Re: High voltage capacitors in audio

On Jun 26, 7:23 pm, Eeyore <rabbitsfriendsandrelati...@xxxxxxxxxxx>
wrote:
MooseFET wrote:
On Jun 26, 7:45 am, Eeyore <rabbitsfriendsandrelati...@xxxxxxxxxxx>
wrote:
MooseFET wrote:
On Jun 26, 7:04 am, Eeyore <rabbitsfriendsandrelati...@xxxxxxxxxxx>
wrote:
MooseFET wrote:
ectoplasm <e_c_...@xxxxxxxxxxx> wrote:

What is it with Z's? Do you mean Z as the symbol for impedance?

As MooseFET said "places where ideally, a small lossy impedance will
be in series". These would be resistors, for dampening purposes?

You could use resistances if you had to. I would suggest lossy
inductors, if cost is no object.

Working left to right.

The ones at the left side of the drawing, reduce the peak current in
the bridge, and block RF. It is a serious bummer when your new
amplifier circuit starts picking up the nearby radio transmitters.

Oh for heaven's sake !

Through the power supply ? Are you being even remotely serious ?

Yes absolutely. Don't think of it as a power supply. Think of it as
the connection to the antenna. The detector would be some diode
junction in the first op-amp.

It looks like this:

Cable House wiring
Audio ============->!================ Mains
Diode

The capacitance of the transformer makes it disappear from
consideration by time you get to the AM band.

You're blowing out of your backside.

Stop inventing non-existent problems for the poor OP.

Oh shut up.

Shut up yourself.

Are you a professional; audio designer ?

I have designed a great many things that work at audio frequencies
some of which were intended to deliver sound to the user and I got
paid for doing this job.

I have learned from experience not to ignore the RF coming in on the
power cable.


I gave him good advice. I didn't suggest a problem I
haven't seen in real life.

There's got to be something seriously wrong if the PSU is causing RF pick up.

Obviously you didn't understand what I said. I will try again.

Imagine the big long wire that is the power wiring of the house. It
picks of RF power as a common mode signal. This connects to the plug
which connects to the transformer. The capacitance from the primary
to the secondaryy of the transformer has a low impedance at RF
frequencies so it goes through the transformer onto the secondary
winding. From there the RF current flows through the ground of the
amplifier to the cable that goes to the signal source.

Now that you can see the path the RF is passing through consider that
the input section of the amplifier and the audio cable may not be very
good at RF frequencies. The op-amp can rectify this RF.




Graham


.

Relevant Pages

  • Re: using step-down transformer as step-up
    ... well at RF frequencies. ... when speaking of running a step-down transformer backwards I ... was thinking of the power supply transformer. ... polite correction would be fine! ...
    (sci.electronics.design)
  • Re: SMPS, control loop?
    ... no-one apparently built an audio amp which *is* just an audio ... SMPS straight off the AC power line? ... converters but with a transformer in the way leakage inductance makes life ...
    (sci.electronics.design)
  • Re: using step-down transformer as step-up
    ...  This is a real question to ... me since I need a high-voltage step-up transformer for an RF amplifier ... I've built a few low power RF amplifiers in the past. ... well at RF frequencies. ...
    (sci.electronics.design)
  • Re: Design Suggestion Requested
    ... But the Ritec RAM 10000 does synthesize a sine wave. ... While the spec may say 50ohms that usually means you should not load it with anything less at high power levels to avoid blowing the final stage transistors. ... The scientist wants the frequency to be adjustable to between 200kHz and 500kHz in single cycle pulses that pulse at rate of between 50Hz and 100Hz. ... But with a typical output of a DSS being 0V to 5V, and assuming the pulse transformer is 80% efficient, and unity gain for the buffer amp, I would need 500A into the pulse transformer. ...
    (sci.electronics.design)
  • Re: Electric Powerlines to be Used For Broadband
    ... The 120V outlets in your house are wired so that some are on one leg ... into receptacles which are on opposite sides of the transformer, ... each transformer providing power to a small number ... That connection sounded pretty bad also. ...
    (comp.dcom.telecom)