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Thought I'd post some initial impressions of the Audiosource 7T amp that we discussed previously.I got mine in today. I ran it in for about 2 hours, then did some listening. I'm not wild about it. It's possible that it needs more break-in, so think of this as a short-term review.
For comparison I'm running my 2.7QR's bi-amped, with an Adcom GFA-5200 for the mid-treble, and the internal amplifier of my Cambridge Audio 540R receiver for the bass. I tried it with the Audiosource just for the mid-tweets, and running full-range.
First off, there is a very slight hum in the amplifier, probably something to do with the problem they had getting FCC certification. It's slight, but noticeable. Overall, I think my previous Bel Canto would kick the socks off this amp. It seems very forward and harsh. The voices just don't sound right, they are just too bright and forward. I'm not hearing any improvement in soundstage or imaging, it just doesn't sound light a high-end component to me, not like what I think a Tripath should sound like.
The Adcom amp I have runs VERY hot, and it's much smoother than the GFA-5235 that I also have, so it might be a tough comparison.
It's possible I may just need to let it break in a little more, we'll see.
Follow Ups:
How do you bi-amp the 2.7's? Take out the jumper, and run additional speaker wires? Two amps, 4 speaker wires per speaker?
Although I don't know the answer to this question, you also might want to confirm that the 7t doesn't invert polarity. I know some tripath implementations do, and that would definitely cause trouble if you are biamping! Maybe try swapping speaker cable polarity for both channels and see if that helps.
I just got mine and I have to say it is a bit noisy too -- some hum and hiss. I don't find mine harsh or objectionable, however, but it is a bit washed-out, and the top end gets glassy at higher levels. I'm not using it very hard -- much less than what would be needed for Maggies (haven't passed 0.63W on the dial, and that was pretty loud for my system). It is less revealing than my usual tube amps, less resolving, and lacks the mid-bass / mid-range. May be good for subs, but it seems to have some potential for improvement.
Overall, for the price, I'm still quite happy with it.
Just to comment on powering your 2.7's because I also have a pair. Dump the Adcom.When I bought the 2.7's, I first powered them with an Adcom GFA-5500. I loved the bass slam the amp gave, but it was really harsh in the highs. I ended up sending the Adcom to Stan Warren to have him modify it. In the meantime, I bought a Sunfire Stereo Amp (the standard 300w/ch one). It was so much smoother than the Adcom, it was unreal. The only thing the Adcom did better was the last bit of bass slam. When I got the Adcom back from Stan Warren it was better, but still not near the Sunfire so it was sold.
I think you would be shocked at how much better the 2.7's would sound with a better amp behind them. You can find some great amps for under $1000 used, things like the Hafler 9500 series, Sunfire Stereo Amp, Conrad Johnson MF200, etc..
Don't be too hasty. Adcom has some good amps in their lineup. I've had some that I didn't like, and some that I did. Most Adcom amps are harsh, but for some reason this little guy isn't. This one also runs a LOT hotter than many other Adcom amps that I've seen. From what I understand, if the Adcom runs hot, then it's probably a design that's closer to the original Nelson Pass design.In fact this amp is quite laid back and mellow, much more so than any comparable Adcom or other amp in it's range that I've heard.
Since the Audiosource didn't work out. I'm going to hold off and get some ICEPower monoblocks when I get around to it. It looks like B&O is selling turn-key modules now, and they are selling them cheap these days. Looks like I can get a killer 400 watt ICEPower amp for under $1k.
I'd be interested in giving them a try.Or did you mean that manufacturers can get them and are now offering less expensive amps. What killer 400w ICEPower amp are you referring to for under $1k?
Initiative comes to those who wait.
- Alex, "A Clockwork Orange"
Yeah, they are only available to manufacturers. But B&O has a version of the module with a built-in power supply, so manufacturers are literally just wiring them to the speaker connectors, inputs, and IEC power socket, that's it.The new Bel Canto amps use it, as do these:
http://murano-audio.com/
http://www.d-sonic.net/
Thanks for the links, the Murano unit looks very interesting and well-built. I found that the US distributor is selling the P-1000s monoblocks on Ebay for $899 each plus shipping. Seems like a good value, but I'd be interested to learn how much the P-500s costs since I don't really need all that power.Something else to consider ... according to the ICEPower 1000ASP datasheet, their amp modules have an 8k ohm input impedance. This could be problematic for some preamps/sources if they are used as is with no input buffer or transformer. The D-Sonic amps offer a input buffer upgrade for $65 to address this issue (though no details are give about its design). The Murano amps include a Lundahl input transformer to raise the input impedance to 40K ohm, which I believe is similar to the approach that Jeff Rowland takes.
And one last thing to keep an eye on, there are several different amps with ICEPower modules offering around 100wpc (8 ohm). However, there are two different modules that offer this output... the 250ASP and the 200ASC (which D-Sonic uses in their 200S amp). Supposedly the 250ASP has a more robust power supply and may be a better sounding unit. I do know that PS Audio uses the 250ASP in their GCC/GCA-100 amps, and the 200ASC in their lower-priced Trio amps.
Initiative comes to those who wait.
- Alex, "A Clockwork Orange"
I should elaborate, my Adcom running hot seems to indicate a high-bias voltage, so it's probably running closer to class-A than a cooler running Adcom. I've heard the cooler running Adcoms and didn't like them, but this little 5200 is nice.
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