HI, MY TUBE AMP , 300B SE , HAVE A PROBLEM.
THEY HAVE ONE ALPS BLACK BEAUTY EACH CHANNEL.
LEFT CHANNEL OR NOT HAVE MUSIC BEFORE DE 3RTH STEP OR IN THE 4TH IS ALL THE VOLUME , MORE SOME NOISE.
THIS HAPPENED TO ANYONE BEFORE?
CAN THE ALPS BE BROKEN?
CAN THERE BE ANY PROBLEM OF GROUND ?
THE FIRST VALVE SOCKET IS GROUNDED.
UPLOAD A PHOTO.
THEY HAVE ONE ALPS BLACK BEAUTY EACH CHANNEL.
LEFT CHANNEL OR NOT HAVE MUSIC BEFORE DE 3RTH STEP OR IN THE 4TH IS ALL THE VOLUME , MORE SOME NOISE.
THIS HAPPENED TO ANYONE BEFORE?
CAN THE ALPS BE BROKEN?
CAN THERE BE ANY PROBLEM OF GROUND ?
THE FIRST VALVE SOCKET IS GROUNDED.
UPLOAD A PHOTO.
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It looks like the signal input and ground connections to the pot are reversed. How is the other channel wired?
All good fortune,
Chris
All good fortune,
Chris
I think that the connections to the pot are OK (not reversed).
Did you check if the groundbus coming from the pot makes good contact with the ground of the input plug?
Could you post the schematic? Or atleast post what the first tube is?
This is what I make of the connections of the visible tube socket:
My guess is that this is a pentode wired as a triode (with pins 7 and 9 being the anode and screen grid or vice verca). But what puzzles me is what is going on at pin 8 (in combination with pin 3). If pin 3 really is the cathode, than what is pin 8? And why is it connected through 110 Ohm of resistance to ground?
Did you check if the groundbus coming from the pot makes good contact with the ground of the input plug?
Could you post the schematic? Or atleast post what the first tube is?
This is what I make of the connections of the visible tube socket:
- pin 1 = not connected
- pin 2 = control grid
- pin 3 = cathode ?
- pin 4 = filament
- pin 5 = filament
- pin 6 = not connected
- pin 7 = anode or screen grid ? (connected to pin 9)
- pin 8 = ??? (two 220 Ohm resistors in parallel going to the ground bus)
- pin 9 = anode or screen grid ? (connected to pin 7)
My guess is that this is a pentode wired as a triode (with pins 7 and 9 being the anode and screen grid or vice verca). But what puzzles me is what is going on at pin 8 (in combination with pin 3). If pin 3 really is the cathode, than what is pin 8? And why is it connected through 110 Ohm of resistance to ground?
The pot connections are correct. That is how i have done mine with no problems.
Exact model number of potentiometer?
RK40 is available in several versions.
Sample: old RK40 inside (in right RK27).
RK40 is available in several versions.
Sample: old RK40 inside (in right RK27).
It would help in the diagnosis if the OP were to include information like:
1, this is my new construction
or
2, I've had this for a while and it's now broken
3, This channel acts differently from the other. (This might be assumed, but assumptions can be wrong).
The most (maybe the only) important part of troubleshooting any problem is to define the problem. The definition of the problem is the other side of the coin of the solution of the problem.
All good fortune,
Chris
1, this is my new construction
or
2, I've had this for a while and it's now broken
3, This channel acts differently from the other. (This might be assumed, but assumptions can be wrong).
The most (maybe the only) important part of troubleshooting any problem is to define the problem. The definition of the problem is the other side of the coin of the solution of the problem.
All good fortune,
Chris
