Apexorca systems

[Apexorca]

Originally Posted by Charles

Beautiful Carl! I love your whole system but seeing those Krell 750 FPB monoblocks brings back wonderful memories. These are special amps and the equal of anything on the market today. Perfect for you system.

Best,

Charles

Thanks!

I'm thinking about by-amping my spikers with one more pair of Krell 350Mc. One pair for the treble and midrange and one pair for the 15´woofers. I'v read about this. My speakers respond very well to by-amping. Even tri-amping is possible and it sounded really great I'v heard.

[Charles]

Carl, If those are FPB 350's I agree. I owned a FPB 700 stereo amp (700 watts.ch). It was a monster. Can you find a pair? Are they available?

[Apexorca]

Originally Posted by Charles

Carl, If those are FPB 350's I agree. I owned a FPB 700 stereo amp (700 watts.ch). It was a monster. Can you find a pair? Are they available?

Thank you for your input. I'm here to learn and get better at this hobby so every point of view and listen to many initiated friends different experiences is to be considered and helpful.

At this point I'm not sure that more power than 350mc delivers is better i my system. I explain why.

I think it is possible to find almost any FPB products if I put in some effort.
Since the range is old it's not possible to contact a dealer and try some products side by side.
More power in the FPB-range is not always better for the over all sound quality. In my system the 350mc delivers power needed. Before I bought the 350mc I'v learned by some former long term Krell dealers, importers and Krell technician in Sweden that the 350mc and 450mcx may be the best over all sounding amp in the FBP series unless your speaker are very demanding and is in the need of even more power. They explain this independently of each other. I can not say that I tried this side by side my selves, but these guys have a lot of experience of Krell since early days and they all are quite confident. They don't think my sound would benefit from bigger Krell amp. I'v been explained that one reason for this can be that the very special and clever way Krell designed the klass A monster power is with a lot of transistors and the more powerfull they are the signal goes through many more transistors. The "original signal" therefore can be affected due to a long signal path through a lot of components, but more powerful. So, the 350mc delivers needed power for my system and therefor I don't get better sound quality from more power.

My Gryphon Antileon, on the other side, with only 150 watt more traditional klass A sometimes starting to have some trouble with higher and more live like volymes and dynamics. Otherwise it sounds really great at lower volymes. My speakers are 92db and lack no power when played with the 350mc. My system really comes to life in better way with Krell. This is even more obvious with a good reel to reel source that is capable of much better dynamics than Vinyl and digital source can deliver. Actually the lack of power in my Gryphon was not really discovered before I tried reel to reel with good quality master copies. Reel to reel, good big speakers and with fast powerful amps delivers the best live like sound you can imagine.
When using a reel to reel machine in your system it will reveal both how good it can sound and where your week parts are. I'v heard this in many systems including my own.

[Charles]

Carl, the key is the peak power demand for the Fenice. Dan A'gostino says that his amps typically should run at no more than 10%. I can say with my XVX, I have never exceeded about 100 watts peak. Typically most material demands between 6-12 watts peak to be quite loud.

Since your Fenice is more sensitive than my XVX you should be fine. I saw a pic of the 750's on the internet. They are monsters. I assumed yours were 750's. I had forgotten just how huge the 750's were. Each one had a 3,000 watt power supply as I understand. My FPB 700 had a 6,000 watt supply.

Certainly, if you plan on bi or tri-amping, use 350's. The only drawback to these amps is their heat and current draw. They run hot despite the sliding class A bias. However, my opinion is that if you can put up with the heat, they are the best amps on the market. D Agostino designed these amps in his prime when electricity was cheap and no environmental concerns. Because of their true class A status, they can never be improved upon. Class A remains the best amplification and always will.

Best,

Charles

[Apexorca]

Originally Posted by Charles

Carl, the key is the peak power demand for the Fenice. Dan A'gostino says that his amps typically should run at no more than 10%. I can say with my XVX, I have never exceeded about 100 watts peak. Typically most material demands between 6-12 watts peak to be quite loud.

Since your Fenice is more sensitive than my XVX you should be fine. I saw a pic of the 750's on the internet. They are monsters. I assumed yours were 750's. I had forgotten just how huge the 750's were. Each one had a 3,000 watt power supply as I understand. My FPB 700 had a 6,000 watt supply.

Certainly, if you plan on bi or tri-amping, use 350's. The only drawback to these amps is their heat and current draw. They run hot despite the sliding class A bias. However, my opinion is that if you can put up with the heat, they are the best amps on the market. D Agostino designed these amps in his prime when electricity was cheap and no environmental concerns. Because of their true class A status, they can never be improved upon. Class A remains the best amplification and always will.

