So I did a bit of reading on the subject. Krell claims that the FPB amps can deliver Class A power to its full rating. Due to a process called Sustained Plateau Bias II it raises and lowers the bias as demand dictates. Of course this is what Krell has to say in the owner's manual.
In practice, it does an amazing job of performing this function. A Google search on sustained plateau bias 2 brings up much interesting reading. And I found one article where the writer performed some tests on my exact amp, which makes it all the more interesting for me anyway.
http://audioinvestigations.blogspot....teau-bias.html
Some mumbo jumbo about what he measured as he pushed the amp. It seems it has about 4 levels of bias it jumps back and forth between as required. Keeping it in Class A at all times. Well all times except if it runs hot. If the amp gets too hot, it will lower the bias level and let it run into A/B to keep the temp within safe parameters. Or if it runs out of current. So, that brings up many variables. Speaker load, current demands, room temp, and the volume you are trying to achieve, and others. But, if your speakers present an easy load, and your room is cool, and you aren't trying to break the windows, it should remain in Class A pretty much all the time.
If you really want to get into some heady reading, I read most of this:
https://books.google.com/books?id=7d...s%20II&f=false
That really takes me back to my college days. Great stuff if you're having trouble sleeping. And there was a whole page on Google on the subject, if anyone was interested enough to read it all. But these modern designs allow us to have large class A amps that would have been cost and weight prohibitive in the past. Not that a $10k amp that weighs 130lbs is practical.
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My MF A1000 was supposedly class A all the way. It certainly got damn hot and had a lot of cooling fins.
Regards,
Grant .... ؠ ......Don't be such a big girl's blouse
I've said it before and I'll say it again: democracy simply-doesn't-work.... ..... ...... ...... ................... ..... ..... ..... ..... .....
FIIO K7 BT, M11 PLUS, BTR7, KA5 - OPPO BDP-103D - PANASONIC UB450 - PANASONIC 4K ULTRA HD TV - PIXEL 6 - AVANTREE LR BLUETOOTH - 2* X600 SOUNDCORE - HEADPHONES INCLUDE, FIIO, NURAPHONES', FOCAL, OPPO, BOSE, CAMBRIDGE, BOWER & WILKINS, DEVIALET, MARSHALL, SONY, MITCHELL & JOHNSTON - 2*ZBOOK'S- MERCURY BD ROM, ROON, QOBUZ, TIDAL, PLEX, CYBERLINK, JRIVER - MULTI HDD'S -
Oh my god! There's nothing wrong with the bidet is there?
“Nothing discloses real character like the use of power. It is easy for the weak to be gentle. Most people can bear adversity. But if you wish to know what a man really is, give him power. This is the supreme test. It is the glory of Lincoln that, having almost absolute power, he never abused it, except on the side of mercy".
“You see these dictators on their pedestals, surrounded by the bayonets of their soldiers and the truncheons of their police ... yet in their hearts there is unspoken fear. They are afraid of words and thoughts: words spoken abroad, thoughts stirring at home -- all the more powerful because forbidden -- terrify them. A little mouse of thought appears in the room, and even the mightiest potentates are thrown into panic.”
"You don't have free will. You have the appearance of free will.”
“There's a war out there, old friend. A world war. And it's not about who's got the most bullets. It's about who controls the information. What we see and hear, how we work, what we think... it's all about the information!”
***SMILE, BE HAPPY***
Location: KY - Scotland
Posts: 5,495
I'm Mike.
My wife says I'm Class A and I'm definitely hot all the time 😊
But I might be biased 😂
Regards,
Grant .... ؠ ......Don't be such a big girl's blouse
I've said it before and I'll say it again: democracy simply-doesn't-work.... ..... ...... ...... ................... ..... ..... ..... ..... .....
FIIO K7 BT, M11 PLUS, BTR7, KA5 - OPPO BDP-103D - PANASONIC UB450 - PANASONIC 4K ULTRA HD TV - PIXEL 6 - AVANTREE LR BLUETOOTH - 2* X600 SOUNDCORE - HEADPHONES INCLUDE, FIIO, NURAPHONES', FOCAL, OPPO, BOSE, CAMBRIDGE, BOWER & WILKINS, DEVIALET, MARSHALL, SONY, MITCHELL & JOHNSTON - 2*ZBOOK'S- MERCURY BD ROM, ROON, QOBUZ, TIDAL, PLEX, CYBERLINK, JRIVER - MULTI HDD'S -
Oh my god! There's nothing wrong with the bidet is there?
