Adcom Gfa-555

Lowell_M

dkg999 is going to stop over at my place next week with a couple of Outlaw monoblocks to demo on my RTi70's. I am very much looking forward to the experience to see if my ears hear a difference between my H/K 635 and the Outlaws. At this point I am doubting (without much reason I guess) that I will hear a difference, so want to step into external amps with little commitment.

I've been drawn to the Outlaws as a bang-for-the-buck entry into separate amplification since there are some pretty decent used deals out there.

But.. I have seen ADCOM GFA-555's on ebay and audiogon quite frequently for around $350. That seems like a low price for 200wpcx2. Is there something wrong with this particular amp? I'm not sure what they cost new, Is there some reason that they don't hold their value?

If I determine that external amplification is for me....shoudl I stay away from the ADCOM GFA-555, or is it a decent amp? Am I missing something?

Sami

IMO the 555 is an overkill for the 70's, you should be more than fine with even 545. Also other great used options you could try out from the flea market, don't be blinded by the WPC numbers (just a friendly advice that many in this forum will surely agree with).

Lowell_M

Sami wrote:

IMO the 555 is an overkill for the 70's, you should be more than fine with even 545. Also other great used options you could try out from the flea market, don't be blinded by the WPC numbers (just a friendly advice that many in this forum will surely agree with).

I've been going with Cfrizz's 200 wpc min rule. Plus, the Outlaw's are 200 wpc and I am demoing those next week and thought the 555 would be a close comparison. I still don't really know what I want to do, but I think listening next week will tell me a lot.

Really, the biggest question of my post is.... Is the GFA-555 a nice amp? They seem to go cheaper than other 200 wpc amps. (Watts being the only point of comparison I really have without listening)

zombie boy 2000

+1 for Sami... don't get too caught up in wpc. My SM-70 Pro is rated at 25wpc and is more than adequate for my speakers (which are rated at 4 Ohms and 87 sensitivity). Quality is always something to take into consideration, just as much as quantity...

That being said, more than a few people on this forum sing nothing but praises for the Adcom 555II (esp at its pricepoint). If you can snag one at $300, which is not unreasonable, give it a spin.

Lowell_M

zombie boy 2000 wrote:

+1 for Sami... don't get too caught up in wpc. My SM-70 Pro is rated at 25wpc and is more than adequate for my speakers (which are rated at 4 Ohms and 87 sensitivity). Quality is always something to take into consideration, just as much as quantity...

That being said, more than a few people on this forum sing nothing but praises for the Adcom 555II (esp at its pricepoint). If you can snag one at $300, which is not unreasonable, give it a spin.

Cool, thanks. The way I look at it...might as well plan ahead a little bit. never know what I get the itch to upgrade to LSi's.

billbillw

Adcoms sell cheap because they were never that expensive to start with, and there are so damn many of them out there for sale at any given time.
For the price, they are hard to beat.

Lowell_M

Are they comparable to Outlaw, then?

Willow

FWIW I'm in the process if buying the outlaw mono. Got one on the way...and then will have to uy my other 2. I too am using a HK the 335 mond you, but I can't wait to have them hooked up. I have read nothing but good reviews on them. I like what they offer, small,lots of power. Just what my wife ordered....;)

DarqueKnight

a_mattison wrote:

But.. I have seen ADCOM GFA-555's on ebay and audiogon quite frequently for around $350. That seems like a low price for 200wpcx2. Is there something wrong with this particular amp? I'm not sure what they cost new, Is there some reason that they don't hold their value?

They hold their value very well. No audio component is perfect, but no, there is nothing "wrong" with the GFA-555 in the sense of a functional defect or design flaw.

The original GFA-555 was manufactured from 1985-1991 and had an MSRP of $800. The current Orion Bluebook value is $399. This means that the "youngest" GFA-555 you will find on the used market will be at least 15 years old. A 15 year old (or more) amp selling for 40% or more of its original retail value is pretty good.

The GFA-555 was replaced by the improved GFA-555 Mk II in 1991 which was manufactured until 1997. The Mk II version was more stable into low impedance loads and had a smoother midrange and top end. The Mk II version had an MSRP of $900 and has a current Orion Bluebook value of $405. The "youngest" GFA-555 Mk II you will find on the used market will be at least 9 years old. Again, A 9 year old (or more) amp selling for 40% or more of its original retail value is pretty good.

At its market introduction, the GFA-555 was widely applauded for its high performance to price value and still is today, 21 years later. I have a GFA-555 Mk II in my system at work and thoroughly enjoy it.

Lowell_M

DK, Thank you! I had no idea how old these amps were. I was looking for exaclty what you just said. What can go wrong with an older amp? Are they pretty bullet proof, or is there a common repair that needs performed?

