Hard to believe if it is the "normal" class A. Of course no disadvantage that's why this can be use for marketing advantage as well.
I have built two amps that switch to class B above 30W or more. One of them is the famous JLH amp. Some old amps like Marantz have amps with manual switch to change the design from high power class B to low power class A.
One design goal that will compromise sound quality is the safety and stability. PA amps are clearly need to be bullet proof.
Bryston could be a better amp, and there are many better amps for home use. You just need headroom for your typical speaker.
That's not the safety/stability I'm talking about.
PA amps should be "bullet proof". There are many things that can happen in the "field". People may parallel many speakers such that the amp must be stable with very low impedance. Amp must be stable against cable capacitance also. High power amps especially PA ones must have current limiters, over voltage protection, and so on.
Bring a high end amp to the field intended for PA, and it will blow up.
The compromise of the stability can be for example in the limited bandwidth, slew rate, etc.
The same amp, can be modified to have better sound quality but less stability, by, for example, reducing the miller compensation.
Those complex amps DO have different sound character/quality than the Zeus or ZCA posted by Steve. And this is what makes confusion to a lot of people regarding why bad recording can sound bad with "good" speakers.
I don't do small, I like a bit of headroom.
My woofers are 91dB/1W and run off 350Wrms, mids 95dB and get 250W, treble about 107dB with 175W and a 95dB supertweeter driven by 70W.
(I didn't choose them, they chose me by being available cheap s/h. Since I got them s/h prices more than doubled for them. I paid £825 for the lot which is less than the smallest one costs new.)
The first 3 all use MC2 Audio amps which I like a lot. To me they sound a fair bit better than the Brystons I've heard.
Or any other amp for that matter.
I might change speakers/drivers but I will definitely keep the MC2s.
@Jay MC2 doesn't use that in marketing at all. It just came up during a telephone conversation I had with their designer Ian McCarthy who used to work closely with some guy called Tim de Paravicini when he founded E.A.R.. The other MC2 designer founded Klark Teknik in the '70s.
Previously I mentioned about the two amplification "styles" as also questioned by other poster. Both has its own strength or character.
I like to have both strengths and characters in my amps. But if you only have the strength of one amplification "style" you will never know what has been missing.
Indeed, sonic, woofer control, or the likes, are the most important parameter for enjoyable sound. For this you need headroom (or overrated current supply and power), trans-conductance, and the like.
The better the above performance, the more you like it.
But if your system also maintain the characters of the other "style". An improvement in one character may be a degradation with the other character.
In my systems, I have never been able to incorporate opamps or switching supply without degrading a character that I like to maintain. That is a "character" that you can hear with a Zeus or ZCA.
It is a tough job, because those two different "characters" are rarely can go together.
I've got no issues with op amps.
Whatever recording you listen to it will have gone through dozens if not hundreds of them.
There is no such thing as an op amp free recording chain.
As for switching I have no opinion as I have never owned or listened at length to a class D amp or one with a switching PSU.
With regards to 'character' I'd prefer my amps not to have any.
Whatever recording you listen to it will have gone through dozens if not hundreds of them.
There is no such thing as an op amp free recording chain.
As for switching I have no opinion as I have never owned or listened at length to a class D amp or one with a switching PSU.
With regards to 'character' I'd prefer my amps not to have any.
Yes i can see that. And i understand that also.
Recording quality =/= reproduction quality
If you listen to the class D ncore, you will like them better than the mc2, i'll guess.
Many PA amps use switching. You need very hi voltage to get very hi wattage. And most transistors cannot handle the required voltage. Hence switching.
Those who say that cone materials have characters usually have more sensitive ears than those who say that there is such thing as wire with gain.
I doubt I would but if you feel like sending me an nCore I'd give it a go. ;-)
MC2 also make amps with switching PSUs which I spent a few hours with alongside my non-switching ones. They sounded identical to me. The audio circuitry is identical so I wouldn't expect much difference anyway.
We also had a Phase Linear around which was quite poor in comparison.
It was noisy with a flabby bass, some harshness and lacking in detail.
Recently MC2 introduced their own take on class D but 2500W/8Ohm per ch. (9600W bridged) is seriously over the top. I have not heard those knowingly.
As for cone material I very much prefer paper to the alternatives.
I'll keep on championing this Visaton TW 70 cone tweeter. 
But you folks are currently interested in amplifiers. This is what I currently use:
Decent Rotel RA-931 25Wpc tranny amp. A Class AB output amp with two opamp stages in the preamp.
The correct way to use an opamp is like this:
In practise you compromise good Common Mode rejection with tone controls and gain control. It's worth remembering that good mixing desks usually use 600 ohm balanced line rather than unbalanced "whatever it is" that HiFi amps use. So, yes, mixing desks used loads of NE5534 opamps or similar, but they use them CORRECTLY.
Let's take you young whippersnappers down memory lane with the classic Radford STA25 valve power amp, which used an entirely transistor preamp stage.
Good bit of gear, that. The trick was to get the valve bias right, then it sang sweetly in the midrange and could convince you the musicians were in the room. In those days the usual setup was a Goodmans 10" woofer and 3" tweeter in a big closed box. I know AllenB remembers it well.
(Historical note. I lent my Radford to my brother, who blew it up and sold it for a tenner. Idiot.)
But you folks are currently interested in amplifiers. This is what I currently use:
An externally hosted image should be here but it was not working when we last tested it.
