selcuksiyoni: the difference between the diagram of the Mk1 and Mk2 is substantial, and apparently the sound is too. Well worth the upgrade particularly considering the fairly low cost and effort to do it.
We know how the Mk1 and Mk2 looks inside.. HOWEVER, if you can somehow manage to provide me the exact dimensions of the boards and where their mounting holes are, within 1mm tolerance, I may just be nice and do the assembly of a board for you (just the labour) for free
You can realize the need for accuracy or the new boards won't fit on the mounting standoffs.
Unfortunately I doubt if it will be possible to measure with such accuracy without removing the boards first though..
We know how the Mk1 and Mk2 looks inside.. HOWEVER, if you can somehow manage to provide me the exact dimensions of the boards and where their mounting holes are, within 1mm tolerance, I may just be nice and do the assembly of a board for you (just the labour) for free
You can realize the need for accuracy or the new boards won't fit on the mounting standoffs.Unfortunately I doubt if it will be possible to measure with such accuracy without removing the boards first though..
That would REALLY be great
So remember what I'd want:
1) The exact length and width of the board
2) The positions of the four mounting holes
3) Not so important but while you're at it the positions of the 8 wire pads at the top running to the heatsink.
The hole positions are the most important. The board dmensions I estimated from the pictures I saw is 150mm wide and 193 mm high (5.9" x 7.5"). The centres of each mounting hole pair are 40mm apart, and each centre is 12mm from the board side edge. The bottom hole is 31mm from the board's bottom edge.
All these figures are however likely to be as much as even 30% off, which isn't usable. So please make very sure you have these info correct, and that you also describe each parameter properly so I know what exactly you refer to. A drawing would be even better of course.
On another topic, I've just heard that a direct comparison between a KSA100 Mk1, KSA100 Mk2 and a KSA50 clone leaded to the Mk2 winning by a large margin, followed by the KSA50 clone and KSA100 Mk1, each with their own pro's and cons. It may very well be that this project is the Nemesis of the KSA50 clone
Apparently the Mk2 had a much more involving and warm character, with the Mk1 being congested in comparison and the KSA50 clone having lots of detail but lacking the bass grip of either.
So remember what I'd want:
1) The exact length and width of the board
2) The positions of the four mounting holes
3) Not so important but while you're at it the positions of the 8 wire pads at the top running to the heatsink.
The hole positions are the most important. The board dmensions I estimated from the pictures I saw is 150mm wide and 193 mm high (5.9" x 7.5"). The centres of each mounting hole pair are 40mm apart, and each centre is 12mm from the board side edge. The bottom hole is 31mm from the board's bottom edge.
All these figures are however likely to be as much as even 30% off, which isn't usable. So please make very sure you have these info correct, and that you also describe each parameter properly so I know what exactly you refer to. A drawing would be even better of course.
On another topic, I've just heard that a direct comparison between a KSA100 Mk1, KSA100 Mk2 and a KSA50 clone leaded to the Mk2 winning by a large margin, followed by the KSA50 clone and KSA100 Mk1, each with their own pro's and cons. It may very well be that this project is the Nemesis of the KSA50 clone
Apparently the Mk2 had a much more involving and warm character, with the Mk1 being congested in comparison and the KSA50 clone having lots of detail but lacking the bass grip of either.Hi Pwatts,
the mica and/or polystyrene caps will need other than 5mm pitch.
Polystyrene come in body lengths starting at about 8mm and could use 0.4inch pitch. Check if 680pF will fit this, it might need 0.5inch.
Mica comes in 0.23inch and 0.35inch pitch.
Unfortunately polypropylene will probably not fit any of these, excepting some suit 0.4inch.
Four holes spaced at 0.12, 0.23, 0.17 cover pitches of 0.23, 0.35, 0.4 & 0.52 and will suit most options without wasting too much board space.
Is the c8/9 pitch 2mm or 0.1inch?
Could you add the hole diameter to the BOM?
the mica and/or polystyrene caps will need other than 5mm pitch.
Polystyrene come in body lengths starting at about 8mm and could use 0.4inch pitch. Check if 680pF will fit this, it might need 0.5inch.
Mica comes in 0.23inch and 0.35inch pitch.
Unfortunately polypropylene will probably not fit any of these, excepting some suit 0.4inch.
Four holes spaced at 0.12, 0.23, 0.17 cover pitches of 0.23, 0.35, 0.4 & 0.52 and will suit most options without wasting too much board space.
