You don't need close to 200wpc

mhardy6647

megasat16 wrote: »

Hehe...Mark, you just reminded me to go and listen to my amp. I let it sit idle since a couple of hour ago.

This Class A amp grows likes Gold in the Sun. No stinking Tube needed.

Pure Class A doubles down all the way to 2 ohms load. The whole chassis is essentially the heatsink to dissipate heat. Sweet and Pure as snow (not you Snow :biggrin:) but feeling guilty as hell just leaving it on.

:-)

The Paramours are of course likewise; but a 2A3 flat out dissipates what? 20 watts? The envelopes are hot as the bejeebers, of course, but overall not the kind of thing to impact the electricity bill too severely. Class A and sensitive loudspeakers saves money and the environment too ;-)

Can you tell my wife is out of town this weekend...?\

FTGV

megasat16 wrote: »

and there are some old Krell Pure Class A amps that comes close to that number.

As did IIRC some of their sustained plateau bias models.Though these used a variation on the dynamic or sliding bias scheme developed by Pass when he was at Threshold to improve efficiency.Purists might not agree it's real Class A since bias levels change with changes in signal level and one wonders about the circuits transparency and added complexity.


My first exposure to pure Class A was with Classe's first amplifer,the 25 watt DR35 VHC(short for very high current) driving a pair of Infinity IRS 2's.I was absolutely floored with the authority and sense of ease in which this 25 watter was driving those behemoth Infinity's.

megasat16

mhardy6647 wrote: »

:-)

The Paramours are of course likewise; but a 2A3 flat out dissipates what? 20 watts? The envelopes are hot as the bejeebers, of course, but overall not the kind of thing to impact the electricity bill too severely. Class A and sensitive loudspeakers saves money and the environment too ;-)

Can you tell my wife is out of town this weekend...?\

Mark,

No wonder why a man alone in the house for a few hours can brighten so much just listening to his stereo! :biggrin: There is no house chores to do, and no errands to run while being the man of the house again. Just a perfect timing to listen to some tunes and crank it up high.

I, of coz, am the true believer of the efficient speakers and pure Class A amps regardless of Tubes (Triode / OTL or Transformer coupled) or SS. I have a long standing plan to make a flea powered active line array since a couple of years ago. But the driver choices, funding and work commitments are a setback for my high sensitivity DIY OB line array plan. But efficient Low and Mid drivers for OB type are really not very many.

FTGV

mhardy6647 wrote: »

I am not the least bit interested in this topic ;-)

Since when?:biggrin:

But a Class A amplifier will not have (can not have) any waveform crossover or "notch" distortion.

Precisely.

mhardy6647

megasat16 wrote: »

Mark,

No wonder why a man alone in the house for a few hours can brighten so much just listening to his stereo! :biggrin: There is no house chores to do, and no errands to run while being the man of the house again. Just a perfect timing to listen to some tunes and crank it up high.

Meh, just had to make myself dinner :-)
Listening to A Prairie Home Companion now on the Yamaha stuff and the Polk Monitor 7As in the family room...

megasat16

FTGV wrote: »

As did IIRC some of their sustained plateau bias models.Though these used a variation on the dynamic or sliding bias scheme developed by Pass when he was at Threshold to improve efficiency.Purists might not agree it's real Class A since bias levels change with changes in signal level and one wonders about the circuits transparency and added complexity.


My first exposure to pure Class A was with Classe's first amplifer,the 25 watt DR35 VHC(short for very high current) driving a pair of Infinity IRS 2's.I was absolutely floored with the authority and sense of ease in which this 25 watter was driving those behemoth Infinity's.

Fred, I think you are right about Krell using sustained plateau biasing models. I also think there are early generations of KSA series are in full Class A biasing (not sustained plateau) and may be some MDA amps too are in pure Class A. They may not be SE since I am not too sure about whether they are pushed-pulled or SE.

Older Class A from Pioneer (M22), Denon (got a few), Krell, ML, Classe, Luxman are all sweet Class A units. I think there are a few other worthy brands that I forgot to mention here. The thing I love about Pure Class A is that it's just sound so coherent from the lows to mids and the highs. It's probably the special attribute of Class A amps that people fall in love in the first place. And older Tubes amps are mostly Class A amps just coincidentally.

I am still looking for the M22 and it's only 30WPC and not many people wanting to sell them, I suppose.

megasat16

mhardy6647 wrote: »

Meh, just had to make myself dinner :-)
Listening to A Prairie Home Companion now on the Yamaha stuff and the Polk Monitor 7As in the family room...

The cost of fixing dinner for a day freedom isn't that bad, don't you say? :redface:

FTGV

megasat16 wrote: »

I also think there are early generations of KSA series are in full Class A biasing (not sustained plateau) ...

Yes on the earlier KSA's.

They may not be SE since I am not too sure about whether they are pushed-pulled or SE.