“Nothing discloses real character like the use of power. It is easy for the weak to be gentle. Most people can bear adversity. But if you wish to know what a man really is, give him power. This is the supreme test. It is the glory of Lincoln that, having almost absolute power, he never abused it, except on the side of mercy".
“You see these dictators on their pedestals, surrounded by the bayonets of their soldiers and the truncheons of their police ... yet in their hearts there is unspoken fear. They are afraid of words and thoughts: words spoken abroad, thoughts stirring at home -- all the more powerful because forbidden -- terrify them. A little mouse of thought appears in the room, and even the mightiest potentates are thrown into panic.”
"You don't have free will. You have the appearance of free will.”
“There's a war out there, old friend. A world war. And it's not about who's got the most bullets. It's about who controls the information. What we see and hear, how we work, what we think... it's all about the information!”
***SMILE, BE HAPPY***
Arkless Electronics-Engineered to be better. Tel. 01670 530674 (after 1pm)
Modded Thorens TD150, Audio Technica AT-1005 MkII, Technics EPC-300MC, Arkless Hybrid MC phono stage, Arkless passive pre, Arkless 50WPC Class A SS power amp, (or) Arkless modded Leak Stereo 20, Modded Kef Reference 105/3's
ReVox PR99, Studer B62, Ferrograph Series 7, Tandberg TCD440, Hitachi FT-5500MkI, also FT-5500MkII
Digital: Yamaha CDR-HD1500 (Digital Swiss army knife-CD recorder, player, hard drive, DAC and ADC in one), PC files via 24/96 sound card and SPDIF, modded Philips CD850, modded Philips CD104, modded DPA Little Bit DAC. Sennheiser HD580 cans with Arkless Headphone amp.
Cables- free interconnects that come with CD players, mains leads from B&Q, dead kettles etc, extension leads from Tesco
That was what they said re it... 16 output transistors.. specs were
Power output : 2x 50W (Class A, 8 Ohm)
MC input : 600µV
MM input : 8mV
Line inputs : 350mV
S/N ratio : > 60dB (MC)
> 75dB (MM)
> 85dB (lines)
RIAA accuracy : ±0,7dB
THD : < 0,5% (20Hz...20Khz)
Channel separation : > 85dB
PC : 215W continuous
Dimensions : 48,3 x 12,2 x 33,5cm (A1000)
19,4 x 12,2 x 33,5cm (PSU)
Weight : 11kg (A1000)
7kg (PSU)
Regards,
Grant .... ؠ ......Don't be such a big girl's blouse
I've said it before and I'll say it again: democracy simply-doesn't-work.... ..... ...... ...... ................... ..... ..... ..... ..... .....
FIIO K7 BT, M11 PLUS, BTR7, KA5 - OPPO BDP-103D - PANASONIC UB450 - PANASONIC 4K ULTRA HD TV - PIXEL 6 - AVANTREE LR BLUETOOTH - 2* X600 SOUNDCORE - HEADPHONES INCLUDE, FIIO, NURAPHONES', FOCAL, OPPO, BOSE, CAMBRIDGE, BOWER & WILKINS, DEVIALET, MARSHALL, SONY, MITCHELL & JOHNSTON - 2*ZBOOK'S- MERCURY BD ROM, ROON, QOBUZ, TIDAL, PLEX, CYBERLINK, JRIVER - MULTI HDD'S -
Oh my god! There's nothing wrong with the bidet is there?
“Nothing discloses real character like the use of power. It is easy for the weak to be gentle. Most people can bear adversity. But if you wish to know what a man really is, give him power. This is the supreme test. It is the glory of Lincoln that, having almost absolute power, he never abused it, except on the side of mercy".
“You see these dictators on their pedestals, surrounded by the bayonets of their soldiers and the truncheons of their police ... yet in their hearts there is unspoken fear. They are afraid of words and thoughts: words spoken abroad, thoughts stirring at home -- all the more powerful because forbidden -- terrify them. A little mouse of thought appears in the room, and even the mightiest potentates are thrown into panic.”
"You don't have free will. You have the appearance of free will.”
“There's a war out there, old friend. A world war. And it's not about who's got the most bullets. It's about who controls the information. What we see and hear, how we work, what we think... it's all about the information!”
