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bierfeldt
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Thoughts on ADCOM GFA 555se Power Amp and GTP 602 Preamp

Here is my situation:

I am putting together a system for my living room. The plan is for this to be a 2 channel system for music only, no video.

I have been unable to sell my Kappa 8.1 speakers for what I think is a reasonable price so I plan to keep them and get a new power source. I have been looking around and found this ADCOM deal. They have both units at a reasonable price and they will accept trade-ins on my old Carver equipment discounting the price further. This is a significant trade in - hundreds of dollars.

My question is what are people's thoughts on the Adcom equipment to power the Infinity's which are very revealing and are power hogs. This would provide about 250 watts into 6ohms. Is this a good choice? What about alternatives realizing anything under 200 watts at 6 ohms will be inadequate.

I have not decided on inputs yet other than it will have a turntable, SACD and ipod feeding it.

Allen Fant
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Adcom is a great amp on those

Adcom is a great amp on those Infinity speakers. You might want to seek out the Adcom 565 mono block amps for even more power/more current.

BillB
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+1 for Adcom

They also work forever.  You'll never have to repair them.

bierfeldt
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Done some reading and am pretty sold on the Amp

The question is, what about the pre-amp.  I have heard great things about the Amps and not so great things about the pre-amp.  I am wondering if anyone has first hand experience with it.   The website is also not terribly helpful.  One oddly specific question, does anyone know if it supports MM and MC cartridges?  I downloaded the book and it says nothing surrounding the Phone input. 

pentode
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My ca. 2001 GFP-710 preamp

My ca. 2001 GFP-710 preamp adds significant bass coloration if the tone control switch is not in the defeat position.  The remote went bad right after the warranty expired and a bad solder joint caused volume control to randomly go to full volume.  Can you imagine a more distructive problem? They want $100 for a new remote, so I'm doing without and my repair job is still holding for the motorized volume control.

The mated GFA 5500, 200 watt, power amp has one side which runs noticeably hotter and I wonder whether it exerts enough control over the dual 8" poly woofers in my Paradigms.  The woofers will sometimes bark at real low frequencies and moderately loud (~95dB) volumes.  It could be the woofers, as one was bad out of the box when new.

I realize these aren't the same as the author's planned purchase; just some feedback about my ten year old gear.

JoeE SP9
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Adcom

Adcom amps have a well deserved reputation for being able to drive just about any load in existence. The two GFA-545's I have do a stellar job driving a pair of ESL's and a sub. Older series I Adcoms are old and their electrolytic capacitors should be replaced. When they fail (they will) they'll dump DC into your speakers (very bad).

IMO the GFP-750 is the Adcom preamp to get.

If one side of any power amp is running hotter than the other there is probably a bias or DC offset problem (maybe both) with that channel.  

soulful.terrain
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Adcom
JoeE SP9 wrote:

Adcom amps have a well deserved reputation for being able to drive just about any load in existence. IMO the GFP-750 is the Adcom preamp to get.

Exactly Joe. I couldn't agree more. I have a first generation Adcom GFA -555 that I purchased new. I have had this amplifier for 23 years with absolutely NO problems except for an on/off switch that I replaced myself. Nelson Pass, of Pass Labs fame was an intregal force in designing the Adcom. That in my opinion, is a testament to Adcom. 

I now use the Adcom in a second system in my office at home. I see no reason to ever get rid of this solid performing amplifier.

I also mated that amp with the older GFP-565 that performed splendidly.

Not sure if the 750 has tone controls like my 565 did, but nevertheless a great choice IMHO.

 

Good luck,

Mark

pentode
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I'm so embarassed.  Yes, I

I'm so embarassed.  Yes, I figured the bias had drifted and was going to open the amp to check.  It's been awhile since I've gone over the system and with the recent change to my sub woofer, I listened closely to each speaker individually.  

Surprise, suprise!  No wonder one side was running noticeably warmer ... one of the speakers lost its woofers.  The bi-wired bass leads broke off from the banana plugs.  The reasons it took some months to realize the problem is that I don't sit and critically listen often enough, lately, and too much upper bass leaked from my poor sub set up, obscuring the lack of lows from the one speaker.  When I installed the new low pass filter, I finally noticed that one speaker seemed lacking.

Any suggestions to obtain a new preamp remote?  One source wanted $100.  There's almost nothing inside and the remote is cheaply made.  I could see $20 and they'd still make $15 profit.

bierfeldt
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Thank you

I very much appreciate the feedback and am going to pull the trigger on this once I get the trade in valuations back from Adcom. 

soulful.terrain
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Found one for you

 

Here's a nice Adcom GFA-555 for sale n A'gon.

 

 

http://www.audiogon.com/cgi-bin/cls.pl?ampstran&1319773879&/Adcom-555-MK-II-stereo-amp--so

 

Update: I see that this one has sold. But, if you keep looking on AudiogoN, Good used Adcom amps pop up quite frequently.

