timber matched amps vs timber matched speakers [Archive] - Audio & Video Forums


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09-04-2004, 08:27 PM
This may be a dumb question, i know the value of having a timber matched speaker system. I currently own a Klipsch RF-7 speaker system. All 7 of my speakers are timber matched. I currently power the speakers with an Onkyo TX-SR-900 reciever. I have been looking at an Adcom amps on ebay. i want to drive the fronts with more power (200 watts a channel vs 110) for more dynamics and a cleaner punchier sound at lower volume levels when im listening to 2 channel sources.
if i do this will the fronts overpower the rest of the system or sound tonally different when im in surround?

ive been looking at two different amps one is the GFA-555 the other is the GFA 5503.

This Guy
09-04-2004, 08:47 PM
The fronts won't overpower the system only if you calibrate your system with an spl meter and make sure every speaker is producing the same amount of sound as all the others. And no they won't sound much different, if at all. It hasn't even been proven that different SS amplifiers sound differerent than each other (I believe it's possible, but the chnages would be subtle).

09-05-2004, 12:30 AM

Whether or not similarly constructed amplifiers have signature sounds which can be differentiated from one another is source of much debate and definitely a topic of discussion for the "Audio Lab" board. But that these supposed differences are due to a property of an amp known as "timbre" is not. Timbre can only come from an object which has acoustic properties; that is, an object which vibrates or resonates or otherwise physically energizes the atmosphere around it to create sound waves. Unless an amplifier is struck by an object, it does no such thing, nor is it intended to. An amp doesn't produce sound, it accepts an input electrical signal and either amplifies or attenuates the signal before outputting it to the transducers (speakers) where that electrical energy is converted to sound waves. Ideally, the amp shouldn't alter the signal in any other way except with respect to its' output level -- but that would be a perfect amplifier.

I understand what you are getting at by your question, and I have to say that I really like "This Guy's" answer to you. If you're interested in more than just opinions and anecdotal information from audio enthusiasts about the merits of the proposed upgrade to your system, you should post your question in the Audio Lab board too. There you will get the added input from a group of enthusiasts who take a particular interest in what the scientific community has to say about supposed audible differences in audio equipment. Like I said to begin with, this topic is a source of much debate within audio circles; if you think you can learn something valuable by listening to that debate, the Audio Lab board is the place to go; otherwise just hang out here a little longer and I'm sure some advice will be forthcoming.

As far as my specific advice goes... I don't think you want to hear it, because outside of the typical debate I've already mentioned, I am of the opinion that stereo (2 channel) music systems and home theater systems don't mix well. Past experience has taught me that most other enthusiasts on these boards don't share my opinion... and that's fine. But in my opinion, it is very difficult to build an affordable audio system which does an outstanding job of both stereo and home theater sound reproduction. I think it is common to have a system which does very well with one format and perhaps acceptable with the other, but optimizing a system for either format will inherently create compromises to the other. This is why I have two seperate systems in my home and I couldn't be happier with that arrangement. My advice is to do the same thing I have done or decide which format is most important to you and then build your system around those design criteria; accepting the compromises which inevitably must be made for the other format. I realize that there will be those who say upgrading the amp can't hurt -- to which I reply that there are many other factors which go into setting up a high quality 2 channel rig and if those factors are not going to be addressed as well then the value of the amplifier upgrade loses much meaning.

So my bottom line is... if you're considering this upgrade to improve your music stereo listening, which I believe is your stated goal, I wouldn't bother. I don't believe it will make an appreciable difference to justify the cost, nor would adding the extra wattage to the mains for home theater purposes unless you have no subwoofer in your system and you are directing all of the low frequency information to the mains -- then it may be worthwhile. Unless you're considering an amp purchase as the first step towards building a seperate stereo system, I would bother. But that's just my opinion; I'm certain others will disagree. Best of luck whatever you decide.


09-05-2004, 03:17 AM
As noted above, "timbre" isn't what you'll notice when changing amplifiers on your mains. That said, every A/B comparison I've done when comparing a higher power/quality amplifier to a lesser one HAS revealed a sonic difference. The highs typically sound smoother and less harsh while the mid/lows generally sound much tighter, more controlled and defined, sometimes slightly louder. The result is a positive one and allows you to listen to the system at a higher db level with less distortion.

The most recent comparison that illustrated this point to me was a mid level Denon or Onkyo (I forget which) HT receiver VS a Carver A400X. Same speakers, same listening environment, same decible level. I had the shop owner toggle back and forth between the amps while I sat in the listening position and evaluated. No contest. This comparison was done using both amps well below the clipping and/or distortion threshold. Given the relative ease of sourcing quality used 2 channel amplifiers (ebay/audiogone etc), any HT receiver with pre-outs can be easily supplimented with extenal amps for a much better listening experience.

09-05-2004, 07:32 AM
"...any HT receiver with pre-outs can be easily supplimented with extenal amps for a much better listening experience."

I would only point out that the quality/cleanness of the receivers' preamp stage must be taken into consideration AND that the resultant sound is "much better" is a relative outcome. Not trying to invalidate your input, I just believe that these are variables which Jamison should be made aware of.


09-05-2004, 07:49 AM
You make a good point, and one that definitely should be taken into consideration for this application.

09-05-2004, 08:35 PM
thanks for the Info i think im going to try to aquire an amp. I am looking at an Adcom GFA-555 a 3 channel amp rated at 200 x 3 RMS. does anyone have any opinions on this amp ? I am Running Klipsch RF-7 Mains and an RC-7 center. the mains have an SPL of 102db and the Center is 99db so they ought to sing.

