neumann SAL 74b new needle alignment
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- chrisaterika
- Posts: 3
- Joined: Mon Apr 07, 2014 8:08 pm
- Location: buena park, ca
- Contact:
neumann SAL 74b new needle alignment
Hello,
I was hoping to get some help with step by step instructions on the SAL 74b alignment procedure when replacing your needle on your cutting head [SX74 head, VMS70 lathe].
I understand that we first check our pickup response with our tone disc [100hz, 1000hz, etc.] and once my PU is at 0 we cut a tests groove using our oscillator at 1khz and A/B between our cut [monitor input] and our oscillator tone [feedback input]. Then compensate +/-dB if needed on my drive level to get to zero out my meter and re-check my monitor vs. feedback vs. pickup.
Assuming I did all that correctly and everything's at 0 next we check 100hz and I start to get confused.
If at 100 cycles I'm -3dB this means my curve isn't correct so I have to go back to my 1k tone and add 3dB to my feedback? After that my 100hz should adjust but wont my 1khz now stay -3dB?
I've seen this done before and it worked were 1khz and 100hz came out at 0 but I want to know the mechanics behind this so I can do it myself correctly. Please let me know if anyone can help or if anything I mention above isn't right.
Best,
Christopher
I was hoping to get some help with step by step instructions on the SAL 74b alignment procedure when replacing your needle on your cutting head [SX74 head, VMS70 lathe].
I understand that we first check our pickup response with our tone disc [100hz, 1000hz, etc.] and once my PU is at 0 we cut a tests groove using our oscillator at 1khz and A/B between our cut [monitor input] and our oscillator tone [feedback input]. Then compensate +/-dB if needed on my drive level to get to zero out my meter and re-check my monitor vs. feedback vs. pickup.
Assuming I did all that correctly and everything's at 0 next we check 100hz and I start to get confused.
If at 100 cycles I'm -3dB this means my curve isn't correct so I have to go back to my 1k tone and add 3dB to my feedback? After that my 100hz should adjust but wont my 1khz now stay -3dB?
I've seen this done before and it worked were 1khz and 100hz came out at 0 but I want to know the mechanics behind this so I can do it myself correctly. Please let me know if anyone can help or if anything I mention above isn't right.
Best,
Christopher
Re: neumann SAL 74b new needle alignment
Hi,
I think you have to re-establish the "0" reference level at 1Khz (more drive) since the gain has been reduced by 3db with the added feedback. Then go back to 100hz and re-check. Should be correct.
Mark
I think you have to re-establish the "0" reference level at 1Khz (more drive) since the gain has been reduced by 3db with the added feedback. Then go back to 100hz and re-check. Should be correct.
Mark
- chrisaterika
- Posts: 3
- Joined: Mon Apr 07, 2014 8:08 pm
- Location: buena park, ca
- Contact:
Re: neumann SAL 74b new needle alignment
Thanks Mark, Ill give that a shot.markrob wrote:Hi,
I think you have to re-establish the "0" reference level at 1Khz (more drive) since the gain has been reduced by 3db with the added feedback. Then go back to 100hz and re-check. Should be correct.
Mark
Chris
Re: neumann SAL 74b new needle alignment
You should check against the NAB disc first. Sometimes the playback electronics are out of alignment. Use the NAB disc to check playback levels, remember that a few of the frequencies are slightly up or down (Len remembers, I forgot off the top of my head.)