mxweas wrote:
So I heard some clipping and decided to check those pots again. At 100% resistance its only brought down to about 9v. I'm using the exact trim pots linked in the tutorial from mouser. Though the trim knob faces sideways for some reason. Any Ideas?
I'm betting you're testing what I tested.
I *was* testing the voltage at the tube PLATE - (Tube Pins 6 or 1) - this will give you close to 9 volts, maybe a bit more, but I was confused that I wasn't getting 6 volts. You won't be able to get this down below around 9 volts.
The bias value he intends you to find is actually tested at the IRF510's 'Source' pin (or where it joins to the LM317 INPUT - same).
Here, you'll get a range such that you can (by adjusting the pots) set to 6 volts (or really, 1/2 of your input voltage; if you're providing 12.8 volts, then you're looking for around 6.4 volts at this point).
I haven't experienced clipping yet; just some excessively strong high frequencies (I've been calling it 'brightness').
I've changed from earbuds to some phones and it seems to be really superb now - great highs but very strong lows as well.
Surprising flatness - strong all 'round.
I had to change out my heat sink for a bigger one. It was just getting too hot for the little 'VGA stick-on sink.
Now that I've got it in a 'settled' state, I need to shoot some photos of it.
Mike Y
Dallas, Texas