89lbs but only 150 wpc, what is the catch ?

[qguy]

Looking at an Usher R1.5, it is 89 lbs, 150 watts per channel at 8 ohm, guessing the first 25 watts is in class A as the R2.5 is 250 wpc AB/50 wpc Class A. Idle current is at 250 watts for the R1.5. From what I read, the amp is based on Nelson Pass' Stasis design. My Rotel RB-1090 is around 85 lbs but delivers 380 wpc in AB, 0.0000001 wpc in class A The question is, why build an amp that weighs a ton, idles at 250 watts, but only delivers 150 wpc in Class AB?

 

[jhjove]

From reading about this amp, it's class A. In the "off/standby" mode it is draining 55 watts of electrical power.

"...output stage uses 8 pairs of transistors in parallel for each channel and the heat sinks are gigantic.....Everything is bombproof and massively over designed. The mains transformer is gigantic and the output transistors are mounted on a slab of copper that is about 2 cm thick!"

Why build this? Because someone can.

--Joe

 

[opnly bafld]

The Usher is a high bias class A/B, the Rotel is a very low bias class A/B.
For a given output, high bias class A/B needs a better power supply and a lot more heat dissipation, both add to the weight and cost.

 

[E-Stat]

The question is, why build an amp that weighs a ton, idles at 250 watts, but only delivers 150 wpc in Class AB?

Better sound quality in terms of transparency and dynamic capability. Stiff linear power supplies are heavy.

Virtually identical watts/lb as my VTL MB-450s and former Threshold Stasis 3.

 

[opnly bafld]

I hope this doesn't turn into something like the "damping factor" thread.

 

[qguy]

Be patient

I hope this doesn't turn into something like the "damping factor" thread.

 

[turboyam]

I wouldn't complain about a heavy, low power amp, i would, on a lightweight, plastic 1000 What? ''modern'' one tho

 

[egellings]

Class A at that power and not using switchmode technology means big iron. 490 pounds per cubic foot.

 

[opnly bafld]

I wouldn't complain about a heavy, low power amp, i would, on a lightweight, plastic 1000 What? ''modern'' one tho

There are modern lightweight high power amplifiers that will go toe to toe with anything ever made; might not be available at every budget.

Now if you are referring to a lightweight class A amp that has 1,000 watts, I have not seen one.

 

[audiotemp]

I hope this doesn't turn into something like the "damping factor" thread.

To heck with damping factor, that amp has a "circumgyration" spec.

 

[Lavane]

The difference between a couple 120wpc power amps I played with recently was very noticable, and not just the weight difference.

 

[God_Of_Hi-fi]

Usher R1.5'e bakıldığında, 8 ohm'da kanal başına 89 lbs, 150 watt, ilk 25 watt'ın R2.5 olarak A sınıfında olduğunu tahmin ediyoruz 250 wpc AB/50 wpc A Sınıfı'dır. R1.5 için boşta akım 250 watt'tır. Okuduğum kadarıyla, amfi Nelson Pass'ın Stasis tasarımına dayanıyor. Rotel RB-1090'ım 85 lbs civarında ama AB'de 380 wpc, A sınıfında 0.0000001 wpc sağlıyor Soru şu ki, neden bir ton ağırlığında, 250 watt'ta boşta çalışan, ancak AB Sınıfında sadece 150 wpc veren bir amfi üretelim?[/ ALINTI]


Sorun, amplifikatörün yapısından kaynaklanmaktadır. Aynı sorun Pioneer SX-1980 modelinde de mevcuttur. Kanal başına 270 watt yazmasına rağmen, 40 kg'lık dev amplifikatör kanal başına sadece 100 watt'a sahiptir.
These devices have to work at very high temperatures in order to produce transparent sound and they need to consume 2-3 times the energy from the mains. They have to have huge heavy cooling cast iron radiators in order not to scorch the motherboards due to this heat (Actually, their motherboards are scorched at the end). how heavy they are.Umarım bu bilgiler size yardımcı olacaktır..

 

[E-Stat]

There are modern lightweight high power amplifiers that will go toe to toe with anything ever made...

I use one of arguably the best switchers available in the garage system - an Ncore based model - but they still cannot match top end transparency of better class A/AB amps to these ears.

 

[Northwinds]

Idk, those Lab Gruppen amps sound phenomenal for such light weight. Not sure what class they are but it sure is not A or AB. The power cord being over 2" in diameter does give me pause though. Perhaps a separate 200A service box is needed hehehe but 20000w (burst) or 4800w @ 4ohms does appeal to my insane side

 

[Lavane]

Some of the new Pro audio amps and others are using switching power supplies with Class D amps driving discrete output stages. Light weight and plenty of power in a smaller package.

 

[opnly bafld]

I use one of arguably the best switchers available in the garage system - an Ncore based model - but they still cannot match top end transparency of better class A/AB amps to these ears.

Ncore? Not even close to the best.

FWIW I never said anything about class D.

 

[mister-fixit]

The question is, why build an amp that weighs a ton, idles at 250 watts, but only delivers 150 wpc in Class AB?

Sounds like a serious question maybe, and there's no rational answer IMO. It's the 'karma' of the audio world that over rules rational thought processes which appeals to some 'philes ..

Uniqueness sometimes sells well too....

 

[rothwellaudio]

The question is, why build an amp that weighs a ton, idles at 250 watts, but only delivers 150 wpc in Class AB?

Some amps are designed for high efficiency. Some are not. The consumer has a choice of which type of amp they want to buy.

 

[onwardjames]

The difference between a couple 120wpc power amps I played with recently was very noticable, and not just the weight difference.

My Threshold 400a is rated at 100 wpc.

It walks all over my 200 wpc Denon, and most anything else I have.

 

[Lavane]

My Threshold 400a is rated at 100 wpc.

It walks all over my 200 wpc Denon, and most anything else I have.

I had a Sony ES power amplifier rated at 120wpc I worked on for another AK'r, and have a Kenwood rated for the same. The Sony with the heavier transformer and much better power supply did the same with the Kenwood. Specs on paper were very close.