I did recheck all of the values all were correct, but I did have a few problems that added up ,first bad pre tube,semi broken wire, bad vol pot,and a missed jumper on the mid pot .the amp is up and running and pics will follow just need to clean some of the work from the diagnostic process
thanks
neil
Structo wrote:I would double check all resistor values.
It's easy to mistake a 470R with a 470K or similar.
Over at the Metro forum there is one resistor that frequently gets the wrong value installed, the guys there know the symptoms very well and when questioned, the builder quickly realizes his mistake.
Not saying that is why your OD is screwed up but it can certainly cause symptoms like that.
I can read color codes pretty well but whenever I start a new build I like to meter all my resistors then tape them to a piece of heavy stock paper with the value notated.
Not unheard of to have an out of spec value.
bigmik wrote:finished up a el 34 hrm build last night and it fired right up or so I thought
voltage seemed fine throught biased it kind of cold and plugged in,something wasn't right had sound but the input volume was all that worked the clean and the gain volume had no affect on anything. cool miswired somthing no big deal ,pulled the board this afternoon and went back through through the amp didn't find anything so I suspected a cold solder joint, reinstalled the board and reflowed all the solder joints checked all of the tube pins to ground to make shure nothing was touching and fired her up again . sill not right only the OD channel was working kind of really weird distortion happening ,SHIT !!! .strum a few more cords and FIRE starts shooting from one of the power tube sockets !!!!! fuse blows and I am shakeing like a leaf WTF .didn't know what happened ,drained the caps and started checking and found that the heaters has contunitity to ground ,disconected the heater wires fron the tube socket and they are shorted to ground.what would cause this to happen after the amp was on for quite a while????
thanks
neil
I'm guessing you had some kind of funky problem with speaker/load wiring, or a bad solder connection on the OT taps or impedance selector or a severe mismatch, turning the volume up with no speaker connected can give you similar symptoms and usually results in tube failure, smoke/flame/burnage and arc points near pin 3 on both tube sockets. (also makes you wonder from then on what kind of damage you may have done to the OT).
quite possibly could have been as the arc point was between pin 3 and pin two but only on one tube socket ,I did reflow EVERY solder joint in the amp just in case . I was definately was scared that it took out the trannys only time will tell if it did any long term damage, but the amp was run quite a few hours and appears to be OK
This amp has definately tried my patience I have never built an amp that had has many cumulitive problems as this one,component and opperator error
heisthl wrote:
I'm guessing you had some kind of funky problem with speaker/load wiring, or a bad solder connection on the OT taps or impedance selector or a severe mismatch, turning the volume up with no speaker connected can give you similar symptoms and usually results in tube failure, smoke/flame/burnage and arc points near pin 3 on both tube sockets. (also makes you wonder from then on what kind of damage you may have done to the OT).
