Hi Folks
I am looking to replace the 4 40000 uf 75vdc capacitors in my old krell ksa 50, but I am having no joy searching the internet.
Do I have to use exactly the same spec of components. if not what can I use and where can I get them.
please go easy on my as mechanics is my trade not electronics, I do understand V=IxR if that helps.
The amp seems to have difficalty drive ,bias and offset all check out on my meter also it heats up as normal.
it sounds as if you are feeding it a signal with no bass and lots of treble.
Im realy stumped on this one and any help would be most welcome.
Kindest regards:
I am looking to replace the 4 40000 uf 75vdc capacitors in my old krell ksa 50, but I am having no joy searching the internet.
Do I have to use exactly the same spec of components. if not what can I use and where can I get them.
please go easy on my as mechanics is my trade not electronics, I do understand V=IxR if that helps.
The amp seems to have difficalty drive ,bias and offset all check out on my meter also it heats up as normal.
it sounds as if you are feeding it a signal with no bass and lots of treble.
Im realy stumped on this one and any help would be most welcome.
Kindest regards:
Are you absolutely sure this is the power supply capacitors ? This could be a problem with the capacitors in the feedback path.
As for the power supply capacitors, you can use any similarly sized capacitors that have 75V or better voltage rating, and a similar amount of capacitance. While i've not seen the KSA 50, Krell usually use screw terminal capacitors. 47000uF 80/100V should work provided they physically fit
edit: Apparently the KSA 50 has 50V power supply rails. If that's the case, 63V rated capacitors will be fine.
As for the power supply capacitors, you can use any similarly sized capacitors that have 75V or better voltage rating, and a similar amount of capacitance. While i've not seen the KSA 50, Krell usually use screw terminal capacitors. 47000uF 80/100V should work provided they physically fit
edit: Apparently the KSA 50 has 50V power supply rails. If that's the case, 63V rated capacitors will be fine.
Yes, the symptom of supply caps going bad is usually hum breakthrough and lack of response at the bottom end. Which version of the Krell is it?
As for where to source parts - both Farnell and RS have these types of capacitor
http://uk.farnell.com
http://rswww.com
http://uk.farnell.com
http://rswww.com
Thanks guys.
The amp is a ksa 50 mk1 very early ,it shares a lot of parts with the orijinal ksa 100 so I suppose krell just used components at hand to build the 50.
I have found a few caps rated about 47000 100vdc the same size and also a few at 37000 uf 63 vdc.
Their is no bottom end to the sound things went pear shaped ages ago when I attempted to adgust the bias and managed to snap of a roc cap 16v 1000uf next to the bias pot. so I replaced all 4 with black gate ones then set up the bias and off set .
I keep on telling my self that I should leave things alone, but I cant help it, i HAVE TO TAKE THINGS TO BITS ETC.
Im not 100% sure the caps are dead people are suggesting that they may be the problem as the amp is 20 years old.
Any thoughts?
The amp is a ksa 50 mk1 very early ,it shares a lot of parts with the orijinal ksa 100 so I suppose krell just used components at hand to build the 50.
I have found a few caps rated about 47000 100vdc the same size and also a few at 37000 uf 63 vdc.
Their is no bottom end to the sound things went pear shaped ages ago when I attempted to adgust the bias and managed to snap of a roc cap 16v 1000uf next to the bias pot. so I replaced all 4 with black gate ones then set up the bias and off set .
I keep on telling my self that I should leave things alone, but I cant help it, i HAVE TO TAKE THINGS TO BITS ETC.
Im not 100% sure the caps are dead people are suggesting that they may be the problem as the amp is 20 years old.
Any thoughts?
Resetting bias and offset is not bad, more like common sense.
If you have a MKI, and the big cans are the original ones, you can be sure that they are causing it. Or near death.
+20 years and those temperatures is a killer combo.
Only question i have is whether you replaced the 16V caps between the feedback resistor and ground in the right position, +and - where they belong ?
If you have a MKI, and the big cans are the original ones, you can be sure that they are causing it. Or near death.
+20 years and those temperatures is a killer combo.
Only question i have is whether you replaced the 16V caps between the feedback resistor and ground in the right position, +and - where they belong ?
If I had the 16v caps the wrong way round could this be causing the problem.
The amp was fine before I started to fiddle with it, do caps sudenly give up of is it a gradual process.
sorry for the silly questions but if I dont ask I will never now.
Cheers
The amp was fine before I started to fiddle with it, do caps sudenly give up of is it a gradual process.
sorry for the silly questions but if I dont ask I will never now.
Cheers
beckypumps said:
Yep.
in practice there is less than 1 volt across the series 16v caps.
Hooking them up the wrong way need not kill them, but the effect is peculiar.
I would change the big ones just the same, there should be little left in them.
That's ok, a few of us have had a little practise with Krells around here! 🙂
BP, can you take a pic of the boards so we can see what you've done?
BP, can you take a pic of the boards so we can see what you've done?
I've got a cunning plan !
Join the Krell thread and build new Krell clones, you'll be the first one with a finished Krell and the bestlooking chassis.
Join the Krell thread and build new Krell clones, you'll be the first one with a finished Krell and the bestlooking chassis.
Ive taken a pict of the board im just trying to work out how to down size it as the file size is to big.
I hate computers
I hate computers
With referance to one of lloyde macs drawings. if I have c5 and c6 the wrong way round (which may be the case) will this give me the funny bass affect.
http://home.ca.inter.net/~lloyd.maclean/Krell/KSA50.pdf
http://home.ca.inter.net/~lloyd.maclean/Krell/KSA50.pdf
Hmm, I don't see how they would make as much difference as you seem to note. What's your bias set to?
edit: just checked the pics on Lloyd's site, and your caps are the right way round. I don't suppose you might have damaged C9 or C12?
edit: just checked the pics on Lloyd's site, and your caps are the right way round. I don't suppose you might have damaged C9 or C12?
I set the bias to 620 mv as per Loyds drawing.
The + should face the outer edges of the board and the - should face each other.
The black gate caps have a gold strip down one side which signifies + or- both gold strips are faceing each other. so they are mounted + - - + or - + + - either way you think that this wont cause the loss of bass?
The + should face the outer edges of the board and the - should face each other.
The black gate caps have a gold strip down one side which signifies + or- both gold strips are faceing each other. so they are mounted + - - + or - + + - either way you think that this wont cause the loss of bass?
As far as I know c9 and c12 are ok
http://home.ca.inter.net/~lloyd.maclean/Krell/Krell.htm
assuming that im looking are the right components
http://home.ca.inter.net/~lloyd.maclean/Krell/Krell.htm
assuming that im looking are the right components
As classic audio gear goes it should be kept all original if you want to maintain its actual value. I am pretty convinced that the KSA-50 clone thread has actually increased the value of KSA-50's in general. If it were my amp I wold be getting the Krell replacement caps right from the factory... if they will sell them to you. They should actually say Krell on them. They were probably chstom made and will be expensive to get .......... It all depends on how original you want to keep it.
Mark
Mark
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