Author Topic: Adcom GFA-555, 545, etc.  (Read 29770 times)

BrentoRudra

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Adcom GFA-555, 545, etc.
« on: July 11, 2011, 08:17:10 AM »
Once again adventures with Mr. Zen. Evidently he had a hand in the Adcom designs, beginning with the GFA-555.

I have an old GFA-535 which somebody modded and at one point was my reference with a smalller system. I used Kef Q-80 speakers, an Audiolab preamp (I forget which), Rotel RCD-855 disc player. Contentment. I knew there was MORE, and more is always better, but when I was rational I reallly was content with this rig. It had the same kind of synergy as my current Conrad Johnson/Rotel RB 991 amp/Vandersteen 2ce. Lookng at it, I realize I've simply made a jump over the years to a quality tube preamp, the always reliabe Rotel amps of the 90s, and of course Vandersteen speakers which, for me, are the end of the line.

Even so. I'm seriously looking at Pass designs within my range (Adcom, Nakamichi Stasis) beause there is a certain moreness of what I like to them.

Any thoughts. For example the Adcom GFA-555 is straight out Mr. Zen. So are the Nakamichi Stasis amps. The 555 and the Nak PA-7 both have the 200 watts of the Rotel, giving me the headroom I like, and that additional something that Pass adds to things.

Then there is the compromise of the GFA-545, which is up in two places for $200. I've heard good things about this one, too, and it's in my comfort zone.

Say, tell, share. Show me a rose or leave me alone.

Offline allenzachary

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Re: Adcom GFA-555, 545, etc.
« Reply #1 on: July 11, 2011, 10:04:09 AM »
This is right up my alley: upper mid-fi from the late '80's.

I managed a hi-fi store in New Jersey during the late '80's and Adcom was one of our bread-and -butter lines.  I am a big fan of the GFA-555 as it is a truly good sounding amp at a very moderate price.  Our original selling price for the three Adcom amps, the 535, 545 and 555 was $349, $499 and $749 respectively.

Of the three, I liked the 545 least.  They all had the same character and sound quality, but I felt that the 545 offered the least value.  I suggested to customers that they either stay with the 60WPC 535 or jump up to the 200WPC 555.

I have always been a fan of Pass designs.  I love the Threshold and Pass lines, high dollar, but delicious.

Yet, when it came time to buy my own upper mid-fi amp, instead of Adcom, I chose a B&K ST202 plus, which I still use.  B&K made three amps as well and they competed directly for the same business as Adcom.  Their ST140 was rated at 105WPC and sold for $499 and frankly kicked the 545's butt.  They also made two versions of the ST202, with one being called the ST202plus. Both ST202's sold for around $700.  According to B&K, the 202 was designed to drive lower impedance speakers, like 4 ohm Infinity or basic planar type speakers.  The 202plus was designed for speakers with 8 ohm impedance or higher.  I own B&W 802's which are a nice comfortable 8 ohms, so I chose the 202plus.

Comparing the two, I felt that the B&K had slightly less grain and a little more open sound. 

Being that the 2C's are 8 ohms and require 40-160WPC you may want to consider a B&K ST140.  it's a gem of an amp and a used one can be had for around $200.  I imagine the 2Ce's requirements are similar.

http://cgi.ebay.com/B-K-COMPONENTS-ST-140-POWER-AMPLIFIER-TORIDIAL-VERSION-/220774236663?pt=LH_DefaultDomain_0&hash=item33672b81f7

BrentoRudra

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Re: Adcom GFA-555, 545, etc.
« Reply #2 on: July 11, 2011, 11:34:29 AM »
OK. Here's something I always forget to address. I listent to full orchestra classical music for the most part:Beethoven (modern orchestra), Wagner, Bruckner, Mahler ... but also chamber Jazz like Bill Evans, Miles Davis, etc., big band Duke Ellington. Not much rock. This is an important consideration. So. What is your musical taste?

BrentoRudra

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Re: Adcom GFA-555, 545, etc.
« Reply #3 on: July 11, 2011, 04:19:08 PM »
Well, now I see we've got the 202Plus up, which I put the first bid on, marked the others, including the one you referred me to. What is the "Toroidal Version"? Looks like nothing but big fat transformers inside!

Offline allenzachary

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Re: Adcom GFA-555, 545, etc.
« Reply #4 on: July 11, 2011, 05:07:30 PM »
I listen to a variety of musical styles, at this point centered around jazz.  I enjoy classical and symphonic music, but it is not as well represented in my collection as I'd want it to be.  Although the larger version of my speakers were a standard monitor in classical recording studios.

B&K amps featured toroidal power supplies. The toroid structure increases efficiency (so your amp draws less power from the wall) and tend to run cooler since they have more surface area.  They also act as a barrier to noise and interference.  A toroidal power supply is indeed a big fat transformer.