***SMILE, BE HAPPY***
I would expect that these give class A into 4R, 50W, if they dissipate that much! Nice!
If an amp is specified as say 20W into 8R, class A, then it will only give 10W class A into 4R.... it may well double its power to 40W yes, but only the first 10W will now be in class A. I suspect Barry's amp is biased at probably double the class A current actually needed to give 25W. This is excellent but not cheap!! This means that when the amp is close to voltage clipping into 8R (at 25W) it is still nowhere near to coming out of class A
Arkless Electronics-Engineered to be better. Tel. 01670 530674 (after 1pm)
Modded Thorens TD150, Audio Technica AT-1005 MkII, Technics EPC-300MC, Arkless Hybrid MC phono stage, Arkless passive pre, Arkless 50WPC Class A SS power amp, (or) Arkless modded Leak Stereo 20, Modded Kef Reference 105/3's
ReVox PR99, Studer B62, Ferrograph Series 7, Tandberg TCD440, Hitachi FT-5500MkI, also FT-5500MkII
Digital: Yamaha CDR-HD1500 (Digital Swiss army knife-CD recorder, player, hard drive, DAC and ADC in one), PC files via 24/96 sound card and SPDIF, modded Philips CD850, modded Philips CD104, modded DPA Little Bit DAC. Sennheiser HD580 cans with Arkless Headphone amp.
Cables- free interconnects that come with CD players, mains leads from B&Q, dead kettles etc, extension leads from Tesco
Arkless Electronics-Engineered to be better. Tel. 01670 530674 (after 1pm)
Modded Thorens TD150, Audio Technica AT-1005 MkII, Technics EPC-300MC, Arkless Hybrid MC phono stage, Arkless passive pre, Arkless 50WPC Class A SS power amp, (or) Arkless modded Leak Stereo 20, Modded Kef Reference 105/3's
ReVox PR99, Studer B62, Ferrograph Series 7, Tandberg TCD440, Hitachi FT-5500MkI, also FT-5500MkII
Digital: Yamaha CDR-HD1500 (Digital Swiss army knife-CD recorder, player, hard drive, DAC and ADC in one), PC files via 24/96 sound card and SPDIF, modded Philips CD850, modded Philips CD104, modded DPA Little Bit DAC. Sennheiser HD580 cans with Arkless Headphone amp.
Cables- free interconnects that come with CD players, mains leads from B&Q, dead kettles etc, extension leads from Tesco
Sounded bloody marvellous and I really should have kept it
Regards,
Grant .... ؠ ......Don't be such a big girl's blouse
I've said it before and I'll say it again: democracy simply-doesn't-work.... ..... ...... ...... ................... ..... ..... ..... ..... .....
FIIO K7 BT, M11 PLUS, BTR7, KA5 - OPPO BDP-103D - PANASONIC UB450 - PANASONIC 4K ULTRA HD TV - PIXEL 6 - AVANTREE LR BLUETOOTH - 2* X600 SOUNDCORE - HEADPHONES INCLUDE, FIIO, NURAPHONES', FOCAL, OPPO, BOSE, CAMBRIDGE, BOWER & WILKINS, DEVIALET, MARSHALL, SONY, MITCHELL & JOHNSTON - 2*ZBOOK'S- MERCURY BD ROM, ROON, QOBUZ, TIDAL, PLEX, CYBERLINK, JRIVER - MULTI HDD'S -
Oh my god! There's nothing wrong with the bidet is there?
“Nothing discloses real character like the use of power. It is easy for the weak to be gentle. Most people can bear adversity. But if you wish to know what a man really is, give him power. This is the supreme test. It is the glory of Lincoln that, having almost absolute power, he never abused it, except on the side of mercy".
“You see these dictators on their pedestals, surrounded by the bayonets of their soldiers and the truncheons of their police ... yet in their hearts there is unspoken fear. They are afraid of words and thoughts: words spoken abroad, thoughts stirring at home -- all the more powerful because forbidden -- terrify them. A little mouse of thought appears in the room, and even the mightiest potentates are thrown into panic.”
"You don't have free will. You have the appearance of free will.”
“There's a war out there, old friend. A world war. And it's not about who's got the most bullets. It's about who controls the information. What we see and hear, how we work, what we think... it's all about the information!”
***SMILE, BE HAPPY***