Hello - I just finished an express, the amp sounds great overall but there is one area where the notes have a buzziness to them almost like a doubleing effect, only on the high E string from the 12th fret to the 15th or 16th (also the same notes on the b string) above or below that all is well. I was tinking of changing the value of the .0022 cap thats between the plate of V1 & the grid of V2 but I figured I would see if anyone here had any ideas.  .   . Other than that one small detail this amp is really great, chimey clean to rockin hard great note definition & lots of sustain. 
any sugestions are appriciated  "  JOE
			
			
									
									Express finished - one small concern
Moderators: pompeiisneaks, Colossal
Express finished - one small concern
Resistors not Transistors !
						Re: Express finished - one small concern
does this happen with more than one guitar?
			
			
									
									
						Re: Express finished - one small concern
Yes it happens with both guitars that I have tried. I just finished trying a whole host of things buy nothing helped, I tried 8 or 10 diffrent preamp tubes in a sorts of combinations, larger - up to 220 uf - cathode bypass caps changed the 47pf PI plate cap to 180pf then .0047 with a 120k resistor across it (highgains recent post) I changed the .0022 cap between V1 plate & V2 grid up to .0068. . Maybe I should have tried the most obvious & easiest first - a diffrent speaker - Ill plug it into a 2x12 cab later & let you know the result. . By the way what speaker,s do you guys like with this amp??does this happen with more than one guitar?
JOE
Resistors not Transistors !
						Re: Express finished - one small concern
Hello
This sounds like a speaker problem. I've had some speakers do this, and took replacement cones or an entire replacement speaker to get rid of it.
Cheers!
Shermock
			
			
									
									
						This sounds like a speaker problem. I've had some speakers do this, and took replacement cones or an entire replacement speaker to get rid of it.
Cheers!
Shermock
Re: Express finished - one small concern
So it turns out I was trying to fix a problem that didnt exist,(ive heard the term "cone cry" before & I think I now know what it sounds like), I pluged her into a 2x12 with sammi's in it and wow - what a diffrence, I dont think this amp was meant to be played thru a single 12" speaker, I cant wait to plug her into a 4x12. 
JOE
			
			
									
									JOE
Resistors not Transistors !
						