kmj said:
Original had TO-3 devices... Our PCB has TO-247/TO-3P.
I hate to break the news, but I am not going to offer different components for a kit... We will vote on desired components, make a part list and then order. No mix matching on free time..
1. Dale resistors as minimum standard, but we can go up if voted.
2. Semi's will be ON Semi unless voted different.
3. Caps? Anyone....?
I still have NOT seen a list of desired Caps....
oops, TO-3 is not the same as TO-3P......my mistake
Well, than whatever the majority desides works for me
Sorry, since I buy most of my components from one and the same destributor I feel that my knowlage of different brands/types is to limited for me to add to the list (would probably mess something up
)
Howdy pinkmouse,
Any chance you have a pdf of the board that one might import into a bitmap file to modify and use the original TO3 devices? Not too much trouble for me to make my own two sided board. No disrespect to your fine work, just like to make it as much like the original as possible.
Regards,
Elvin
Any chance you have a pdf of the board that one might import into a bitmap file to modify and use the original TO3 devices? Not too much trouble for me to make my own two sided board. No disrespect to your fine work, just like to make it as much like the original as possible.
Regards,
Elvin
matching
Hi Guys,
Using resistors that give around 0.5v at idle gives really good current matching in the outputs. I have 48 outputs (24pairs) that, in circuit, with no matching of transistors or resistors are within +-5% of the nominal. Initially I measured each and everyone of 'em to make sure all the outputs were pulling their weight, now I'm less worried, I do a quick test to make sure each pair is functional, but nothing quantitative.
The damping factor of the amp is increased by the amount of feedback, and while this is not a super high feedback amp, the resultant DF is still >100 until quite high frequencies; and based on my reading anything over ~50 is gravy.
If 'high' values of Re could be said to have any 'negative' effect it is the reduction in output power into very low (<1ohm) impedance loads, and the subsequent heating of the resistors...
For all those waiting on the high power krell info, I'd like to apologise for the ongoing delay; I'm planning a wedding, plus a couple of receptions, getting construction done on my house and trying to remain sane...I am preparing schematics and a BOM, it should get posted before the end of the month. If the government wants to mess with established time keeping principles why hot add a couple more hours in the day, lord knows I need 'em...
Stuart
Hi Guys,
Using resistors that give around 0.5v at idle gives really good current matching in the outputs. I have 48 outputs (24pairs) that, in circuit, with no matching of transistors or resistors are within +-5% of the nominal. Initially I measured each and everyone of 'em to make sure all the outputs were pulling their weight, now I'm less worried, I do a quick test to make sure each pair is functional, but nothing quantitative.
The damping factor of the amp is increased by the amount of feedback, and while this is not a super high feedback amp, the resultant DF is still >100 until quite high frequencies; and based on my reading anything over ~50 is gravy.
If 'high' values of Re could be said to have any 'negative' effect it is the reduction in output power into very low (<1ohm) impedance loads, and the subsequent heating of the resistors...
For all those waiting on the high power krell info, I'd like to apologise for the ongoing delay; I'm planning a wedding, plus a couple of receptions, getting construction done on my house and trying to remain sane...I am preparing schematics and a BOM, it should get posted before the end of the month. If the government wants to mess with established time keeping principles why hot add a couple more hours in the day, lord knows I need 'em...
Stuart
geezer1944 said:
Elvin, the best bet is just to make up a couple of new can type output boards, and use the existing main and driver layouts. I didn't do a T03 design simply because everyone's heatsink/layouts were liable to be different. All you need on the layout are the output devices and the Emitter resistors. Should be dead simple.
geezer1944 said:
I'm not Pink mouse, but I can answer your question...
The boards he designed are 3 sections.
1. Main brd
2. Driver IC brd
3. Output brd for TO-247/TO-3P
You an just use the first two and P2P wire the TO-3 devices like the original. I'm SURE some one wanting a 5 million watt amp would appreciate your output brds...
