Looking for a new (modern) amplifier

[JoeESP9]

From the Yamaha web site.

A-S801
Receiver / Integrated Amplifier
Minimum RMS Output Power (8 ohms, 20 Hz-20 kHz) 100 W + 100 W (0.019% THD)
High Dynamic Power/Channel (8/6/4/2 ohms) 140 / 170 / 220 / 290 W
Damping Factor 240
Frequency Response 10 Hz - 100 kHz +/- 1.0 dB

Although it says dynamic power, it sure looks like not only 4 and 6 Ohm ratings but also a 2 Ohm rating.

 

[musichal]

I think the real point here is a matter of choosing the right tool for the right job. If your speakers are demanding, or if you intend driving multiple pairs with one amp, then make your choice based on your needs. I've seen some claims that the Klipsch Forte 1, while very sensitive, is not as easy a drive as one might think. I certainly have had no issues with an A-S500 on them, so the tool fits my need.

 

[OnTheBlitz]

From the Yamaha web site.

A-S801
Receiver / Integrated Amplifier
Minimum RMS Output Power (8 ohms, 20 Hz-20 kHz) 100 W + 100 W (0.019% THD)
High Dynamic Power/Channel (8/6/4/2 ohms) 140 / 170 / 220 / 290 W
Damping Factor 240
Frequency Response 10 Hz - 100 kHz +/- 1.0 dB

Although it says dynamic power, it sure looks like not only 4 and 6 Ohm ratings but also a 2 Ohm rating.

Yamaha's are beefy. When I had multiple M85's that were bridged I use to drive loads that were 2 ohms. My current A-S2000 and A-S2100 will drive 2 ohm loads too.

My 2000 and 2100 both outperform my Sony TA-N77es even though it supposedly has 2.5x more power.

What I really want now is the new C-5000 preamp, paired with two of the new M-5000 amps, bridged. Just need to win the lottery and Yamaha needs to release them for sale in the USA.

 

[Schurkey]

From the Yamaha web site.

A-S801
Receiver / Integrated Amplifier
Minimum RMS Output Power (8 ohms, 20 Hz-20 kHz) 100 W + 100 W (0.019% THD)
High Dynamic Power/Channel (8/6/4/2 ohms) 140 / 170 / 220 / 290 W
Damping Factor 240
Frequency Response 10 Hz - 100 kHz +/- 1.0 dB

Although it says dynamic power, it sure looks like not only 4 and 6 Ohm ratings but also a 2 Ohm rating.

Yes, that's what you're SUPPOSED to think. The lawyers (not the engineers) have made sure of that.

Printed right on the back panel, by the speaker cable terminals, the thing says 4-ohm impedance MINIMUM. We can only hope they're referring to "nominal" rating, which means the 2-ohm "dynamic" rating would be for only part of the frequency range, and probably of minimal duration.

WHAT is the "High Dynamic Power/channel" test protocol? Blowing 220 watts into a 4-ohm or 290 watts into a 2-ohm load for one second isn't much of a test. Blowing 220 watts into a 4-ohm load for 1/60th of a second is even worse. I notice that Yammie isn't telling us HOW they achieved those figures. They aren't even saying whether or not the Strangulation Switch was engaged during the testing.

By comparison, the FTC rating method is spelled out exactly for everyone to see--and backed by Government enforcement if the manufacturer "cheats". It's a thorough, comprehensive test that even includes pre-conditioning so, for example, an amplifier that's had the heat sink minimized to cut costs can't show up for the testing after being refrigerated to forty-below so it won't overheat while the test is run.

Yamaha is pulling some reprehensible stuff these days. But they're not the only ones. It's getting common again--which is what brought on the FTC protocol to begin with. Prior to the FTC protocol in the early '70s, each manufacturer had some "special" testing method that couldn't be compared to any other manufacturer's method, and which largely were based on wishful thinking and dirty tricks.

 

[OnTheBlitz]

Wow^ Guess I might as well throw my A-S2000 and A-S2100 in the trash now since they are junk.

 

[Schurkey]

Wow^ Guess I might as well throw my A-S2000 and A-S2100 in the trash now since they are junk.