Best,

Charles

Good input! Did not know about Dan's specific headroom-number "Dan A'gostino says that his amps typically should run at no more than 10%." I'll like that!
Headroom for the poweramp working in listening volymes is a good thing. Agree. If the power really is needed, with tricky load that som speakers possess, get more power. Every speaker has it's maximum. For big speakers like mine and yours that can produce sound around 115-120db of I make a fair guess. 120db-130db makes real pain. After that it does not help with more power. The speaker construction, has this limit. More power does not help. Your ears hurts and you get it not louder. So the power should be delivered in more like normal comfortable listening db. Like you say normally probably not over 100watt is needed for that. For most Krell, it's headroom enough. 1 watt makes 92 db spl, thats loud!!! 2 watt makes it 95db, 4 watt 98db, 8watt 101db, 16watt 104db, 32 watt 107db 64, watt 110db, 128watt 113db... should be enough... I think. But its not just 10% of the 350's max prestanda. It's more like 30%. So yes, 113db would use the 750's if watt-power is the only shit. It's a guess, but I don't think so in this case. If I ever try these two amps side by side in my system
I would let you know how the test came out. I promise. Not likely to happen unfortunately, but very interesting.

What do you think about the more subtle characteristics in 350's and 750's? Like timbre, resolution and so on. I'm afraid that you can miss some things there.
Do you think thats true, as "they say"?


I like these kind if discussions.
Thanks Charles.

[Charles]

Originally Posted by Apexorca

Good input! Did not know about Dan's specific headroom-number "Dan A'gostino says that his amps typically should run at no more than 10%." I'll like that!
Headroom for the poweramp working in listening volymes is a good thing. Agree. If the power really is needed, with tricky load that som speakers possess, get more power. Every speaker has it's maximum. For big speakers like mine and yours that can produce sound around 115-120db of I make a fair guess. 120db-130db makes real pain. After that it does not help with more power. The speaker construction, has this limit. More power does not help. Your ears hurts and you get it not louder. So the power should be delivered in more like normal comfortable listening db. Like you say normally probably not over 100watt is needed for that. For most Krell, it's headroom enough. 1 watt makes 92 db spl, thats loud!!! 2 watt makes it 95db, 4 watt 98db, 8watt 101db, 16watt 104db, 32 watt 107db 64, watt 110db, 128watt 113db... should be enough... I think. But its not just 10% of the 350's max prestanda. It's more like 30%. So yes, 113db would use the 750's if watt-power is the only shit. It's a guess, but I don't think so in this case. If I ever try these two amps side by side in my system
I would let you know how the test came out. I promise. Not likely to happen unfortunately, but very interesting.

What do you think about the more subtle characteristics in 350's and 750's? Like timbre, resolution and so on. I'm afraid that you can miss some things there.
Do you think thats true, as "they say"?


I like these kind if discussions.
Thanks Charles.

Carl, Back in those days the Krell dogma was the larger the amp the better the sound. I believe the 750 has a 6,000 watt supply. I believe your 350 has a 3,000 watt supply. These are true monster class A amps. They have no capacitor banks. They have double the number of transistors and these are special transistors. The engineering of these old amps is incredible. The new Dags have capacitor banks. Their power supplies are smaller for a given wattage. They do not run 100% class A. To my mind there is nothing on the market today that can match a Krell FPB 750 monoblock amp. Nothing. Period. Not even close.

So D'Agostino would say that if you want the absolute best, it is the 750. Just look at the thing on the internet. It's huge. But my o my the heat. You would need excellent ventilation. I can't conceive of 4 of them. 6 for tri amping would be unimaginable. But the sound through your Fenice's incredible.

Best Charles

p.s. If you double 750 until you get to 1 ohm you get 6,000. That's why the 750 has a 6,000 watt supply. Using a full CAST system and the KRC HR updated version in excellent working order, there is no better amplification system, IMO. However, these amps are not for me. They run too hot and are too large. I think they are quite reliable but my FPB 700 quit at about 10 years and had to go back to the factory and be completely rebuilt. After that it worked perfectly until I traded it for the Mac 1.2KW's. They did not sound as good as the FPB 700. I am completely satisfied with the sound of my new 1.25's which has a sweeter more detailed sound with excellent bass. But nothing can match a FPB 750, IMO.