Is the c8/9 pitch 2mm or 0.1inch?
Could you add the hole diameter to the BOM?
Geez, I missed alot today! Gotta work though....
The heatsink we selected has at least twice the radiating area that the original Krell sink had. Also keep in mind that the KSA-100 either sucked air from the top down or blew up into the amp... either way this provides some air circulation around that driver heatsink. When I build mine the driver heatsink will be near one end of the air tunnel for plenty of air movement over it.
Mark
The heatsink we selected has at least twice the radiating area that the original Krell sink had. Also keep in mind that the KSA-100 either sucked air from the top down or blew up into the amp... either way this provides some air circulation around that driver heatsink. When I build mine the driver heatsink will be near one end of the air tunnel for plenty of air movement over it.
Mark
Like the KSA-50 you could go somewhat higher with some minor changes to a few resistors. Other than the KSA-50, KSA-80 I have not seen any other Krell schematics. The KSA-80B runs with +/- 53 volts, KMA160 with +/- 63, KSA-200 +/- 77, and KMA-400+/- 90 volts on the rails. These amps are fully differential though and contain completely different circuitry than the KSA-100.
Mark
Mark
Comparing a KSA100mk 1 vs KSA100mk2
Hi
I have both units and my impression is that the KSA100 mk2 wins hands down despite the fact that I am currently using a 3 KVA 220 volt stepdown with the KSA100 mk2. In fact there is a realism in their sound that is quite stunning.
In my opinion the KSA 100mk2 has a much fuller sound than the KSA100 mk1, seems to image better and is much more detailed. Once the PSU has been reconfigured to run from 220 Volts I am hoping for the same bass tightness I have with the KSA100 mk1.
My KSA50 clone sounds a bit thin compared to the KSA100 mk2 and I am now wondering if it is worthwhile to retrofit the KSA50 clone with the KSA 100 clone boards ?
Jozua
Hi
I have both units and my impression is that the KSA100 mk2 wins hands down despite the fact that I am currently using a 3 KVA 220 volt stepdown with the KSA100 mk2. In fact there is a realism in their sound that is quite stunning.
In my opinion the KSA 100mk2 has a much fuller sound than the KSA100 mk1, seems to image better and is much more detailed. Once the PSU has been reconfigured to run from 220 Volts I am hoping for the same bass tightness I have with the KSA100 mk1.
My KSA50 clone sounds a bit thin compared to the KSA100 mk2 and I am now wondering if it is worthwhile to retrofit the KSA50 clone with the KSA 100 clone boards ?
Jozua
Hi,
there seems to be a dual identity regarding KSA50 Klone bass developing.
Some are saying that the 50 has really strong deep bass and others are consistently saying the 100 beats it every time.
Is the power supply the difference between the two opposing sides, or is it in the implementation/selection of the PCB components?
Whichever, we need to understand the mechanism to ensure that all the builders of the 100 get the full benefit of this renowned bass ability.
there seems to be a dual identity regarding KSA50 Klone bass developing.
Some are saying that the 50 has really strong deep bass and others are consistently saying the 100 beats it every time.
Is the power supply the difference between the two opposing sides, or is it in the implementation/selection of the PCB components?
Whichever, we need to understand the mechanism to ensure that all the builders of the 100 get the full benefit of this renowned bass ability.
Hi mpmarino
Look at my post #265 here:
http://www.diyaudio.com/forums/showthread.php?s=&threadid=78129&perpage=10&pagenumber=27
It clearly says 52V rails from 41V AC but this stands for the mk-I version
The KSA 80 had 53V rails voltage as Mark mentioned.
Regarding KSA 100mk-II a qualified guess would be the same as in the mk-I: ±52V.
Regards
Look at my post #265 here:
http://www.diyaudio.com/forums/showthread.php?s=&threadid=78129&perpage=10&pagenumber=27
It clearly says 52V rails from 41V AC but this stands for the mk-I version
The KSA 80 had 53V rails voltage as Mark mentioned.
Regarding KSA 100mk-II a qualified guess would be the same as in the mk-I: ±52V.
Regards
Hi,
I have seen +-48Vdc mentioned on schematics
This would easily give 100W into 8ohms.
However, some report that the 100 is capable of approaching 160W. This would certainly demand higher voltage rails.
A nominal +-52Vdc might get to 140W or even 150W and with a little bit of mains overvoltage, 160W would be on from about +-54Vdc.
