Author Topic: Series Pickup Height (Read 608 times)

flpete1uw · « **on:** December 30, 2013, 05:11:24 PM »

I have a 75 Series 1 Bass Short Scale Bass SN# 215 that I?ve been trying to master. The clearance on the 12th fret is .080? (Low but not that low) and the open string clearance to the neck pickup E string is .130? and about .125 on the G. On my newly acquired Stew-Mac String Action Gauge.
According to this post by Dave http://club.alembic.com/Images/16271/16384.html?1107731593 describing pickup heights the distance as a starting point should be ~1/4?. Here?s my dilemma, I used to set the action lower but as stated in the above post the pickup output sounds hot and noisy and I do get a Low end roll off. Raising the action helped some (Much more low end and usable) but I feel it still could be better. My problem is the pickups on this old girl have warped to a point where that is as low in the body of the bass as it will go. (The classic too much pressure on the 2 outside screws causing deformation) In the mean time I reversed the outside screw positions but I don?t have 30 years to correct the problem.
Any ideas on gaining more of the natural low end back. Also I?m somewhat concerned about the ?magnetic damping' that I may be getting. This Bass has been a Bear of a learning curve for me and I find that any little adjustment makes profound differences in sound. At least the trajectory has been to the good side of better sound.
~Pete

jazzyvee · « **Reply #1 on:** December 31, 2013, 02:05:58 AM »

Here is a start if you want to tame the hot output, you can lower the trim pots.
http://club.alembic.com/Images/16271/50896.html?1208917987

There is also a link on that page to the humcancelling procedure if you are getting noise in your output.
Jazzyvee

flpete1uw · « **Reply #2 on:** December 31, 2013, 03:41:57 AM »

Jazzy,
Thank you and yes I'm aware of these settings. What I'm referring to is the quote from Dave on his link The pickups will sound progressively 'hotter' the closer they get to the strings. And noisier: You'll begin to hear string noise, fret rattle a little more. Emphasis on the string and fret rattle. If I??m reading this correctly the distance of the pickup and string is at least partially correlated to string noise? If part of the solution is to lower the output of the pickups it??s certainly worth a try. My problem is, to the best of my knowledge a physical one in that the pickups are warped and I cannot lower them in the Bass cavity any lower. I almost wish I could sand them down to fit

This is the least of the issues for when I raised the action (And improved my playing technique some??) A lot of the rattle and noise has been eliminated. The main thing at the moment is the Bass roll off which seems correlated to the pickup height.
~Pete

jzstephan · « **Reply #3 on:** December 31, 2013, 07:59:36 AM »

Is it possible to remove the pickups from the bass, take the adjusting screws completely out of the bass, replace the pickups, and then screw all four screws on the top side of the pickups? That should get you a little lower and having the force evenly applied to reduce the warp. I like my pickups low to get a woodier tone.

flpete1uw · « **Reply #4 on:** December 31, 2013, 08:15:10 AM »

John,
Thanks for the input and I'm doing just that.
Great minds think alike, minus routing out the Bass (NOT!!) or somehow either unwarping or shaving down the edges of the pickups I'm stuck with this height. The previous owner really let the pickups warp throughout the 38 years of her life.
~Pete

gtrguy · « **Reply #5 on:** December 31, 2013, 10:27:21 AM »

I have an extra set of pickups with the same problem. I wonder what the cure is... They seem to work fine though. http://club.alembic.com/Images/394/143817.html?1367861650

(Message edited by mica on January 02, 2014)

lbpesq · « **Reply #6 on:** December 31, 2013, 10:38:49 AM »

I suspect you could sand the high spots on the bottom down bit?

Bill, tgo

flpete1uw · « **Reply #7 on:** December 31, 2013, 11:32:33 AM »

David,
That?s about it, my pickups could be twins. They sound fine as far as I can tell. I went so far as to send them along with the electronics back to the Mother Ship and they checked out fine.
Bill,
Shaving down will be the last resort. Curious how much before you get to the coils / magnet?
What I?m experiencing is that small amounts of adjustments make large differences.
~Pete

sonicus · « **Reply #8 on:** December 31, 2013, 11:54:56 AM »

Perhaps ,it would be prudent to make an inquiry regarding new replacement pickups and leave the original ones as they are. It might be worth it .

flpete1uw · « **Reply #9 on:** December 31, 2013, 01:49:43 PM »

Wolf,
That is an option, if I recall correctly the Series pickups are made to be a matched set. Something to do with the coil windings, even if they are the same # of turns, wire differences could create different outcomes. So each are made to match the other and the Dummy coil. Someone more knowledgeable than me on this please chime in! My Bass?s dummy pickup is loose in the cavity (Old Glue) so I can easily remove it. Curious if all the pickups and spaces for all Series basses stayed the same dimensions through the years. In other words retrofitting new pickups to an old Bass.
~Pete
Wow 7 more hours to a New Year on the East Coast!

JimmyJ · « **Reply #10 on:** December 31, 2013, 11:24:53 PM »

Hey Pete,

A couple comments. First, as you read the rest of that post you pointed to, Dave goes on to say These effects are not as pronounced with ALEMBIC or other so-called 'low impedance' pickups...

In my experience the difference of 1/8 in pickup height won't noticeably alter your output level or tone. With Alembic's system it's almost more important where you want to feel the pickup with your fingers.

That said, if you really want to recover the small distance lost to your bent corner you should completely remove the screws under the low points and only use the two upper screws to mount the pickup. Or ... just sand off the low points until they are flatter. The coils and magnet have not been effected by this deformation so they are still in the flat area. You should be able to safely remove some material from the lowest point of the bent corner without a problem. Just don't crank down the mounting screws too hard afterwards as this area will be slightly weaker structurally.

That's my 1.5 cents.
Jimmy J

flpete1uw · « **Reply #11 on:** January 01, 2014, 04:05:27 AM »

Hi Jimmy,
Your 1.5 Cents is always welcome! Thank you for taking the time to read through this post.
I did see that quote as well and initially that??s what I was hoping to find. However when I readjusted the neck action to a slightly higher setting I noticed a profound gain in low end so my thinking is that if I can get the settings to a basic starting point I can readjust from there. Being from the Studio world I??m big on references, to have settings and a starting point to get back to if things get to weird.
I??m sure part of this is my lack of understanding of the Series electronics. (2 filters 2 Q??s) and the never ending desire to get things right. And also part knowing enough to make things dangerous ??
I have the pickups in the way you have suggested and that has helped some. In fact each time I make a small change the sound improves almost exponentially. Maybe getting the pickups to be 1/8?? from the lower level will suffice? And yes I will be careful.
Happy New Year!
~Pete

gtrguy · « **Reply #12 on:** January 01, 2014, 11:07:40 AM »

I think the pickups might have a sort of 'cage' around them in all that epoxy they are made with, but that would not be out at the ears where sanding might take place. I'll probally mount the bent ones I have on a board and see if time might stfaighten them out again.

flpete1uw · « **Reply #13 on:** January 01, 2014, 11:48:44 AM »

David,
Best of luck with that. I might suggest it took a long time for this to happen it might take some time to correct. Please keep me posted on your findings.
I'm so close I can taste it, I just don't want to do anything foolish. Interesting thought on the pickup construction sort of a Faraday cage?
~Pete

cozmik_cowboy · « **Reply #14 on:** January 01, 2014, 08:54:08 PM »

Maybe, with the p/ups mounted straight to the body through the lower holes, put the other screws in with a little tension, and see if you can slowly tighten them & flatten the ears back out ( it would, of course, be a long-term project).

Peter