Question about manual?

[jrebman]

BH folks,

I was reading through the manual last night and I came to the section on page 62 where you are wiring the output tube cathode resistors and something seems amiss with the following steps:

( ) Trim the lead of each
1.6k ohm 10W
wirewound resistor to
1/4. (6mm). Insert one
resistor in 6L and 16L.
Don

 

[Paul Joppa]

I think you have the terminals numbered incorrectly. With the chassis face down for building and with the front nearest you, Terminals 1-5 are at the front of the left-hand output tube, 6-10 front of the driver (in the center), 11-15 at the front of the right-hand output tube, and 16-20 at the back of the driver. So the row of three terminal strips closest to you is numbered sequentially left to right; then the lone strip further back continues the numbering scheme.

The large 1600 ohm resistors just exactly fit fore-and-aft between the front and back terminal strips that are mounted by the driver tube. Terminals 6, 8, and 10 are grounds, terminal 8 being the single-point chassis ground. They surround terminals 7 and 9 which are the input to the driver grid, providing some shielding of the most sensitive point in the circuit.

 

[jrebman]

Paul,

You got it -- my interpretation of the text was such that I thought they were numbered in order from front-to-baack and left-to-right, meaning 1 through 5 n front of the driver, 6 through 10 behind the driver, and then 11-15 on the left output tube and 16-20 on the right output tube (with the plate position as you indicate.)

Numbers were off, but my reasoning seems to have been correct.

Thanks for the clarification.

Just got the circuit boards done today.

-- Jim

 

[jrebman]

Ok, I now see that I made a couple of incorrect assumptions about this whole step, but I now have it all clear.  Thanks again, Paul.

-- Jim