Does A More Powerful Amplifier Make Speakers Sound Better?

[Chrispy]

No. He didn't leave anything out. His question is plain and simple. And very good. What was it that you didn't understand about the O.P.?

It's too simple, thus my somewhat vague answer to match.

 

[restorer-john]

I don't claim to undestand the PE technology, I remember reading about it in my youth when my brother was considering adding a NAD PE power amp to his 3020a.

Commutating power supply rails basically. Switches in a 2nd, much higher voltage rail to provide for increased voltage swing when needed. Not designed for continuous high power operation, but effective and results in a lower disipation in normal conditions. The switching occurs at a high level, so any non-linearities around the action are insignificant. Fell out of favour due to many spectacular failures with all the main brands (NAD, Kenwood, Pioneer, Yamaha etc) and issues around diode glitching.

Power Envelope (PE) was NAD's second name for the design. It was originally marketed as Power Tracker.

There is a high res original NAD 2200 brochure I uploaded to HiFi engine which goes into detail on the design here:
https://www.hifiengine.com/manual_library/nad/2200.shtml

The first big brand to successfully market Class G was Hitachi, with their monster HMA-8300 in 1977.

 

[Doodski]

The first big brand to successfully market Class G was Hitachi, with their monster HMA-8300 in 1977.

Wasn't that called Dynaharmony or some such name by Hitachi?

 

[restorer-john]

Wasn't that called Dynaharmony or some such name by Hitachi?

Yes, I have one in my storeroom given to me when it blew up.

 

[atsmusic]

Today's speakers are garbage.
There are hundreds of vintage speakers with sensitivity of 94 or higher.
That and an 80 / 100w AB amp is all it takes.

I had my klipsch speakers like 25 years ago with a 200 watt amp and that clipped when I turned them up. Klipsch are known as being very efficient too.

 

[escksu]

100W can easily clip during peaks in dynamic recordings with mainstream loudspeakers.

My issue isnt about the power, its the cost. Aud1500-3000 for an amplifier is not considered affordable. I would say it quite expensive. Not that many pple are willing to fork out that amount.

 

[Doodski]

Here are details about the NAD 7240PE and it's Power Envelope circuitry.
I'm curious what the amplifier rail voltages are versus the output RMS power and dynamic power specs relative to the power supply Power Envelope rails when quiescent.
The pre-amble is that the +/- 43VDC power supply is operating pretty loose and the +/-71VDC Power Envelope supply is operating loosely too. There is also the ~25A/ch peak output current that NAD claims is a specification. According to my calculations for the NAD 7240PE to output 25A peak per channel the rails would be @50VDC peak, the load would be 2 Ohms and the amp would be outputting 625WRMS per channel. The 25A peak spec seems optimistic at best.
If the 43VDC supply was tightly regulated then the output RMS power would be ~116WRMS/ch.

According to the Service Manual specifications (and my calculated rail and current supply.).
40 Watts RMS @ 8 Ohms output (requires a 25.3 VDC rail @ 3.2A peak.)
50 Watts RMS @ 8 Ohms output (requires a 28.3 VDC rail @ 3.5A peak.) (Clipping power.)

Dynamic Power output power as per the Service Manual specifications (and my calculated rail and current supply.).
160 Watts RMS @ 8 Ohms output (requires a ~51 VDC rail @ 6.3A peak.)
200 Watts RMS @ 4 Ohms output (requires a ~40 VDC rail @ 10A peak.)
250 Watts RMS @ 2 Ohms output (requires a ~32VDC rail @ 15.8A peak.)

With a slew rate of 15V/micro second @ 25.3VDC rail supply that means the amplifier bandwidth is up to ~ 95KHz. I could not find a NAD bandwidth specification to compare to.

The power supply amplifier rails are ~@ +/-71VDC for the Power Envelope and +/- 43VDC for the regular supply. Obviously the Power Envelope circuitry cannot sustain the additional power output for much time.
If the amplifier could sustain the rails voltages for enough time the theoretical peak power output would be:
@ +/- 71VDC the output RMS power would be ~@315WRMS/ch into 8 Ohms @ 8.9A peak.
@ +/- 71VDC the output RMS power would be ~@630WRMS/ch into 4 Ohms @ 17.8A peak.

As per the Power Envelope circuitry it can amplify and output up to 200 milisecond tone bursts @ 100WRMS/ch.

 

[Rottmannash]

Commutating power supply rails basically. Switches in a 2nd, much higher voltage rail to provide for increased voltage swing when needed. Not designed for continuous high power operation, but effective and results in a lower disipation in normal conditions. The switching occurs at a high level, so any non-linearities around the action are insignificant. Fell out of favour due to many spectacular failures with all the main brands (NAD, Kenwood, Pioneer, Yamaha etc) and issues around diode glitching.

Power Envelope (PE) was NAD's second name for the design. It was originally marketed as Power Tracker.

There is a high res original NAD 2200 brochure I uploaded to HiFi engine which goes into detail on the design here:
https://www.hifiengine.com/manual_library/nad/2200.shtml

The first big brand to successfully market Class G was Hitachi, with their monster HMA-8300 in 1977.

I bought my 1st NAD amp back in 1979? while in college and it was wonderful for its time-a 3140. Now have a 2nd one as a spare. Still sound pretty good for ancient technology. Has the old "soft clipping" and "speaker lead compensation" circuits as well.

 

[DanielT]

Doodski

Interesting.

Out of sheer curiosity, do you think that old NAD receiver is sensibly constructed?

There is no receiver I intend to buy but I am curious.

 

[Doodski]

Doodski

Interesting.

Out of sheer curiosity, do you think that old NAD receiver is sensibly constructed?

There is no receiver I intend to buy but I am curious.

