Tweedle help....

[bluesy]

Novice newbie here....please go easy on me. Built a TweedleDee Deluxe with the great information available here. I don’t understand schematics and used the layout that’s here. She’s running. Voltages are very close to what was posted on CW’s documentation. Except for one. At the intersection of the 1M and 3.3M resistors I get 3.4V as opposed the the documented 21.58V. In looking through everything many times I can’t seem to find anything wrong Tried different pre tubes hoping that might help. No luck. Can anyone steer me toward a solution? Thank you all for your audio endeavors.

[norburybrook]

Do you have the jumper wire connecting that node to the top of the 0.022uF cap from the 100k plate resistor?


M

[fred.violleau]

I had the exact same voltages. Did you do the exact original layout, or did you add a master Volume?

Fred.

[bluesy]

The jumper from the 1M/3.3M intersection goes to the top of the .022. I have 3.4V there also.There is nothing from the .022 to the 100k. I don’t see it on the layout.

[bluesy]

I do not have a master volume. (Yet) I followed M Hartman’s layout.

[fred.violleau]

Did you try to roll tubes as well to see if it is not related to a bad triode ?

Fred.

[bluesy]

Tried swapping a couple different sets of tubes......no luck. Fred, you said that you had the same voltages....do you still have 3.? Instead of the documented 21.58?

[martin manning]

What are voltages at each end of the 4k7 bias resistor (the one that connects to pin 8)? Those will give a better idea of the bias point.

[bluesy]

Those voltages are 409 and 358. I thank the brain trust for this input!

[martin manning]

I would have expected something close to 50V on the cathode (pin 8) end, and a few volts lower on the other end. You seem to be off by a factor of ten.

[bluesy]

Oops....45.1 and 40.5. Last post was voltages from the 4.7k between B+1 and B+2. Sorry.

[Mr. dB]

Novice newbie here....please go easy on me. Built a TweedleDee Deluxe with the great information available here. I don’t understand schematics and used the layout that’s here. She’s running. Voltages are very close to what was posted on CW’s documentation. Except for one. At the intersection of the 1M and 3.3M resistors I get 3.4V as opposed the the documented 21.58V. In looking through everything many times I can’t seem to find anything wrong Tried different pre tubes hoping that might help. No luck. Can anyone steer me toward a solution? Thank you all for your audio endeavors.

Could we see a photo?

[bluesy]

Yes, it needs cleaning up.

5D881F07-853E-4B0E-8A01-F0447B5A3EC2.jpeg

[bluesy]

.....and yes, I will button up the disasters!

[martin manning]

Those voltages would suggest your PI is doing ok. The 22V is an actually an erroneous reading due to meter input impedance. Does the amp work, i.e. make sound?