[Apexorca]

Originally Posted by Charles

Carl, Back in those days the Krell dogma was the larger the amp the better the sound. I believe the 750 has a 6,000 watt supply. I believe your 350 has a 3,000 watt supply. These are true monster class A amps. They have no capacitor banks. They have double the number of transistors and these are special transistors. The engineering of these old amps is incredible. The new Dags have capacitor banks. Their power supplies are smaller for a given wattage. They do not run 100% class A. To my mind there is nothing on the market today that can match a Krell FPB 750 monoblock amp. Nothing. Period. Not even close.

So D'Agostino would say that if you want the absolute best, it is the 750. Just look at the thing on the internet. It's huge. But my o my the heat. You would need excellent ventilation. I can't conceive of 4 of them. 6 for tri amping would be unimaginable. But the sound through your Fenice's incredible.

Best Charles

p.s. If you double 750 until you get to 1 ohm you get 6,000. That's why the 750 has a 6,000 watt supply. Using a full CAST system and the KRC HR updated version in excellent working order, there is no better amplification system, IMO. However, these amps are not for me. They run too hot and are too large. I think they are quite reliable but my FPB 700 quit at about 10 years and had to go back to the factory and be completely rebuilt. After that it worked perfectly until I traded it for the Mac 1.2KW's. They did not sound as good as the FPB 700. I am completely satisfied with the sound of my new 1.25's which has a sweeter more detailed sound with excellent bass. But nothing can match a FPB 750, IMO.

My KRC-HR with phonostage sounds better than my evo 202 and that was a surprise for me but maybe not for more initiated enthusiasts.
I just read this qoute from an interview with Dan.

HP: Whilst at Krell you created some of the most iconic audio products ever, I certainly remember lusting after some of the big Krell amps in my teens and beyond, which are the products of this time that are standouts for you and why?
DD: The KRC-HR Preamplifier with phonostage and the KSA250 amplifier. Both were milestone products for Krell. They were sonic breakthroughs for my company and sold very well. Our company grew dramatically after the introduction of these models.
HP: What is your sonic philosophy – the core set of beliefs upon which you base your designs – and has it changed over time? How does it differ from that of other manufacturers of high-end amplification?
My sonic philosophy hasn’t changed over time but my approach to how I get there has changed significantly.
In the past, I was always searching for the latest and greatest technology in audio. Sometimes, that pursuit became more important than the end result.
With D’Agostino, I am only interested in the emotional connection that comes with listening to music.

[Apexorca]

What do you all think about Bi-amping. I'm curious about it.
In the 90's I used it in an Arcam set up with two stereo amps. It was ok at that time.
4 monos are tempting.

How would it be with 2 more 350mc? Thats makes 4. One to midrange-tweeter and one to the lower frequencies per channel?
I'v read that Sonus faber The Sf and Aida respond great to bi- or tri-amping.
What would be the expected with 4 krell 350Mc in this configuration appart from a high temperature in my listening room?

[Masterlu]

Originally Posted by Apexorca

What do you all think about Bi-amping. I'm curious about it.
In the 90's I used it in an Arcam set up with two stereo amps. It was ok at that time.
4 monos are tempting.

How would it be with 2 more 350mc? Thats makes 4. One to midrange-tweeter and one to the lower frequencies per channel?
I'v read that Sonus faber The Sf and Aida respond great to bi- or tri-amping.
What would be the expected with 4 krell 350Mc in this configuration appart from a high temperature in my listening room?

I’m a huge fan of bi-amping/tri-amping.

My SF Aida’s are tri-amped/tri-wired w/ Burmester 911’s. Never sounded better; in fact a big improvement over bi-amping.

[Charles]

Originally Posted by Apexorca

What do you all think about Bi-amping. I'm curious about it.
In the 90's I used it in an Arcam set up with two stereo amps. It was ok at that time.
4 monos are tempting.

How would it be with 2 more 350mc? Thats makes 4. One to midrange-tweeter and one to the lower frequencies per channel?
I'v read that Sonus faber The Sf and Aida respond great to bi- or tri-amping.
What would be the expected with 4 krell 350Mc in this configuration appart from a high temperature in my listening room?

Carl, I agree with Ivan. Also, the 350's will not put out the heat of a 750. These amps are very rugged even though they run hot. I can only imagine how pure class A sounds through your Fenice. These amps run class A 100%. In addition, there is no capacitor bank lag with high current demand. The engineering is amazing. The Krell dogma was the larger the amp the better the sound. By employing 4 350's you are in effect doubling the size of the amp, achieving the equivalent of a 750 per channel with the benefit of bi-amping. I can't imagine what 6 350's (tri-amping) would sound like. It would be beyond me.

Best,

Charles