The Hafler DH101 I own contains what I suspect are problematic Darlington transistors. Specifically MPSA13 and MPSA63. I have read that BC516 and BC517 can take their place.
My belief was that MPSA13 and MPSA63 were obsolete which led me to look for substitutes. Consequently I shall shortly be receiving the BC516 and BC517 which I ordered.
But I have since learned that transistor manufacturers other than On Semi produce MPSA13 / MPSA63 and those are still available. Can I proceed with using BC516 / BC517 or would it be recommended to obtain non-On Semi made MPSA13 and MPSA63?
My belief was that MPSA13 and MPSA63 were obsolete which led me to look for substitutes. Consequently I shall shortly be receiving the BC516 and BC517 which I ordered.
But I have since learned that transistor manufacturers other than On Semi produce MPSA13 / MPSA63 and those are still available. Can I proceed with using BC516 / BC517 or would it be recommended to obtain non-On Semi made MPSA13 and MPSA63?
MPSA13 and MPSA14 are from the same family (NPN Darlington) and both show availability. MPSA63 should also be available. If you do substitute, double check the lead configuration before installing. The BC516 looks like it has higher gain and BW. Careful with AM Radio stations and oscillations. . .
Thanks EV. for the reply. I made the substitution and the problem I was experiencing appeared to be eliminated.
I say appeared because I can only assess results by ear and my hearing has been degrading for over 10 years to the point of using hearing aids for the past 3. Pre-amp operation has been restored but I do not consider myself able to detect if sound quality was affected.
Also around 3 years ago, I moved to a mountainous area and have found zero AM stations within range. And, not owning an O scope. I cannot check for oscillations.
I say appeared because I can only assess results by ear and my hearing has been degrading for over 10 years to the point of using hearing aids for the past 3. Pre-amp operation has been restored but I do not consider myself able to detect if sound quality was affected.
Also around 3 years ago, I moved to a mountainous area and have found zero AM stations within range. And, not owning an O scope. I cannot check for oscillations.