Axiom Home Page Forums General Discussion Technical Questions Buying an older receiver

OK, I've been considering my options and I think the most expedient way to get a pair of M80s into my livingroom is to look for a used receiver as a short term solution.

I,m not sure what I can reasonably expect to pay, but was hoping to keep it at or below $150.

I'm currently looking at a Yamaha RXV1050 and am curious as to what something in the specs means:
Dynamic Power per channel (by IHF dynamic headroom measuring method) 8/8ohms 160w/190w

Jason. I will look into ecost.com as suggested in the other thread.

Once you settle on a model or two, I'd recommend you check eBay as well if you are comfortable shopping there. I bought a used Pioneer receiver from eBay several years ago and it has served me well (and continues to, seven years later). Just make sure if you go that way that you find someone with a high feedback rating so you know you're dealing with someone honest.

Just missed out on an older Yami because I've forgotten my password. I use ebay about once every 1.5 years.

I don't know that I put much stock in the rating system because sellers are able to 'rate' a purchasor. I've heard a number of stories on retailatory ratings.

You should check some of the older threads for Onkyo's as well. I know JohnK usually sends people to one site for refurbs but I can't remember it nor desire to look it up

You can get an Onkyo 505 refurb for about that price at accessories4less.com

Definitely valid, but sellers with hundreds or thousands of positive ratings still paint a good enough picture in my book. I tend to steer clear of anyone whose feedback shows that they've had the same complaint multiple times... (i.e. non-responsive, item not as described, etc.). If buyers leave that kind of feedback more than once, especially knowing that they'll likely earn a negative feedback themselves from the seller, it's an indication to look elsewhere.

E-bay commentary over, back to audio talk.

PS: I'm surprised no one here has volunteered to sell you some of their own older equipment. This seems like the kind of crowd who has 2-3 old receivers around the house without a defined purpose... (or, if everyone is like me, we don't have a purpose for them now, but know that sooner or later we'll buy enough speakers to need another receiver!)

Sorry, but my old Denon receiver is destined for my screened room, once the budget allows for some Alqs. A SB3 is already in position for this; so the entire CD collection as well as std radio on tap

Checked the refurbed Onkyos out. US only. I didn't see a 505, but the 504 is only 75w/channel.

Jason, you mentioned that you have used ecost. What are the shipping charges like into Canada?

I bought my PF60 from them and the shipping costs for that unit wasn't too bad, I don't remember the exact cost, but it was about $70. However I just tried to 'purchase' some receivers from them and they all stated it wasn't possible to Canada, looks like the protectionist economy style of thinking is starting to take over. although I could still get the PF60 sent up.

I just looked at amazon.com and they have a Yamaha RXV461 shipped:
Items: $215.96
Shipping & Handling: $120.10

Total Before Tax: $336.06
Estimated Tax:* $0.00

Order Total: $336.06
Which I think isn't too bad. Funny thing is it is from 6ave. and if you go to 6ave they won't ship up here but Amazon will!

No luck with Denon refurbs either. Canadians need not apply...

Fred, dynamic power is a valid method of measuring amplifier output suggested by the IHF. It's measured by applying a tone burst for 20 milliseconds on and 480 milliseconds off every half second. The idea is that 20 milliseconds roughly corresponds to the length of a musical peak on a instrument, following which the sound level falls off. This tends to give a number about 20-30% higher than the continuous power rating which the FTC regulations require for amplifiers advertised in the U.S. The basic FTC requirement is at least two channels driven simultaneously at the full rated power for at least five minutes continuously.

You beat me to it. I bet that restriction is placed on the refurb units by the manufacturer.

I think I can do better used locally with a little patience.

Johnk,

Do you, in your vast arsenal of audio knowledge, have a chart anywhere that illustrates the dynamic range of instruments?

Vast arsenal indeed. I missed your reply while typing john.

I'll have to mull over what that means for a little while.

Thanks.