All PP I believe.D'Agostino seemed to favour fully complimentry-symmetrical circuits and did'nt mind throwing lots of parts at a design.

heiney9

mhardy6647 wrote: »

I am not the least bit interested in this topic ;-)

Might I just mention that there is only one Class A: it means output devices biased "on" 100% of the time. No ifs, ands, or buts. It is extremely inefficient; an amplifier operating in Class A dissipates maximal power at idle. It actually runs a trifle cooler when amplifying signal! But a Class A amplifier will not have (can not have) any waveform crossover or "notch" distortion.

Single ended class A, more specifically, is considered "true" Class A. The Aleph is 30wpc and it idles at 200wpc, meaning the output devices are full on all the time whether a signal is present or not. It makes a nice room heater in Winter.

I again agree 100%. There are so many quasi class A monikers manufacturer's use to create the illusion an amp is class A. Most amps, probably 90%+ on the market are class A/B, meaning they are biased into class A to a point maybe 3-5wpc then they are class B amps. They are not single ended.

If you want an excellent explanation take a look here on pp 5 in the "Under The Hood" section, best analysis I've read so far.

http://www.passlabs.com/pdfs/reviews/XA100.5_eprint.pdf

H9

FTGV

heiney9 wrote: »

There are so many quasi class A monikers manufacturer's use to create the illusion an amp is class A. Most amps, probably 90%+ on the market are class A/B,

Many of which are fine examples of the art of audio amplifer engineering with excellent sonics to boot.

mhardy6647

Don't get amplifier bias classes and amplifier topologies mixed up. Single-ended has to be Class A; you can do push-pull in class A, B or AB (which is essentially an intermediate bias point).
http://www.aikenamps.com/SingleEnded.htm

I'll look at the Pass article (which I've probably seen before)

We won't concern ourselves with Class AB1 and AB2 at this time :-)

http://www.aikenamps.com/ClassA.htm

N.B. I like the vacuum tube references because the concepts are (for me, at least) easier to understand in the context of tubes. The definitions and applications are identical for solid state amps, too, though.

megasat16

FTGV wrote: »

Yes on the earlier KSA's.All PP I believe.D'Agostino seemed to favour fully complimentry-symmetrical circuits and did'nt mind throwing lots of parts at a design.

Yep....

FTGV wrote: »

Many of which are fine examples of the art of audio amplifer engineering with excellent sonics to boot.

and Yep! There are really nice Class A (not only SE but other) amps and then, there are really nice Class AB amps.

heiney9

FTGV wrote: »

Many of which are fine examples of the art of audio amplifer engineering with excellent sonics to boot.

Fred, didn't mean to infer there weren't some great ones, but many are marketing department terms that are used to mislead.

New Class A, Dynamic Class A, Super linear Class A, Dynamic Linear Drive, and on and on..........

H9

FTGV

heiney9 wrote: »

Fred, didn't mean to infer there weren't some great ones

OK cool Brock ,was'nt sure if you were headed that direction or not given your very high bias toward a particular flavour.

FTGV

heiney9 wrote: »

New Class A, Dynamic Class A, Super linear Class A, Dynamic Linear Drive, and on and on..........

H9

I'll add having owned one back in the day some of these Japanese sliding bias quasi Class A designs were real dogs.Prime examples of measurements not corelating with the sound.

megasat16

FTGV wrote: »

I'll add having owned one back in the day some of these Japanese sliding bias quasi Class A designs were real dogs.Prime examples of measurements not corelating with the sound.

But but...they are not NP love child 30s.

I kid, H9. I kid.

Last Word in this amp thread that goes nowhere....

Bigger is not always better! But there are certainly Bigger and Better things in Life.

"NEED" DOES NOT EQUAL TO "WANT"! Kudos to those who can live with the "need" and live without the "want". I am trying hard to be among you one day.

Peace out! :biggrin:

pearsall001

Here's an interesting article that compares two quality amps, a 2watt amp & a 200watt amp with some very interesting results. The results didn't surprise me though. It pretty much confirms what's been talked about in this thread. Give it a read.
http://news.cnet.com/8301-13645_3-20029188-47.html?tag=cnetRiver

TroyD

BlueFox wrote: »

Sorry, for not being engineering precise. :rolleyes:

In bridged mono mode they are rated at 800W/ch into 4 ohms. Class A for some initial number of watts, and then switching to class B. I have not been able to find any spec, or review, where they say at what point it switches between class A to class B. However, since I mostly listen to classical in the 60-70db range I suspect most of the time it is operating in class A mode. It sure generates the heat for that. I love it in the winter, but in the summer it can get unbearable. I need to get the AC fixed.

Last night I did an experiment after I posted. I just threw out the 120db number. Its purpose was not be an exact figure, but just to indicate that when it is loud it still is clear and precise, but you cannot talk to the person next to you. I put Lady Gaga on and cranked it up to 105db. That happened at -35db on the dial. Anyway, at 105db she was just loafing and more than happy to go higher, but I chickened out since I did not want my neighbors calling the police.

Well, if you are just going to throw random numbers out, why bother? I mean, what does it add to the conversation? I'm not an engineer either but if I'm going to add something to a conversation I try to be at least somewhat educated on what I'm talking about, especially if I'm trying to make a point.

