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Wrench722

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Wrench,

I'm by no means an expert on amplifiers, though I have some experience with two of Adcom's older amps. I had a 2-channel 100watt amp new in the late 80's. It ran a pair of Chorus I's.

Later in 1993, I purchased an ADCOM GFA-6000 and aGTP-550 Surround Processor with the same Chorus's and added an Academy center and Heresy II's.

I must say that my experience with ADCOM and Klipsch is an earbleeding experience. I ran this setup for about 10 years before purchasing a Sunfire Theater amp. I had no idea how extremely HARSH the ADCOM amp really was. I would highly recommend the ADCOM with any other product other than a horn loaded speaker.

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The 5xx series is a good one. The price is a touch high, but not out of the ballpark.

The originals (not the series 2) were designed by Nelson Pass and highly regarded. There is some controversy on whether the series 2 is step down, or did it fix some problems.

One issue might be the noise floor. The specs show that it is not the quietest amp in the world. While adequate for most systems, the Klipsch cabinets (I believe you have K-Horns) can be brutally revealing.

I have tried the little brother (Adcom 535) and it sounded fine on my K-Horns and on my Cornwalls and noise was not an issue. The things are solidly built and some folks have tweaked them (usually caps on the power supply as a starting point). If this concerns you (I would be concerned) you may want to check that it has not been "worked on".

My brief expereince with the Adcom 535, gave me no "earbleeds", but I prefer a very clean & detailed sounding amp.

Good Luck,

-Tom

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I ran an ADCOM GFA535(2) with the ADCOM GTP400 on Khorns with no problems. Still have both of them. They don't put out the kind of power the 545 does but Khorns don't require much power. These were supposed to be about the best that ADCOM ever produced.

Re: the power.

You may be thinking of the GFA 555 which was 200 watt. The 545 was 100 watt and the 535 was 60 watt. I don't imagine there would be an appreciable difference between the 60 watt & 100 watt versions.

The K-Horns do not present a low impedance to an amp (all are capable of provideing suffient levels of current) and with their efficiency, as you point out, high wattage is not required.

-Tom

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Hi Tom,

I would leave this one to oscarsear, he seems to know about the amps. The 545 was a direct coupled amplifier and may very well have been the best that Adcom produced. You don't need to be concerned about the overall amount of power as much as the quality of the first few watts. You will probably never use more than 20-25 watts with a pair of Cornwalls or K-horns as they will be unbearable beyond that, so quality is of more importance than quantity. There is some risk with a direct coupled amplifier of damaging the speakers though. They sound most clear and have the best bass performance possible but they can pass pure DC voltage to the loudspeaker if there is DC offset in components in front of it (a tube preamp might be a prime example).

I never really liked the 555 and agree with the poster who used them for 10 years and found them to be very harsh. I even find Sunfire gear to be somewhat harsh and if that is a major improvement, you can only imagine what it was like before! Perhaps the best amp they ever produces was the GFA-1A, but if not then I would vote for the GFA-545 II. The newer GFA-5800 had a warmer sound but was even more colored and I could not get past that. They did away with the brightness but not the noise. I can't recommend any of them with the larger Klipsch speakers. They would be OK for the smaller types with lower efficiency though.

-Bill

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I used Adcom with my KHorns, amps GFA535 and 545, and 545II..preamps GFP565 and GFP710..I also had their trio, top of the line (CD) GCD750, (PRE) GFP750, and the (AMP) GFA5802..and that combo was the worst sounding components (and most expensive Adcom!) I ever had mated to my Horns! I was ready to give up hi fi! As for the rest..I had no complaints with their amps, they weren't overly bright, but I prefer tubes. As for their preamps..the 565 is still my favorite SS preamp.

Just my 2 cents.

Steve

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I ran an ADCOM GFA535(2) with the ADCOM GTP400 on Khorns with no problems. Still have both of them. They don't put out the kind of power the 545 does but Khorns don't require much power. These were supposed to be about the best that ADCOM ever produced.

I had the same combo before Juicy Music, Aragon. I'm thinking that somebody told me these two units were actually one of the last few items manufactured here in the U.S.

TW

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Wrench,

I'm by no means an expert on amplifiers, though I have some experience with two of Adcom's older amps. I had a 2-channel 100watt amp new in the late 80's. It ran a pair of Chorus I's.

Later in 1993, I purchased an ADCOM GFA-6000 and aGTP-550 Surround Processor with the same Chorus's and added an Academy center and Heresy II's.

I must say that my experience with ADCOM and Klipsch is an earbleeding experience. I ran this setup for about 10 years before purchasing a Sunfire Theater amp. I had no idea how extremely HARSH the ADCOM amp really was. I would highly recommend the ADCOM with any other product other than a horn loaded speaker.

On the other hand, I have recently changed my HT speakers, I maybe too general in rendition of ADCOM and Hornloaded speakers not being a good match.

I broke out my old ADCOM gear and hooked up my Heresy II's on the mains with a DIY Sub driven off the center channel of the GFA6000. I must say that after a few days of "Moderate" listening levels, the Heresy's sound fine. I had never tried Heresy's as mains with this amp, I always used my Chorus I's, they were harsh in the midrange. I'm finding out that the Chorus is a very "forward" speaker, similar to Lascala's, of which I loaned this ADCOM gear to a buddy who has a pair of early 70's Lascala's and they were extremely harsh.

This leads me to believe that ADCOM and Forte combo would be an even better choice, so there should be a home audition with your gear and you ultimately decide, if possible.

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