Krell Kav 2250 Bias

[K-amps]

I see no way forward until it is established whether the transistors are genuine and until the fakes have been replaced. And not just the outputs. Yes, oscillation is about the only reason for low dc current yet high dissipation.

Replacing all fakes with originals should sort the oscillation worry all by itself, provided no other changes have been made while repairing the amp. Ime Krell don't go nuts matching transistors, at least in the amps i have had matching was no better than 20%.

I'd agree with that given the 0.68 ER's

 

[Deceiver777]

So if you look in amp from top, you notice the left channel have lot lot more space to breathe, but right channel heatsink have 2cm space to breath, maybe that's why its hotter by 3C ddgrees?

 

[Deceiver777]

So when i push 7mV on both channels, amp draw 0.52A.

But numbers increase need some time, not immediately.

 

[Deceiver777]

Delete

 

[analog_sa]

Do you have a scope?

 

[Deceiver777]

Nope i sold it long time ago.

 

[Deceiver777]

So i get SM for bias and etc, you are all wrong, - it way way lower than you mentioned...

I do not send it becouse i get this in a hard way.

 

[Bumble 1]

so it has bias trimpot, amp is hot around 75C degrees under 4ohm stable load.
I mean speakers with stable 4ohm impendance.

i measured 5mv across 0.68ohm emmiter resistor.

Sounds a bit high in temp.. The amp runs maunly class a/b .. Mine is barely warm to touch on the right hand side where the power output boards are..