Hi all,
I'm new to the forum here, so I thought I'd say hello to everyone. Beware, I tend to be verbose! 😉
I've been away from the audio scene for quite a while now and am getting interested again. I'm an EE, 47 years old (gosh, where has the time gone???). I became interested in electrical engineering in the mid 70s through my interest in audio. This started with an experience I had listening to power amps. The older brother of a friend of mine had a pair of Magneplanar speakers, and he claimed that he could hear the difference between power amplifiers with them. I told him this was very unlikely, since speakers have about 100 times the distortion of amps. He responded by playing two different power amps - one a Harmon Kardon Citation 60 watt amp, and the other a Marantz unit with about twice the power. I figured that if there was any difference at all, the higher-powered unit would sound better since the speakers weren't very efficient. But this wasn't the case at all. It was quite clear that the Citation sounded not only different from the other amp, but much better. The friend's brother had exactly the same view, but didn't tell me until afterward. This experience really stuck in my mind.
Then later, I read an article in Audio magazine regarding "TIM distortion" in power amps by a guy from Georgia Tech named Marshall Leach. I was fascinated by this article, and wrote him a letter. He responded by sending me lots of information about the EE program there, and I ended up going to school there.
I thought of designing my own power amp for a time, but instead I became interested in learning how to do software development, which I never did in college, since using computers was such a pain in the **** back then. I now do software development for a living, working on circuit simulation software used by EEs for design in the microwave frequency range. So software development is no fun for me anymore. I've recently become interested in designing an amp again.
What's got me really excited now is this freeware SPICE simulator LTSpice. I picked transistors such that I could find SPICE models for them, and figured out how to get the models into LTSpice. What's awesome about SPICE is that the models predict distortion behavior and transient performance including nonlinearity. Awesome! I've done some simulations and post-processing of the output stage nonlinear characteristics and have done some analysis of the crossover distortion versus bias for a few configurations. I'll post some of my results in the thread on class B vs class AB in the solid state forum. I think what I'll also do is put up a primitive web site with some of these results too - such as graphs of the nonlinear characteristics in the crossover region.
One problem though - I'm not very good with my hands. I'm not a total klutz, but I also cannot come even close to the kind of work that some of the folks here do. So if I do get around to actually building the thing, 😉 I'll need tips and advice from the experienced builders. The areas where I can help are more on the analytical side - running simulations and general analog design and engineering issues.
Well, that's all for now. I still have to do my taxes, so it may be another week before I post again. It's great to be here!
I'm new to the forum here, so I thought I'd say hello to everyone. Beware, I tend to be verbose! 😉
I've been away from the audio scene for quite a while now and am getting interested again. I'm an EE, 47 years old (gosh, where has the time gone???). I became interested in electrical engineering in the mid 70s through my interest in audio. This started with an experience I had listening to power amps. The older brother of a friend of mine had a pair of Magneplanar speakers, and he claimed that he could hear the difference between power amplifiers with them. I told him this was very unlikely, since speakers have about 100 times the distortion of amps. He responded by playing two different power amps - one a Harmon Kardon Citation 60 watt amp, and the other a Marantz unit with about twice the power. I figured that if there was any difference at all, the higher-powered unit would sound better since the speakers weren't very efficient. But this wasn't the case at all. It was quite clear that the Citation sounded not only different from the other amp, but much better. The friend's brother had exactly the same view, but didn't tell me until afterward. This experience really stuck in my mind.
Then later, I read an article in Audio magazine regarding "TIM distortion" in power amps by a guy from Georgia Tech named Marshall Leach. I was fascinated by this article, and wrote him a letter. He responded by sending me lots of information about the EE program there, and I ended up going to school there.
I thought of designing my own power amp for a time, but instead I became interested in learning how to do software development, which I never did in college, since using computers was such a pain in the **** back then. I now do software development for a living, working on circuit simulation software used by EEs for design in the microwave frequency range. So software development is no fun for me anymore. I've recently become interested in designing an amp again.
What's got me really excited now is this freeware SPICE simulator LTSpice. I picked transistors such that I could find SPICE models for them, and figured out how to get the models into LTSpice. What's awesome about SPICE is that the models predict distortion behavior and transient performance including nonlinearity. Awesome! I've done some simulations and post-processing of the output stage nonlinear characteristics and have done some analysis of the crossover distortion versus bias for a few configurations. I'll post some of my results in the thread on class B vs class AB in the solid state forum. I think what I'll also do is put up a primitive web site with some of these results too - such as graphs of the nonlinear characteristics in the crossover region.
One problem though - I'm not very good with my hands. I'm not a total klutz, but I also cannot come even close to the kind of work that some of the folks here do. So if I do get around to actually building the thing, 😉 I'll need tips and advice from the experienced builders. The areas where I can help are more on the analytical side - running simulations and general analog design and engineering issues.
Well, that's all for now. I still have to do my taxes, so it may be another week before I post again. It's great to be here!
Welcomed aboard Andy, this is a great place for what you like.
I guess you could be intrested on the SuperSymmetry thread going on the Pass Labs forum.
And for hardware the member to look for is Peter Daniel and of course others.
Happy listening.
I guess you could be intrested on the SuperSymmetry thread going on the Pass Labs forum.
And for hardware the member to look for is Peter Daniel and of course others.
Happy listening.
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