selcuksiyoni said:
Smart choice.
Although i haven't seen such a clean KSA interior in at least 10 years yours looks like it is in real need of a refreshing.
Those small red Roederstein capacitors haven't been produced for quite some time, the ones on the board are overdue for retirement, and there are much better electrolytics nowadays.
You might as well go for an entire new set of boards.
Consider a fresh set of output devices as well, your KSA looks like a classic specimen that deserves to be kept in shape to show to your kids.
OK, this is basically it: my estimation of the board dimensions was out by almost 20mm, and here is the adapted version. This should fit perfectly on the original's mounting standoffs, with the wire pads also in the same place. I would however strongly suggest that selcuksiyoni print it out and see if it really fits accurately enough on his amp.
The upside is that there's more than enough space for the heatsink on top now, and I could add yet another electrolytic pair.
Unfortunately I could not increase the size of C1. Either use a 5mm MKP cap, or mount an axial cap such as a polystyrene vertically. Apologies to those who wanted to use something like silver mica.
PLEASE people, somebody should crosscheck the layout. I found a few small problems with it as well as the BOM, meaning that nobody has done a careful analysis yet.
The upside is that there's more than enough space for the heatsink on top now, and I could add yet another electrolytic pair.
Unfortunately I could not increase the size of C1. Either use a 5mm MKP cap, or mount an axial cap such as a polystyrene vertically. Apologies to those who wanted to use something like silver mica.
PLEASE people, somebody should crosscheck the layout. I found a few small problems with it as well as the BOM, meaning that nobody has done a careful analysis yet.
Just print it out as-is and it should be OK, not any "scaled-to-fit" options. You can check if the board dimensions are really 164x142mm (which they should), and if they are, take it home and proceed to the mounting hole locations. The wire pad locations would also be nice but a few mm off will not be the end of the world.
Jacco: no need to get sarcastic about the Mk2 upgrades. The Mk1 I serviced with the Mk2 boards were never serviced or upgraded since it was sold (new), so unless the agents did the upgrade to the new amp before selling it, that is not what happenned. BTW so far I've seen four different KSA100 schematics. One was this Mk2 one, the other the one very similar to the KSA50, one used current regulators in the LTP and the fourth was some hand-drawn picture. Sometimes changes happen without being properly documented; AR's 1970 speakers are a classic example of this where every two weeks they changed the designs.
Jacco: no need to get sarcastic about the Mk2 upgrades. The Mk1 I serviced with the Mk2 boards were never serviced or upgraded since it was sold (new), so unless the agents did the upgrade to the new amp before selling it, that is not what happenned. BTW so far I've seen four different KSA100 schematics. One was this Mk2 one, the other the one very similar to the KSA50, one used current regulators in the LTP and the fourth was some hand-drawn picture. Sometimes changes happen without being properly documented; AR's 1970 speakers are a classic example of this where every two weeks they changed the designs.
Not meant as a sarcastic remark.
If they never had an upgrade and those MK-IIs were not part of a conversion phase from MK-I to MK-II it's a puzzle.
I can imagine that Krell still had MK-I hardware when they started the MK-II production, shame to throw it away.
But running across a couple of them all the way in South Africa sounds a bit too accidental.
Your explanation sounds the most logical. I can imagine that the Krell factory wasn't that well organised in the early years, a bit chaotic is more likely. Companies probably need 10 years to mature.
If they never had an upgrade and those MK-IIs were not part of a conversion phase from MK-I to MK-II it's a puzzle.
I can imagine that Krell still had MK-I hardware when they started the MK-II production, shame to throw it away.
But running across a couple of them all the way in South Africa sounds a bit too accidental.
Your explanation sounds the most logical. I can imagine that the Krell factory wasn't that well organised in the early years, a bit chaotic is more likely. Companies probably need 10 years to mature.
Probably indeed. Especially in the early years of many companies they continuously kept on modifying products without making official revisions or sticking with one design.. which naturally made servicing them a nightmare. Same thing happens with racing bikes (and I imagine cars), where the Japanese have sometimes upgraded the CDI and gear mappings more than once a year - which makes finding parts for older discontinued models a huge and very expensive task.
Here is the quote for the heatsinks. Pretty expensive if you ask me...... We might want to look around some more.
M&M Metals Heat Sink Extrusion Quote
Date:
10/4/2006
Part Number:
MM14300
Extrusion Cut Length (Feet) =
6
Minimum Order =
$200
Quantity (Bars) 4
Total Feet 24
Price each $72.98
Extended Price $291.92
Leadtime:
2 - 3 Days ARO
FOB:
Carrollton, Texas
M&M Metals Heat Sink Extrusion Quote
Date:
10/4/2006
Part Number:
MM14300
Extrusion Cut Length (Feet) =
6
Minimum Order =
$200
Quantity (Bars) 4
Total Feet 24
Price each $72.98
Extended Price $291.92
Leadtime:
2 - 3 Days ARO
FOB:
Carrollton, Texas
Comparing the Ksa50 with the Ksa100
Mark
My audio system consist of Krell pre-and_power amps with Newform Research R45 Ribbons using Scanspeak Relevators as bass units. My CD player is very old but heavily modified. (When I find a universal player that sounds high end I change the CD player- for the moment it stays put). I would consider my system as fairly revealing depending on the criteria you prefer to use. On well recorded CD’s I can easily hear mixing errors (sudden volume adjustments) and background sound (cars and trains) which are inaudible on most systems.
