Alembic Guitars Club
Alembic products => Alembic Basses & Guitars => Topic started by: Mlazarus on August 13, 2022, 07:43:23 PM
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Hello everyone. I hope you are enjoying the weekend. I read this 2007 topic called: Low volume on bridge pickup". So, with this Series 1 bass player, he stated that the pickup gains on the back were maxed but did not understand why the bridge was sounding lower. Now, in my case, the pickup gains are maxed on my 82' Series 1 as well, yet the NECK pickup volume is lower compared to the other pickup (The opposite of the other player's situation). Mica, explained, based on his picture that the pickup connectors were on backwards and that the fangs need to be facing up. In my case (as you can see in the picture) my connectors don't have fangs to indicate the direction of connection. So how will i know if the connectors or on correctly. Note: These are the MK-11 2695 connections. Thank you for any input.
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Hey Michael,
I believe your connectors are the "right way up" even though they don't have obvious "fangs" and are not marked with the traditional "T", "B" and "H". Nor do not have the color coded stickers used in later years. But the underside of these connectors have two visible slots (as you can see in that other thread) so it looks like yours are correct.
FYI, the connector furthest to the right in your picture (closest to the edge of the board) should be the bridge pickup. Hum canceller in the center. And Neck pickup closest to the center of the board.
But I did notice something else... The opamp for your neck pickup (black muilt-pin chip closest to the center of the board) is a "5534" but doesn't match your others. Though I can't see the opamp under your ribbon cable, that center one has definitely been replaced at some point and is not the same as the other 4 chips on your board. Now I don't know enough about the specs of these chips to know if that would make any difference - though probably somebody in here does - and I'm not even sure Alembic still uses the NE5534AN. But these chips are not expensive so you might think about getting a matching one for that socket. Just a thought.
Jimmy J
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Thank you, Jimmy. Where would i get that NES5534AN? If I'm looking at the correct one, it's the one that is closest to the rainbow strip, correct? BTY, what is that rainbow strip for?
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Oh, it's to the right of that one. sorry.
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Here is a much better picture of the series 1 electronics. I circled the 5534 chip. Also, what is the object circled in blue? It looks different and smaller than the two on the left. Is that normal?
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Yes, you can see that one you've circled in red doesn't match the others. But I don't mean to send you on another long thread of concern and worry about your axe! This tiny detail we've noticed may have nothing to do with your differing pickup volume levels because I would think all 5534 chips would have similar amplifying gain specs. So this may not mean anything. DON'T PANIC!
I expect this has already been mentioned in one of your other threads but, swapping the outer two pickup connectors is a great way to diagnose how your board and pickups are working. If you swap those and the difference in gain also changes making the neck pickup (coming through the other channel of the board) much louder than the bridge pickup, then you may be on to something.
Not sure where to find these original NE5534AN chips because they may have been discontinued... D'OH!! And I don't know what the best current replacement chip might be. So wait for somebody in here who actually knows what they're talking about (maybe even Mica) to pitch in and make some suggestions. That advice may also be to ignore this little anomaly and just sit down and play that bass!!
The little metal can you circled in blue is a JFET or - in my layman's terms - a hi-fi, fast, low-noise, dual-transistor audio amplifier which is the first stage of our preamp board.
Jimmy J
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Your various 5534s should be pretty much the same. You can carefully pull them (instructions online show how easy it is) and swap them around if you want to compare them). Note the alignment notch for reinstalling them.
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Thank you. Yes, i will not panic. I'll just wait for others and Mica. I will do the Upgrade though (for the hum and to update what is needed.). I'm sure Ron will notice and clean up things like that and more. It's worth it to me. In the meantime, I Will play my bass! Lol. It sounds great. Has potential for more.
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If i were to get a new op amp online. Ive seen one from phillips:https://www.ebay.com/itm/202692816005?mkcid=16&mkevt=1&mkrid=711-127632-2357-0&ssspo=DeH9N6xGRA-&sssrc=2349624&ssuid=VO-aAtw4Ry-&var=&widget_ver=artemis&media=EMAIL.
It looks like a plug and play, but i would want direction from Alembic to do it or not. All i know there is a difference in both pickup volumes. I just turn up the neck volume. Perhaps, the bridge is set brighter and higher and i just notice the difference.
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See, I was afraid my observation might have this effect on you. Don't obsess over this! And maybe hold off on buying any EBay parts for the moment. (That is not an "AN" chip you pointed to. Here are 5 closer for $1 each: https://www.ebay.com/itm/401500440826?hash=item5d7b4a88fa:g:8Z8AAOSwmgJY5Kal. But it's EBay so you never know what you're gonna get. Hold off this!)
