Gus G Fire Review

Re: Gus G Fire Review

So how do these pickups sound without the preamp?
Any resemblance to other Duncan you've tried?
I'm guessing between Demon and Distortion neck. :scratchch
 
Re: Gus G Fire Review

baron55 said:
Looks like pickups using external preamps are going to be actually noisier since the preamp is amplifying the noise generated by the passive pickups. So this looks like the norm.
The sealed actives are quiter since the preamp is sealed and shielded in the pickups themselves.
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This should not be the case. The bmp was designed to solve this problem of the preamp amplifying noise as much as the primary signal. That's why it amp's each coil individually, then sums--not just to cancel 60 cycle hum, but other noise as well. And, it works. It has made my passives much louder without bringing up the noise proportionately. In fact, they are quieter than they were when i ran 'em passive. Something seems to be wrong w/the OP's set. I wish Frank would get in here. He could explain the dual differential preamp & why you should not be getting the noise you have. I didn't find any other reviews of the Gus's, but it would be helpful to know if others had similar experience.
 
Re: Gus G Fire Review

Guston7 said:
This should not be the case. The bmp was designed to solve this problem of the preamp amplifying noise as much as the primary signal. That's why it amp's each coil individually, then sums--not just to cancel 60 cycle hum, but other noise as well. And, it works. It has made my passives much louder without bringing up the noise proportionately. In fact, they are quieter than they were when i ran 'em passive. Something seems to be wrong w/the OP's set. I wish Frank would get in here. He could explain the dual differential preamp & why you should not be getting the noise you have. I didn't find any other reviews of the Gus's, but it would be helpful to know if others had similar experience.
Click to expand...

I am going to plug in a Duncan Full shred I have lying around to see if there is any difference.

If the preamp does amplify the coils seperately, then I agree it should cancel when summed back together. It is defineatley not a ground loop since I can make it vary the amplitude by tilting the guitar in different positions. But the noise is exactly the same noise you would get on a single coil through a high gain amp.

So basaically from what you guys have said, the preamp may not be canceling out the hum and noise.

Interesrting is that if I run both humbuckers together the noise drops considerably. I have twice re-installed eveerything checked continuity and grounds and everything checks out. I even bypassed the pickup delector switch and and went from the preamp out to preamp in and that had no effect on the noise.

Thanks for all the suggestions. And by the way, I love how these pickups sound!
 
Re: Gus G Fire Review

Something doesn't sound right. Either something of ours is broken or there's a connection not made somewhere. The BMP-1 is extremely quiet, and the pickups are of course humbuckers. I've played the Gus system through dimed 50 and 100 watt Marshalls and it's an extremely quiet system. The BMP-1 is adding maybe 10-14dB of gain, but it's WAY quieter than if you just stuck a 10-14dB boost after a humbucker because it's working to cancel noise even within the preamp.
 
Re: Gus G Fire Review

Thanks Frank,

Here is a hi res pic of the conenctions with lables of what the wiring is. Also the coaxial cable is crounded to the preamp and output jack.


Connections.jpg
 
Re: Gus G Fire Review

Well, you certainly have the pickup wires in the same way I do. I am not seeing the 5-way & shielding ground wires going into the bmp. They may be there & I just can't see them?
 
Re: Gus G Fire Review

I am just on an iPhone, but can't see anything going into the 3 "Ground" connections on the BMP.
 
Re: Gus G Fire Review

Guston7 said:
Well, you certainly have the pickup wires in the same way I do. I am not seeing the 5-way & shielding ground wires going into the bmp. They may be there & I just can't see them?
Click to expand...


The ground wire is the braided shield from the coaxial cable so there is ground. The 5 way switch only needs ground if you want to split the coils (ground them out) The Gus G has no provisions for this anyway which is no big deal.

BTW I did to the conventional non-coaxial leads (all three hot, battery negative and ground) to the jack with the same noise.

Also tried grounding the bridge as well, no change either way.
 
Re: Gus G Fire Review

Just for fun I bypassed the selector switch and went from the Pickup out direct to the pot input. Same noise no change.

So basically bypassing the switches. Pickups into BMP, still makes the noise.
 
Re: Gus G Fire Review

I don't mean the signal negative that you would use for coil splitting. I mean the common ground for the switch case, pot cases, and that nice copper foil shield you have. All that should get common grounded with your pickup baseplates (bare), by going into the Ground inputs on the BMP. Maybe that's not the problem, but it is the big difference between your wiring and mine. In the pic above, your pickup bare wires aren't doing anything...I think?
 
Re: Gus G Fire Review

Can't tell if the BMP is grounded to the rest of your circuit, as Guston7 is suggesting. Assuming your copper foil is soldered at all the junctions, so it all is going to ground, take a wire from that center ground terminal (the one that appears currently unused) and wire it to the shielding foil. I can't tell in the photo what you're doing with the sleeve of the coax output jack cable.
 
Re: Gus G Fire Review

Guys,

Grounds are fine. If you take a meter to any of the ground terminals of the BMP and to the shielded foil and to the ground on the input jack, you get continuity (zero ohms). and if you plug the cable into the jack as designed, you will also see ground on the negative termonal of the battery.

