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Hi folks,
I'm very new to AA, and have recently started looking into building a 2/5 channel system. The information on this and other forums has been incredibly valuable. However, I'm still overwhelmed by the options out there for amplifiers. My budget is mid-fi, so I'm looking at used Rotel, emotiva, arcam, outlaw and sherbourn.
One thing I've not seen is any kind of quantitative comparison of different amplifiers. Did I miss something on this or another forum? For my own benefit, I'm putting together a spreadsheet of some basic features of different amps: Things like: Ratio of 4/8 ohm power, Watts/per dollar value, and average selling price of used gear at online auction (how well do these hold their value?)
There are other aspects of amplifier build specifications that I honestly don't understand. Can anyone suggest some additional metrics or indices that are important indicators of amplifier build quality/performance?
Thanks for any suggestions.
Zdog
Follow Ups:
There is no technical, published spec for manufacturer reputation, but do your legwork. Don't buy some exotic, ultra tweaked amplifier from a company that might not be in business in 5 years or less. Stick with major companies with a reputation for quality and durability. Amplifiers certainly do sound different, but a novice has a lot more to worry about. A super duper amplifier that blows up and cannot be easily repaired sounds pretty crappy.
Age affects solid state electronics. Power supply capacitors fail eventually, even in the very best equipment. You are rolling the dice on equipment that is more than 10 years old. Mechanical items such as switches also fail. Every internal component is subject to failure, and some transistors can no longer be obtained for repair.
Look for good heat management (big heatsinks) and plenty of venting. A big (heavier) transformer and power supply caps will typically outlast smaller, marginally applied components. Every time power is cycled on/off, the life span is shortened.
Of all the components in a stereo, the amp probably affects the sound the least. This is an asylum. People here go on about amps and will gladly make you crazy, too. Buy an amp in your budget range that has the basic features you need. Start listening; don't obsess over whether it's the best amp in the world.
Personally, I never cared much for Rotel sound, or any Class D amps. Investigate the newer generation of chip amps, also called gainclones. Some major manufacturers now employ these, and they produce superb sound with minimal fussy circuitry and are incredibly reliable. If you care to learn about it, there are simple kits available that can give you excellent value.
Peace,
Tom E
All of the above is good advice. Another brand I wouod consider rather strongly is NAD - a lot of component for the money. I suggest looking on Audiogon (if there is no dealer near you so that you cant audition used equipment and hear for yourself -always and unarguably the best arbiter).
I went Parasound on a recent upgrade cycle. I had become disillusioned with my 'd' integrated using ICE modules.
I think Parasound is a REAL sweet spot and great value. The Newish P5 preamp is quite full-featured and the PAIR of A23 biamping my panels has more than enough headroom to more than take the place of the previous 500x2 'd' amp.
I'd be careful buying used NAD. For a few years there, problems existed and reliability suffered as a result.
I had a NAD 1700 tuner / preamp from the mid '80s which was 100% and made prior to the 'problems' of the mid 90s, if that's when it was!
As for a 10 year 'be careful' time for used equipment? I'd be more worried about something which has SAT for that long and would PAY a tech to ramp it up using a Variac before committing to full line voltage.
I'd figure caps in-use should go 20 years before even be THINKING of replacement, and than not without reason. When replacing caps? Go for 105c rated and AT LEAST the same voltage, if not slightly higher.
Too much is never enough
...the most important metric is watts/ch - in a larger room listening to loud rock for example, you will need more power than listening to chamber music in a smaller room.
The only way to determine how an amplifier sounds is to listen to it with your speakers.
Highly rated amplifiers will all make your speakers sound different.
My advice is to find speakers you love first, than match an amplifier to them.
The metric you WON'T see except in extremely RARE cases is an amps ability to work into a REACTIVE load.
Speakers are NOT resistive. Most persons look at OHMS in the Impedance spec and equate that to the OHM of DC resistance. Not so.
Speakers look like either a Capacitor or an Inductor to an amp. And it varies constantly as a function of frequency.