09-05-2004, 08:37 PM
the model number is GFA-5503 sorry

09-07-2004, 01:57 AM

I think Adcom represents one of the best “bang for the buck” products available, especially as far as their amps go. You’ll likely be very pleased with this amp, although as an upgrade to the front three channels I’m not sure it fits exactly with your stated goal of improving 2 channel listening. Don’t get me wrong. I think it makes a lot of sense to upgrade the front three channels if you’re going to upgrade a Home Theater system. The problem I see is in understanding your overall goal of system building -- being sure of what it is you want to accomplish. The direction I see you headed with this amp upgrade is not in the area of improved stereo listening, but towards a “separates” HT system. This is not a bad thing, it’s a good thing… IF you enter into that arena knowledgeably and with some planning. One of the things I have commonly said over my years of posting here is, “never be afraid to invest in good quality amplification and speakers“. There have been many changes in audio over the years -- surround sound, new surround formats, hi rez musical formats, multichannel hi rez musical formats, etc… but the need for those two things has remained a constant and is not likely to change anytime soon. One of the other statements I have made in the past is that, “few who go the “separates” route ever regret it or are inclined to go back to a receiver based system”. The main point I want to make to you is that the upgrade bug bites hard and doesn’t let go easily. If you make this upgrade now, at some point in the future you are likely to ask yourself, “I wonder how it would sound to upgrade the rest of my amp channels? It can’t hurt to add better amplification; after all, I really should be at 200 wpc all the way around. Then my system would sound more balanced.” You’ve already questioned whether upgrading the fronts will “unbalance” your HT system and you haven’t even made the upgrade yet. And once you decide to step up the amplification to the rest of the speakers, soon you’ll be wondering if your “quasi-separates system” might not sound better if you went completely separates, driving it with an audiophile grade pre/pro instead of just a receiver. Do you see where I’m going with this?

Before you start down the slippery slope, NOW is the right time to ask yourself the important questions; what your overall goals are and how this amp fits into those plans. The Mosfet output of this amp might give you a slightly more “musical” presentation which would be good if better stereo music listening is what you desire. On the other hand, if you believe in such sonic differences (which would be a driving force in making this upgrade choice) then you do have to believe that it will effect the overall balance of your HT system. This goes back to the point I was making in my previous post to you… are you willing to make compromises to your HT system for the sake of better 2 channel presentation? If you can answer that question in the affirmative, then at least you do so with knowledge and foresight. If however, the answer is “no”, it might make more sense to look at a multichannel amp which upgrades ALL of the amp channels instead of just the front three. There are some seven channel amps out there, including one from Adcom. There are also other configurations which might work for you and save you money in the long run; such as buying a 2 channel amp for the mains now and then adding a 5 channel amp later. Or… buying a 5 channel amp now and relegating the rear center speakers to the receivers’ amps, leaving you with the option of buying a two channel amp to power them later. There are any number of options and configurations which can work, including not upgrading at all. I’m just encouraging you to think some of them through now rather than having regrets in hindsight.


09-07-2004, 09:07 AM
thanks for the help I was going to just buy a 2 channel amp but the price im going to get the amp for is dirt cheap prob half the price of the 2 channel model.

09-07-2004, 11:37 AM
Who can argue with a bargain! I hope you enjoy the new amp. Maybe you wouldn't mind letting us know what you think of it once you've had it in your system for awhile? Best of luck.


09-09-2004, 08:41 AM
well my deal with my amp fell through after thinking things through im going to wait till i can afford a 5 channel or seven channel amp.
thanks again

09-24-2004, 12:26 PM
well. i went ahead and purchased two adcom amps a GFA 555 which was in an unopened box and mint. the other one is a GFA 5006. i have the GFA 555 driving my RF-7's and the GFA 5006 is a 6 channel amp which i bridged at 175 x 3 driving the center and surrounds.
so far i love the combination everything is cleaner and punchier. my next question is this: is there a device or powerconditioner that i can turn everything off by remote?? the 5006 will turn on or off when it senses a signal but the 555 will not. i also dont havea 12 volt trigger on my receiver either.

equipment list:
Fronts: Klipsch RF-7
Center: Klipsch RC-7
Surround Klipsch RS-7
back Surround: Klipsch RB-75
Subwoofer: Velodyne HGS -18 (purchased virtually new for 500 bucks from an IDIOT)
Receiver: Onkyo TX-SR 900
DVD SACD DVD A: Pioneer Elite DV 47A
CD player: Pioneer PDRW - 839
TV: Panasonic TAU 36
BTW i am getting addicted to this stuff and loving it. :-)

09-26-2004, 01:51 PM
Does the GFA 5006 have a "switched" outlet on the back panel? If so, you might be able to plug the GFA 555 into that outlet and when the GFA 5006 senses a signal, it will power up both amps as it comes on. You should however, check the specs to see if the outlet can support a device rated at that wattage.

There are definitely devices which can do what you want, but they may be pricey. It just depends on how much you are willing to spend. I'm sure Panamax makes something with sequential startup but there are others as well.

Congrats on the amps! As I indicated in my previous posts, I believe you were wise to think this thing through and come up with a solution which adressed all of your amp channels. Sounds like you have no regrets so far and are happy with the improvements you hear. Well done.


09-28-2004, 02:21 PM
no the amp does not have a switched outlet. however i decided to also purchase a monster HTS 3500 theater reference power center for $150 it can switch the amps on and off safely. I know its prob overkill and overpriced but the small town i live (population 660) in has frequent brownouts and power-outages. i think the surge protection/powerconditioning will give me some piece of mind. they just came out with a city newsletter stating that they wanted to build a new substation because the old one is overloaded as it is. Not very encouraging to an audio enthusiast. I am also eventually going to upgrade the electrical service in my home and am hoping to run a 20 amp dedicated circuit to my home theater/ soundsystem.