Basically it means that dynamic power is a secondary spec. To determine if an amp meets your application, look at continuously rated power.

...and ignored entirely when thinking about amp headroom?

I'd ignore it entirely, yes. Because I doubt that composers obey the 20msec/480msec duty cycle spec .

Now of course if you found two amps that had the same specs, price, etc but one had higher dynamic power, buy that one. That's what I mean by a secondary spec.

Mo, there's an interesting(and pricey)book on musical instruments which can be examined in part by clicking the preview button here . For example, scrolling down to p.31 shows a chart of some instrument dynamic levels.

Tex, you may want to research synthesizers as you would get pretty attack, sustain and release for each instruments. After you have the shape of the fundamental wave, the synthesizer will then add the harmonics and you will get a final waveform with peeks that can reach quite high, but for very, very brief periods.

"Dynamic range" can be used to many sauce and is sometimes used (quite often here in this forum) as the difference between the lowest sustain level and the highest one (the part our brains are actually registering as low/loud). It can also mean the difference between the highesr point in a waveform and 0db. The various definitions are all good, it's just a matter of using the one appropriate to your needs.

I am sure you can get simple synt programs on a PC to experiment.

You can also look at samples for Samplers as they may be more "real life" and easy to check with a wafeform viewer.

And I am sometimes wondering which sauce we are talking about.

Given that this stuff is defined and quantifiable one would think that it is well understood in the audiophile community, but it sometimes seems not.

I see head room numbers being quoted and they seem to contradict each other. For example to the folks at Crown, 6db headroom (from average) is nothing and is considered adequate only for compressed pop/rock music, yet I have seen it suggested here, by inference, that 6db amp headroom is just fine for all music.

I always think of headroom being the power available above the average C-weighted (thats the slow one isn't it?) spl measured when you are listening to a given piece of music.


Can you quantify that at all? How high, how long, and can we hear it? Crown allows for short term inaudable clipping in their power recommendations, but they don't explain what that means.

Hmm... a brief (1 hour) sidetrack to do some internet searches suggests that we can indeed hear it (at least in theory). In fact, the speed of the attack is one of the auditory cues we use to determine what instrument it is we are listening to.

I would love to hear more on this from you Eric. I suspect you have done a lot of reading on the subject.

Denon AVR 685 in Scarberia, $180

http://www.redflagdeals.com/forums/showthread.php?t=562937

Scarberia? Is shipping from a distant solar system included in that price?

Luckely I live in that distant solar system (otherwise known as Southern Ontario) so its just a short trip.

I'm still hung up on this idea that I need a minimum of 100wpc. Playing with one of the power calculators, I'm beginning to wonder, particularly for a temporary solution...

You most likely do need 100wpc. I listen to a half watt nominal and a 90W/ch amp is just right for 98% of the music I listen to. With some well-recorded classical pieces it's a different story. I could use a few hundred watts.

Well, if Mr. "1/2 watt" says I need 100wpc...

Back to the search.

Yep. I guess you need a gigawatt then, eh ?

or one that goes to Eleven.

Hi Fredk,

I usually tell consumers to ignore "Dynamic Power Output" ratings in watts, as it's a misleading spec intended to convince buyers that a stereo or AV receiver has enormous power reserves available for driving low impedances. "Dynamic Headroom," expressed in dB, is a useful spec but few manufacturers ever quote it.

Large amounts of real dynamic headroom, sometimes as much as 6 dB, which some NAD amplifiers often possessed, was based around a "loose" power supply that would switch in extra output devices or voltage rails for large momentary increases in power output. The continuous power output rating would typically be much less, often as little as 30 watts or 50 watts per channel.

A used stereo receiver or stereo integrated amplifier would likely be fine for driving the M80s, as older units often had enough heat sinking and output device cooling to handle 4-ohm loads without the problems associated with many current AV receivers driving lower impedances.

Regards,

Thanks for the reply Allen. The Crown website mentioned that peak power and continuous power are within one watt of each other so what you say makes a lot of sense.