Solid State Guitar Amp Forum | DIY Guitar Amplifiers

Hi guys!

Having found this electronic model of speaker impedance (http://tamivox.org/dave/speaker/graphs.html), I set about doing some simulation.

Here is a screenshot comparing two current feedback situations. Both achieve almost exactly the same voltage transfer curve against identical speaker models. But one is some 7 decibels louder, due to using a smaller current sensing resistor. Using a smaller resistor in the CF line and larger DC blocking cap makes the curves nearly the same.

Indisputably, less is not more: more is more! Except maybe in current sensing resistors.

LTSpice .asc file is incluced; strip the .txt suffix. (Maybe the BBS should allow .asc files).

The speaker impedance page I linked to is guitar oriented: the first set of parameters given are for a "typical guitar speaker", so I used exactly those values.

Keeping things bone simple, I didn't model amp details like the output inductor, and Zobel network.

The CF topology and choices of feedback resistors, as well as the way input is is patterned after a power amp I use; adjust to taste.

BTW looks like I registered here on April 20, 2011. Just passed my 15th birSSday.　🎂🎉🥂

When I joined, Posh Spice and Sporty Spice were still 30 something, right?

The one for me that never grows old: LTSpice!