticed the little built-in "on/off" switch on the side/bottom of the amp board! I switched it on, and I got music! Classic ID-10-T error on my part.
Anyway: config is as follows: FLAC files (from CD rips) on computer, optically connected to Emotiva XDA-1 preamp/DAC, to power amp via XLR, to Salk Songtower speakers. Original power amp was a QSC RMX2450 "pro" amp; new amp is obviously the SDS-470 kit.
This are my initial impressions only, since I've only been able to listen to music for 20--30 minutes at a time over the last few days. So far, it seems to me about the same as the QSC. And that's not a bad thing! I was completely happy with the sound quality of the QSC. My goals for the SDS470 were (1) lower power consumption; (2) same (or improved) sound quality; and (3) have fun. Going by those three criteria, this was a complete success.
On the power consumption front, I'm using an AC Watt meter (Kill-A-Watt). The SDS470 seems to pull about 22 Watts, both at idle (no music) and typical listening levels. I haven't really cranked it up yet. Compared to the QSC, which pulled 40--60 Watts between idle and music. A definite improvement in power usage. As I suggested above, I'd like to get a switch-mode power supply (SMPS) to see if I can further reduce idle power consumption.
Regarding the "have fun" thing: I definitely enjoyed the electronics aspect of this. But I didn't particularly enjoy working on the case. I bought an aluminum Par-Metal case on Ebay. If I go forward with the dual bridged sds470 monoblock project, I think I'll just bite the bullet and pay for professionally machined and finished enclosures. I even went bare-minimum on my design: combined fuse+IEC, no power switch, two XLR inputs and four speaker binding posts. For a future build, I'd like to have two switches (mains power and amp board power), separate IEC and fuse holder, plus all kinds of LEDs. I just don't have the patience for all that drilling and cleanup.
Anyway, as for the sound quality discussion (what everyone is probably most interested in). On the very first listen, as I mentioned briefly above, I really couldn't tell much difference between the SDS470 and the RMX2450. On a few rare occasions, I thought I've heard a little bit of sibilance... but lately, I haven't heard that.
Not sure if I imagined it or not. Also: depending on the input gain setting of the pots, I can hear a very faint hiss coming from the speakers when my ears are a few inches away or less (and there is no music playing). Adjusting the gain fixes this though.
I don't know if my ears are getting used to the unit, or it's being "broken in" (a concept I'm not sure I really believe in anyway), but last night I felt like the amp had a little different "character" from the QSC. Is it better? Maybe. It does sound great, there is no doubt about that. I'm just not sure if the difference is all in my head or not. It's too annoying to keep switching between the two amps, so I try to just go from memory (I'll be the first to admit I have an awful memory
). But last night, I thought I was experiencing a bit of what I've read so much about on this thread, particularly increased instrument separation and a bigger soundstage.
Ultimately, I just need to spend more time with it. But so far so good. Next step I believe is to give a SMPS a try. If that proves successful, then I might move forward with the monoblock idea. At a minimum, I would spring for a professionally machined and finished enclosure.
I'll try to find some time to post pics."
PEut-être que finalement le QSC RMX2450 à 500€ neuf et 200€ d'occasion est la véritable bonne affaire
Allez, je vous taquine, c'était pour tempérer un peu l'enthousiasme... mais ils doivent bons ces petits amplis, faut les essayer