Actually, it's been finished a while, but I just didn't get around to taking pictures. So without further ado I present my first project: a gilmore dynamic headphone amp with a superregulator powersupply! W00T! More info can be found on my superregulator and gilmore pages.
Help yourself to the pictures below.
So how does it sound? Good. Better than good. I have Philips HP890 headphones, and my hifi system just doesn't have the power to drive them well. The gilmore does not saturate at all. The power in the bass is amazing. It has no problem at all driving these puppies. Wow. It's such a pleasure to listen.
Some odd stuff I ran across... I didn't bother to match the transistors, leds and resistors (as is recommended). I would play around with different leds in the current sources and find pairs that would give me the least DC offset at the output. First set I tried gave me less than 1mV with the servo on. I figured I was lucky. Then, I blew a led. So I just soldered in another one, measured the DC offset and it was still below 1mV. What's with all the stories of large DC offsets?
And then there's one small problem. It hums. A little. No, really, just a little. Can't hear it unless there's hardly any input at all. But it's annoying. I've tried shielding the mains cables, added a grounded metal plate between the PSU and the amp, but it's still there. It goes away if I talk the amp further away from the PSU, so I'm guessing it's currents induced by the magnetic field from the transformer. I should have gotten a larger enclosure.
Superregulator:
Whole thing:
Help yourself to the pictures below.
So how does it sound? Good. Better than good. I have Philips HP890 headphones, and my hifi system just doesn't have the power to drive them well. The gilmore does not saturate at all. The power in the bass is amazing. It has no problem at all driving these puppies. Wow. It's such a pleasure to listen.
Some odd stuff I ran across... I didn't bother to match the transistors, leds and resistors (as is recommended). I would play around with different leds in the current sources and find pairs that would give me the least DC offset at the output. First set I tried gave me less than 1mV with the servo on. I figured I was lucky. Then, I blew a led. So I just soldered in another one, measured the DC offset and it was still below 1mV. What's with all the stories of large DC offsets?
And then there's one small problem. It hums. A little. No, really, just a little. Can't hear it unless there's hardly any input at all. But it's annoying. I've tried shielding the mains cables, added a grounded metal plate between the PSU and the amp, but it's still there. It goes away if I talk the amp further away from the PSU, so I'm guessing it's currents induced by the magnetic field from the transformer. I should have gotten a larger enclosure.
Superregulator:
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
Whole thing:
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
Banned
Joined 2002
The parts are relatively easy to get. It's much easier in the US than in Europe, I'm sure. I don't have spare boards. I etched them myself. I can send you the layouts in Postscript.JasonL said:
You really are crazy, aren't you?kevin gilmore said:
I can see the lights dim when I power this sucker up already. That monster of yours requires its own nuclear power station.No seriously - next thing might be putting it in a different enclosure to get rid of the hum. Then, I'm going to look into a preamp/amp/speakers. I got interested in those Apogee ribbons, but I'm not sure it's worth the trouble.
Cheers,
Alfred
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