coco wrote:
Loose connection? Did you try another guitar? Bad guitar cable, try another one?
That's definitely not a possibility. Problem exists on multiple guitars and multope cables.
coco wrote:
Bad cap somewhere? For fun, try a lower gain tube in the PI.
You know, I initially built this amp with with a 12AT7 ( I think it was in the PI) and it wasn't nearly as noticable...but I still heard an underlying fuzz...so I suspect that it just reduced the buzz in the overall mix.
coco wrote:
Could be a maxed out tube - too much gain - bad parts around the tube or bad bypass cap.
You know, these are the two possibilities I keep coming back to...somewhere in here, there's gotta be a bad component that's forcing a preamp tube to act nasty. The problem is issolating the part. I know that I can determine a bad cap by seeing if there's voltage on both ends (thanks to s2)...but if there's a resistor in parallel...how do I then determine that?
For example, let's take v1. The off the cathode, you've got a 1.5K resistor and a 25uf cap. Without soldering....I'm sure I can determine that the resistor is ok....but if I crank up the amp and measure voltage on either end of the cap/resistor pair...Wont I get voltage on either end of the cap, since a resistor is in parallel with the cap?
coco wrote:
Hang in there..
Don't you worry....I'm not giving up on this one, if it kills me....or I die before I solve it!
![Mad :x](./images/smilies/icon_mad.gif)
... or both!
![Shocked :shock:](./images/smilies/icon_eek.gif)