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Line Magnetic 845 Premium bias setting. Advice needed!

Hello everyone,

I recently got a used Line Magnetic 845 premium and I need some help with bias setting.

I am not entirely sure how to adjust the bias with the knobs in the front. 
I believe the correct bias setting is 70mA for the 845 tubes (V1-V2) and 45mA for the 300B tubes (V3-V4).

Here is a photo a small video to see how its setup at the moment:

https://app.photobucket.com/u/mpolyzos75/p/243cc263-f1e0-44b8-8191-30b26d923a30

https://app.photobucket.com/u/mpolyzos75/p/947469e5-f99d-445c-ab8c-d2a8d3aba496

Are the knobs set to the correct setting?

Any ideas are appreciated. 
Many thanks.
mika75
facten
2,878 posts
 
@jjss49

" wow line magnetic doesn’t supply a manual with proper instructions on how to set tube biasing?! that brand is supposed to be cream of the crop "

I don’t know what the story is with the manual that came with the LM amp in question, but the manual that came with my LM 518IA  (845 tubes) was straightforward in words and pictures as to how to bias it.




facten
2,878 posts
 
@mika75
I found you the manual online for the 845 Premium; link is below. The bias instructions are on page 9 and are straightforward.

https://www.line-magnetic.eu/images/line-magnetic/pdf/Manual-LM-845PREMIUM-UK.pdf

mika75 OP
6 posts
 
@facten 
Thank you for this. It doesn't explain clearly what the knobs on the front do though. Anyway its all sorted now. 
:-)
facten
2,878 posts
 
@mika75

I might be wrong but reading the manual I think that what the front knobs do is allow you to monitor the bias of each tube via the bias meter next to them . You can probably double check that with Jonathan.

On the 518 there’s a small toggle type lever next to each 845 tube that when moved shows the bias on the front meter, If the 845 premium doesn’t have them then checking the bias may be as I note above
mika75 OP
6 posts
 
@facten 
👍🏻
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