Allen Fant
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Mark,   have you bought a

Mark,

 

have you bought a pair of mono-block power amps yet? Still shopping around?

soulful.terrain
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Hey Allen
Allen Fant wrote:

Mark,

 

have you bought a pair of mono-block power amps yet? Still shopping around?

 

Hi Allen,

Not yet, still looking. I still am drawn to the Classe' CA-M400's. About 90% certain that will be my choice. I did get a chance to hook-up a Classe' CA-200 and I was impressed with its performance. I can only imagine what the monos will do for my system.

Allen Fant
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Yes Mark, Classe' power amps

Yes Mark, Classe' power amps are very sweet sounding. How is your new listening space compared to your old houses' listening space?

soulful.terrain
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needs work

Needs work. highly reflective.

commsysman
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AMPLIFIER SOUND

I don't know where you are with your system after several months, but I do have some experience with that equipment, so I thought I would chip in.

The amp I would rate a 6 on scale of 1 to 10; not bad at all, but just barely in the "high-end" range of sound quality. The preamp I would rate about a 3 or so; it's not something any audiophile would listen to for long if he has experienced some good stuff. It's not one I would recommend to anyone; very mediocre.

If you want amplification with a MUCH higher level of sound accuracy and less distortion that will put a BIG smile on your face, you should buy the NAD 375BEE and forget about Adcom. NAD offers much better sound quality at every price point than Adcom! Look at the Recommended Components in Stereophile over the years, and you will find 10 NAD products recommended for every Adcom....duhhh. Think there might be a reason for that? (as a matter of fact, I can't remember a single Adcom product in there for over 10 years...)

If you want to get to a 9 or so and REALLY smile from ear to ear, the Ayre AX7e would be a good choice, but that is $3500, and the NAD is an incredible value at only $1500. As for power...the Ayre might not have what you need, but the NAD has all of the power you can use; no question about that!! It will blow the doors off with almost any speaker made!

P.S.- There are VERY few phono stages included in preamps that are worth a damn!!

It is much better to buy a seperate dedicated phono stage.

The Musical Fidelity phono stage that Audio Advisor and Music Direct sell for about $150 is simply wonderful. I have an Audio Research phono stage (model PH-5) at one of my houses which is very good...which I paid $2000 for. I have the Musical Fidelity at the other house and it's very very close in sound quality; not much difference. It's a fantastic deal!

jojo57jojo
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Adcom GFA-555se Stereo Amplifier

You must work for Adcom. They have one of the worst history for needing repairs just Google it.

jgossman
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Hafler

Recap an old Hafler.  I can speak for it and I've compared it, while not side by side, with music I know pretty well on comparable systems.  You can't really beat it without a big check book.

bierfeldt
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Interesting thoughts

I have really dragged my feet on this and never did pull the trigger on the Adcom equipment.  I have been really indecisive on what I want to do.  Thus far I bought new speakers and no longer need a massive amount of power thus I am trying to decide between a few different items as my budget is flexible:

- Parasound Halo P3 Preamp with an A23 Power Amp

- NAD 375BEE,

- Moon 240i 

- Musical Fidelity M3i. 

For comparison at a lower price I am going to try and demo the

- Rega Brio R

- Marantz PM8004 

And for a higher price

Krell s-300i

Marantz PM-15S2B 

If I can't find something I like among those, I am just way to picky.  Plus, it gives me a range of about $900 to $2500.  I will admit, my gut has me leaning toward the Parasound equipment with a Rega Phono Stage.  This is largely because I prefer separates but who knows. I am trying to go into this with an open mind. 

jackfish
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What speakers did you end up with?

Parasound is sound.

bierfeldt
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I have an interim set and am building a set

So I bought a set of B&W M1's with a Mirage Omni Subwoofer.  Not great speakers but serviceable and they meet my wife's requirement for being small and my requirement of not sounding terrible.  She hated my Kappa's both for their size and the tinniness of the electrostatic tweeters.  I am using the M1's to tide me over until I complete my first speaker project. 

 I bought a set of Monacor Kevlar Mid-Ranges and Monacor Dome Tweeters.  I still need to get the right crossovers and am working on drawings to give to a furniture fabricator.  I don't have the right tools to produce my own speaker cabinets and I have a good friend who does fabrication.  He will make them to my specs out of MDF and apply a cherry veneer. 

Assuming the project is succesful, I will round it out buy upgrading to a nicer sub, most likely a Sunfire HRS or True.  The nice thing about that Mirage Sub is it is very musical and not very....boomy and I know that the Sunfires will deliver that nice clean, crisp bass sound I want. 

If my speaker project fails to deliver which is certainly possible, I have a list of speakers I will demo.   

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