I have read alot of bad comments on the Crown DC-300A. I have had mine for over 30 years partnered with a McIntosh C-28 Pre-amp. My speakers are Klipsch K- horns. I have NEVER had a repair on any of these and think alot of the posts are not accurate, or people abuse the equipment. I listen to my system daily.
I too have read unfavorable things about the Crown DC-300 series which includes the "A". These amps are from the early 1970's when power transistor technology was still young and evolving. And power transistors do age with use and go bad, especially when run hot. And yes, I suspect some of the amps were worked hard (abused?) in services like PA and sound reinforcement and industrial use like vibration tables etc.
But in your system they loafed along with ease. I say this because Klipsch horns are very efficient. You can drive them loud with flea power amplifiers. And your Crown is a class AB type which is more efficient then a comparable class A, albeit with a different sound. So it just never has to work hard. I also happen to own a DC-300A, but have never used it. I actually have several soiled state amps in my collection but prefer tube amplifiers myself.
But in your system they loafed along with ease. I say this because Klipsch horns are very efficient. You can drive them loud with flea power amplifiers. And your Crown is a class AB type which is more efficient then a comparable class A, albeit with a different sound. So it just never has to work hard. I also happen to own a DC-300A, but have never used it. I actually have several soiled state amps in my collection but prefer tube amplifiers myself.
The DC-300 and 300A were the ultimate in technology back in the 70s. They are still sought after as they are reliable but can die if overloaded for too long.
Because they work down to DC, if your pre amp has a fault a pushes a volt or so of DC out, the DC-300 will amplify it, (as it is designed to do), fry the speakers and the resulting short circuit load will overload the amplifier.
In my experience of over 40 years of sound engineering with these and newer Crown amps have never had a problem but then, I am looking after the PA.
Transistors do not degrade and the semiconductors in the DC range are good for up to 75 Centigrade, at that point the amplifier will feel like a room heater and shut down.
Back in the 50s and 60s, germanium transistors were the latest semiconductor, (Westinghouse produced XB113 type) and they had a gain around 5 - 10 if you were lucky. They have a shelf life of 25 - 30 years, silicon is not the same.
Because they work down to DC, if your pre amp has a fault a pushes a volt or so of DC out, the DC-300 will amplify it, (as it is designed to do), fry the speakers and the resulting short circuit load will overload the amplifier.
In my experience of over 40 years of sound engineering with these and newer Crown amps have never had a problem but then, I am looking after the PA.
Transistors do not degrade and the semiconductors in the DC range are good for up to 75 Centigrade, at that point the amplifier will feel like a room heater and shut down.
Back in the 50s and 60s, germanium transistors were the latest semiconductor, (Westinghouse produced XB113 type) and they had a gain around 5 - 10 if you were lucky. They have a shelf life of 25 - 30 years, silicon is not the same.
I beg to differ with you. I have repaired enough commercial (ENI) RF amplifiers to know this. When replacing the paralleled output transistors, that were once matched, and viewing them on a Tek 576 curve tracer they were all over the place gain wise. This may not be as obvious with audio power stages who's heat is mostly from DC. But I believe there is a difference when RF heat is involved.
- Status
- This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.