Ok.... If you had the choice between 2 Outlaw monoblocks used for $500ish or a $400 Adcom 555 mkII, which would you choose? (for sonic performance...not one unit vs. two)

DarqueKnight

Typically, with older amps, the power supply filter capacitors (electrolytic type) can begin to "dry out" after about 15 years. The electrolytic caps on the input driver board can also dry out after a similar amount of time. The capacitor drying out becomes apparent by the sound of hum in the output and/or hum coming from inside the amp case. This drying out does not always occur. It depends on the quality of the caps to begin with and how the amp has been used (or abused). If the caps do need to be replaced, it is not a difficult or expensive repair.

The GFA-555/555 Mk II, as are most Adcom amps, are considered to be well-made, virtually bulletproof designs that have stood the test of time.

I have no personal experience with Outlaw amps, so I cannot say which I would prefer. I do know that Outlaw amps are well regarded here on the forum and have received favorable reviews in the audio press. There are lots of web references and reviews of both Adcom and Outlaw.

cfrizz

AMattison I see that you and others are getting confused because I’m saying one thing about amplifier power & the guys are saying something else. It’s because we have 2 completely different mindsets when it comes to this hobby!

What I have noticed is the guys are CONSTANTLY upgrading in small incremental steps. They might start out with a 50wpc amp, then go to 100, then 150, then 200 etc. Each time singing its praises until they go up another notch!

This enables them to scratch their audio upgraditis itch & try out new things while spending less money at the time.

I am at the total opposite end of the spectrum! I want to make the best & biggest purchase that I can the first time around & keep it for years! The reason being, I have neither the space, patience or most importantly money to operate in that manner.

It’s also wasteful as far as I’m concerned. If they totaled up the amount of money they have spent doing little upgrades, they probably have purchased their systems 10 x over! But that’s what they like so have at it.

I’ve been serious about my audio equipment for the last 25 yrs. or so, and I have learned a lot & have tried to pass that knowledge on consistently. But it usually goes against the grain & view point for the majority of the guys here whose info can change for any given situation.

I have always been lucky enough to get good equipment the first time around. I started out 16 yrs ago with separates by Rotel. A 50wpc amplifier & a stereo prepro. The amp ran my then & now Polk RTA-8T’s. They sounded great. About 4 yrs ago I ran out of inputs on the back of my prepro & decided to enter the HT market. By this time I was living on my own & couldn’t afford another Rotel, so I went to Tweeter & got a Denon receiver with the proviso that it should at least be the equivalent of my Rotel equipment. That got me the Denon 3802 & I couldn’t tell a difference between its 110wpc to my 50wpc separate amplifier, so I was happy. Now anyone that dares to tell me that my Rotel amp is not a good quality amp I’m going to call a liar! All things being equal I was probably getting about 50wpc from the Denon rather than 110. At this time I was still 2 channel.

I slowly got more speakers, then in 2004 I found Club Polk! I slowly read & soaked up as much info as I could get. (that was in plain english) And the guys were more than willing to help me improve my system & I have learned a lot.

I started thinking about getting the LSI’s & I asked if my receiver could handle it & I was soundly told NO! They said I should get a high current separate amplifier & plug it into my Denon I equate high current with high wpc! I bought a 205wpc Parasound 2 channel amp & my Polk SPEAKERS CAME ALIVE! Now the amplifier recommendation for them is I think, 30-250wpc I then realized that they sounded good with 50wpc but they sound OUTSTANDING with 205wpc. You just don’t know how different they sound until you hear it for yourself.

I also believe in planning for the future, that is why I went with such a high powered amp. And knowing that I will never have to worry about hurting any of my equipment due to insufficient power is a relief.

I was skeptical in the beginning about needing so much power, but in the 2 yrs I have been on this club has shown me that MORE is better because I’ve seen more “HELP I’ve blown my tweeter or my receiver went into protect mode WHY??? threads than you can shake a stick at!

So after seeing all of those threads & knowing for myself what that power can do for mine or ANYONES speakers, I have settled on 200wpc as the minimum wattage for all 8/4ohm tower speakers & also for any bookshelves that are 4ohm.

So if it sounds contradictory to what everyone else is saying, they have only themselves to blame! I’ve watched, listened & learned the lessons that these guys like learning over & over & over again in search of the perfect sound or just to satisfy their upgrade itch!

Cathy

Jockos

I currently have a GFA-545, GFA 5500 from adcom. Both are Great. I previously had a GFA 555II. The GFA 555II was excellent and I regret selling it. I did consider the Outlaw monos but I wondered how they got enough power supply capacitance in such a small chassis so I ended up with adcoms.

