No, DF is defined using speaker nominal impedance not actual impedance at any particular frequency.Galu said:
Yes, provided that the 8 and 4 are nominal speaker impedances. Note that putting a 4 ohm speaker on the amp means that damping probably has decreased.
Basically, DF is an attempt to quantify output impedance in a way which looks impressive but is easy to grasp by nontechnical people. 'DF=80' looks so much better than 'output impedance=0.1 ohms'. 'DF=160' looks even better (twice as good?), but in fact it is well into the realm of diminishing returns. As I said, damping varies something like 1 +1/DF.
Basically, DF is an attempt to quantify output impedance in a way which looks impressive but is easy to grasp by nontechnical people. 'DF=80' looks so much better than 'output impedance=0.1 ohms'. 'DF=160' looks even better (twice as good?), but in fact it is well into the realm of diminishing returns. As I said, damping varies something like 1 +1/DF.
That's a good summing up DF96!
Allow me to add the information I have unearthed in the hope that it will assist others unfamiliar with the topic.
The output impedance of the typical transistor amp is very low, due to the use of negative feedback, and the damping factor consequently so high that it doesn't pose an issue.
Valve amps have higher output impedances leading to lower damping factors which may be an issue, particularly in relation to Single Ended designs with zero feedback.
The secret lies in matching loudspeaker to amplfier. Under damped loudspeakers are best coupled with transistor amps, while over damped loudspeakers are best suited to valve amplifiers.
This is where active speakers have the advantage, as the matching has already been done for you!
Allow me to add the information I have unearthed in the hope that it will assist others unfamiliar with the topic.
The output impedance of the typical transistor amp is very low, due to the use of negative feedback, and the damping factor consequently so high that it doesn't pose an issue.
Valve amps have higher output impedances leading to lower damping factors which may be an issue, particularly in relation to Single Ended designs with zero feedback.
The secret lies in matching loudspeaker to amplfier. Under damped loudspeakers are best coupled with transistor amps, while over damped loudspeakers are best suited to valve amplifiers.
This is where active speakers have the advantage, as the matching has already been done for you!
Valve amps can have adequately low output impedance, although not as low as solid-state. Fortunately, there is no technical advantage in extremely low output impedance - for SS it is almost a byproduct of NFB added for other reasons. Hence well-designed SS and well-designed valve amps can drive the same speakers.
DSCk
This is competent cable and lies flat. It isn't cork coloured so you'd have to paint it. Maybe they do a transparent version.
Much better idea. 🙂
@scottjoplin: Cork floor tiles are very 1970s...high time for a makeover. 😀
If recycling is a passion then stick the cork to your walls to damp reflections.
You could make a pile of cork tiles to lift the cable off the floor.
This remark is made in penitence for suggesting that valve and SS amps can drive the same speakers.
This remark is made in penitence for suggesting that valve and SS amps can drive the same speakers.
The Wikipedia definition seems a little ambiguous, it talks about using only the resistive part of the impedance, then later goes on to say
"A high damping factor indicates that an amplifier will have greater control over the movement of the speaker cone, particularly in the bass region near the resonant frequency of the driver's mechanical resonance. However, the damping factor at any particular frequency will vary, since driver voice coils are complex impedances whose values vary with frequency."
Reading around it does seem to be largely a made up term for marketing purposes. I'll probably use 0.75mm to be on the safe side
Back in fashion, haven't you heard, the authentic hipster look. They're dipoles, so I won't be damping the reflections......
What curve...you didn't mention this in your OP. So you want a copper cable that is cork coloured and lays flat on the floor and curves at the same time?
Anything else you want while I'm emailing Uri Geller?