Dimarzio liquifire crunch lab 7 60 cycle hum. Normal ?

[mightyboy88]

Hi guys,

i have installed a new set of Dimarzio liquifire7 and crunch lab7 onto a Ibanez rg7420 guitar.

My wiring setup is as such

Neck & Bridge Humbuckers -> Pickup selector switch -> Active Buffer Circuit -> 25k volume pot -> output

I really dig the tone and the feel of these pickups but it seems like there is quite a substantial amount of hum, especially at high gain settings and when the volume pot is full.

It sounds abit like 60 cycle hum i get from my strat. However the hum is killed when i use the pickup switch is at the centre(aka neck+bridge).

I connected my pickups in series and i have grounded the pickups, pots and bridge and the active circuit too.

Is this normal for high output humbucker pickups? Would it be helpful if i do shielding?

Thanks for the help !

 

[Jumpin'Jellybean]

I think at high gain it is normal. Shielding would help and so would a noise gate.

 

[mightyboy88]

Thanks sire

 

[ShredAddict]

shielding won't help as much as you think it would. have you considered the point where you might have installed the pickups out of phase?

 

[mightyboy88]

shielding won't help as much as you think it would. have you considered the point where you might have installed the pickups out of phase?

Hi, i installed the pickups based on the standard humbucker series wiring method from the dimarzio manual. Whereby the wiring is like this

Is it possible that my pickups are wired out of phase?

From the instructions i think it means that when the 2 pickups are out of phase with one another you would need to flip the polarity of one of the pickups. But when i play the pickups in centre position(aka neck + bridge together) i get the same output plus hum cancelling

IS it possible that my neck and bridge pickup are both out of phase by themselves? As in the 2 single coils in each humbucker are out of phase

 

[GoodBadUgly]

Dimarzio liquifire crunch lab 7 60 cycle hum. NOT Normal !

It sounds like you have a ground loop problem. These can be quite tricky to cure.
The fact is just 'hooking' all the grounds together without a 'strategy' can cause ground loops. Small micro currents due to a very small difference in ground potential (not all grounds are exactly 0v).
In my experince, the best solution is to use a 'star grounding' architecture with the bridge volume pot case as the center of the star.

Sheilding only helps if you are in an envirnment with LOTS of stray electric fields ( a room w/ poorly grounded flourescent lights for example) and is generaly not needed for humbuckers. Also some trivia, hum here in Singapore is 50hz, US is 60 hz

Hope this helps with your problem.

FYI: I have a liquifire in my Ibanez S series, with 500K Gibson pots and have no hum problem at all, so you should be able to solve this

 

[mightyboy88]

It sounds like you have a ground loop problem. These can be quite tricky to cure.
The fact is just 'hooking' all the grounds together without a 'strategy' can cause ground loops. Small micro currents due to a very small difference in ground potential (not all grounds are exactly 0v).
In my experince, the best solution is to use a 'star grounding' architecture with the bridge volume pot case as the center of the star.

Sheilding only helps if you are in an envirnment with LOTS of stray electric fields ( a room w/ poorly grounded flourescent lights for example) and is generaly not needed for humbuckers. Also some trivia, hum here in Singapore is 50hz, US is 60 hz

Hope this helps with your problem.

FYI: I have a liquifire in my Ibanez S series, with 500K Gibson pots and have no hum problem at all, so you should be able to solve this

hey bro tts some real nice advise you have down there man, so i should try to hook up the grounds from the pickups directly to the volume pot? Should i connect all the grounds to the same spot on the volume pot? Could you care to elaborate on the star grounding system? It sure does sound interesting man

Right now i have the grounds of the pickups connected to the common ground of my onboard buffer preamp and then out to the volume pot case, i think i will try to ground the pickups directly to the volume pot and see if it helps the situation. Thanks bro

 

[GoodBadUgly]

Glad to be of help :=)
What kind of buffer board are you using? Do you have a schematic and/or layout drawing of the buffer board?

Also, slightly off topic, why are you using a buffer board? Those pickups driving a 500k load sound awesome!

