Re: New 18W Superlite TMB/Arc Welder for a minute
Posted: Sun 02/07/21 7:15 pm
Thanks for the tips.
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New 18W Superlite TMB/Arc Welder for a minute
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Re: New 18W Superlite TMB/Arc Welder for a minute
Posted: Mon 02/08/21 1:41 am
I shielded the guitars that need it. But there is one that keeps having that.. oh well... I'm fine with that..
Re: New 18W Superlite TMB/Arc Welder for a minute
Posted: Mon 02/08/21 1:42 am
Just a quick update:
When using 7189 tubes in an EL84 build, although the normal operating 7189 plate voltages are listed as higher handling, the recommended operating screen voltages are the same as EL84s. The B-node screen dropping resistors, therefore, will need to be increased to protect the screens when targeting higher 7189 plate voltages.
I designed my build for a slightly higher B+ of 364V rectified (running 120V into the PT 110V primary), so with the S-lite schematic values, that placed my 7189 screen voltages at 350 VDC, which is 20V over the maximum. My mistake for not checking that. I will up the screen resistor values, possibly replace my tubes and return and report!
As a quick test, I variac'd my AC down to 110V and the amp just sounds killer. KILLER. Not sure whether to marry my Brown Box to this amp or knock my power string down after the OT primary tap.
When using 7189 tubes in an EL84 build, although the normal operating 7189 plate voltages are listed as higher handling, the recommended operating screen voltages are the same as EL84s. The B-node screen dropping resistors, therefore, will need to be increased to protect the screens when targeting higher 7189 plate voltages.
I designed my build for a slightly higher B+ of 364V rectified (running 120V into the PT 110V primary), so with the S-lite schematic values, that placed my 7189 screen voltages at 350 VDC, which is 20V over the maximum. My mistake for not checking that. I will up the screen resistor values, possibly replace my tubes and return and report!
As a quick test, I variac'd my AC down to 110V and the amp just sounds killer. KILLER. Not sure whether to marry my Brown Box to this amp or knock my power string down after the OT primary tap.
Re: New 18W Superlite TMB/Arc Welder for a minute
Posted: Mon 02/08/21 6:51 am
Test your voltages at the 110VAC source, then adjust B+ to match at normal source voltage. You shouldn't need to replace the tubes, but if you do, send the old ones my way.
Re: New 18W Superlite TMB
Posted: Sat 03/06/21 6:20 pm
I just installed a Metro Zero Loss effects loop after working out some voltages. After adjusting the levels, it sounds great. It did pull my power string voltages down a bit from its current draw, so I'll adjust it back up and I should be golden. To test the 7189s at their full plate voltage potential, I'll need to use a different transformer, but this amp sounds great as is.
Re: New 18W Superlite TMB
Posted: Mon 03/08/21 2:34 pm
Looking sweetViperDoc wrote: ↑Sat 03/06/21 6:20 pmI just installed a Metro Zero Loss effects loop after working out some voltages. After adjusting the levels, it sounds great. It did pull my power string voltages down a bit from its current draw, so I'll adjust it back up and I should be golden. To test the 7189s at their full plate voltage potential, I'll need to use a different transformer, but this amp sounds great as is.
