Where to measure the bias on P180?

[13oots2]

Am a bit of a newbie but want to measure the bias on my Musical Fidelity P180. Which resistors on the image do I measure across? Also roughly what would the bias settings be for this amp, it uses 10 pairs of 2sk135 2sj50.

Thank you in advance

 

[JonSnell Electronic]

P180?
Looks like MF but I don't recognise the model number.

 

[13oots2]

It is definitely MF and came out in 1992 it was one of the lesser known Tim De P's designs. I can take my one apart and upload a better picture.

 

[JonSnell Electronic]

MF don't list a P180, or indeed a P anything.

 

[13oots2]

The P stood for power amp, P140, P170, P180, P270, P370 are the main mosfet designs.

 

[djk]

What is the value of the resistors in the row between the two channels?

100mA per output is good for the 2sk135 2sj50 pair.

 

[fredeb]

Am a bit of a newbie but want to measure the bias on my Musical Fidelity P180. Which resistors on the image do I measure across? Also roughly what would the bias settings be for this amp, it uses 10 pairs of 2sk135 2sj50.

Thank you in advance

Check out this page : Musical Fidelity A1 › Other models

 

[13oots2]

I have managed to work it out thanks. Bias is 89.4mV on both channels and DC offset is about 4.5mV on both channels. I may replace the electrolytics at some point but all seems well at the moment😀