Marcus Miller Jazz Mod Time

[timloudon]

I've decided it's time to get rid of the grounding problem on my MM (CIJ).

I found [url="http://www.talkbass.com/wiki/index.php/Silencing_the_Noise_on_a_Marcus_Miller_Signature_Bass"]this article[/url] some time ago on TalkBass.

I'm going to go through the steps and rewire as the article suggests.

I've decided to photograph things to show you all, and also incase anything goes wrong.

Here it is all taken apart:


I hope this all goes well.

Has anyone else tried this?

[timloudon]

Well. I've decided that I'd better do a sketch of the wiring in the bass before I get started, since I have to go into town and get a few things tomorrow.



Compare with the wiring diagram on the guide:



There is one thing that isn't mentioned on the guide - the yellow wire going into the pre-amp is not soldered to anything (the red circle).

What can this be?

[timloudon]

It seems I've come up against one or two problems. Surprise, surprise.

It seems buying a cheap soldering iron produces cheap results. I'm having trouble melting the solder in the two unconnected terminal on the output jack (see below) - it just wont melt!




Presumably my soldering iron just wont get hot enough. And maybe I should hand it over to someone who knows what they're doing!

Any suggestions?

[Low Down Dave]

The biggest problem musicians often face when they start soldering is not the iron its self, but the tip is too big and it will not transfer the heat properly. Get yourself a fine tip and magically the solder will flow effortlessly. It is well worth preserving and getting the soldering technique sorted as it will come in very handy over the years. A quick couple of tips: Make sure you tin the contact points and wire well, and have solder on the iron, clean the tip regularly on the damp sponge to keep it clean and all joints shiny.


Dave.

[thebeat]

If you're using lead free solder you'll need a specialist soldering iron....normal irons won't be any use as the don't get hot enough.

[timloudon]

Cheers for the advice guys.

I've decided to get some outside help - in the form of someone who knows what they're doing, i.e. someone who's just finished building their own compressor.

I'll be taking some pictures today, so I'll show you all what he's done. It all looks very neat now.

[timloudon]

Well, it's all fixed now. This is what happens when you get a professional to do it:

Here's the cavity properly properly shielded, i.e. the foil helping the conductive paint and foil of pickguard make contact.



Here's one of the pickups when shielded. It's not on this picture, but the foil shielding has a cable soldered to it which is then attached to the ground point in the cavity.



Here's the electronics when properly finished. The second photo shows the extent to which this chap takes care- all the joints are shrink wrapped, and cable are tied and grouped.




Here's it all put together!



The best bit about this, he did it all for £30. What a lovely man.

In regards to the online guide which the wiring is taken from - it's not mentioned that the signal grounds (pickups and preamp) and the equipment grounds (bridge and pickup shields) make contact through the tip end of the resistor at the output jack - the lower jack terminal in the posts above. This is a very important point - I forgot to mention this, which left me with a massive hum.

I've put some DR Fat Beams on it, and it sounds awesome!

[Hamster]

I can't really understand how they left the factory like this - it's such a simple thing to get right the first time round?

[Marcus]

Now all you have to do is Rip out that 50c pre-amp and install and Aguilar OBP1

You'll love the result of that !!!

Nice mods there......

[Weird War]

That looks much better - spaghetti junction has been tamed!

[timloudon]

[quote name='Weird War' post='417920' date='Feb 23 2009, 10:02 PM']That looks much better - spaghetti junction has been tamed![/quote]



Even though it's tucked away inside, it still satisfies my tendencies for tidiness!

[Thunderthumbs]

That's really weird......I asked a mate of mine who also owns one if he'd ever suffered from hum, which he hasn't, so it was just me.....then lo and behold this appears!

I have read the Talkbass one before, and wondered whether I'd be brave enough to have a stab at it......but thinking much the same, I know a friend that'd do a much better job than me.

Great topic. Thanks very much for it.

[Thunderthumbs]

Question:

Anyone know whether there would be any difference shielding the pickup cavities rather than the pickups themselves?

[Alex-Wright]

Hi guys,

Great post - saw the instructions online and tried myself (well, handed them to a more electronically savvy dad!)

After following the instructions, I've plugged in the newly insulated beast, and the hum is much LOUDER than before, and instead of it disappearing when I touch the grounded bridge, it gets louder still! Needless to say, I'm most confused!

From that very limited description, does anyone know what may be wrong?

The only difference I can see from the original instructions is that I've insulated the whole cavity with copper, and instead of wrapping the pickups with copper, I've lined the inside of the plastic pickup shield with copper (I don't know the proper name - it's the bit you can rest you thumb on to play and slide off to see the pickup coil) - this was to avoid the copper touching the other wires and shorting stuff out...

Any help would be much appreciated. Can take pictures of wiring if anyone is kind enough to take an interest...

Thanks in advance,

Alex.

[73Jazz]

[quote name='timloudon' post='407051' date='Feb 12 2009, 12:25 AM']It seems buying a cheap soldering iron produces cheap results. I'm having trouble melting the solder in the two unconnected terminal on the output jack (see below) - it just wont melt![/quote]

As far as i know, it has nothing to do with cheap.
Due to RoHS certifications, they have to change the consistency of solder.
So if you are having a weak soldering rod, the solder will not melt as usual.
I did have the same problem before with some solder i bought new

Edited July 11, 2011 by 73Jazz

[brensabre79]

[quote name='Alex-Wright' post='1299412' date='Jul 10 2011, 11:04 PM']Hi guys,

Great post - saw the instructions online and tried myself (well, handed them to a more electronically savvy dad!)

After following the instructions, I've plugged in the newly insulated beast, and the hum is much LOUDER than before, and instead of it disappearing when I touch the grounded bridge, it gets louder still! Needless to say, I'm most confused!

From that very limited description, does anyone know what may be wrong?

The only difference I can see from the original instructions is that I've insulated the whole cavity with copper, and instead of wrapping the pickups with copper, I've lined the inside of the plastic pickup shield with copper (I don't know the proper name - it's the bit you can rest you thumb on to play and slide off to see the pickup coil) - this was to avoid the copper touching the other wires and shorting stuff out...

Any help would be much appreciated. Can take pictures of wiring if anyone is kind enough to take an interest...

Thanks in advance,

Alex.[/quote]
Sounds like the shielding is making contact with the signal.

Personally I would shield the cavity (i.e. the wood) rather than the inside of the P?U case. Try removing the pickup case and plug in to an amp to see if this changes the situation - if it does remove the shielding from inside the Pickup case. If not it may be that one of the wires or the pot lugs is touching the shielding in the control cavity.

In any case, if the hum gets louder when you touch the shielded bridge then a contact between the signal and the ground is being made somewhere.

[Alex-Wright]

Thanks very much for your response, brensabre79 (Bren I assume?)! I'll give it a go and let you know how I get on...

Alex.

[Alex-Wright]

Hi again,

After metering the resistance of the soldering job, it shows no connection between the white pickup wires and the shielding, and the problem is there even when the control plate is removed (away from the cavity), so the pot lugs touching is probably not the root cause. In addition, removing the pickup covers does not stop the loud buzzing, so I'm quite confused...

I'm wondering about how the initial setup differs from the talkbass tutorial's end result: It suggests removing the solder on the lugs on the end two pots and attaching the new ground wires there - originally the case of the pot was used at this point to connect the black pick-up wires and the original ground wires which ran between the pots (which I removed).

Do you know if this may be where the connection with the pick-ups is being made? When I meter between the lug connection and the body of the pot there is no connection but there is with the white wires coming from the same pot dependant on the position of the knob.

Thanks again,

Alex.