Help for repair my KSA 100

[Alex helge]

Hi, her forum partners

I should like the Motorola MJ 15024/25 or MJ 21193/94 to build in my KSA 100. Must these Transistors his selectiert ?
I will a batten with 25 Motorola transistors to buy.
This batten with 25 Motorola is from any fabrication or Serie.

Must his the driver - transistors selectiert too.

Has the Dale wire- resistor a lot of inductivity ?
Can I to build metall - resistor with 3 or 5 Watt?
How is the sound difference between Dale resistor or metall resistors?

Many thanks for your answer
and sorry for my bad english

Best regards
Alex

[jean-paul]

and sorry for my bad english

You should hear our pronounciation of the german language !

Jean-Paul

[Alex helge]

Hallo,

Ich möchte gerne die Motorola MJ 15024/15025 oder MJ 2119394 in meine KSA 100 einbauen. Müssen diese Transistoren selektiert werden ?
Ich wollte eine Leiste mit ca. 25 Transistoren aus einer Serie kaufen, weil diese dann wohl aus einer Produktion sind.
Kennlinien und Stromverstärkung sollen dann wohl nicht stark zwischen den Einzelnen Transistoren abweichen.

Wie ist das mit den Treiber Transistoren muss ich diese Selektiert kaufen?
Sind die jetzigen Treiber Transistoren MJE 15030/15031 in der KSA 100 Selektiert ?

Was ist der Dahl Widerstand genau für ein Widerstand ?
Hat der Dahl Widerstand eine große oder keine Induktivität?
Was kann ich für den Dahl Widerstand sonst noch Einbauen?
Wie ist der Klangliche Unterschied zwischen dem Dahl und anderen Widerständen die ich dafür benutzen kann?

Vielen Dank für euere Antwort
Gruß Alex

[jewilson]

I am EE and I have several Krell amps. Having said, that I would not work either one of them with out a schematic and the correct parts numbers. Also, the output transistors need to be matched or it might smoke.

Of course, it impossible to get schematics from Krell. Maybe some one in the forum has them.

[jean-paul]

Here it is again.

[jewilson]

Strange, when I've looked inside my amp it sure seems as though it has bunch more parts.

It would make sinse that the KMA250 would have more output devices, and that would be it.

[jean-paul]

Originally posted by Alex helge
Hallo,

Ich möchte gerne die Motorola MJ 15024/15025 oder MJ 2119394 in meine KSA 100 einbauen. Müssen diese Transistoren selektiert werden ?
Ich wollte eine Leiste mit ca. 25 Transistoren aus einer Serie kaufen, weil diese dann wohl aus einer Produktion sind.
Kennlinien und Stromverstärkung sollen dann wohl nicht stark zwischen den Einzelnen Transistoren abweichen.

Wie ist das mit den Treiber Transistoren muss ich diese Selektiert kaufen?
Sind die jetzigen Treiber Transistoren MJE 15030/15031 in der KSA 100 Selektiert ?

Was ist der Dahl Widerstand genau für ein Widerstand ?
Hat der Dahl Widerstand eine große oder keine Induktivität?
Was kann ich für den Dahl Widerstand sonst noch Einbauen?
Wie ist der Klangliche Unterschied zwischen dem Dahl und anderen Widerständen die ich dafür benutzen kann?

Vielen Dank für euere Antwort
Gruß Alex

Excuse me, it won't happen again :

Ich wurde nur die Originaltypen verwenden. Mann weiss nicht was passiert wenn die Ft von den neuen Transistoren hoher ist.
Schau bitte die Datenblatter ob das so ist und uberleg mal ob es das Risiko wert ist. Alle Kondensatoren und Dioden bitte verwechseln fur Neue.

Man soll die Transistoren selektieren, das Idee om eine Leiste zu kaufen is ein gutes Idee. Selbstverstandlich wurde Ich auch die Treibertransistoren selektieren.

Die Dale serie RCLNT5 ( so sieht es aus am Bild ) ist mir nicht bekannt und auch mit Google habe Ich wenig Information gefunden. Nicht so fremd weil die sind aus 1984. Sehr wahrscheinlich sind es 5W Prezisions-leistungswiderstande mit niedriger Induktivitat ( wichtig ! ). Am besten kaufst Du die aus einer neue Serie von Dale.

[jean-paul]

Originally posted by jewilson
Strange, when I've looked inside my amp it sure seems as though it has bunch more parts.

It would make sense that the KMA250 would have more output devices, and that would be it.

There seems to exist a KSA100-II that is different. Dunno because I never owned one. Just read it on this forum once.

[cocolino]

Yesterday Alex contacted me about the cable and I gave him my phone number on that occasion. Later he called me and explained the matter.
As obviously Alex has problems to express himself in English, I take the liberty and try to explain it again (I guess this is in his sense).

One thing I think You should know - Alex has no clue about electronics. His "electrician" as he says, does the work.
However, the amp was basically okay before the guy tried to readjust the bias on one channel of the amp as it seemed to be underbiased somewhat. While adjusting he shorted one channel somehow and has blown the driver/output transistors as well as those Dale resistors.

Initially Alex intended only to have replaced the electrolytics (what is already done meanwhile), what IMO was a good idea.

Now after this accident things look much more complicated and as it seems a Krell service would be in order - but as Alex said he had the amp at Krell already (in former times) and they charged him DM 800 (~$400) for replacing one transistor and a few other parts that took 2 hours (as he brought the amp from 500km away, he waited until it was repaired so he could take it with him right again). I can understand that now he fears that for a (much more) damaged amp they would charge him more than the amp could be worth.

I mentioned the matching thing to him already and he seems to be in the wrong (IMO) believe that he can buy matched sets of transistors from a supplier (I have never heard about this and I doubt that this is real) or that he can get away without matching (what I doubt also) by buying transistors from the same batch. I told him chances probably are higher to ask here in the forum if there is anybody who can sell him 2 matched sets (2x4 per channel) of whatever is suitable (I can´t help here because I lack the experience too). Maybe somebody?

About the Dale resistors: Alex can`t seem to find them anywhere and I have to say me also don`t know where to get them. I suggested to replace them eventually with non-inductive MPC metal-band (?) types (see picture). They are easy to get in the required value/wattage. Any comments if those are okay?

[cocolino]

and BTW:
The driver board from Alex KSA-100 is from a KSA-100 MK 2 version. Whatever this is it seems to be very different from
the schematic above. Here a picture from the actual board I got from Alex. Apart from the 5 transistors of the driver/bias stage and the 4 small transistors in the plastic case, I can count 8 transistors MORE than in the schematic shown above.