The NAD 7240PE is a nicely constructed amp. I'm not into this kinda gear myself but for the price range and the dynamic power it's OK. It is sensibly priced in that they designed for a market and they achieved that in the pricing. I'm more the linear power output kinda shopper if I where looking at practicality. I consider a practical amp to be ~70W to 100W plus dynamic peaks and linear output with impedance and power changes. In brief I think a linear outputting 75W@8R, 150W@4R and 300W@2R is a very good size amplifier while keeping the amplifier price down and the power bill down too.

 

[restorer-john]

The 25A peak spec seems optimistic at best.

The peak current numbers are usually derived from a single cycle (1KHz/1mS) driven into 2R. Basically wind it up until the waveform flattens, take a peak voltage reading, square it and divide by 2R.

The single cycle means you won't blow fuses, OPTs, vaporize PCB tracks or generally have a bad day.

The dynamic headroom is a 20mS burst and NAD liked to brag about their 500mS ability.

 

[DanielT]

I bought my 1st NAD amp back in 1979? while in college and it was wonderful for its time-a 3140. Now have a 2nd one as a spare. Still sound pretty good for ancient technology. Has the old "soft clipping" and "speaker lead compensation" circuits as well.

A NAD 7240PE, or someone similar I can think would be ok to have in a second system. I think it's better to use old stuff than to throw it away.

That old. Maybe it needs a recap? I do not know much about recap though.There are probably threads on ASR about recap, when, how, what and why recap that is.

Maybe this applies to recap?
If it ain't broke, do not fix it

Edit:
By the way, I use a vintage NAD 3020 in my small summer cottage. A cool little racer.

 

[restorer-john]

In brief I think a linear outputting 75W@8R, 150W@4R and 300W@2R is a very good size amplifier while keeping the amplifier price down and the power bill down too.

But as you know, such an amplifier will be very expensive. To get an amplifier to even approach doubling down needs a phenomenally large, well regulated PSU and a huge number of OPTs along with extreme attention to any voltage drop, anywhere.

Most of the advertised "doubling down" ratings are just derated 8R and 4R numbers to tie in with the 2R and look good on paper.

 

[Doodski]

The single cycle means you won't blow fuses, OPTs, vaporize PCB tracks or generally have a bad day.

The thought had crossed my mind that they must be really pushing the "envelope" no pun intended.

 

[restorer-john]

Maybe this applies to recap?
If it ain't broke, do not fix it

This is true. But it is prefaced with having the amplifier tested periodically to ensure it is still within spec, having internal visual inspections and sampling some random capacitors in known failure areas for values/esr.

 

[Beershaun]

Putting my favorite video about this topic here. "It's all about that bass." If you want to move some big woofers and make loud low notes, you need more power than moving small tweeters to make loud high notes.

 

[Doodski]

But as you know, such an amplifier will be very expensive. To get an amplifier to even approach doubling down needs a phenomenally large well regulated PSU and a huge number of OPTs along with extreme attention to any voltage drop, anywhere.

Most of the advertised "doubling down" ratings are just derated 8R and 4R numbers to tie in with the 2R and look good on paper.

Yes, a 75W/ch amplifier power supply must be hefty like a 1KVA transformer and 40,000 microFarad/ch smoothing would do it. I still think if a amp can be rated linearly even if it is derated to nurse the numbers together that it is a pretty good amp. I suppose I'm thinking of stuff like Krell, Threshold, Perreaux and Kinergetics Research etc etc. For a linear lower output class A amp they start at about $1000.00 USD nowadays on the used market.

 

[DanielT]

Putting my favorite video about this topic here. "It's all about that bass." If you want to move some big woofers and make loud low notes, you need more power than moving small tweeters to make loud high notes.

Hmmm. But in that case, it should be possible to use several amplifiers. Divide the signal and let a sufficiently powerful amplifier take care of the lower frequencies and less powerful amplifier for the rest. I know that it is possible to do that, but the question is whether it is a sensible solution?

That particular aspect was perhaps addressed in the video you posted. I have not looked at it yet.

 

[Doodski]

I know that it is possible to do that, but the question is whether it is a sensible solution?

It is a very sensible solution to use a active crossover before the amp stages. That makes for some great sounds and lotsa power for each driver.

EDIT: ... and then there is the amplifier sizing that peeps argue about. I'm all for using the biggest baddest amps available for a active crossover system. Some peeps argue that small amps are required for tweeters and midrange etc.

 

[DanielT]

It is a very sensible solution to use a active crossover before the amp stages. That makes for some great sounds and lotsa power for each driver.

EDIT: ... and then there is the amplifier sizing that peeps argue about. I'm all for using the biggest baddest amps available for a active crossover system. Some peeps argue that small amps are required for tweeters and midrange etc.

Aha! Got an idea (it has probably already been up for discussio on this forum). I think is probably the case that we are less sensetive to distortion in the lower regions, say between 20-100 Hz. Or how about that? To then let some big ass powerful cheap PA amplifier take care of the amplification for one or more subwoofers? Go for a hell of a lot of power/watts where that is.

Then the crux is that many big PA amplifiers have fans, but it can,hopefully, be changed to a quieter ditto. Or throw the ugly bastard in some closet and slam the door shut. Problems with wiring then maybe.

Edit:
Come to think of it, there are class d PA amplifiers without a fan

Output Power: 2 x 400 W at 4 Ohm / 2 x 220 W at 8 Ohm / 1 x 800 W at 8 Ohm (bridged)

https://audiosciencereview.com/forum/index.php?threads/behringer-a800-stereo-amplifier-review.10499/

Or an even more powerful PA amplifier.

There are plenty of used PA amplifiers by the way. This is probably the case in most countries. So much power can be obtained very cheaply. Did a quick check now, just as an example. This see picture, I saw sold as used for $ 180 now, for example.