Based on a design by Knut Harald Nygaard. Frequency range from dc to above 1 Mhz, 40W output, slewrate 200 V/uS. Been on my system for the past three or so years, having replaced a Plinius integrated. They sound exceptionally good to me, hope you like the pics.
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Judging only by the thread title, I'd hazard a guess the design is fig. 4.4. of this article:
DC Coupled Amplifiers for Audio
DC Coupled Amplifiers for Audio
Well, if anyone would know, it would be you!
So, have you done a FFT of the harmonics?
And, what is ur position on the relatively high THD figure of 0.02%?
How does that look at a higher freq, btw?
Asking a few other things too...
why not an F5 (similar power level, lower parts count, and same input pretty much)
and also... aw crud, lost the thought...
interesting design idea...
_-_-bear
So, have you done a FFT of the harmonics?
And, what is ur position on the relatively high THD figure of 0.02%?
How does that look at a higher freq, btw?
Asking a few other things too...
why not an F5 (similar power level, lower parts count, and same input pretty much)
and also... aw crud, lost the thought...
interesting design idea...
_-_-bear
Lol, yes, that's the one. Only difference is that I doubled the output transistors and added some bells and whistles to it.
I didn't know you posted here, so I'll take the chance to congratulate you on a wonderful design. This was my third attempt at trying to build something that would replace the Plinius. I built the Hiraga 20W which sounded very sweet, but didn't have enough power, then the KSA50 which I hated, and then yours, which I fell in love right from the first moment I heard it.
At first I didn't want to waste money on the front pannels because I wasn't sure if it would be just a fad, but three years latter I think they deserved a nice face plate. So I ordered some and took some pics while I was at it, hence this thread now. (btw, where are all my posts from back then???).
The monoblocks are being driven by a preamp based on Walt's composite with the AD811 and are driving a couple of ATC SCM12 monitors.
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looks like schematics are here: http://www.andiha.no/articles/audio/powerfig/klassea1.gif
Knut, I'm surprised that you "hated" the KSA50 - I'd be curious to know a bit more about why you didn't like it ?
Knut, I'm surprised that you "hated" the KSA50 - I'd be curious to know a bit more about why you didn't like it ?
Hi, its me that said that not Knut. I remember the KSA50 as something dull, not very high-end, more like hi-fi. It didn't do anything obviously wrong, but it didn't excel in any area either. This is just my opinion, I know there's a lot of people happy with it so just a matter of taste.
You must be a F5 fan, I dont like its sound at all, with BW 604s it sounds thin lifeless, weakest amp on bass Ive ever played through my system, the only good I found is the mids and highs are as good as or better than my electrocompaniet but overall its a far cry. Like they say, one mans gold is another mans junk. They may work better with other speakers but at the moment Im not going to change speakers just to suit a particular amp.
Nice solid designs that should perform and sound pretty good.
Interesting vas that is used, ever try hawksford or baxandall type vas on these amps ??
The F5 amp is a chameleon of sorts. The sound alters depending on the power supply, the bias points, the output devices used, and other subtle factors like the resistors too... I happen to not use them on bass - I usually use a Crown MacroTech (ultra high DF, eh?) for that, the F5 was heard on a pair of horns with compression drivers (it is only <25watts), so the "first watt" bit definitely applies. It was scary good, this particular implementation. The same physical amp with other parts and other variations sounded a bit flat and dull. Odd that it does change like that. All OT, and FYI, imho, etc...
I am interested in this amp though...
@Andrew, are you suggesting that the FB should be returned as current only?? Is there a schematic you can post that shows this being done? I do not know.
_-_-bear
Good ears you have there. Or at least, we may have the same preference.
For me it is so obvious. For others, even after hearing them, they will not be able to decide.
Something is definitely wrong with KSA50 and almost all Krells. I think KSA50 is so popular because it gives unique mid-range character to "impress" inexperienced listeners.
My hypothesis is simple, and may be scientifically illogical, but who cares, and I don't want to try to explain. But I strongly believe that you should not take the output from both drivers emitter and output emitter like that` kind of output arrangement (attachment).
It is better to connect the positive-side driver's emitter to negative-side driver's emitter (floating). Even grounding the emitter seems to be a bit better. For perfection, I don't even like it when the VAS (like in the Knut's amp), grounded.
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