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> Gibsons And Pcb In The Control Cavity
VikingBlues
post Feb 23 2013, 09:26 AM
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Last year I got a Gibson SG Classic with P90 pickups. It seemed like a good idea at the time.

But after the "honeymoon" period I realised the sound needed tweaking. Not enough clarity and natural sustain for my liking. I have Tonerider Vintage Alnico 2 P90s in a PRS SE guitar and they sustain wonderfully well and have a crystal clarity when payed clean. Moving the pickups away from the strings and playing around with polepiece heights on the SG helped a bit, but not enough. Currently it is, for what I want to play, and to my ears, a long way behind the PRS SE in qualities.

So I started wondering about pickups, and then when researching those found that the Sg has 500k tone pots but 300k volume pots. Wondered about the effect of changing the volume pots to 500k and maybe something on the wiring.

So I opened up the control cavity and was surprised to find this:

Apparently since 2008 SGs have their pots and electrics mounted on a PCB.

There's a good picture at the top left of one of these boards in the link below to the "The Guitar Aging Studio".
Gibson PCBs - Guitar Aging Studio
I see that the summary that went with the picture said in particular (I've underlined the bit that caught my attention):-
The first thought was to replace the 300k volume pots with regular 500k ones, but viewing at the pcb, it was clear that the flat, narrow signal paths on the board are also a very significant reason for sound degradation, since they obviously kill higher frequencies, compared to a good quality, branched wire, which offers way more surface and supports higher frequencies on the signal.

I have seen a number of reports suggesting that ripping out the PCB (possibbly voiding the warranty?) and changing to convential wiring with 500k volume pots instead of 300k cleans up a lot of the muddiness and make sthe instrument totally different tonally. This benefit is mentioned in the text of the top middle picture of that link above.

It's a PCB that is not greatly user friendly for the player upgrading with aftermarket pups and electrics. "We are now working on making this system more friendly by allowing mods and aftermarket parts. I am hoping to release this in the next few months. It really isn't easy right now and we have to improve it". The words of Henry Juszkiewicz (no less) posted on a Gibson forum in July 2010. I have so far seen no signs or comments to sggest that this happened.

Though there is a small business in the Netherlands that makes replacement PCBs for Les Pauls (don't know if any use for an SG) which ARE user friendly ... non solder capacitor changes, and supplied with replacement moulex connectors for pickup changes, with the little bonus of a few switches for changing the PCB between 50s and modern wiring.

Generally many comments on Gibson and other forums point to the use of the PCB as being purely a way of saving labour in the guitar construction. I don't feel much inclined to investigate the PCB further - I don't have the technical knowledge to know what I'm looking at! Everything is soldered to the PCB and the pickup connectors are particular moulex connectors.

I'm feeling that any attempt I make to upgrade the guitar will, if I don't get the right result for me, leave me with a guitar without the stock Gibson parts that will reduce its resale value. With it's all mahogany neck and body and P90s it is a much more similarto my PRS SE than I thought at first (except for thehot pickups and the PCB) so I'm feeling inclined just to cut my losses at this point and sell it. It would be a fine guitar for someone that plays music with more overdrive and power - just a bad choice for me given my musical tastes.

Always good to get other peoples thoughts in these situations though - sometimes get to close to a problem like this and can't see the wood for the trees.


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MHD Pickups
post Feb 23 2013, 08:56 PM
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I deal exclusively with a guy named Matt over at martinsixstriongcustoms.com. He does after market harnesses. Truly amazing and affordable. i would start with the harness and go from there. I have his stuff in 6 of my guitars with 3 more being built. i have tried and used several others and for me his are the cleanest and easiest to drop in.


As far as the PCB goes get rid of it. You will notice a huge diff in the tone and sustain. Seriously.


300k vs 500k. for me I use 300k on guitars that have a higher output pickups, seems to add a bit of lets call it balance. For the SG it should have 500k pots, more open and better clarity. Do the harness upgrade, and if that does not work then start looking at aftermarket pups, you may find with the harness you may not need them.

This post has been edited by MHD Pickups: Feb 23 2013, 08:59 PM


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DC DOES NOT EQUAL OUTPUT. Dc is a resistance value and that is all. It WILL NOT tell you what it will sound like, it WILL NOT make you sound like another player.
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VikingBlues
post Feb 25 2013, 08:26 AM
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QUOTE (MHD Pickups @ Feb 23 2013, 07:56 PM) *
I deal exclusively with a guy named Matt over at martinsixstriongcustoms.com. He does after market harnesses. Truly amazing and affordable. i would start with the harness and go from there. I have his stuff in 6 of my guitars with 3 more being built. i have tried and used several others and for me his are the cleanest and easiest to drop in.


As far as the PCB goes get rid of it. You will notice a huge diff in the tone and sustain. Seriously.


300k vs 500k. for me I use 300k on guitars that have a higher output pickups, seems to add a bit of lets call it balance. For the SG it should have 500k pots, more open and better clarity. Do the harness upgrade, and if that does not work then start looking at aftermarket pups, you may find with the harness you may not need them.


Thank you for the advice on the wiring harness and the pots - certainly a step that appeals most if i keep the guitar. Thanks also for the link - always good to have a personal recommendation forany makers of these harnesses. smile.gif

I'm waiting (might be a long wait) for a reply from Gibson - due to concerns I've seen voiced I've asked them if my getting rid of the PCB invalidates the warranty.


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