If you feel like messing around with this, try this simple experiment first: Swap the two pickup connectors so the bridge pickup is plugged into the connector near the center of the board and the neck pickup is plugged into the connector near the edge. The bass's front panel controls and p/u selector switch will also be switched when you do this - but observe what happens to the output levels of the two individual channels. Is the neck pickup now much louder than the bridge pickup? Or do they still seem to be around the same level as before?
When you have the chance to try that, let us know the results.
Jimmy J
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Also, I've been reading online a bit and seen where audio folks will sometimes get a batch of these chips and "audition" them to find which ones have the best signal to noise specs. Apparently they vary. I don't know if that's standard practice or not and I don't know if Alembic actually goes through this "cherry picking" process either. It may be a pointless exercise for the way our preamp boards are using these components.
So again, we're getting caught up here in some extremely small details and losing focus on what we're trying to help you troubleshoot. Try the above experiment when you get the chance.
Jimmy J
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Michael, it sounds like you have already decided to have the electronics upgrade done. If that is the case it would be best to just leave the existing electronics as they are. You will be paying for Ron's expertise, nobody else can diagnose your electronics and make any necessary upgrades and repairs better than Ron will be able to. I second Jimmy's suggestion to swap the pickup leads, it doesn't require removing/changing components and should give you a much better idea about why the pickup volumes are different. Meanwhile it does not sound like the disparity in pickup volume makes it impossible to play the bass so stop worrying so much and try to enjoy it. The Series basses have volume and gain controls, if the pickups don't sound balanced I change either the gain or the relative volume to even it out, for now I suggest you do the same.
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That's why in the previous messages i stated -- I would want direction from Alembic and sure Ron would cover everything about the upgrade. I'm not this panicking kid that wants to experiment. To old. It's just an interesting topic to learn about what makes these instruments work the way they do. And by chance IF Mica or Ron said that 5534 can be replaced and it will make a difference (with their own chip), i have a hunch they would make the changes at their shop.
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Jimmy, thanks for your observations. There must be alot of people who worry. This is not my 1st Alembic. They are very stable pieces of work.
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StephenR, your right too. The bass sounds great. Althought the gains are MAXED in yhe back, these is always the Bass anp volume and gain to make up.
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StephenR, your right too. The bass sounds great. Althought the gains are MAXED in yhe back, these is always the Bass anp volume and gain to make up.
The gains in the back don't have to be maxed. You should use them to compensate for the inherent volume differences between pickups, and then you can use the full range of the volume knobs to find your sound(s). If the bridge pickup is relatively loud, adjust in the back. If you adjust the pickup height, again compensate with the gain. You can turn down the gain for the louder pickup, or turn it up for the other pickup.
If you find the difference in pickup output cannot be compensated by using the gain controls, then there might be an issue with the electronics.
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Adriaan, those are practical methods I can try. Maybe the neck pickup needs to be raised.
I seem to be maxed out on raising the front pickup, so can I raise it with a thin layer of
foam?
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OK people, I did research online about the difference between the neck and bridge volume. Open this site.
https://producerhive.com/ask-the-hive/bridge-vs-neck-pickup-when-you-should-use-each/#:~:text=Bridge%20pickups%20have%20higher%20resistance,making%20it%20a%20little%20brighter.
So, it makes sense that the wiring of the bridge pickup is more for a louder sound. That is because the bridge pickup MUST be able to compensate for the LIMITED string vibration over the pickup. Whereas the Neck is picking up much more string vibration, which if the wiring was as much as the bridge, than the neck would possibly pickup too much vibration, thus making the sound louder and muddier. As for the different op Amp 5534, that component is probably the intended original part for the interaction of the neck pickup. Interesting stuff. Playing is better, but i like understanding the science behind it as well. I'm feeling better.
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Adriaan, those are practical methods I can try. Maybe the neck pickup needs to be raised.
I seem to be maxed out on raising the front pickup, so can I raise it with a thin layer of
foam?
No foam. There should be two screwheads sticking out on opposite corners, and two screwheads hiding underneath the remaining corners. Loosen the two visible ones, then adjust the height by turning the screws underneath, finally lock in the height with the visible screwheads - just make sure they're snug, do NOT overtighten them or you may crack the pickup housing.
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... oh and while I said screwheads, they're actually bolts and they go into threaded inserts, not bare wood.
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Will do. Thanks.