Lowell_M

I'm with you Cathy! Bring on the power!!!! Never buy the V6 Camaro...go for the V8!! (if they still made Camaros I guess, but you get the analogy)

Thursday the 2nd is when I am demoing the Outlaws, so I will let you know how it goes.

Systems

Great post Cathy,It is better to have too much power than not enough.A large amp with a big power supply will be lofing along most of the time but when needed it will have greater headroom and sound less stressed on demanding material(.eg. War of the Worlds) than the amp section in a typical reciever.Depending on the speakers even a 200 watt amp can be driven into clipping by some of the more dynamic soundtracks.Also a smaller amp is more likely to be driven into hard clipping(hi distortion) which can damage tweeters.

cfrizz

Thanks AM & GV! I appreciate it!:) I am just trying to stay consistent & give people good advice that will cost them more up front but a whole lot less down the road since they won't have to continually upgrade the same peice of equipment!

And the way I see it, those who are married will have less squawking to listen to when upgrade time does come. At least you won't hear:

(wife) "Didn't you just get an amplifier 6 months ago??? Why do you want another one?"

(you) "Well that one doesn't have enough power"

(wife) "You should have gotten the right powered one in the first place, now you're spending money twice for the same kind of equipment!"

:eek:

VR3

Yeah....

I maxed out a 545 on the RTi70 on several ocasions...

*cough*

cfrizz

LOL! Like it a little loud do ya Sid? How's your hearing doing?:eek:

Vr3MxStyler2k3 wrote:

Yeah....

I maxed out a 545 on the RTi70 on several ocasions...

*cough*

cfrizz

Have they stopped making Camaros???:eek: :eek: I love the look of that car!!!

And you gave the perfect analogy to the point I was trying to make!

a_mattison wrote:

I'm with you Cathy! Bring on the power!!!! Never buy the V6 Camaro...go for the V8!! (if they still made Camaros I guess, but you get the analogy)

Thursday the 2nd is when I am demoing the Outlaws, so I will let you know how it goes.

VR3

cfrizz wrote:

LOL! Like it a little loud do ya Sid? How's your hearing doing?:eek:

Whats that?? You need to type louder!

heiney9

Vr3MxStyler2k3 wrote:

Yeah....

I maxed out a 545 on the RTi70 on several ocasions...

*cough*

Find that hard to believe. Perhaps at insane levels. I have yet to find the max level of my 545, well just as the clipping light start a faint flicker, and it's effing loud at that point, louder than I am somfortable with. Not saying the 545 is the ****, but that little effer amazes me sometimes.

I'll tell you what, Doug and I have been meaning to set up a meet and just never get around to it. If we can coordinate the 3 of us getting together I'll pack up my 545 and bring it over when Doug brings the Outlaws, that way atleast you can hear what an Adcom sounds like. Not saying this will work out as my schedule is crazy sometimes and I know since Doug splits his time between 2 places his is even crazier, but we'll see what happens. What are you using as a pre? You're HK?

Just to add what DK stated. The original GFA series was in fact designed by Nelson Pass and was pretty much the same as the regular production model of series I amps. Adcom made some cost cutting measures which they felt very minimally affected the performance, but the circuit design was essentially the same.

The series II amps were different in a few ways and had very little extra input from Nelson Pass. Series II amps are capacitor coupled meaning rather than using a differential pair of tranny's to "couple" the front end (input) to the backend (output) they used capacitors. This can affect the sound depending on the type and quality of the coupling cap and this is the most likely culpret in series II amps sounding flat with age (as the caps can wear out). They also used a servo control called a DC Servo to control/adjust any DC offset current at the output. You can minimize and virtually eliminate any DC offset by using high quality matched pairs of tranny's however this can be expensive and when using bi-polars the DC offset can flucuate with variances in operating temp.. What DC servo's allow for is the correction of DC offset until the output section reaches thermal stability and it also helps control DC offset as the tranny's and coupling caps age. As a whole a good thing, but another stage in the circuit and matching pairs of high quality trannies can reduce DC offset to a point where it has no audible impact on the sound.

Personally I prefer the series I amps because they are direct coupled, with a more simplistic design (less parts). All Adcoms have no current limiting circuits and have no output coils. I love the high quality simplistic design of the Adcoms. Simple is better, IMO. Are there comprable amps out there? Sure, but they are a classic and you could do much worse for more money.

The reason they are so inexpensive is because of the low original MSRP and because the GFA-555 was the single best selling amp in history so there are many many examples out there to choose from.

One last thing here are a few links to the original review by Stereophile. Pretty high praise at the time.

http://www.stereophile.com/solidpoweramps/678/

http://stereos.about.com/od/amplifierreviews/fr/Adcom_GFA555.htm

H9

cfrizz

Snort, WAAAAAAAAAA!!!!:D

CAN YOU HEAR THIS OR ARE YOU TOTALLY DEEF!;)

Vr3MxStyler2k3 wrote:

Whats that?? You need to type louder!