Or you could look at the owner's manual, where you'd find a proper set of FTC ratings for 4-ohm loads (150 watts/channel) and this model has no Strangulation Switch because Yammie built the thing to drive 4-ohm nominal speakers WITHOUT needing crutches. I'd bloody hope they could do that, considering the thing is $3500 on Amazon.

Glad I could help dry your tears.

https://usa.yamaha.com/files/download/other_assets/5/332925/web_VAA8450_A-S2100_om_U_EnFr_D0.pdf

https://www.amazon.com/Yamaha-S2100...qid=1542336670&sr=8-1&keywords=Yamaha+A-s2100

 

[OnTheBlitz]

Or you could look at the owner's manual, where you'd find a proper set of FTC ratings for 4-ohm loads (150 watts/channel) and this model has no Strangulation Switch because Yammie built the thing to drive 4-ohm nominal speakers WITHOUT needing crutches. I'd bloody hope they could do that, considering the thing is $3500 on Amazon.

Glad I could help dry your tears.

https://usa.yamaha.com/files/download/other_assets/5/332925/web_VAA8450_A-S2100_om_U_EnFr_D0.pdf

https://www.amazon.com/Yamaha-S2100...qid=1542336670&sr=8-1&keywords=Yamaha+A-s2100

No tears here buddy. In the end it's all just numbers on paper. The question is, how do they sound? Well, I can say, great! Also glad I did not pay even close to retail. Thanks for the links. I have the Service and Users manual for both. I always get service manuals before purchasing gear to review all schematics and layout before purchase.

What you running?

 

[Schurkey]

What you running?

An eBay Acurus 200x3 that I paid $350 for, used. It's driving my "less-than-4-ohm" speakers nicely. 200 wpc into 8, 250 wpc into 4. The two-channel version which has the same power supply will throw 350 watts per channel, but of course isn't trying to supply the third channel. The Acurus is fed by an Aragon Stage One preamp/processor that can now be had used for $350--$400, although they started out at $4K and I paid about half that "new, closeout" about fifteen years ago.

The Aragon 8000-series power amps have been in storage for over a year. Manufacturer claims they're stable into less-than-one-ohm loads. The stereo version is FTC rated for 200 wpc into 8, 400 wpc into 4, and "increasing" power into 2 and 1 ohm loads--but not FTC rated for less than four.

Unlike many manufacturers that conjure up wild "ampere" specs in the same way that some brands throw around "watts" specs (i.e., with no mention of HOW the testing is done) Aragon says these amplifiers will throw 20 amperes "continuously" (they will eventually overheat, but not instantly--no music signal is likely to exceed their thermal limits) based on the + and - line fuses of 10 amperes each, for each channel.

Clearly, I would rather buy quality used components and keep them for decades, than buy "new" stuff.

 

[OnTheBlitz]

An eBay Acurus 200x3 that I paid $350 for, used. It's driving my "less-than-4-ohm" speakers nicely. 200 wpc into 8, 250 wpc into 4. The two-channel version which has the same power supply will throw 350 watts per channel, but of course isn't trying to supply the third channel. The Acurus is fed by an Aragon Stage One preamp/processor that can now be had used for $350--$400, although they started out at $4K and I paid about half that "new, closeout" about fifteen years ago.

The Aragon 8000-series power amps have been in storage for over a year. Manufacturer claims they're stable into less-than-one-ohm loads. The stereo version is FTC rated for 200 wpc into 8, 400 wpc into 4, and "increasing" power into 2 and 1 ohm loads--but not FTC rated for less than four.

Unlike many manufacturers that conjure up wild "ampere" specs in the same way that some brands throw around "watts" specs (i.e., with no mention of HOW the testing is done) Aragon says these amplifiers will throw 20 amperes "continuously" (they will eventually overheat, but not instantly--no music signal is likely to exceed their thermal limits) based on the + and - line fuses of 10 amperes each, for each channel.

Clearly, I would rather buy quality used components and keep them for decades, than buy "new" stuff.

Looks heavy duty. Here are internals of the 2000 & 2100 (internet pics)
2000:

2100:

Not bad for 100W Ch. 8 ohm. Using them biamp. 2000 to drive the low, 2100 high and as the preamp. These outperform my Sony TA-N77es, sonically. The 77 looks cooler though.
TA-N77ES (top) - this is my mini-system: