Nakamichi PA-7 bias trimpots... - diyAudio
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Old 11th October 2012, 09:20 PM   #1
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Default Nakamichi PA-7 bias trimpots...

Could anyone who has any experience with replacing the bias trimpots on the Nak PA-7 please let me know what multi-turn trimpot is best to use.
Essentially need to know the resistance rating..but any further info would help.
The trimpots on my PA-7 are wonky to say the least and I can't get a steady bias setting at 40mV.


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Old 11th October 2012, 11:33 PM   #2
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shoot me your email and i'll send you a scan (tiff's) of service manual...

vr 101 - 4.7k
vr 102 - 150 ohm

Last edited by Old'n'Cranky; 11th October 2012 at 11:36 PM.
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Old 11th October 2012, 11:48 PM   #3
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Hey Old'n'Cranky

I have a copy of the service manual.It shows the bias trimmers to be 150R semi-fixed or something like that..I wouild like to install multi-turn trimpots and want to know what other owners have or had installed.

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Old 11th October 2012, 11:51 PM   #4
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Also mine and another I have inspected internally have no vr101(4.7k) which I assume to be the offset trimmer. It's possible this was a revision as the serial numbers on these two amps were quite far apart.

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Old 12th October 2012, 12:08 AM   #5
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vr 101/201 are dc offset adjustments.

and i do believe their are several 'revisions' of this amp.
manual i have covers "pa7/pa7e"

No mention of 'power ratings' for the trimmers, so id suspect whatever 'bournes' multi turn floats ya boat
Bourns are what i've fitted into my Pass Labs x150.

sorry i can't be of more help.
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Old 4th December 2015, 11:09 AM   #6
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Service Manual

Click the image to open in full size.

vr 101 - 4.7k
vr 102 - 150 ohm

Can I exchange VR101 to 5kohm trimpot and VR102 to 200ohm? I can't get 150 and 4,7kohm.
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Old 2nd December 2016, 10:27 PM   #7
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Join Date: Nov 2016
I am new on the Forum but i have a question about
Nakamichi Pa7.
There are no Dc trimpots on it...
Is this right?
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