True. The better amps monitor the DC output and disconnect the speaker during a fault.no speaker protection against direct current
As DVDdoug implied, nobody (except hobbyists) make amps with the huge output cap anymore. Like quasi-complimentary, it has gone into the dust bin of time.In the late 70's they made a big deal out of these amps
Well there you go.it's better to do without it as it's a large, cumbersome, and potentially unreliable part
Also, counter intuitively, the energy storage in the capacitor causes increased output stage dissipation as the turnover frequency of the capacitor and speaker impedance is reached...Well there you go.
Good point. I remember "tuning" cheap sub drivers that way.Also, counter intuitively, the energy storage in the capacitor causes increased output stage dissipation as the turnover frequency of the capacitor and speaker impedance is reached...
Also, having seen it unfold (yeah, I'm old), everybody started with tube topologies, and slowly unique topologies were invented for SS that were much more appropriate.There are also things like a DC servo that can be used instead .
Many old designs are from a time when every discrete part had a substantial cost , nowadays a designer does not have to be that frugal.
Exactly! As an example we've shifted away from using electrolytic capacitors in 'bootstraps' in power amplifier design to discrete transistor constant current sources in the voltage amplifier stage that precedes the output stage...There are also things like a DC servo that can be used instead .
Many old designs are from a time when every discrete part had a substantial cost , nowadays a designer does not have to be that frugal.
Oh and another major point is that output caps are going to generate large amounts of even-order distortion if they're electrolytics. If the AC voltage across the cap exceeds 100mV (requiring 250,000uF of output capacitance for an 8 ohm load in a 50W amp) then you're going to get 10ppm distortion at 20Hz. Most output caps are around 2200uF so you can see where this is going...Also, having seen it unfold (yeah, I'm old), everybody started with tube topologies, and slowly unique topologies were invented for SS that were much more appropriate.
Ah but how does is SOUND... I have it on good authority that the Qcomp output has more midrange insight and bass authority when using an authentic Plessey 470uF axial capacitor and original RCA 2N3055sI'd say no one misses the output cap, or quasi-complimentary for that matter, except a small group of determined hobbyists.
Ah but how does is SOUND... I have it on good authority that the Qcomp output has more midrange insight and bass authority when using an authentic Plessey 470uF axial capacitor and original RCA 2N3055s
I would still consider quasicomp if sheer ruggedness was a major concern. Besides, with a Baxandall diode in the driver stage, distortion performance can actually be improved quite a bit.I'd say no one misses the output cap, or quasi-complimentary for that matter, except a small group of determined hobbyists.
I think I still prefer to add output devices for ruggedness, unless fidelity is a secondary concern.I would still consider quasicomp if sheer ruggedness was a major concern. Besides, with a Baxandall diode in the driver stage, distortion performance can actually be improved quite a bit.
Somewhat but IME it's still nowhere near as good as a CFP output stage which allows a good deal of paralleling of the output devices and much better thermal stability... It also lets you get the output closer to the rails which is never a bad thing.I would still consider quasicomp if sheer ruggedness was a major concern. Besides, with a Baxandall diode in the driver stage, distortion performance can actually be improved quite a bit.
Conversely, real audiophiles adore large, cumbersome, and potentially unreliable partWell there you go.