Re: Steven
Hi Jan,
It's not so important as long as everyone understands what is meant or when the polarity in the circuit diagram is clear, but it is the first time that I see the open box side used as the -.
In the IEC symbol overview the + is indicated as an open box, the - as a black box.
http://www.kpsec.freeuk.com/symbol.htm
Steven
ACD said:Caps are not upside down
Small line are + , box line are -
Hi Jan,
It's not so important as long as everyone understands what is meant or when the polarity in the circuit diagram is clear, but it is the first time that I see the open box side used as the -.
In the IEC symbol overview the + is indicated as an open box, the - as a black box.
http://www.kpsec.freeuk.com/symbol.htm
Steven
I appears that the MJE,MPSA, and MJL components are available from
http://www.onsemi.com/ as samples. 25 pieces each, you pay the shipping. Quick calculation, over $150 USD worth of parts. Won't hurt so much when you let the magic smoke out of'm. Or build more than one. My woman is always saying "Why buy one, when you can get two for twice as much?"
Prosit
http://www.onsemi.com/ as samples. 25 pieces each, you pay the shipping. Quick calculation, over $150 USD worth of parts. Won't hurt so much when you let the magic smoke out of'm. Or build more than one. My woman is always saying "Why buy one, when you can get two for twice as much?"
Prosit
Re: Steven
This drawing technique is non-standard, non-IEC and confusing for most. Usage of it is probably so because of a local CAD program that used a wrong symbol. Never seen it before, even schematics of very old radios use the symbol with the + pole drawn as a hollow box and the negative pole as a filled box. I suggest to draw schematics according international standards to avoid exploding caps/safety issues as this is an international forum read by international members.
ACD said:For the 25 years I have been "fooling around" with electronics in Denmark, electrolytic caps have always been drawn like this (sometimes the square bow is filled out) and the CAD software we use here also draws the caps this way
This drawing technique is non-standard, non-IEC and confusing for most. Usage of it is probably so because of a local CAD program that used a wrong symbol. Never seen it before, even schematics of very old radios use the symbol with the + pole drawn as a hollow box and the negative pole as a filled box. I suggest to draw schematics according international standards to avoid exploding caps/safety issues as this is an international forum read by international members.
Jan,
the "high/low" bias switch arrangement should be in parellel with 5K pot (R126), not R124 (4K7). It will be much easier to get it to work. I suggest two 5K multi turn pots so one can choose exact bias values.
Second suggestion is to allow the output transistors to be left outside the feedback loop altogether by taking the feedback from the midpoint between 25ohm resistors (take feedback from the driver transistors, not the speaker terminal). This way you can play with the amount of overall feedback - from 100% if you connect midpoint of 0.5 Ohm resistors with 25 Ohm ones, all the way down to zero if you leave that link open, or anywhere in between by using appropriate resistor value. BTW your schematic seems to be missing the link between midpoints. And the original hand drawing indicates zero Ohm links there indicating that maybe Krell contemplated this from day one.
I left the output transistors in my KSA100 (in reality KMA200) clone completely outside the feedback loop. Distortion figures may suffer a bit, but I prefer it this way (for one reason or another).
Bratislav
the "high/low" bias switch arrangement should be in parellel with 5K pot (R126), not R124 (4K7). It will be much easier to get it to work. I suggest two 5K multi turn pots so one can choose exact bias values.
Second suggestion is to allow the output transistors to be left outside the feedback loop altogether by taking the feedback from the midpoint between 25ohm resistors (take feedback from the driver transistors, not the speaker terminal). This way you can play with the amount of overall feedback - from 100% if you connect midpoint of 0.5 Ohm resistors with 25 Ohm ones, all the way down to zero if you leave that link open, or anywhere in between by using appropriate resistor value. BTW your schematic seems to be missing the link between midpoints. And the original hand drawing indicates zero Ohm links there indicating that maybe Krell contemplated this from day one.
I left the output transistors in my KSA100 (in reality KMA200) clone completely outside the feedback loop. Distortion figures may suffer a bit, but I prefer it this way (for one reason or another).
Bratislav
Hi all,
Been viewing this thread with interest. I was wondering about the diodes on the KSA-50 clone schematic. What diodes are used the positions of D109,D110 and D201,D202? Would standard 1N400x diodes work in these locations?
From the first schematic posted by bra, Zener diodes at location ZD101, ZD102 should be 27V, correct?
Thanks,
Dan.
Been viewing this thread with interest. I was wondering about the diodes on the KSA-50 clone schematic. What diodes are used the positions of D109,D110 and D201,D202? Would standard 1N400x diodes work in these locations?
From the first schematic posted by bra, Zener diodes at location ZD101, ZD102 should be 27V, correct?
Thanks,
Dan.
I guess I wasn't clear enough. Don't run feedback resistor (R130, 12K) all the way off the output stage via long wire. Run it direcly off the mid point R127/R128.
Then use the link (yes, "what link") to juggle overal feedback amount by leaving it open, short circuit or any other value in between. You could add a position for another resistor just betwen the link formerly known as Miss Ing and R127/128 midpoint. DIYers can then play with various values and decide what they linke best (and whether they can hear it or not which could be another long thread in itself )
Bratislav
Then use the link (yes, "what link"
) to juggle overal feedback amount by leaving it open, short circuit or any other value in between. You could add a position for another resistor just betwen the link formerly known as Miss Ing and R127/128 midpoint. DIYers can then play with various values and decide what they linke best (and whether they can hear it or not which could be another long thread in itself )Bratislav