The pot itself touches the foil and provides ground to the terminals and the bmp is grounded to the input jack as well. I actually isolated the pot to see if a loop was the issue, still same issue. At the moment the pot is touching the foil. Also the foil, provide ground to the switch housing as well, already checked that.

As I said in my pevious post that I bypassed the switch completely and the noise is still the same.


Connections2.jpg
 
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Re: Gus G Fire Review

All I can say at this point is that sound clip (noise) sounds nothing like any Gus G or any pickup into a BMP I've ever heard. There is always the chance of something faulty, but you're telling me that you can "beep test" from any ground terminal on the BMP to the foil, the ground at the output jack, etc. so I have no place to go. Personally I would never assume that the pot's physical contact with shielding tape would establish a strong ground for the BMP. I would still solder a wire to a known ground, and screw it into one of the BMP ground terminals. I'm not saying that would solve your problem, just that long term you should have a stronger connection to ground than that.

After this, you can try a different pickup(s) into the BMP and if the noise is better then the problem is in the pickups. If not, the problem remains in the preamp or the wiring. Either way we'll replace anything/everything for you, I'd just like to get it isolated first.
 
Re: Gus G Fire Review

frankfalbo said:
All I can say at this point is that sound clip (noise) sounds nothing like any Gus G or any pickup into a BMP I've ever heard. There is always the chance of something faulty, but you're telling me that you can "beep test" from any ground terminal on the BMP to the foil, the ground at the output jack, etc. so I have no place to go. Personally I would never assume that the pot's physical contact with shielding tape would establish a strong ground for the BMP. I would still solder a wire to a known ground, and screw it into one of the BMP ground terminals. I'm not saying that would solve your problem, just that long term you should have a stronger connection to ground than that.

After this, you can try a different pickup(s) into the BMP and if the noise is better then the problem is in the pickups. If not, the problem remains in the preamp or the wiring. Either way we'll replace anything/everything for you, I'd just like to get it isolated first.
Click to expand...


Thanks Frank,

Here are some pictures of the rewired setup identical to the wiring diagram minus the tone pot.

As for grounds. The ground lead soldered to the output jack connects to the ground terminal to the BMP. This automatically grounds the volume control because it is directly solderdd to the BMP in two places, the sheild and the pot leg.

With the unit out and not installed you will get zero ohms between the ground screw terminals and the ground leg of the pot and the pot housing itself. So the BMP is properly grounded to the output jack. But for verification, I did connect the BMP to the bridge ground no change, then connected the pot housing to ground, no change. Also usually ground issues are noticed by changes occurring when you touch a control or metal part on the guitar, doing this has no effect.

I did connect a Bare Knuckle Warpig (ceramic) 21.5K DC resistance, very hot pickup, and the noise was reduced significantly. You would think with a hotter pickup it would get louder. I saw that you had posted on another forum that the BMP-1 rejects noises within the preamp, but if the pickups were noisy, that could be the source of hum. From what I can tell the BMP-1 rejects noise generated by the preamp itself, but not from the pickups like a digital active canceling system like Bose first came out with.

But one thing Frank I noticed in the very beginning. Every single Seymour Pickup I have ever seen, opened and installed, has the conductor cable leaving the lower right hand corner of the pickups if you are looking at the pickup from the guitar front side. Even the Gus G pictures show this. But these pickups have the cable leaving from the Top left.

Now before you say it! LOL They are installed correctly, the adjustment screws are on the top row for the neck and on the bottom near the bridge on the bridge pickup and the Seymour Duncan logo is on the bottom of the pickups. I will send you a pic as well.

http://dl.dropbox.com/u/26196875/1.JPG

http://dl.dropbox.com/u/26196875/2.JPG

http://dl.dropbox.com/u/26196875/3.JPG

http://dl.dropbox.com/u/26196875/4.JPG

http://dl.dropbox.com/u/26196875/5.jpg


Also let me say that from aside from the noise, these are awesome sounding pickups, excellent touch sensitivity not over the top muddy gain and clean up nicely.
 
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Re: Gus G Fire Review

For those who were wondering about the DC resistance. The Bridge Pickup measures about 4.0K on each coil, so if it were wired as a conventional humbucker you would be looking at 8K. The neck pickup measures about 3.5 to 3.6 on each coil, so in humbucking mode it would be about 7.1K

On output, average VAC output is about 1.1 volts on the bridge pickup strumming and E chord pretty hard. To some this may seem low. But the base Gus passives are pretty light wound low gain pickups which is pretty nice.


Comparing this to some other passives.

Duncan Custom Bridge with 500K volume pot and 500K tone pot the average VAC is .329 volts. Since this is passive, the pots load the pickup down.

Dimarzio D activator Bridge with 500K volume and 500K tone is .565 VAC.
 
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Re: Gus G Fire Review

Nice, thanks! I've been trying to find out what the Duncan coil pack winds are like for a long time. Those resistance figures make a lot of sense, to me. I tried many pickups w/my BMP's & the highest resistance pickup I liked (in bridge) w/it is between 13-14k ohms (Evo). I have one set up with PAF Pros (8.4k) and it sounds great. I tried a JB & DD and the bass was just too overwhelming for the clarity I want.
 
Re: Gus G Fire Review

Hmmm. Have you added the additional ground wire suggested by Frank? I'm assuming that if that doesn't do it you have a defective preamp.
 
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