|
Post by gtrjunior on Jul 14, 2016 6:27:16 GMT -5
I've done some pretty dumb things in my time. Once I plugged my speaker cabinet into the the FX return by mistake. And wondered why I had no sound. Your average amp probably would have melted right then and there. (If I had new power tubes lying around I would not hesitate to put them in as a test - you will not hurt your amp) PS: The EQ pedal can definitely act as a boost - especially if you have any level above '0'. I would just remove those pedals for now until you get this sorted. I have an old set of New Production Mullards that came out of my JVM that I'm going to put in the QR hopefully Sunday. Even though I have the eq in the loop the level is set at unity but yeah, it's all coming out until I can get this sorted out.
|
|
|
Post by gtrjunior on Jul 14, 2016 17:38:48 GMT -5
Bias probe was delivered today but I won't have a chance to do anything until the beginning of next week.
|
|
|
Post by gtrjunior on Jul 17, 2016 9:47:35 GMT -5
I'm going attempt my first retube and bias tomorrow....one more question.
Should I take to amp out of Drop B+ mode when biasing? Does it make a difference?
|
|
|
Post by Tempest on Jul 17, 2016 10:39:37 GMT -5
I don't think it will, but I'd go with the normal setting just to be sure...I'm a bit superstitious like that!
|
|
|
Post by gtrjunior on Jul 17, 2016 10:56:13 GMT -5
Yeah I hear that!!! I was leaning toward the normal setting too but just wanted to see if anyone had experience there. I may, just for the hell of it check the plate voltage in both setting just so we know if it changes.
|
|
|
Post by gtrjunior on Jul 18, 2016 11:49:56 GMT -5
So I figured I'd rebias my amp... I read Splawndude's tutorial, I watched the eurotubes video....I'm good to go! I remove the amp from the box and check the plate voltage on all 4 tubes...I'm averaging 470vdc. BTW...in Drop B+ mode the plate voltage dropped to 410vdc, so yeah, it matters that you're NOT in Drop B+ mode.!!
My bias was very cold at @25ma. So I did my math about 5 times and at 65% I should bias at 34.5 mA. I decided to go with an even 34 mA. So i set the bias, waited about 15 minutes to make sure it didn't drift (it didn't). So I decided to remove the probe and hear how it sounded.... That's when it all went south.
As I was wiggling the tube off of the probe...the tube slipped out of my hand and clipped the corner of my cab...yup, it shattered into a thousand pieces. I yelled every profanity I know....but it didn't help. Moral of the story: Don't be a dumbass...like me.
|
|
|
Post by Tempest on Jul 18, 2016 11:57:06 GMT -5
Damn! Lucky it wasn't a KT88, that would set you back some bread. Have you got a spare?
|
|
|
Post by splawndude on Jul 18, 2016 12:01:45 GMT -5
Pop one of your other EL34s in there and bias it up. Closest two pairs mA wise go in inner two sockets. The other two go in outer sockets.
|
|
|
Post by gtrjunior on Jul 18, 2016 12:23:48 GMT -5
Pop one of your other EL34s in there and bias it up. Closet two pairs mA wise go in inner two sockets. The other two go in outer sockets. Even if it's another brand?
|
|
|
Post by gtrjunior on Jul 18, 2016 12:24:13 GMT -5
Damn! Lucky it wasn't a KT88, that would set you back some bread. Have you got a spare? No kidding! They ain't cheap!!
|
|
|
Post by splawndude on Jul 18, 2016 12:29:06 GMT -5
Pop one of your other EL34s in there and bias it up. Closet two pairs mA wise go in inner two sockets. The other two go in outer sockets. Even if it's another brand? yep
|
|
|
Post by gtrjunior on Jul 18, 2016 12:31:01 GMT -5
Ok...doing it now
|
|
|
Post by gtrjunior on Jul 18, 2016 12:32:50 GMT -5
First one... Not even close Re-issue Mullard
|
|
|
Post by splawndude on Jul 18, 2016 12:34:37 GMT -5
If one of your other ones is not even close, then go to half power, cut your ohms in half, and bias with just 2 power tubes for now.
Sorry.
|
|
|
Post by gtrjunior on Jul 18, 2016 12:36:40 GMT -5
2nd...even further apart. Marshall branded =C=
|
|