Anyway, back to the topic. Send me a diagram of how you got your rig wired (include switch wirining, pickups, and pots...) if possible and I can send you some suggestions.
You can send to my email if that is easier (andrew@obamas.asia)
Cheers!

 

[mightyboy88]

Glad to be of help :=)
What kind of buffer board are you using? Do you have a schematic and/or layout drawing of the buffer board?

Also, slightly off topic, why are you using a buffer board? Those pickups driving a 500k load sound awesome!

Anyway, back to the topic. Send me a diagram of how you got your rig wired (include switch wirining, pickups, and pots...) if possible and I can send you some suggestions.
You can send to my email if that is easier (andrew@obamas.asia)
Cheers!

I am using a buffer circuit from general guitar gadjets. Uses the same circuit as this

I use the buffer to reduce impedance to drive the signal better through the wires doesnt serve any eq/boost function to the original pickup sound. And i really dig the tone of these pickups ! haha

I tried star grounding the circuit but it seems like the hum is still present. What i did was i grounded each wire(aka green and bare from the dimarzio pickups) separately to the back of the volume pot, where i soldered everything to the same spot.

Here are some pictures

Is this ok or should i solder each wire to separate points on the same pot?

I would draw up a schematic and send it over to you soon bro. Thanks so much for the help

 

[GoodBadUgly]

You got the general concept of star grounding.
Assuming that your pickups are wired correctly (i.e. Dimarzio Instructions) and the selector switch (Those things can be quite tricky to get right) I belive the problem is the buffer.

The buffer has 2 grounds (signal ground and power ground). These two grounds should only be conected at on place. More than one connection between the sets of grounds and loops can occur. Are you using a proper circuit board for the buffer with a ground plane inside of it or point-to-point wiring? If p-2-p wiring, then I'm sorry to say you'll have a VERY tough time.

I'll take a look at the schematic you send later...

My honest opinion is drop the internal buffer and wire the pickups as two standard humbuckers.

If you really think you need a buffer, then use something like this:

I picked one up on SOFT a while ago and it works really well. Place it as close to guitar as possible and you can drive a 100 ft cable

I think you'll get much more satisfaction from na Old Skool approach

1) Remove the standard 'cheap' grade wire in the cavity. Use good heavy guage cloth covered wire.
2) Star ground to the bridge vol pot
3) Change the cheap selector switch to a high qaulity Ernie Ball 3-way switch (~$15)
4) Switch out the standard pots with high quality ones (alphas are good enough and only about $5 /pc)
5) I use 500k's in both vol and tone for the rich harmonics, 250 k will brighten the sound but the pups will lose some ballz. Up to your personal preference.
6) Change tone cap to an Orange Drop or 'paper in oil' cap. Go ahead and experiment with different cap types and values, you'll be surprised byt the variation this can make.

 

[mightyboy88]

You got the general concept of star grounding.
Assuming that your pickups are wired correctly (i.e. Dimarzio Instructions) and the selector switch (Those things can be quite tricky to get right) I belive the problem is the buffer.

The buffer has 2 grounds (signal ground and power ground). These two grounds should only be conected at on place. More than one connection between the sets of grounds and loops can occur. Are you using a proper circuit board for the buffer with a ground plane inside of it or point-to-point wiring? If p-2-p wiring, then I'm sorry to say you'll have a VERY tough time.

I'll take a look at the schematic you send later...

My honest opinion is drop the internal buffer and wire the pickups as two standard humbuckers.

If you really think you need a buffer, then use something like this:

I picked one up on SOFT a while ago and it works really well. Place it as close to guitar as possible and you can drive a 100 ft cable

I think you'll get much more satisfaction from na Old Skool approach

1) Remove the standard 'cheap' grade wire in the cavity. Use good heavy guage cloth covered wire.
2) Star ground to the bridge vol pot
3) Change the cheap selector switch to a high qaulity Ernie Ball 3-way switch (~$15)
4) Switch out the standard pots with high quality ones (alphas are good enough and only about $5 /pc)
5) I use 500k's in both vol and tone for the rich harmonics, 250 k will brighten the sound but the pups will lose some ballz. Up to your personal preference.
6) Change tone cap to an Orange Drop or 'paper in oil' cap. Go ahead and experiment with different cap types and values, you'll be surprised byt the variation this can make.

