Bugera 333XL schematic

[Carlosraj]

Hi


Does anyone has a schematic for this amp. I need to set the bias. At the bias set point, there is a switch which is selectable between EL34 and 6L6.



Please assist.


Thanks

 

[JonSnell Electronic]

Is this the older type or the infinium?
The infinium is self biasing, assuming the correct valves are selected with the switch. All the switch does is add a 5k6 resistor to the bias chain.

 

[Tesla88]

Schematic here:
Schematics

I own the 333 non XL version, if you buy the Bugera matched tubes, they come with a letter printed on the octal base, justconnect a voltmeter to the RCA Cinch socket, set the switch to EL34 or 6L6GC, set the trimmer according to the table below

https://www.bax-shop.nl/downloads/d...eiding_vervangen_buizen_gitaarversterkers.pdf

 

[JonSnell Electronic]

There is an error on the valve listing; an EL34 is not a 6550A! It is a 6CA7.

 

[Carlosraj]

Thanks alot guys for your info and assistance. I do not know what version this amp is but it has a tube selector switch and a trim pot for bias.

 

[JonSnell Electronic]

I always, if the customer doesn't want to pay for graded Bugera valves, measure the current drawn on balanced output valves. Look for about 45% dissipation to run moderately cool.

 

[Carlosraj]

OK, will do, Thanks