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Hi to all,
hope someone can help out.
My brother bought a second hand JTM45 clone.
It seems like the normal channel works fine and when you crank the volume pot it distorts nicely.
The bright channel on the other hand seems a bit quieter and doesn't distort at all when cranked.
I didn't get to look at it closely. I did quickly measure if everything is connected properly from inputs to about V2 Cathode follower out while parallel working with a schematic.
The rest was all visual through photos.
Anyway at first most of the preamp seems fine. Also the V1 cathodes share a 820ohma and 100uF bypass cap, so the channels should have same gain.
I did notice from photos that the 3 of 4 resistors around V3 Phase inverter look as if they aren't connected.
PI's pin 3 and 8 arw connected to 470 ohm and than the resistors are interconnected with each other as they should be. But it looks as if one 1Meg is not connected to Pin 2 same as the other to Pin 7. Also the 10kOhm seems as if isn't going to presence or anywhere else...
Could this be a problem?
Wouldn't this cause both channels not working or the amp completely?
If not, what would be the symptoms of this?
Here is the photo of this part:
hope someone can help out.
My brother bought a second hand JTM45 clone.
It seems like the normal channel works fine and when you crank the volume pot it distorts nicely.
The bright channel on the other hand seems a bit quieter and doesn't distort at all when cranked.
I didn't get to look at it closely. I did quickly measure if everything is connected properly from inputs to about V2 Cathode follower out while parallel working with a schematic.
The rest was all visual through photos.
Anyway at first most of the preamp seems fine. Also the V1 cathodes share a 820ohma and 100uF bypass cap, so the channels should have same gain.
I did notice from photos that the 3 of 4 resistors around V3 Phase inverter look as if they aren't connected.
PI's pin 3 and 8 arw connected to 470 ohm and than the resistors are interconnected with each other as they should be. But it looks as if one 1Meg is not connected to Pin 2 same as the other to Pin 7. Also the 10kOhm seems as if isn't going to presence or anywhere else...
Could this be a problem?
Wouldn't this cause both channels not working or the amp completely?
If not, what would be the symptoms of this?
Here is the photo of this part:
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