But if you can roll your own from the prints omit the last brd...
Will there be any difference in quality when switching from the original to the others, which ever it may be. I have no experience then it comes to choosing between different transistors but i seem to remember reading somewhere on diyaudio that some people prefered the 15003 (kinda vague, i know).
Not to whine or anything, just courios.
Not to whine or anything, just courios.
Many thanks pinkmouse & rabstg,
Sure is a long thread and by the time I got thru reading it, seems I already missed the group buy for the boards. And seein as how it's not much trouble for me to make boards, I was hopeing there was a pdf of the board available. If it's not and too much trouble for you, I'll just have to redraw the thing. Won't be as pretty as yours tho.
Pretty sure I can handle makeing up can type output boards or hard wiring for the proper heatsink.
I recall this amp when it was the newest thing. Couldn't afford it then and now can't hardly find a used one at all. Not mid life but later life crisis prompts me to have one at last. Still trying to impress the girls.
Again, really fine looking work on your part.
Regards,
Elvin
Sure is a long thread and by the time I got thru reading it, seems I already missed the group buy for the boards. And seein as how it's not much trouble for me to make boards, I was hopeing there was a pdf of the board available. If it's not and too much trouble for you, I'll just have to redraw the thing. Won't be as pretty as yours tho.
Pretty sure I can handle makeing up can type output boards or hard wiring for the proper heatsink.
I recall this amp when it was the newest thing. Couldn't afford it then and now can't hardly find a used one at all. Not mid life but later life crisis prompts me to have one at last. Still trying to impress the girls.
Again, really fine looking work on your part.
Regards,
Elvin
Geezer1944
Everything you need:
Krell KSA-50 clone
Link to Delta Audio (pcb, parts, eagle-files and much, much more )
Everything you need:
Krell KSA-50 clone
Link to Delta Audio (pcb, parts, eagle-files and much, much more
)
Howdy all,
Many thanks for the quick replies to my quest for the pdf of pinkmouse's board creation. With all deference to being polite like my momma taught me to do, as yet no one seems to know if there is a pdf of the board in question. Namely the pinkmouse version, which to my viewing and poor eyesight seems to be much more like the original. As my previous comments tell, kinda like to make a KSA50 as much like the original as possible. Even willing to construct the case to look like the real thing as close as I can.
Have the means to make a proper double sided board in my own shop.
Not really interested in fixin "IMPORTANT CORRECTION" on a board with stuff on it that is not in the original design, however good it might be.
Now if this pinkmouse board has some copyrighted detail preventing one from making ones own board legal like, then I can just draw the dang thing myself. Got the means to do that also. Now don't you all get upset just 'cause the old man is set in his ways and kinda knows what he wants to do. Don't mean no disrespect to no one.
Please excuse that I just got my mind set on making my own piece of the past. It's a nostalgia thing that comes on you after age 60 or so.
Best regards to all,
Elvin
Many thanks for the quick replies to my quest for the pdf of pinkmouse's board creation. With all deference to being polite like my momma taught me to do, as yet no one seems to know if there is a pdf of the board in question. Namely the pinkmouse version, which to my viewing and poor eyesight seems to be much more like the original. As my previous comments tell, kinda like to make a KSA50 as much like the original as possible. Even willing to construct the case to look like the real thing as close as I can.
Have the means to make a proper double sided board in my own shop.
Not really interested in fixin "IMPORTANT CORRECTION" on a board with stuff on it that is not in the original design, however good it might be.
Now if this pinkmouse board has some copyrighted detail preventing one from making ones own board legal like, then I can just draw the dang thing myself. Got the means to do that also. Now don't you all get upset just 'cause the old man is set in his ways and kinda knows what he wants to do. Don't mean no disrespect to no one.
Please excuse that I just got my mind set on making my own piece of the past. It's a nostalgia thing that comes on you after age 60 or so.
Best regards to all,
Elvin