I'd like to replace as suggested V1 and V4 12AX7 tubes in my Acoustic Research SP-6 to see if I can reduce a little of the hiss, it's been 10 years or more, but need some advice.
Where are the adjustments and what are the measurements I should be
adjusting to.
I see info on the SP-6C, not the original one I have.
I have replaced the tubes with new Electro-Harmonix 12ax7's.
Maybe some owners of SP-6 preamps will have some advice to offer on any direction on how to re-biased/service this , it would be greatly appreciated.
Ken
SP6C manual actually suggest that trimmers should be adjusted for lowest possible distortion or if reliable measuring gear does not exist... With original ARC India ECC83:s V3 and V6 (6DJ8) cathode follower cathodes were suggested to be adjusted at 160V and 165V. If ARC India ECC83:s tubes are not available, V3 cathode voltage should be adjusted to 150V and V6 cathodes to 155V.
This information is on page 4 on this manual. Kalvin Dahl e-mailed this manual to me in 2013 and ARC has recently made this manual available on their site.
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Kimmo
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Where are the adjustments and what are the measurements I should be
adjusting to.
I see info on the SP-6C, not the original one I have.
I have replaced the tubes with new Electro-Harmonix 12ax7's.
Maybe some owners of SP-6 preamps will have some advice to offer on any direction on how to re-biased/service this , it would be greatly appreciated.
Ken
SP6C manual actually suggest that trimmers should be adjusted for lowest possible distortion or if reliable measuring gear does not exist... With original ARC India ECC83:s V3 and V6 (6DJ8) cathode follower cathodes were suggested to be adjusted at 160V and 165V. If ARC India ECC83:s tubes are not available, V3 cathode voltage should be adjusted to 150V and V6 cathodes to 155V.
This information is on page 4 on this manual. Kalvin Dahl e-mailed this manual to me in 2013 and ARC has recently made this manual available on their site.
Page not found - Audio Research
Kimmo
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