BDT

george daniel

Good read,, I'm finding that as I get oler and my music taste's change,that tubes (for me) are much more appealing than the mega watt sand amps,,IMHO,,tubes really shine with acoustic and vocals,,much more intimate,,I think that my next tube amp will use EL -84's and not push more than 40 watts.The only one that I regret selling was an Audible Illusions L-1/Belles 350a combo,, it was truly a match made in heaven.Just my two cents worth.

quadzilla

pearsall001 wrote: »

Here's an interesting article that compares two quality amps, a 2watt amp & a 200watt amp with some very interesting results. The results didn't surprise me though. It pretty much confirms what's been talked about in this thread. Give it a read.
http://news.cnet.com/8301-13645_3-20029188-47.html?tag=cnetRiver

It is an interesting article, but brings up a point I haven't seen mentioned (though admittedly, I haven't read every post in this thread). Specifically, that low watt amps are great, but only when paired with highly efficient speakers. 2 watts would probably sound great on my Frazier Concerto Ds, but not so great on my RTi12s.

As is oft mentioned around here, it's all about finding synergy.

thsmith

Have not read all the post on this one but how does one determine "high current" and should current ratings be toughted more so than wpc ?

tonyb

thsmith wrote: »

Have not read all the post on this one but how does one determine "high current" and should current ratings be toughted more so than wpc ?

WPC sells gear to the average consumer. Ever see those HTIB systems that say 800 watts on them ? You put current on a box, the average consumer will go "WTF is that ?"

newrival

interesting quick read on why WPC, the FTC in regards to wattage, and current:

http://www.angelfire.com/electronic/funwithtubes/Amp-FTC-Power.html
http://www.n4lcd.com/RMS.pdf
http://www.stereophile.com/asweseeit/489/

well discussed in this thread:
http://www.audiokarma.org/forums/showthread.php?t=153734

also, a way to check an amp's current is to look at it's specs.
the ones to look at are current (peak to peak) and dynamic headroom.

dynamic headroom is pretty good insight. if you have a 100WPC amp with 3db of IHF dynamic headroom, it is saying that it can deliver instantaneous 200WPC from reserves. This is what keeps a low powered SS from clipping.

BlueFox

TroyD wrote: »

Well, if you are just going to throw random numbers out, why bother? I mean, what does it add to the conversation? I'm not an engineer either but if I'm going to add something to a conversation I try to be at least somewhat educated on what I'm talking about, especially if I'm trying to make a point.

LOL. You really are clueless.

I guess you would prefer something more precise. For example, "You don't need close to 200wpc".

mhardy6647

ahem ;-)

cnh

So what speakers is that Realistic amp hooked up to, Mhardy?


cnh

mhardy6647

That's a test amp :-)
...at the moment, it is hooked to these interesting, utterly bizarre "coaxes" (albeit nominally coaxes!) that I found at the dump yesterday.

stuwee

Great thread, lot's of interesting posts. I have Martin Logan Sequel's, they need current and alot of watts, 200 is more than enough for the room, Lower watts with tubes late at night is magic. I'd love to have a big bruiser SAE 2500 like joeparaski has just for the meters! I have to say my little SAE A202 (100@8ohms) works great with the 'Logans, nice and tight, it seems to sound better when it's 'loaded down', if that makes sense? It must be part of the design, some amps might squawk and distort with a heavy load. 2 ohms is vicious for an amp to deliver with a high current draw.

Do I like power? Hell yeah but little SET tube amps have a special place for me too!!

BtrSound

I am thinking about getting a Rotel RB-985, which is rated at 100wpc and a DIM of 220 wpc. You can see from my signature what my set up is. I primarily watch movies, and when I listen to stereo, I like to listen in Multi Channel, so I do like it loud. Do you all think that this amp would be a good choice or do you think I should step up to something bigger? I am a newbe. I have read this thread, and am more confused if anything, so you all are the experts. I also noticed that you all have higher end amplifiers, which I assume also makes a difference.

here are the Amp specs: http://www.rotel.com/content/manuals/rb985_eng.pdf

If this is not a good choice, what would you recommend. I plan on using the 5 channels fro the front three and rear two and leaving the side two powered by the Denon, since they are used the least.

Also, it's max current output is 40 amps, should I look for something higher?

newrival

BtrSound wrote: »

I am thinking about getting a Rotel RB-985, which is rated at 100wpc and a DIM of 220 wpc. You can see from my signature what my set up is. I primarily watch movies, and when I listen to stereo, I like to listen in Multi Channel, so I do like it loud. Do you all think that this amp would be a good choice or do you think I should step up to something bigger? I am a newbe. I have read this thread, and am more confused if anything, so you all are the experts. I also noticed that you all have higher end amplifiers, which I assume also makes a difference.

here are the Amp specs: http://www.rotel.com/content/manuals/rb985_eng.pdf

If this is not a good choice, what would you recommend. I plan on using the 5 channels fro the front three and rear two and leaving the side two powered by the Denon, since they are used the least.

Also, it's max current output is 40 amps, should I look for something higher?

do you know the sensitivity of your speakers? if not what brand/model? Thats a good amp, we just need some other details to make sure it will get you the most bang for your buck, since the "bang" is what seems to be important in your system