Offline allenzachary

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Re: Adcom GFA-555, 545, etc.
« Reply #5 on: July 11, 2011, 05:15:31 PM »
B&K site: http://www.bkcomp.com/

Nice review of the ST 202, has a comparison to Adcom: http://www0.epinions.com/content_261998349956

Offline richidoo

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Re: Adcom GFA-555, 545, etc.
« Reply #6 on: July 11, 2011, 05:27:06 PM »
Thanks for sharing your experience and knowledge Allen!

Impedance of the Vandy 2ce is extremely benign, but sensitivity is very low at 84dB. 100-200W is about right for classical peaks. The peaks will make you cringe if there is not enough power and the amp clips. This happens on bass drum thwacks and flute spikes, as well as sustained, full orchestra fortississimos. If you weren't on a budget I'd suggest 500W so that impedance dip in the bass can be fed properly at high volumes.


http://www.stereophile.com/content/vandersteen-2ce-signature-ii-loudspeaker-measurements

The Rotel 991 measurements:
http://www.stereophile.com/content/rotel-rb-991-power-amplifier-measurements
They have enough power. What about its sound do you not like?

Offline allenzachary

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Re: Adcom GFA-555, 545, etc.
« Reply #7 on: July 11, 2011, 06:57:19 PM »
My experience with Rotel amps is that they tend to sound a bit thin and "Japanese," for lack of a better word. Nelson Pass designs lean more towards rich and fluid. Both Adcom and B&K amps sound better to me than what I've heard from Rotel.

I can't remember the exact efficiency of my 802's, but 84db sounds right.  They are not terribly efficient, but the ST202plus drives them very well.  They get surprisingly loud, although they never feel that way.  They are always smooth and under control with the amp.  The surprise comes when you try to speak to someone while they are playing and you can't hear yourself because it is so loud. There will be no problem driving the VanderSteens with an ST202plus...or even the ST140.

The good news too, Brent, is that if you don't like the the B&K amp, you can easily resell it.  There is a clear demand for them and they retain their value pretty well, considering they are over twenty years old.

BrentoRudra

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Re: Adcom GFA-555, 545, etc.
« Reply #8 on: July 12, 2011, 04:00:23 PM »
Got my eye on two of them over at eBay.

My DIY friend warns me about the possible want of schematics and service manuals. I haven't looked into this. Important for people who do mods. And I am sure a B&K would want upgrades. Maybe not.

The Rotel amp suffers from none of what you are calling Japanese thinness. I fnd it is a little cooler than I want. Nice soundstage, and with the 200 watts there is plenty of headroom for the Vandersteens. These do require over 100 watts to really come into bloom.


BrentoRudra

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Re: Adcom GFA-555, 545, etc.
« Reply #9 on: July 12, 2011, 04:11:14 PM »
If you weren't on a budget I'd suggest 500W so that impedance dip in the bass can be fed properly at high volumes.

What amp runs at 500 W? Or is that a model number? Well, actually i know there are many amps that run at that but ... well, I have a heating system. My whole reason for pursuing ss at all was to compensate for summer heat, but then I began to like the fuller sound of ss enriched by tube colorations. The Conrad Johnson-Rotel-Vandersteen became reference after a while. I find I'm only using my tubes to audition more sensitive speakers during the colder months, trying to decide which ones I'm finally gonna go with finally. The best I've heard with my tube gear have been open baffles of a specific geometry that my wife won't allow me to keep. They are rather intrusive but I really have NEVER heard anything so wonderful and versatile as these. I'll find the link if anybody reading this thread is interested. They are fine with all types of music and will fill a large room using 15 watts. BUT. Since i can't have perfection, I'll stick with what I've got, can afford to upgrade, can keep and remain married, etc.

Offline allenzachary

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Re: Adcom GFA-555, 545, etc.
« Reply #10 on: July 12, 2011, 04:55:10 PM »
I haven't heard all of the Rotel amps.  The ones that I did get to hear didn't impress me as much as the American budget amps like Adcom, B&K, Hafler, Acurus or even Sumo.  The irony is that B&W, makers of my beloved speakers, are part of the same company that makes and sells Rotel. 

If you are planning on doing the mods yourself, the schematics and service manuals become important.  B&K has a very good reputation for customer service and sold a awful lot of ST140's ST202's and Pluses, especially for a company as small as they are. They certainly understand that there are many units out there that may need service or a modification. I bet that you could still get the info you need form them.

If you want a professional modification, there are several companies who do mods on Adcom, B&K and the like.  One of the companies I used to deal with was Musical Concepts in Missouri.  They took good amps and made them great.  They won't need service manuals to do your mod.  Reach them at www.musicaldesign.com.

