Re: Shunt resistor in DMM and baising Marshalls

"Stephen Cowell" <scowell@xxxxxxxxxxxxx> wrote in message

"Phil S." <psymonds@xxxxxxxxxxx> wrote
How about using, for lack of a better term, the indirect shunt method.

Unhook the primary leads and lift the B+ center tap on your output

No need to disconnect... as long as the amp is not
plugged into the wall!

And, if you think about it... your voltage measurement
will probably give the same resolution as the OP would
get in 400mA mode. You also have to remember the
two different resistances for each side... and it doesn't
separate each valve when using more than one valve
per side (i.e. 100w amps).

Anyway, slavishly setting your bias to a pre-determined
value is not optimal... final bias should be set by ear,
monitoring the dissipation of course.

Thank you Phil and Steve - you're both correct by suggesting
that not only is one going to get an imprecise accurate reading
from using a single method, but that precision is not the true
objective anyway - it's the quality of tone.

One-dimensional thinking = big no no.