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β24 - thoughts about safety and amp control

beta24

Re: β24 - thoughts about safety and amp control

Postby mpa2 » May 24th, 2018, 9:13 am

About his DC protection circuit, he writes "Кроме того желательно обеспечить небольшую емкость, нагружающую оба
выходных провода усилителя к «земле», и, по возможности – достаточно высокое активное
сопротивление, чтобы не нарушались режимы работы системы подачи смещения в выходном
каскаде." :)
It's kind a "Furthermore it is desirable to provide a small capacitance, which loads both output wires to ground and, if possible, a pretty high Z, in order not to disturb the biasing of the output stage"... His amp is a circlotron with FET output stage. I'm sure, BesPav, can explain it better :)
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Re: β24 - thoughts about safety and amp control

Postby BesPav » May 24th, 2018, 9:54 am

mpa2 wrote:The guy writes about "adding some capacitance" between amp outputs and ground.


No, he meant straight to reverse.
:)
For using with this king of relatively deep-feedback circlotrons protection circuit must have small input capacitance and relatively high ohmic impedance for keeping OPS and overall amp stable.

Beta’s OPS is a one-stage source follower, overall amp have moderate feedback depth and is stable with up to 10 uF straight to output terminals(need to say with lowering slew rate, but not one of the different amps will immediately burn with that capacitance), so have no doubt, given protection circuit will work as described.
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Re: β24 - thoughts about safety and amp control

Postby Kabal{MSU} » May 28th, 2018, 2:26 am

BesPav wrote:so have no doubt, given protection circuit will work as described.


After small correction only - the circuit has "copy protection".
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Re: β24 - thoughts about safety and amp control

Postby mpa2 » May 28th, 2018, 2:57 pm

Kabal{MSU} wrote:
BesPav wrote:so have no doubt, given protection circuit will work as described.


After small correction only - the circuit has "copy protection".


I've contacted that guy and can obtain boards from him. Unfortunately the boards are pretty big (10 x 10 cm), contain soft start function "twice", i. e. for two transformers, and mating them with e24 is also a bit tricky... I'll see. Btw, BesPav, thanks for the link.
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