BrentoRudra

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Re: Adcom GFA-555, 545, etc.
« Reply #11 on: July 12, 2011, 05:04:59 PM »
Thanks, I'll look them up. Seems I've heard the name.

BrentoRudra

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Re: Adcom GFA-555, 545, etc.
« Reply #12 on: July 12, 2011, 06:11:21 PM »
So I go there only to be apprised of the news of the GFA-555SE, a brand NEW Adcom classic revamp which they are offering mods for. I think I would like to hear something NEW for a change that both fits my budget and my tates. That way I will have a fairly new preamp, new amp and venerable, reliable speakers, all doing what I want in a grand synergy with which I can be happy for at least a year!

Offline tmazz

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Re: Adcom GFA-555, 545, etc.
« Reply #13 on: July 12, 2011, 08:50:04 PM »
If you weren't on a budget I'd suggest 500W so that impedance dip in the bass can be fed properly at high volumes.

What amp runs at 500 W? Or is that a model number? Well, actually i know there are many amps that run at that but ... well, I have a heating system. My whole reason for pursuing ss at all was to compensate for summer heat, but then I began to like the fuller sound of ss enriched by tube colorations. The Conrad Johnson-Rotel-Vandersteen became reference after a while. I find I'm only using my tubes to audition more sensitive speakers during the colder months, trying to decide which ones I'm finally gonna go with finally. The best I've heard with my tube gear have been open baffles of a specific geometry that my wife won't allow me to keep. They are rather intrusive but I really have NEVER heard anything so wonderful and versatile as these. I'll find the link if anybody reading this thread is interested. They are fine with all types of music and will fill a large room using 15 watts. BUT. Since i can't have perfection, I'll stick with what I've got, can afford to upgrade, can keep and remain married, etc.

Don 'y know what kind of budget you are looking at, but I can tell you that I have owned two amps that put out 500w into lower impedance (4 ohms). The Classe twenty-five and the Moscode 600. Both can be had for somewhere in the area of $1K, plus or minus a little bit. I am sure either one would give you the power you need to drive the bass dip. The Moscode is a hybrid and as such puts out a bit more heat, but also has more of a classic tube flavor to it. I did have some trouble running it for long times during the peak summer heat as my mancave is not air conditioned. I was surprised how much cooler the Classe runs, I can run it all summer long without a real problem. (FYI - My next door neighbor had Classe electronics driving a pair of Vandy 2 series speakers and I always thought it was a good match.) And I didn't expect that mush of a difference in that regard since the A/C input specs are very similar. Feel free to shoot me a PM if you have any specific questions about the amps.
Remember, it's all about the music........

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Offline allenzachary

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Re: Adcom GFA-555, 545, etc.
« Reply #14 on: July 12, 2011, 09:12:43 PM »
The GFA555se retails for $1250 and you can get it for a little over a grand.  That's a pretty big leap from a $350 used amp.  The budget you discussed originally was around $200.  

I understand the attractiveness of a new amp, especially one modeled off a neo-classic.  Still, if you have a thousand dollars or more to throw at an amp, I'm not sure that the Adcom GFA555se is the best choice.  Additionally, the company who makes Adcom is a far cry from the friendly folks who worked out of a humble building in New Brunswick, NJ for old Newt and his son Alec Chanin. It is now owned by a company in Thailand, after having been sold by Emerson Radio.  How Emerson got hold of the proud name, I don't know.

Can you buy used?

Threshold --a company owned by Pass-- S300.  Another 20+ year old amp, but bulletproof.Transparent an liquid. Incredibly fast. http://cgi.ebay.com/THRESHOLD-S-300-Stasis-300-Watt-Power-Amplier-Amp-EXC-/160615974236?pt=LH_DefaultDomain_0&hash=item256575455c Buy it now for under $900.

McCormack DNA1- From the designer of the famous Line Drive PreAmp-- Sweet piece Starting (and probably finishing) at $650.http://cgi.ebay.com/McCormack-PowerDrive-DNA-1-Amplifier-/110714050479?pt=LH_DefaultDomain_0&hash=item19c71257afHere's the Stereophile review: http://www.stereophile.com/solidpoweramps/520

And that was only with a few minutes of goofing around on ebay. I implore you to take your time and explore. There is an abundance of high quality audio out there, if you give it a chance.  

Although I doubt you need the kind of power that Richidoo is suggesting (yet I go against Rich's opinion with great trepidation) either of the amps tmazz is suggesting are good choices too. 


Please take your time and don;t just dive in to that Adcom piece.

Oh, and by the way, I use an Adcom phono cartridge on my TT.  I have for years.  It's wonderful.