Hello everyone. Just noticed the turn on pop on the left channel of the nap250 is a lot louder, so much so i cant really hear the turn on pop of the right channel. Can anyone confirm this for their olive amplfiiers?
Anyone?
When was the amp last properly serviced?
Last by naim should be 2005, i got it recap and biased by third party this year. Oscilloscope shows a perfect match between the 2 channels.
The louder pop on one side existed before the recap this year.
OK, thereâs usually a bit more to a service than just a âre-capâ. Perhaps best for some input from @NeilS who has long experience servicing kit at Naim.
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This could be simply down to component tolerances.
Did the third party set the voltage rails correctly?
Regards
Neil.
Not too sure what voltage rails mean, but what he did was to set the regulator boards to a commonly known value i think it was 39.6V? As well as bias the amplifier boards. Thank you
The correct voltages are +39.3V & -39.9V.
Probably nothing to do with your issue, but they should be set correctly.
Regards
Neil.
A classic case of âSet it to a value in betweenâ 
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If there is an underlying issue of component tolerance / drift it could show up as DC offset at the âspeaker terminals (with speakers disconnected and no input signal). Closely matched transistors ( and Naim are fussy with matching) at the input stages usually result in 25mV or less offset. Easy to measure if you have access to a digital meter. Itâs best to wait a few minutes after switching on the amp to allow it to stabilise before taking a reading. If the offset is low on both channels I wouldnât be too concerned about the uneven pop at switch on.
The DC offset limits we work to when testing an olive 250 are +/-20mV.
Regards
Neil.
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DC offset is low under 10mV for both channels. Thanks for your help guys
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