ARC LS25 mkII tube change

[GeneJazz]

I am thinking of replacing the 2 6H30 tubes. Is this swap and play or do I need to adjust the 2 trimmers on the board? The manual says nothing about this.

 

[GeneJazz]

No one knows? I imagine I am supposed to measure someplace and set the trimmer to a specific voltage...

 

[Zen Mod]

just plug & play

trimpot is for Jfets operation

 

[GeneJazz]

just plug & play

trimpot is for Jfets operation

Thanks for your response.

Can you tell me how to make sure the trimmers are adjusted correctly? I assume I am supposed to measure some location on the board and check for a specific voltage?

I got the preamp 2nd hand so want to make sure everything is good.

 

[Zen Mod]

just check +/20V points

re- set with pot if needed

but - if nobody didn't tweak them , they're probably fine

 

[GeneJazz]

just check +/20V points

re- set with pot if needed

but - if nobody didn't tweak them , they're probably fine

Thanks so much! Exactly what I needed.

The previous owner told me John Rutan of Audio Connection did the tube change couple of years ago. And perhaps he messed with the trimmers...

I want to make sure.

 

[GeneJazz]

Did a voltage check throughout the amp. All looks good. I had to tweak one of the trimmers a very small amount.

The preamp sounds great to my ears.