I have seen +-48Vdc mentioned on schematics
This would easily give 100W into 8ohms.
However, some report that the 100 is capable of approaching 160W. This would certainly demand higher voltage rails.
A nominal +-52Vdc might get to 140W or even 150W and with a little bit of mains overvoltage, 160W would be on from about +-54Vdc.
Hi Andrew,
You're correct in a number of cases. For 0.8mm difference it's not that hard to bend the leads slightly, but OK there's fortunately a lot of space available for the 62pF's to be larger.. damn imperial units; I worked in Metric all the way. That's fixed now.
On the Pinkmouse boards I've swopped the input shunt resistor and the 680pF to allow it to fit and on the Delta boards I mounted it vertically and you're correct that 5mm won't cut the cheese. Space is a bit limited for C1 but I'll see what I can do. For polyprop, the Wima FKP2 680pF 100V is in a 5mm pitch though; in fact all the Vishay and Wima caps I know's pitches are in multiples of 2.5mm.
For those who may have noticed the fairly large resistor footprints (they are 3mm longer than Al's), it is to accommodate some of the more exotic resistors such as Riken or AudioNote. It also makes it easier for the Dale resistors to bend the leads with a tweezer or small pliers to place less stress on the exit joint, and gave me more space to route underneath.
About the voltage rails: The Mk1 I measured up had 52V rails at the bus capacitors.
You're correct in a number of cases. For 0.8mm difference it's not that hard to bend the leads slightly, but OK there's fortunately a lot of space available for the 62pF's to be larger.. damn imperial units; I worked in Metric all the way. That's fixed now.
On the Pinkmouse boards I've swopped the input shunt resistor and the 680pF to allow it to fit and on the Delta boards I mounted it vertically and you're correct that 5mm won't cut the cheese. Space is a bit limited for C1 but I'll see what I can do. For polyprop, the Wima FKP2 680pF 100V is in a 5mm pitch though; in fact all the Vishay and Wima caps I know's pitches are in multiples of 2.5mm.
For those who may have noticed the fairly large resistor footprints (they are 3mm longer than Al's), it is to accommodate some of the more exotic resistors such as Riken or AudioNote. It also makes it easier for the Dale resistors to bend the leads with a tweezer or small pliers to place less stress on the exit joint, and gave me more space to route underneath.
About the voltage rails: The Mk1 I measured up had 52V rails at the bus capacitors.
What does the rest of your system consist of? I find the KSA-50 to have a superb and very real mid and high end to it and so do the many audio people that have been at my place to hear it. Go back through the PASS section and read some of the Pass shootouts where the KSA-50 wins hands down most of the time. I like the low end on my KSA-50 and for a 50 watt amp it is very amazing but as I mentioned its nothing compared to the low end on the KST-100 that we directly compared it to.
The rest of my system consists of a 12B4 line stage baically built as per Brian Beck's design, a Pioneer SACD player, and Dynaudio Audience 9 speakers.
Mark
Breaking news: Thanks to selcuksiyoni's excellent work I now have the exact dimensions and hole positions of the board. I'll update the PCB ASAP and send Mark the Gerbers.
What intrigues me however is the details on some of the models I've seen so far: selcuksiyoni thinks he has a Mk1, but his boards appear to be MK2 and has the relay boards as well. However, the wiring is the standard red and blue and not the bright orange stuff normally found in Mk2's. Same goes for the Mk1 I serviced last year that looked like a Mk1, but the boards also looked like Mk2 boards if I remember. Strange to say the least.
What intrigues me however is the details on some of the models I've seen so far: selcuksiyoni thinks he has a Mk1, but his boards appear to be MK2 and has the relay boards as well. However, the wiring is the standard red and blue and not the bright orange stuff normally found in Mk2's. Same goes for the Mk1 I serviced last year that looked like a Mk1, but the boards also looked like Mk2 boards if I remember. Strange to say the least.
ok .. now i felt stupid.. maybe i have to get that board to ,ok add me to list please.. how much it was?![URL]](/community/proxy.php?image=http%3A%2F%2F%5BURL%3Dhttp%3A%2F%2Fimageshack.us%5D%5BIMGDEAD%5Dhttp%3A%2F%2Fimg255.imageshack.us%2Fimg255%2F2623%2Fkrell12eb5.jpg%5B%2FIMGDEAD%5D%5B%2FURL%5D&hash=ad0f3d147df1e7b52ff119f9ebe31231)
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