[KR500]

I have a new set of Ruby Tubes EL34 power tubes for my Jolida 202A amp and so far they sound just like the Jolida EL34 OEM brown base tubes that came with them when purchased new from their dealer in 07 . It works and sounds very good .
I plugged in my Multitester and set it to the 200 mV setting and got readouts for 3 tubes around 68 or 69 and 1 tube around 58 . This seems close to double the recommended 36-44 mV setting and before adjusting wanted to check for advise . I called the phone number to the dealer ( new tube company ) I purchased it from  and Jolida USA but no answer from either . Hopefully they'll return my call ?
I have the amp volume down all the way and speaker cables plugged in with no input RCA present per the amp biasing procedure in the Jolida manual . I did not turn the screws all the way down per their instruction as I wanted to see what mV setting they had been operating at .
Is it common to have the mV so far off ?
I want to make sure I'm not setting the tester wrong before adjusting the bias setting screws.
It's a new Craftsman MM with a new Duracell 9 volt in it and has worked fine in other instances for me .It has VDC settings of 600 200 and 20 volts then 2000mV and 200 mV.
Any comments appreciated

[FullRangeMan]

El34 tubes are usually biased at around 40mV, so 36-44mV is correct.
The test meter must be in the scale of 200V for more precision.

[KR500]

Thanks for your reply . You meant 200 mV , not 200V ? right ?
I get a reading of zero on the meter in the 200Volt setting, but in upper 60's in the mV setting on the meter

[FullRangeMan]

Correct 200mV DC.

====
Now I realize Bias is a charge,
seems to me it is in the Current(ampere) scale.
Not tension-Volt scale.

So it is in the 200mAmp DC scale.

Unless this amp be very different from the usual.

[KR500]

I decreased the mV setting to manuf. recommended 40mV ( act. 38.4mV ) and the amp works/sounds fine .
It was approx 1/16th of a screwdriver turn for each tube . Didn't expect it to be off that much I guess but they are a different set of power tubes

[FullRangeMan]

Great.

[mjosef]

I did not turn the screws all the way down per their instruction as I wanted to see what mV setting they had been operating at .

Ignoring the specific instruction for biasing new tubes will sometimes result in red-lining one or more tubes and should the fuse not blow in time you will have 'other repair bills' to worry about.
Even if you swap tubes from socket to socket, you will need to recheck the bias.
You will need to monitor the bias over the next month or two with new tubes as they settle in, you will notice some variations.
The bias pot on earlier Jolidas were the single turn kind, current Jolidas have a multi-turn pot which allows for more precise settings.

You don't have to disconnect the source from the amp, just mute the source when biasing.

[Bill Baker]

You always want to turn the bias all the way down when installing new or.different tubes. No two tubes will.have the same results. Your experience with the new tubes measuring much higher than what came out is not unusual. Be sure to stay within the range suggested by Jolida as that will allow the amp to perform in a way it was designed to.
As far as sound goes, you will likely get more or additional "change" from trying different input and driver tubes than you will from the power tubes.

[JakeJ]

Ignoring the specific instruction for biasing new tubes will sometimes result in red-lining one or more tubes and should the fuse not blow in time you will have 'other repair bills' to worry about.
Even if you swap tubes from socket to socket, you will need to recheck the bias.
You will need to monitor the bias over the next month or two with new tubes as they settle in, you will notice some variations.
The bias pot on earlier Jolidas were the single turn kind, current Jolidas have a multi-turn pot which allows for more precise settings.

You don't have to disconnect the source from the amp, just mute the source when biasing.

You always want to turn the bias all the way down when installing new or.different tubes. No two tubes will.have the same results. Your experience with the new tubes measuring much higher than what came out is not unusual. Be sure to stay within the range suggested by Jolida as that will allow the amp to perform in a way it was designed to.
As far as sound goes, you will likely get more or additional "change" from trying different input and driver tubes than you will from the power tubes.

I agree with both mjosef and Bill Baker.  Every tube amp I have owned had exactly the same instructions when changing tubes.  I believe in frequent bias checks for the first couple hundred hours and then once a month.

[KR500]

Thanks for your responses and information
I will always turn the Jolida bias trim pots all the way down before beginning when checking in the future