Amplifier Specs


Can someone explain what slew rate and damping factor are and how they affect an amplifiers sound/performance. Thanks in advance
robk
Hi, Richard. Good to see you here. Thanks for the clarification. Are those numbers bigger the better in general? How about "negative feedback"?
Hello Ken. There are many factors involved in determing "damping factor" and it depends on circuit design, so sometimes bigger is not always better. Damping factor is roughly the ratio of amp output impedence v speaker impedence. So if the amp is, say, 0.1 ohm and the speaker is 8 ohms the factor is approx 80. Negative feedback is used in circuit to control devices, for example transistors, and ensure they give a reasonable performance under repeat conditions. It basically tries to overcome the inherent shortcomings of the device in question and give better performance figures. This is a very rough and ready explanation which I hope helps. Regards, Richard.
How much damping factor you need depends on the speaker you intend to use. Some speakers are specifically designed for use with tube amps that generally deliver low damping. Coupled with an amp with high damping factor will produce an over damped bass response, dry and muddled. I think it has to do with the Q factor of the woofer. Maybe someone out thier in Audiogon land has a better grasp of the tech aspect.Suffice to say, matching the right amp to a speaker can make a huge difference.
You have to consider that speaker cones have a true damping that is determined by lots of factors, including the damping effect of the voice coil resistance. The amp impedence does not add much to the voice coil total resistance and in reality has little effect on the total damping. Speaker damping is usually engineered to achieve the desired low frequency rolloff. The aim here is to get a low damping figure for the speaker system as a whole to get the best bass response. But it is true that getting the right amp to match the speaker system still makes a huge difference.