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Old 26th June 2012, 11:53 AM   #6441
SY is offline SY  United States
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There's a thread for this sort of thing ("Car Talk") in the Lounge.
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Old 26th June 2012, 12:51 PM   #6442
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Quote:
Originally Posted by dvv View Post
One pair! For the love of Christ
For folks who audited the Grand Integra M510 many times, it may be somewhat uncomfortable so witness an Onkyo power amplifier with a single pair of output devices.
Even for the ones who saw budget amps as a Rotel RB850 hit the market it's somewhat odd.

Not so strange if one looks at the extension of the market, a couple of hundred dollars for a power amp that fits in a home theatre surround setup is good enterprising.
I can't imagine anyone in his right audio mind to hook up a power amp, that's not even power rated at 4 ohm, to heavy duty loudspeakers.
The "audiophile" solid state types i see at this forum (and others) in general build way less undersized power amps for the kind of loudspeakers they have (though often mismatched, e.g. a SE class A amp combined with << 90dB/2.83V loudspeakers that have a minimum impedance under 4 Ohm)

Plenty of multi-channel power amps with single pair output stages on the market, but the M-282 is indeed an eyebrow raiser for the oldfashioned power orientated (A1943/C5200).
Goes to show what a softy powersupply and early/rigid 9-pin IC protection can achieve.

(car lounge : Chevy LS9 and aftermarket crate engines, lower $/hp than the '90s 502ci mk6)
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Last edited by jacco vermeulen; 26th June 2012 at 12:56 PM.
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Old 26th June 2012, 01:14 PM   #6443
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There is another point to multiple devices . Better Ft . Like Douglas Self did many NE5532 as a power amp , one can do multiple drivers as outputs . D44/45 perhaps ? Even BD139/140 with care . I suspect some of the super transistors are exactly that .

As you say the budget Rotels had 8 outputs total ( RA 820 , super fast and enough for 100 W amp ) . RA 820 was a conservative 25 W ( 35 W 4R and great into 1 ohm on bursts ) .

http://www.rotel.com/content/manuals...ved/ra820b.pdf

Last edited by nigel pearson; 26th June 2012 at 01:19 PM.
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Old 26th June 2012, 01:16 PM   #6444
dvv is offline dvv  Serbia
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Quote:
Originally Posted by jacco vermeulen View Post
For folks who audited the Grand Integra M510 many times, it may be somewhat uncomfortable so witness an Onkyo power amplifier with a single pair of output devices.
Even for the ones who saw budget amps as a Rotel RB850 hit the market it's somewhat odd.

Not so strange if one looks at the extension of the market, a couple of hundred dollars for a power amp that fits in a home theatre surround setup is good enterprising.
I can't imagine anyone in his right audio mind to hook up a power amp, that's not even power rated at 4 ohm, to heavy duty loudspeakers.
The "audiophile" solid state types i see at this forum (and others) in general build way less undersized power amps for the kind of loudspeakers they have (though often mismatched, e.g. a SE class A amp combined with << 90dB/2.83V loudspeakers that have a minimum impedance under 4 Ohm)

Plenty of multi-channel power amps with single pair output stages on the market, but the M-282 is indeed an eyebrow raiser for the oldfashioned power orientated (A1943/C5200).
Goes to show what a softy powersupply and early/rigid 9-pin IC protection can achieve.

(car lounge : Chevy LS9 and aftermarket crate engines, lower $/hp than the '90s 502ci mk6)
I think it's because it's black.

There will always be a way to rationalize anything. Personally, I think it's an outrage from a company I believed to be wiser than most. Period.
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Old 26th June 2012, 01:20 PM   #6445
dvv is offline dvv  Serbia
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Quote:
Originally Posted by nigel pearson View Post
There is another point to multiple devices . Better Ft . Like Douglas Self did many NE5532 as a power amp , one can do multiple drivers as outputs . D44/45 perhaps ? Even BD139/140 with care . I suspect some of the super transistors are exactly that .

As you say the budget Rotels had 8 outputs total ( RA 820 , super fast and enough for 100 W amp ) . RA 820 was a conservative 20 W ( 35 W in truth and great into 1 ohm on bursts ) .
The key downside to multiple output devices is pairing them. When your output switches, it has to be in as much unison as possible.

The rest is all advantages, bless their little emitters.
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Old 26th June 2012, 01:29 PM   #6446
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I think that's what emitter resistors help with . As far as I know 0R33 will swamp any differences . Mostly the voltage points are very similar on the same device type . Not so MOSFET's . Do NPN and PNP ever make true pairs ? Some still argue for Quasi comp .

Talking of multiples ( forgive ) .

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Old 26th June 2012, 01:44 PM   #6447
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Quote:
Originally Posted by nigel pearson View Post
Do NPN and PNP ever make true pairs ?
A few oldies are.
Example : 2sa968/2sc2238
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Old 26th June 2012, 01:47 PM   #6448
wahab is offline wahab  Algeria
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Quote:
Originally Posted by dvv View Post
I think it's because it's black.
..


Onkyo M-510 on thevintageknob.org

Last edited by wahab; 26th June 2012 at 01:50 PM.
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Old 26th June 2012, 01:59 PM   #6449
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Well back to ripple in power supplies. If you set 2% ripple as your goal UNDER FULL LOAD, then the ripple will be much less at normal output levels. That of course will depend on you amplifier topology.

Most of those funny amplifiers with the red hot glass transistors use more filter stages for the input and gain stages than the output stage. The more normal solid state amplifiers often have an additional RC filter on the input stage.

Now for those who pay attention to critical band research around 30 db of suppression of the low frequency ripple may just be adequate for most users! This seemingly high level would be masked by the actual music content and from the effect of what is shown in the Fletcher Munson research.

Now my OPINION is that those with experience or training can detect artifacts which would be caused by 2% ripple. That would be -34 db at full power without feedback.

But the vast majority of audio gear in production really does have 2% or more power supply ripple at full load.

So a reasonable experiment would be to design a power supply with 2% ripple and a moderately high value resistor bypassed by a switch to a larger capacitor bank that would reduce the ripple to .2%. As the resistor should keep the bank charged you could switch it in and out without harm. Then one could actually listen to see what effect the larger bank really did produce.

Of course that would take all of 10 minutes and B... about it wastes much more time.

Last edited by simon7000; 26th June 2012 at 02:03 PM.
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Old 26th June 2012, 02:19 PM   #6450
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Interesting, So can we consider 2% the magic starting point for ripple ..?
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