Here is the schematic of my connections

My buffer is p2p wiring, where all the grounds merge at one point and one wire goes out to the back of the volume pot

The power ground goes to the input jack so when the cable is plugged in the power ground would meet the signal ground at the back of the volume pot

I guess i will revert to passive wiring den. However i do get the feeling that the problem does not lie with the buffer as when the pickup selector switch is in the middle(neck+bridge) i get no hum.

 

[GoodBadUgly]

Let's not give up on the buffer just yet ;-)

Looking at the diagram, you have removed the tone pot. Is this correct?

Also, pls provide a more detailed diagram of your switch. A photo also would be good.

And each pickup should have 4 wires and a shiled. Can you show me how you got that connected?

And for the buffer, I suggest you split the Power (9v) GND and signal gnd and wire as follows:

 

[GoodBadUgly]

BTW, here is how to split the grounds on the buffer board:

 

[mightyboy88]

BTW, here is how to split the grounds on the buffer board:

Hi bro I managed to solve the problem,

its a real novice mistake on my part, I failed to wire e pickup switch properly one of the lugs should have been wired to the hot wire but I left it bare.

Thanks for e extremely helpful advise bro. I think the next thing I can work on is improving the grouding of my buffer circuit.

once again much thanks for e kind assistance.

Could I ask if you think it is necessary to shield the cavity with copper ans making a faraday cage?

 

[GoodBadUgly]

Great news!
Glad you sorted it out. Those switches, although not complicated, can be tricky.

As for shileding, since you have active electronics in the guitar (i.e. buffer) and Singapore has a lot of flourescent lights, shieding is probably a good idea. Once agin, make sure the shield only contacts the center of the star ground with one wire/connection.

Cheers and good job not giving up on your buffer project!

 

[j_m_s]

btw.. where'd you get the liquifire 7 and crunchlab 7 from?

 

[GoodBadUgly]

I'm am using the 6-string versions. I have yet to completely figure out 6 let alone 7 strings of the guitar!

;-)

I purchased at SV in basement of Peninsular about 4-5 months ago

 

[j_m_s]

haha thanks, i was asking the TS though..

 

[mightyboy88]

ooh i got it from musician friends, during thanksgiving there was a US$20 off for purchases above 200 usd so the deal worked out to be pretty sweet.

http://www.musiciansfriend.com/accessories/dimarzio-dp708-crunch-lab-7-string--bridge-pickup

http://www.musiciansfriend.com/acce...quifire-7-string--neck-pickup/583024000001000

They dont ship to singapore so you would have to use a shipping service like vpost or borderlinx(citibank card holders only) to send it back to singapore

There was a borderlinx promotion of 25% off shipping during thanksgiving and i shipped multiple items back together, which helps to spread out the shipping costs.

All in all i think it cost me only about $220 sing for the pair, which i think is really really worth it

 

[mightyboy88]

Great news!
Glad you sorted it out. Those switches, although not complicated, can be tricky.

As for shileding, since you have active electronics in the guitar (i.e. buffer) and Singapore has a lot of flourescent lights, shieding is probably a good idea. Once agin, make sure the shield only contacts the center of the star ground with one wire/connection.

Cheers and good job not giving up on your buffer project!

Hi bro,

sorry to disappoint you but i realised that my "solution" of rewiring the pickup switch was erroneous as i basically wired a neck+bridge combi in all 3 pickup switch positions without realising it.

I have since rewired a new pickup switch, removed the buffer and wired up a single 500k cts audio tappered volume pot. I have also shielded the electronics cavity using a faraday cage concept.

I realised that while the hiss is much lower as compared to when i had active electronics, in the centre position (neck+bridge pickups) i get virtually no hum

When the neck pickup is activated alone, some hiss is present but that is much lower as compared to that of the bridge pickup

I read some reviews on sevenstring.org that the crunchlab is a noisy humbucker due to its asymmetrical pickup design and i think this probably explains the phenomenon.

However, i dun understand why there is hiss eliminated when the pickup switch in the centre position, is this something normal?

I would shield the pickup cavity soon to further tackle my noise issues haha