So, while the 'impedance curve' or whatever, is sort of important, an amplifiers ability to drive the reactive portion of the impedance is FAR more important.
Not all amps are created equal in this reagard. Pick a pair of amps with the same RMS rating and they will respond differently when you throw reactance into the mix.
Some fairly highly regarded amps fall flat, while a few 'dark horse' amps do rather well.
To repeat points made by others, just to make sure you get it:
The trick is to choose amps and speakers which are compatible. To name a few names? Some B&W speakers are very reactive. Generally not good for tube gear. Magnepan, OTOH, is reasonably resistive and is an EASY load for any amp capable of supplying its sheer power need.
Dont' forget, either, that doubling an amps power is ONLY 3db. It may be easier to purchase more sensitive (not efficient) speakers rather than simply tossing more power at another, less sensitive speaker.
My suggestion would be to purchase speaker AND the amp as a 'pair'. Listen, at auditions, for those things YOU value in music. Rhythm? Pace? Dynamics? 'Slam'? Detail? Fill in the blank with what YOU think is important. Try to find a sales guy to WORK WITH you on this.
Doing a fresh start online and going thru the buy/sell/buy routine would drive ME nuts.
Too much is never enough
nt
Dman
Analog Junkie
nt
You're getting good advice. Yes there are qualitative paramaters, but there is also component synergy and personal preference. Granted, my speakers have a more difficut impedance curve than most, but I have tried more amplifiers than any other component and the difference in sound is significant. And the most eye opening experience I have had was making tweaks and finding a single component in an amplification stage had a significant affect on the sound. The bottom line is there is no substitute to listening to amplifiers with your other components.
Welcome! Zdog.
if you have a local dealer/retailer or 2 check them out to verify your taste in gear. This is a very important step (1st) to get started. There is/are a plethora of excellent used gear in the market- timing could not be better in this regard. IMO, listen, listen and listen prior to buying.
An amp with a big power supply and lots of reserve capacitance will give you a fuller, "ballsier" sound. There are a lot of good amps available nowadaze, look for one that has the specs mentioned above and an aesthetic that is pleasing...
-RW-
Specs won't tell you very much. Emotiva sells for so low a price, that you probably don't have to shop used. I concur that used Arcam and Rotel are probably a good deal, if that's the styling that you like -- for instance, Emotiva doesn't appeal to me style-wise. Sherborn looks very nice, but I've never heard of them before??
You may want to go into this with a pre conceived notion of what amplifier power you want, but that may not tell you the entire story nor even be significant. Knowing what loudspeakers you will likely pair the amplifier with is probably the best thing to know beforehand, though, as well as the size of room (which should be matched with the room dimensions roughly).
Welcome to AA!
I honestly don't think you can make an informed choice based mostly on specs and metrics. Watts/dollar? Nah.
Not sure if your budget permits but I would consider:
Odyssey Stratos, Stratos Plus, or Stratos Extreme. IMHO, the basic Stratos will give you the biggest bang for the buck in this line up. I had all three and the 'upgrades' (and corresponding price hikes) offered only slight improvements. By the time you load these amps up with 'the works', you're in pricing territory where it makes more sense to look at higher end gear to begin with. Again, my opinion based on some experience.
Older amps like Class CA-100/101, CA-200/201. Pass Labs X150.
But I think some of those might be over budget. The Outlaw Audio RR2150 Receiver has an outstanding amp section. They're not pretty in my opinion but sound very good! These sell direct from Outlaw for $699 but I've seen them on sale for $599 now and then.
You might also investigate some class D amps from Onkyo and the likes.
I strongly advise you to avoid Class D amplifiers. Class AB are best. As for receivers the mid-range Sony 1050 is the best value at present.
I do avoid Class D amps after trying several of them over the years. However, they offer excellent performance/price for those who might not be able to afford a good Class AB amp.
Thanks jedrider and AbeCollins for the replies.
