Running a TSE with 5u4g?

[discomonkey]

Hi All,

Assuming I have a transformer that can handle the extra draw from the 5U4G, what other mods should be done to the TSE circuitry to best make use of a 5U4G rectifier instead of the 5AR4? This will be done in a 300B TSE. How bad is it for my output tubes if I don't have the slow warm up of the 5AR4?

Thanks,

M

[rknize]

The 5U4 tubes have more tube drop than 5AR4 types. That means your B+ will drop by about 30V or so. As far as warm up, I wouldn't worry about it.

[discomonkey]

Great! Thanks for the reply Russ - it's good to know that this experiment won't harm my tubes.

Cheers!

[rknize]

I've run the TSE with a 5U4 without issues.

[chrisb]

doncha wanna be a bit more careful with input cap filter on the 5U4 / 5Y3, or even more critically with 5R4?

I'm running one of those fun potato masher Cetron 5R4WGB in a fugly but great sounding rebuild of old Scott integrated - 4mF input cap followed by dual mono choke filtered stage



looks more than a little bit out of scale to the noval driver and output stages


5R4 = 4mF
5U4/5Y3= 32mF
5AR4 = 60mF

[tubelab.com]

doncha wanna be a bit more careful with input cap filter on the 5U4 / 5Y3, or even more critically with 5R4?

Some 5U4's can be picky about the input cap. 47uF is technially too much and may cause sparking inside the 5U4 on power up. Put an inrush current limiter in series with the line voltage input to ease the power up surge.

47uF WILL spark the potato masher. I have seen the fireworks!

[discomonkey]

Originally Posted by tubelab.com

Some 5U4's can be picky about the input cap. 47uF is technially too much and may cause sparking inside the 5U4 on power up. Put an inrush current limiter in series with the line voltage input to ease the power up surge.

47uF WILL spark the potato masher. I have seen the fireworks!

Thanks George. I saw your recommendation for the current limiter in the Simple SE and was going to put it into this build anyway.

Cheers