Damping factor explained - or not?

Status
This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.
Unfortunately there appears to be a law of physics which says that something which acts like a resistor (such as a switched capacitor) has to act like a resistor, and so dissipate energy somewhere (in the switch?). Thermodynamics can be cruel!

But engineers are smart. No reason why you couldnt connect 2 barreries in series while charging then parallel when discharging. Loss is negligible. Change battery to cap, and you get the switched cap converter. The problem is the discrete voltage ratio set. But with 1 inductor and 2 switches there is no such limitation. This is called ClassD amp. No rule against it.
 
Pafi said:
Mine is: no rule against 100 % power conversation efficiency.
True. Irrelevant. A switched capacitor used in place of a resistor is not converting power, but wasting power - just like a resistor.

But who talked about filters and noise?
We did.

We talk about power conversation, at relatively high power.
No. You talk about power conversion. We talk about 'lossless resistors'. Someone suggested using switched capacitors instead of resistors - the usual application for this is filters. No matter: anywhere a resistor is replaced by a switched capacitor you will get the same loss.
 

Then you were offtopic. This topic is about amplifiers and speakers, not about making nonsense jokes about fictional questions. Both noise and switched capacitor filters are offtopic.

No. You talk about power conversion. We talk about 'lossless resistors'. Someone suggested using switched capacitors instead of resistors - the usual application for this is filters. No matter: anywhere a resistor is replaced by a switched capacitor you will get the same loss.

An amplifier is basically two controlled resistors between 2 voltage rails. These can be replaced by combination of controlled switches and reactant elements to give basically the same output, but with negligible loss. In this meaning resistors can be replaced by lossless circuit. Noise has absolutely no relevance.

And even if you talked offtopic it doesn't mean you can pretend like others talked the same stupid thing (what you intentionally made stupid).

If all your intention was to show how a troll behaves - you succeed.

Resistors waste energy. It would be much more efficient if resistors did not do this. Can we have lossless resistors, and so improve sound?

Yes you can. It is called a superconductor.

Sorry for staying ontopic...
 
Pafi said:
Then you were offtopic. This topic is about amplifiers and speakers, not about making nonsense jokes about fictional questions.
Someone asked a question about a fictional speaker without back emf. As this is not possible in this universe, was this off topic too?

Both noise and switched capacitor filters are offtopic.
On this forum the Mods are fairly relaxed about off topic comments, especially when they are triggered by someone else.

An amplifier is basically two controlled resistors between 2 voltage rails. These can be replaced by combination of controlled switches and reactant elements to give basically the same output, but with negligible loss. In this meaning resistors can be replaced by lossless circuit.
"Switched capacitor" is a particular circuit technique used in filters. Nothing to do with high efficiency audio output stages, where capacitance is a loss mechanism.

Yes you can. It is called a superconductor.
No. A superconductor is not a lossless resistor. It is quite a different thing: it is not a resistor as it has zero resistance, and it is not a normal conductor because it excludes magnetic fields.

Sorry if my British humour is not appreciated by everyone.
 
Re current drive of speakers.
What means damping factor if the power amp acts as a current source? The "back EMF" cannot drive any current because a negative feedback of the current source forces total current zero if input is zero ( for example) . Is that dampening?
No, that means that speaker is not being damped at all, period.

Same as if the speaker were unconnected.

In fact, one silly trick I play on my customers sometimes which always amazes them, is that I can infallibly detect whether an amp connected to the shop test speaker is ON or OFF without seeing it :eek:

I just recite some mumbo jumbo and tap the speaker cone, the undamped/unconnected one thumps like a drum skin, the damped one (amp ON) sounds like tapping a bag full of sand.
Try it yourself :p

Of course, your proposed pure current amp would fool me :xeye:

Just a side note: not a grammar nazi but we're talking techglish, and meaning is important: please no conversation for conversion or dampening for damping :)

Or that DIYAudio favorite: torroid for toroid.

That said, I can forgive them:
http://www.pulsor.org/#!color-torroid/cqpu
they are talking BS and nonsense anyway.

Irrelevant?

Hey!!! , they even talk EMF !!!!!!!!!
http://www.pulsor.org/#!the-emf-problem/c18tz

unsurprisingly, also in a twisted way ;)
 
Last edited:
No, that means that speaker is not being damped at all, period.

Same as if the speaker were unconnected.
Just a side note: not a grammar nazi but we're talking techglish, and meaning is important: please no conversation for conversion or dampening for damping :))

dampen
v. moisten, wet; moderate, depress, discourage, dull

but but the more important linear motors , e.g. for industry robots, for ex. precise positioning of robot tools relative to the assembly , are all current controlled and must be perfectly damped and are perfectly damped....

how is that magic or misunderstanding of current drive?

the only , say, connection between electrical world and mechanical world
is via B*l*i = ( mechanical) where i current.
all else is in terms of physics sheer nonsense
 
but but the more important linear motors , e.g. for industry robots, for ex. precise positioning of robot tools relative to the assembly , are all current controlled and must be perfectly damped and are perfectly damped....

how is that magic or misunderstanding of current drive?
Which means controlled torque or force. The current has to be adjusted on the fly to give the wanted motion
 
Status
This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.