Bottlehead Forum

Bottlehead Kits => Moreplay => Topic started by: hryc111 on November 12, 2022, 08:28:33 PM

Title: Another case of high B+ voltage
Post by: hryc111 on November 12, 2022, 08:28:33 PM

I have read earlier threads on high B+ test voltages, where posters were urged not to worry too much about it.  But the value I'm getting -- 336V -- is significantly higher than others, so I thought I would check.   Is this value still within the range of variation you'd expect?  My incoming voltage is 120V. 

I've reflowed most if not all the joints, and double checked all the steps since the last test stage.  Seems to be correctly wired.

Any advice would be welcome.

Title: Re: Another case of high B+ voltage
Post by: Paul Joppa on November 13, 2022, 04:17:14 AM

Were the tubes installed and did their heaters glow?

If there are no tubes functioning, or there is no current drawn from the power supply for some other reason, the theoretical voltage (at 120v power line) is 339.6 volts DC.

Title: Re: Another case of high B+ voltage
Post by: hryc111 on November 13, 2022, 04:27:46 AM

Thank you for answering.

Interesting.  Tubes were installed.  Tubes do glow.  I can send build pictures later today, if that might help.

Title: Re: Another case of high B+ voltage
Post by: Paul Birkeland on November 13, 2022, 04:50:47 AM

The raw B+ test is done first with no components allowing the 6V6 to draw current from it, so it will be pretty high. 336V there is OK and you can continue.

Title: Re: Another case of high B+ voltage
Post by: hryc111 on November 13, 2022, 10:42:16 AM

Thank you!  Onward.