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
If another member doesn't respond I suggest either contacting Jonathan Halpern, US Distributor, or  Goldprint Audio, Taylor is a LM dealer (also an Audiogon member - goldprintaudio)  to see if one of them can help you out

Thank you very much facten.
this where owners manuals really help

otherwise refer to distributor
The manual is very poor unfortunately. Thank you.
mika, if you learn anything, please let us know.
What about sending email to the former owner?  He/she must know how to set bias.
Hello everyone,

Good news!

I emailed Jonathan Halpern from Tone Imports and Charlie Schnyder from Stereo Haven and they both promptly replied within an hour or two and they both said the same thing.
Apparently the knobs in the front are for fine tuning and not of much importance. The bias is adjusted mainly by the screws on the top for each tube. As long as the needles rest on the middle dot for each tube everything is ok.
This has been bugging me ever since I got the amp and I even emailed Line Magnetic in China and still the reply I got was far from useful.
These two guys put my mind at rest. Can't thank them enough!
:-)
@mika75

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 among chi-fi tube amps -- 👎

anyhow, glad you got it figured out...
I know,it's crazy!
But the sound the amplifier makes is so good, makes me forget these things
Glad to hear it, mika! Thanks for letting us know. There's a good chance I'll pick up one of these myself. What speakers will you be using?


@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.




@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

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