Decent Rotel RA-931 25Wpc tranny amp. A Class AB output amp with two opamp stages in the preamp.
The correct way to use an opamp is like this:
An externally hosted image should be here but it was not working when we last tested it.
In practise you compromise good Common Mode rejection with tone controls and gain control. It's worth remembering that good mixing desks usually use 600 ohm balanced line rather than unbalanced "whatever it is" that HiFi amps use. So, yes, mixing desks used loads of NE5534 opamps or similar, but they use them CORRECTLY.
Let's take you young whippersnappers down memory lane with the classic Radford STA25 valve power amp, which used an entirely transistor preamp stage.
An externally hosted image should be here but it was not working when we last tested it.
Good bit of gear, that. The trick was to get the valve bias right, then it sang sweetly in the midrange and could convince you the musicians were in the room. In those days the usual setup was a Goodmans 10" woofer and 3" tweeter in a big closed box. I know AllenB remembers it well.
(Historical note. I lent my Radford to my brother, who blew it up and sold it for a tenner. Idiot.)
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Saw a cheap Rotel the other day
I almost bought a cheap s/h Rotel RA 820 (?) almost too cheap to pass up, but I didnt have the time, at the time. Also at (i think) 25WPC its a little too similar to the Cambridge A1 I have already.
Mind you, can one have too many nice SS amps?
I almost bought a cheap s/h Rotel RA 820 (?) almost too cheap to pass up, but I didnt have the time, at the time. Also at (i think) 25WPC its a little too similar to the Cambridge A1 I have already.
Mind you, can one have too many nice SS amps?
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I almost bought a cheap s/h Rotel RA 820 (?) almost too cheap to pass up, but I didnt have the time, at the time. Also at (i think) 25WPC its a little too similar to the Cambridge A1 I have already.
Mind you, can one have too many nice SS amps?
What!!? We're DIYers! Why not build one or two better DIY amps which you can find at every corners of this site.
True Jay, but show me an amp including PSU, which I can build for less than the Rotel (£40) and id do it. I built Rod Elliots P3 with a 500VA PSU and paralleled devices, several years ago for a college project. The 8 Bourns TIP2955/3055 cost £40 without the rest. Donated that to the college in the end. If i ever go active with a speaker project Id have more of an excuse
I'll keep on championing this Visaton TW 70 cone tweeter.
But you folks are currently interested in amplifiers. This is what I currently use:
An externally hosted image should be here but it was not working when we last tested it.
Decent Rotel RA-931 25Wpc tranny amp. A Class AB output amp with two opamp stages in the preamp.
That looks like my Rotel Tuner. If there is one piece of equipment that is gauranteed to give me listening fatique it's that damn tuner. I should have taken it back the day I bought it (but was probably to sad about the state of the rest of my system after hearing what $100,000 of high end gear could sound like!)
Have you modded the tuner in any way Steve? Mine is awful!!
Tony.
Lucky me. I have bought a lot of better amps in broken condition. I use the power supply and transistors but never bothered with the original circuit.
You don't like multi amping system??!If i ever go active with a speaker project Id have more of an excuse
no I like, I just dont possess an active system.
Im working on an active version of my TQWP, but so far im looking at a five pole op amp based LP, with a series protection cap and 4 pole HP. With what I use passively the result is similar.
Due to the lack of driver coupled reactors the extra active poles were necessary to align phase and smooth the response to mimic my passive equivalent simulation (+/- 1dB through the most important ranges).
Its a work in progress and i dont like the Q that a couple of the 2nd order stages require, a Q of 1 in one stage. Im not sure thats a good idea so Im reading around and trying to lower the higher Q filter stages.
Im working on an active version of my TQWP, but so far im looking at a five pole op amp based LP, with a series protection cap and 4 pole HP. With what I use passively the result is similar.
Due to the lack of driver coupled reactors the extra active poles were necessary to align phase and smooth the response to mimic my passive equivalent simulation (+/- 1dB through the most important ranges).
Its a work in progress and i dont like the Q that a couple of the 2nd order stages require, a Q of 1 in one stage. Im not sure thats a good idea so Im reading around and trying to lower the higher Q filter stages.
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An externally hosted image should be here but it was not working when we last tested it.
RT 950-BX tuner. Yes it does sound awful! Dull. But I don't use radio much since they stopped playing whole intelligent albums and went for the hits.
In fact Rotel are beautifully engineered to a price point aka the Balanced Design Concept, and go on for years. I expect I could replace some output electrolytics with polypropylene and stuff, which was really often the only difference between the pricey models and the budget ones. I did this to a cheap Marantz CD player and it then sounded awesome.
Like most guys, my Ex ended up with most of my stuff driving her TV sound...
Gone are the Delta Sigma DACs and preamps and bridged mode power amps, and in fact it got to a huge heavy stack of 6 units before I decided it was getting out of hand:
An externally hosted image should be here but it was not working when we last tested it.
But I still love Rotel. My man at the local shop sprays the switches every couple of years, makes a difference.
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If this thread is stiil making point of what was posted to be, I would say one big midrange driver one tweeter underneath a silk dome tweeter because it makes the best of both worlds and 2 x 16cm bass drivers per speaker unit because more that often hits the spot with precise shaped kick bass! You could go certainly on the bass up to 22 cm but not more than that because that is another plot and another scenery that comes with it aswell!
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