Experiences of Class A solid-state ?
Harry Lavo wrote:
"Arny Krueger" wrote in message
"Eeyore" wrote
Arny Krueger wrote:
"Eeyore" wrote
Arny Krueger wrote:
In the past the usual approach to this has been to use
a bias circuit that keeps the output devices from ever
turning fully off.
It's that kind of thing.
What do you know about previous examples of this.
Used in some Japanese amps from maybe the late 70s and
early 80s.
I've just generally heard that they hadn't been
brilliantly succesful.
I think the usual phrase used to describe this is
"sliding bias".
Yes.
It seems to me that sliding bias can make power amps
less reliable, by turning minor faults into situations
where lots of power is dissipated in the output stage.
The trick might be to back out the sliding bias feature
when things start going awry, like a shorted load or
some such.
I couldn't comment without seeing a schematic really. I
can't imagine why that should be so.
You haven't come across any then ?
I'm pretty sure I've heard some Technics amps with sliding bias. They sold
them in appliance stores around here in the days of. I seem to recall
their advertising buzzword was "New Class A" or some such.
If that was sliding bias, then my experience with "New Class A" has been
favorable. My lady friend had a Technics Receiver featuring same from the
early eighties, driving KLH speakers which I'm fairly familiar with. I've
listened to full symphony orchestra with that combo, and I'd have to say the
receivers sound was more "sweet" and lifelike than any other receiver I've
heard from the eighties (including Marantz and Yamaha). It sounded far less
"bright", and far more like a current high-quality amplifier.
That sounds encouraging. I can imagine it might have that effect.
Graham
|