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While experimenting with pickup heights, you'll probably find each pickup will have a sweet spot where it sounds just right (this may well vary when using different strings). The nice thing is that you can set the pickup height where you like it for the individual pickup, and compensate for volume differences with the gain controls, even before you start using the volumes to set the blend.
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Michael,
Good going on the research. Yes neck pickups will naturally be generating more "energy" because the string at that point is moving back and forth farther than it does closer to the bridge. But our preamp boards are not "preset" to compensate for that, both channels of our boards are supposed to be identical. That's exactly what the rear panel trim controls are for, so you can balance the two levels to your liking.
Also, when "maxed out" these basses can put out nearly a line-level signal. You can actually - almost - drive a power amp without any other preamp in between. So in order to use these with "normal" pedals and amps you probably don't want to run your board wide open. And that gives you the opportunity to set the balance as you'd like. Plug in another one of your basses and set the amp at a reasonable volume. Then plug in your Series bass, neck pickup only, front volume control wide open, and use the rear panel trim pot to set a level so the volume from the amp is similar to the other bass. Then turn on both pickups and use the rear panel trim pot to dial in the amount of bridge pickup you want to balance the tone to your liking.
One other great thing about the way these axes work is that trimming the volume, either with the rear panel trimmers or the front panel volume controls, DOES NOT effect the overall tone. Unlike passive guitar circuits, the frequency response doesn't change as the volume gets lower.
Oh, and as Adriaan explained, the pickups are held in place with 4 bolts. The two whose heads you can see are holding the pickup down while the two in the opposite corners are holding the pickup up. If you wanted to raise the pickup you would loosen the top two bolts, put a small Phillips screwdriver through the two holes and turn the bolts underneath counter-clockwise until the pickup is where you want it. Then "snug" down the upper two bolts - don't over-tighten. Try to keep the pickup in the same plane as the strings. To lower the pickup, reach through the holes and turn the bolts underneath clockwise to the depth you prefer, then snug down the upper ones. Make sense?
Jimmy J
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Yes, it all makes sence. Alembic has such a different and innovative way of thinking. I wonder if other companies have copied they're concepts. Its been many many years since i owned an Alembic. With my Distillete back in the 90s i dont think i did much with it. Thanks guys.
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Jimmy! Man, I adjusted the neck pickup raising it. Now that monster bass unleashed POWER! Just enough before the strings hit the pickup. The magnetic field doesn't affect it.
So, then I switched the selector from bridge to neck: volume matches without lowering the gains on back to match. All I had to do after was lower the gain because I got more power and hum from the amp. I fixed that by lowering the gain on the Amp (MarkBass 15, 250 watt). I knew deep down I had to raise pickups, but I learned more about the bolts underneath the pickups. I always thought there were just two top screws. I don't remember moving the pickup on my distillate to see underneath. I'm glad I did. One thing I discovered is there are hollow openings on the body near the bolts, so to be careful if you have to replace a bolt, because it can fall inside the body cavity, then have to shake it out. Interesting architecture.
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Alright Michael, that's excellent progress! And you're getting to know that bass inside and out. These axes are not like any others. They're built with several unique and innovative features which is why they not only look cool but also sound frickin' amazing.
Jimmy J
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This 82' and probably all the older ones have more than enough power. I swear, I had to lower the gain one the little Markbass 15 (which is a powerful amp). This Alembic with "blow up the amp cabinet like a balloon. lol. I still treat the bass like holding a baby though. Skinny neck.
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I think there is a sweet spot on pickup height where they sound the best. I try to find that spot and then adjust the gain trimmers to even them out to what I like.
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My height is just before pickup hits string when pressing on frett. The magnetic field does not effect it.
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There are more options than everything-to-the-max. If that's the one that works for you, then that's excellent. But you might be surprised what you can find elsewhere on the spectrum.
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Oh i'm sure. BTY, which type of Alembic do you have?
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Epic, Spoiler and Series II.
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Sounds like you got it all sorted out with the help of the club. The 5534 ICs in there all have similar date codes and I suspect they are original. Same with the FET. Just enjoy it until you have an appointment to get the RF upgrade.
Thanks for the help, everyone!
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Yes, i will enjoy playing. I look forward to the great things in the future. Bty, what is the rainbow ribbon for?
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Yes, i will enjoy playing. I look forward to the great things in the future. Bty, what is the rainbow ribbon for?
Love is love. ♥️
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I hear ya. But that ribbon must be for the pots.
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Yes, the "rainbow ribbon" is what connects everything except the pickups to your preamp board. Power, controls, p/u selector switch, etc. It terminates in a large multi-pin connector right there at the corner of the board.
Jimmy J
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NASA could use Ron's help! Lol.