VR3

Hehe, loud and clear Cfrizz!

My room is... amazingly absorbant...

It absorbs bass, sound, yada yada like theres no tommorow.

Just to give you an example, in my room - 10.5x10.5x8 - you would think a PCi subwoofer would demolish it. However, my subwoofer is set to 12 oclock on the volume knob, flat on the preamp and 65hz on the crossover and thats about average listening levels, maybe a tad hot...

cfrizz

It must be otherwise your mother would have killed you by now! LOL!

Sami

Cathy, why not buy a 500WPC pro-amp then if the power is the only thing that matters?

I currently have a 100WPC Aragon 2004 hooked up into a set of LSi15's. I guess that meets your criteria since it doubles the watts in 4ohm. But anyway, I thought what matters is how good it sounds, not how much current it can output. The car comparison isn't really apples to apples but would I rather get a car that has less horsepower and handles beautifully or a V8 Camaro that goes fast on a straight line? I'll take the first please...

cheddar

I think Cathy's just trying to be practical is all. Get enough power on all your channels and avoid a lot of incremental upgrades in the future. I get that.

But still, you know us guys, if we can get the 2 seater sports car that can get to 200 mph or the 5 seater sedan with ample freeway legal power for the same price, you know what we're more likely to do.

Lowell_M

Sami wrote:

Cathy, why not buy a 500WPC pro-amp then if the power is the only thing that matters?

I currently have a 100WPC Aragon 2004 hooked up into a set of LSi15's. I guess that meets your criteria since it doubles the watts in 4ohm. But anyway, I thought what matters is how good it sounds, not how much current it can output. The car comparison isn't really apples to apples but would I rather get a car that has less horsepower and handles beautifully or a V8 Camaro that goes fast on a straight line? I'll take the first please...

You da man.... We are both being simplistic is all, I don't know much about the differences in amps and was looking for some advice. If you're not going to provide any...go away. .....Wanna talk about cars? ...ever taken an F-body Camaro around an open road course? Very balance car with plenty of torque to pull it out of a corner and pass the Nos-overstressed, blue smoke coming out the back rice grinders that are a lap behind. A 97 Camaro is not a straight line-only car by any means...

You either drive like a grandma or are way too proud of your overstressed Honda Civic. My Nissan Altima handles great, the RX300 handles pretty well for an SUV too, but DAMN do I miss the power.

cfrizz

Until I joined this club I didn't know what pro-amps were! And since they are not sold in HOME audio stores I wouldn't think of using one for my HOME equipment!:D

I'm also not a car person, so I don't really know the difference between V6 & V8 or what it even means. But I assume that the V8 is more powerful than the V6!

Sami wrote:

Cathy, why not buy a 500WPC pro-amp then if the power is the only thing that matters?

I currently have a 100WPC Aragon 2004 hooked up into a set of LSi15's. I guess that meets your criteria since it doubles the watts in 4ohm. But anyway, I thought what matters is how good it sounds, not how much current it can output. The car comparison isn't really apples to apples but would I rather get a car that has less horsepower and handles beautifully or a V8 Camaro that goes fast on a straight line? I'll take the first please...

Sami

cfrizz wrote:

Until I joined this club I didn't know what pro-amps were! And since they are not sold in HOME audio stores I wouldn't think of using one for my HOME equipment!:D

But the point of course was, more power doesn't equal better sound. Otherwise I'd still be listening to the Samson S1000 I had for a while.

cfrizz wrote:

I'm also not a car person, so I don't really know the difference between V6 & V8 or what it even means. But I assume that the V8 is more powerful than the V6!

Yes, but, but...I understand the power within the same amps, and same car chassis. But lets take a 200WPC Adcom and a 100WPC McIntosh or Krell. Which would you have?

Systems

I took it she was comparing the Denon reciever to the Parasound amp not a cheap pro unit.
I agree though I,am not giving up my 120 wpc Bryston for a 250 wpc Behringer any time soon.

Sami

a_mattison wrote:

You da man.... We are both being simplistic is all, I don't know much about the differences in amps and was looking for some advice. If you're not going to provide any...

I did. Don't look at the power numbers, look at the amp. Lots of amps out there that will sound very good with low power rating, and quite honestly have much better power supply (that is what matters) than some of the higher rated units

a_mattison wrote:

You either drive like a grandma or are way too proud of your overstressed Honda Civic.

If you say so, then so be it.

a_mattison wrote:

My Nissan Altima handles great

If you say Altima handles great then I do understand if you think Camaro is not a straight line machine. I have a Altima SE-R (2005) as a daily driver. It's not bad but I wouldn't call its handling great.