Timeline for Complex Dummy Speaker Load Impedance
Current License: CC BY-SA 3.0
10 events
| when toggle format | what | by | license | comment | |
|---|---|---|---|---|---|
| Aug 15, 2013 at 18:04 | history | tweeted | twitter.com/#!/StackElectronix/status/368070615439519744 | ||
| Jul 11, 2013 at 17:10 | comment | added | Dave Tweed | A couple of misconceptions: First of all, this is definitely NOT a class-A amplifier. The output transistors are biased to operate (as near as I can tell) in pure class-B. Secondly, even if the collector load on Q3 and Q4 varies, this will have minimal effect on the rest of the circuit. | |
| Jul 11, 2013 at 14:36 | answer | added | user3624 | timeline score: 1 | |
| Jul 11, 2013 at 13:52 | comment | added | squarewav | @Dave Tweed - This amp is "sensitive to the load" because the current in each transformer primary depends on the current in the secondary (the load). And the current on the output is frequency dependent when connected to a speaker whereas it would be flat with a 4 ohm resistor. So for example, if the speaker had a spike in impedance at 400 Hz. That would reduce the load at that frequency back to the collector of Q2. And because this is a class A amp, this would affect non-linear behavior in subtle ways and, more important, in not so subtle ways when pushed (which is what I intend to do to it). | |
| Jul 11, 2013 at 10:46 | comment | added | Dave Tweed | You need to be clearer about what you mean by "sensitive to the load" and "complex frequency response". In particular, why do you think the latter will help you diagnose the former? | |
| Jul 11, 2013 at 7:18 | comment | added | Andy aka | I'm not sure what you are trying to ultimately achieve | |
| Jul 11, 2013 at 6:13 | history | edited | squarewav | CC BY-SA 3.0 |
typos
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| Jul 11, 2013 at 5:57 | comment | added | Anindo Ghosh | Two speakers facing each other and closely mounted, would result in a noticeably higher effective impedance of the output. Each speaker is also effectively a microphone, so it would generate back-EMF corresponding to incident sound, opposing the drive signal. The arrangement will also add some frequency response maxima and minima due to acoustic resonance and magnetic coupling effects. This is true even if two mismatched speakers are used. | |
| Jul 11, 2013 at 5:54 | history | edited | squarewav | CC BY-SA 3.0 |
added idea about tactile transducers
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| Jul 10, 2013 at 23:51 | history | asked | squarewav | CC BY-SA 3.0 |