What Does This Resistor Do?

[syscokid]

… I would try increasing that dropping resistor more, maybe go ahead and try a 2k2, as your screen voltage is still higher than the plate…

I certainly will try. Yesterday I placed an order with Mouser for a 3w 1k, 1.5k, and a 2k, plus some other items that probably won’t arrive for another five days. But the 6L6 plate voltages are 356v, and the screen is 351v!!!

… and the preamp voltages are also high.

What range are you suggesting?

… Do you know what the OT primary impedance is? My guess would be it is 4k in 6L6 mode and 8k in 6V6 mode.

That’s a good question because I would like to know too. PT and the OT are made by Heyboer to David Allen’s specs. I don’t recall anywhere in the amp kit’s documents that show the tranny specs. This motivates me to send a request for more info from Heyboer.

[syscokid]

I just found this info from the days when Allen Amp’s used to offer their tranny’s for individual sale:
TO11S Heyboer output transformer rated 4,000 ohms primary to 4 or 8 ohms secondary. It is the same as the above TO11C but mounted on its side the short way to prevent transformer coupled hum. It will now be the standard OT for the 10W Chihuahua. Excellent choice for a 6L6 or EL34 single-ended amp using either a 4 or an 8 ohm speaker load. 3-1/8" mounting centers.

[martin manning]

Sorry, I had the a/g2 voltages reversed, looks fine. On the preamp voltages, you can see all of the 12AX7 cathode voltages are high. Maybe increase the last dropper from 10k to 12k and see how that looks and sounds.

TO11S Heyboer output transformer rated 4,000 ohms primary to 4 or 8 ohms secondary.

Ok so putting an 8-ohm load on the 4-ohm tap gets you 8k for a 6V6, and 8-ohm on the 8-ohm tap gets you 4k for 6L6 or EL34.

[syscokid]

Yesterday I tried a 12k then a 15k, for the "last dropper" that feeds V3 and V1. The 15k reduces the plates to V3 by 12v to 13v. For V1, the plate voltage is reduced by 9v and 8v respectively. Altered the original schem again to show the new values for the two dropping resistors and the new voltages when a 6V6 is used, then the new voltages when a 6L6 is used:

Chihuahua Schem Modded Droppers and Tonestack R, 1-21-24.jpg

I'm liking these little mods to the voltages a lot and planning to keep it like this. Thanks for everybody's help...