Fender Bassman 50 AB165 Rebuild Questions

[Enzo]

Please look at the schematic, upper right under NOTICE. Read note #1.

This is just a guitar amp, not a precision lab instrument. A few percent variation in voltages is expected.

[mikeydee77]

And note #4

Adjust for minimum hum

[misterc57]

After some trials, I swapped that 15K to 11.8K and I now have about 31mA on each tube! Thank you!

[g1]

After some trials, I swapped that 15K to 11.8K and I now have about 31mA on each tube! Thank you!

One of the resistors you replaced was a 220K (at the junction of the two 10K's coming off the balance pot).
In the later picture it is a very small bodied part. It does not look to me like the color code for a 220K, please double check it.

[misterc57]

One of the resistors you replaced was a 220K (at the junction of the two 10K's coming off the balance pot).
In the later picture it is a very small bodied part. It does not look to me like the color code for a 220K, please double check it.

Thank you!

Yes, I find myself doing a double take every time I use those. They are very precise 220K 1/2 W Metal Film

Mouser part # 594-SFR16S0002203FR5





Reading the spec I just noticed these only have a 200V operating voltage. https://www.mouser.com/datasheet/2/4..._1-2568165.pdf

I also used a pair of these between the coupling cap and plate of the 6L6. I wonder if I should have used a higher V resistor?

[misterc57]

These are the (2) 220K (highlighted) I also replaced with these small resistors. I have everything buttoned up but now I wonder if these resistors with a 200V operating range should be changed?

Thank you

[g1]

These are the (2) 220K (highlighted) I also replaced with these small resistors. I have everything buttoned up but now I wonder if these resistors with a 200V operating range should be changed?

I think the PI plates and power tube plates are roughly opposite phase. So yes, it would be a good idea to put a higher voltage rating resistor there.

[loudthud]

Those resistors look like 1/8W carbon film. Did you measure them at 220K ? The color code looks all wrong.

[misterc57]

They are a small package resistor. They are 220K (measured) and they are 1/2 W. https://www.mouser.com/datasheet/2/4..._1-2568165.pdf

I will swap them out due to voltage rating.

Thank you

[Chuck H]

I have some of those tiny resistors (purchased accidentally). I never use them. I find them aesthetically unpleasing

[misterc57]

I have some of those tiny resistors (purchased accidentally). I never use them. I find them aesthetically unpleasing

I agree. I also did not realize what I was purchasing at the time.