In another life, I am a data analyst, so my instinct still tells me that if we had a graph/statistical models showing cost as a function of age + power + 8/4 ohm ratio + ??? that we'd actually learn something about what amps were good investments. I wish online auctions would let me scrape data from their site as I could make all of this work in real time...
That said...after more reading, I've been scared off from buying older very high qualtiy amps (almost went for a Levinson Proceed Amp 5, until I saw so many posts on failures and the cost to repair a 130 lb. amp.
Anyways, thanks again for the advice! I'll keep looking, but leaning toward a new emotiva.
Zdog
"In another life, I am a data analyst, so my instinct still tells me..."
That it's really the corrolation coefficients that matter? Probably. But how the heck do you establish it?
Many years ago I got the notion that I needed a more powerful amplifier, perhaps one with a lower output inpedance but knew that I wanted to stick with the general style I had: transistorized push-pull. (In hindsight, maybe I just wanted to buy something new..)
Since I didn't care what it looked like or cost (within reason) I was ready to roll, I had my requirements: > 120 W/ch. SS. The power requirement was figuring it needed to be at least 3dB more than my existing unit. That was long enough ago that there still several dealers within a 50 mile radius so I could drag stuff home.
The bottom line: They all sounded differently. Some moreso than others but I wasn't really expecting any sonic shifts beyond just more ummph in the transients. It was an ear-opener and in general I only listened rather than measured. However one unit was doing something that was so eerie that I hauled home some gear and sorted it out. Even when no music was playing it was making me nervous just being turned on. That turned out to be a problem with very narrow transients from the reverse-recovery of the rectifiers making their way into the output via the C-E capacitance in the bugs and being reproduced by my film tweeters.
I'm still using the amplifier I bought now about thirty years later so it was probably worth the effort. But the specifications and topology really aren't adequate to characterize the performance of home audio gear for fussy listeners. I think they could be improved quite a bit but there doesn't seem to be much interest.
Try reading some of morricab's posts while you are in the analytical frame of mind, he finds corrolation between the pattern of the distortion harmonics and the quality of the sound. In preamps at least I have found a correlation between the group delay and the SQ. The sooner the first inkling of signal shows up at the other end, the better. This may be an oddball way to see T.I.M.
IMHO the 'routine' specifications: THD, Frequency response, Power out at 1KHz, Output impedance, were more useful in the old tube era when they were written. We never characterize every possible parameter of anything, it would just be insane. A lot of things are just intrinsic in certain materials and topologies so the old Specs. look at the areas where tube designs tend to come up short and they also reflect what was commonly measurable then. Audio frequency spectrum analysers simply didn't exist. For that matter even scopes were rare.
If we really had the machine/man interface well defined your approach would have merit, as it is you will be looking for patterns in what is essentially noise.
Wish that it weren't so but that's the state of the art...
Rick
My background comes with a LOT of statistical process control, so I'm kind of data driven, myself.
If you get a chance, take a look at my post about REACTANCE and how amplifiers are seldom measured for performance INTO such loads.
That may help you close the gap on some of your musings. Also, One OTHER thing to toss into the mix, espcially when dealing with group delay and such would be BANDWIDTH. My new stuff is very wide bandwidth and sounds much better than the previous 'D' amp with the output Zobel getting in the way.
Too much is never enough
"look at my post about REACTANCE and how amplifiers are seldom measured for performance INTO such loads"
Yup, right on. And it isn't just power-amps either, preamps have the similar issues. They don't have to deal with mechanical reactance and resonance but on the other hand they usually face worse dielectric absorption problems and RF ringing issues. Having a lot of bandwidth just sort of takes the load off unless something downstream doesn't!
Rick
I'd be scared off from buying very old amps too but within about 10 years or less, I'm not too concerned.
I think you will find it impossible to determine a good value amp simply on data metrics and analysis. There's something much more subjective that is much more important. How it sounds! Good luck.
Emotiva make very nice amps. One of their older versions, IPS or MPS models, or their new Gen 2 models would probably be a very good buy...
-RW-
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