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Bartolini MK1

C

creabass

Apr 22, 2009
8
0
Ostrava, Czech Republic
#1
Hello,
recently bought used Ibanez SR 505 and I am wondering
is this how the MK1 preamp should really look...

If anybody has any basses with this preamp, please check
and confirm. Help really appriciated:help:

I'm asking since the signal is quite wierd. It has a lot of hiss and noise in treble, less in mid and none in bass. It's noisier than my JB with single coils.

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#2
Yes that is the correct preamp. I have read that this is a licensed Bartolini preamp and pickups. So its made by some factory overseas.

There are a few replacement options for you. I only know the exact replacements for the 4 string version. perhaps you can check out the dimensions of pickups here to compare and see. http://www.bestbassgear.com/

I bet there are at least a set of nordstrands or Barts that will drop in easy.
 
#3
There is no other way to correct the noise? What about making
better shielding? Any info on what actually generates the noise?

I couldn't find any other solutions from the net, than changing the preamp, but also it seems that nobody didn't try to fix it as it is.

Unfortunately I lack electronical knowledge to pursue the matter
myself without any questions.

And in the end even if I dont have decades of experience in playing neither in basses in general, "split coils with active EQ are noisier than passive single coils" seems like a really wierd statement - i feel there must be somethig wrong.
 
#6
I do remember the one i had was also noisy. The moment i got a chance to try and record with it is when i realized it was going back from where it came!
Personally, i just didnt want to drop pickups and preamp into it.
I decided it was either replace or return and so i just returned it.
I hope you can also resolve your dilemma.
 
#7
creabass said:
There is no other way to correct the noise? What about making
better shielding? Any info on what actually generates the noise?
[snip]
And in the end even if I dont have decades of experience in playing neither in basses in general, "split coils with active EQ are noisier than passive single coils" seems like a really wierd statement - i feel there must be somethig wrong.
Click to expand...
It's not at all unusual for an active EQ to generate some hiss. The cavity is already shielded. I had a Lakland 55-01 with the same preamp and it hissed when I cranked the treble. So I didn't crank the treble. ;)

Regarding single coil pickups, that's a whole different type of noise (60 cycle hum), which is canceled out in a typical J bass when the volumes are at matching levels.
 
#8
Hey ashtray, could you make a simple wiring diagram for passive
setup of MK1 pups and EQ? I assume that volume and
balance knob will be working even after going passive?

Sounds like an easy thing to try out and easily restorable as well.

Steve I would be happy to have "some hiss" instead of "big pile of hiss". It's not about cranking the treble since this bass has enough
treble at flat position. It's about not cutting the treble...
 
#12
ashtray9 said:
It's just a mediocre preamp. Maybe you got a really bad one. I took mine completely out and went passive. Much better.
Click to expand...

I did that on a Spector NS94 with cheap electronic and it is much better without the preamp.

I also tried some Cort bass with MKI inside and I didn't like it at all. I would replace everything in the long term.

Be careful before replacing your pickups and pre. I put a bartolini in a washburn rb2500 and it still sound crap. I did the same in a washburn X600 and it was a big improvement.
 
#16
creabass said:
Hey ashtray, could you make a simple wiring diagram for passive
setup of MK1 pups and EQ? I assume that volume and
balance knob will be working even after going passive?
Click to expand...

As always, do a search. I got the mod from a Lakland thread and re-posted in this forum a while back. Your volume will still work but you will lose the balance pot. Being crazy I decided to go further and wire both pups to the output jack... The tone made another improvement. I can now hear the tone of the wood in the signal :)
 
#18
My 2010 SR505 hisses a little with treble boost, but that's gonna happen with any EQ. It also has pretty awful 60Hz hum.

A great way to tell if it's 60Hz hum or hiss, is to try this: hold the bass up in front of you, its back flat to the floor. Does the hum go away? If so, it's either one of two things: single-coil pickups, or, in my case, faulty assembly.

What do I mean by faulty assembly? See the attached photo. During assembly, the pickup mounting screws were driven straight through the pickup wiring. In normal noise environments, it worked ok, but on a stage with all that electrical hum, it was unbearable. I was squelching my bass using the volume knob between songs.

The solution looks like new pickups because the remaining good wire is just too short to fix (about half an inch.) I'm guessing, mine is not the only one like this.

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#20
It's too short to shield properly. Having such noise issues already, I'm not going to chance it.

The Bartolini MK1's are not a full, dual-bar humbucker. The pickups are only magnetic on their top right and bottom left. Opposite polarities, so each MK1 is essentially like the two staggered pickups in a Fender Precision Bass, but packaged in one homogeneous "soapbar."

They are significantly lighter than the replacement BC5's going into it, which are definitely full-width humbuckers. The MK1's measured around 6.5k Ohms, and given that there is essentially only half the wire in there as opposed to a BC5, I'm guessing that the MK1's are connected internally in series. The BC5's measure about 15.5k in series.

Interestingly, I see a piece of copper tape on the bottom edge on both MK1's. Unsure what that goes to internally but I get 56 ohms to ground on one and 220 ohms on the other.

I just checked the MK1's again very carefully. The upper magnetic area is only for the D and G strings. The lower magnetic area is for the B, E, and A strings. Unless some very precision assembly was done, this could be a problem for hum cancellation due to unequal winding size. It is the very nature of the humbucking process (two identical coils, of opposite magnetic polarity, connected together in series or parallel) which reject induced noise. Any change in that relationship (magnetic, electrical, spatial, or otherwise) can affect the noise rejection ability. Maybe the damaged lead wasn't the biggest culprit in my noise issue?

In case anyone else reads this and is looking to replace their MK1's... the BC5's are a close fit, but the mounting holes do not line up. (Three-hole instead of two, and the one single hole is not in exactly the same place. So I'm waiting for two filled-in holes to dry before drilling all new ones.
 

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