There could be many reasons why my clone sounds thin. I have a second Clone 50 in the pipeline (currently on hold due to the KSA100mk option) that I wanted to build with a different PSU. I want to use active crossovers in my system for which I prefer to use identical amplifiers.
I have thought of increasing the existing KSA50 clone transformers output from 25-0-25 to 30-0-30 or using better PSU caps or using better wires but quite frankly the KSA100MK2 clone option is just so much more appealing.
The interesting thing is that my KSA50 clone pcb uses top notch components whereas my KSA100Mk2 using 20 year old run of the mill components sounds much better in respect of bass, mid’s and tops. It fact I still consider the sound as stunning and very captivating I shudder at what could be possible if I replace the boards of my Krell KSA100mk1 with a top notch Mk2 board.
It is therefore very important to me that the new clone boards must not only sound good but visually be build to standard that matches the existing boards before I rip out the old KSA100 Mk1 boards.
Jozua
Mark
My audio system consist of Krell pre-and_power amps with Newform Research R45 Ribbons using Scanspeak Relevators as bass units. My CD player is very old but heavily modified. (When I find a universal player that sounds high end I change the CD player- for the moment it stays put). I would consider my system as fairly revealing depending on the criteria you prefer to use. On well recorded CD’s I can easily hear mixing errors (sudden volume adjustments) and background sound (cars and trains) which are inaudible on most systems.
There could be many reasons why my clone sounds thin. I have a second Clone 50 in the pipeline (currently on hold due to the KSA100mk option) that I wanted to build with a different PSU. I want to use active crossovers in my system for which I prefer to use identical amplifiers.
I have thought of increasing the existing KSA50 clone transformers output from 25-0-25 to 30-0-30 or using better PSU caps or using better wires but quite frankly the KSA100MK2 clone option is just so much more appealing.
The interesting thing is that my KSA50 clone pcb uses top notch components whereas my KSA100Mk2 using 20 year old run of the mill components sounds much better in respect of bass, mid’s and tops. It fact I still consider the sound as stunning and very captivating I shudder at what could be possible if I replace the boards of my Krell KSA100mk1 with a top notch Mk2 board.
It is therefore very important to me that the new clone boards must not only sound good but visually be build to standard that matches the existing boards before I rip out the old KSA100 Mk1 boards.
Jozua
Well there's no guarantee of the difference between the old and the new boards since the layout and components are different in a number of places, but the layout is definitely more compact and efficient, the improvements/enhancements can only be positive and the newer components provided better simulated results. Add to that better quality passive components and everything points to an overall better product; besides it's easy to put the old boards back if the newer ones sound disappointing for some reason.
I'm not following the logic here.
The KSA100 came before the KSA50, the KSA50 was a lower cost model for who the 100 was a bit too much.
Anyone stating the KSA100 MK-I beats a KSA50 ?
Sure the KSA100 MK-II can do better than the KSA50, it came after the KSA50 and cost nearly twice as much.
It would have been very foolish of Krell had it been the other way around.
A bunch of folks here built a bunch of different KSA50s, judging one variant doesn't speak for another.
It costs a lot more to construct a KSA100, it better be on top of the 50.
Actually almost all reviewers familiar with the KSA-50 will tell you that the 50 is still hands down one of the best amps ever made and a handful of reviewers still use the KSA-50 as a comparison base or cornerstone when doing reviews. I think it also made the top ten amplifier list at Stereofool. Speaker and room sizes taken into account the 50 should be the better of the two. The KSA-100 was for the most part specifically designed for driving the big Apogee ribbon speakers.
I have a Pioneer DV-45a multi player and as far as multi players go its the best one untill you get to the 1500.00 price range and even then you're going to have tog et really picky about the differences. There are also many mods you can do to the DV-45 if you want to. The best thing about it is that it does not use DSP processing instead a seperate D to A for each format. The best of all three worlds. I did at one time own a Krell KBL and it was pretty good but the 12B4 blows everything I've owned in the line stage department off the map.
DV45a
Mark
I have a Pioneer DV-45a multi player and as far as multi players go its the best one untill you get to the 1500.00 price range and even then you're going to have tog et really picky about the differences. There are also many mods you can do to the DV-45 if you want to. The best thing about it is that it does not use DSP processing instead a seperate D to A for each format. The best of all three worlds. I did at one time own a Krell KBL and it was pretty good but the 12B4 blows everything I've owned in the line stage department off the map.
DV45a
Mark
Hi Mark,
a bit off topic, so sorry to all others.
The DV45a spec says dvd-r and dvd-rw.
I thought the -r&-rw and +r&+rw only applied to recorders/blank discs. If a -rw or +rw disc is recorded on a compatible machine, will the dv45 play any type of dvd disc no matter which type of recorder it is recorded on?
My dvd+rw recorder says it makes recordings compatible with any dvd player. I have no way to check the accuracy of this statement.
a bit off topic, so sorry to all others.
The DV45a spec says dvd-r and dvd-rw.
I thought the -r&-rw and +r&+rw only applied to recorders/blank discs. If a -rw or +rw disc is recorded on a compatible machine, will the dv45 play any type of dvd disc no matter which type of recorder it is recorded on?
My dvd+rw recorder says it makes recordings compatible with any dvd player. I have no way to check the accuracy of this statement.