Treble roll off problem on 1990 USA Fusion

[Ricey]

I recently restored my 1990 USA Fusion to stock Jackson PUPS. I got the PUPS from a Charvel Model 6, so I used the Model 6 mid-boost circuit in place of the wah/wah circuit normally found on a Fusion. When I ramp the volume knob down to clean up my sound, I lose a lot of highs. I once owned a Model 6 and recently had the opportunity to play two others and none of them suffered from this problem. As a matter of fact, when my amp was set up for heavy distortion, the Model 6 would clean up and get BRIGHTER when I turned the volume down. This was one of my favorite features of that guitar.

The only change I made from a stock Model 6 circuit is that I specified that I wanted a push/pull tone pot so that I could get an extra PUP combination (Bridge + Neck) not normally found on a guitars with a 5 way PUP selector. The only push/pull pots the guy had were 500K; whereas, the Model 6 circuit normally uses a 250K pot. Would this pot on the TONE pot change cause treble roll-off when ramping down the VOLUME pot? I did not think that the tone and volume pots interacted in this way. Is there some other compontent that might me missing like a resistor or something?

Thanks,
Ricey

[sambencuda]

Re: Treble roll off problem on 1990 USA Fusion

You'll probably get more replys in the Tech forum. This forum is for the general discussion of Jacksons and Charvels.

Good Luck.

[Ace]

Re: Treble roll off problem on 1990 USA Fusion

When you roll off your volume pot, the first thing that you loose is high end. You can install a small capacitor on your volume pot to bypass the high freqs, but this is not a stock feature on a Model 6. Using a 500k tone pot in place of a 250k pot will cause your tone pot to roll of more high end faster.

[toejam]

Re: Treble roll off problem on 1990 USA Fusion

What Ace said. Every guitar I've ever tried has lost a little high end when turning back the volume control.

[jazzman]

Re: Treble roll off problem on 1990 USA Fusion

The cap will take care of your problem. I did the same thing on a couple of my guitars. The value of the cap is guitar/amp dependant though. I called a repair guy and told him what I had and suggested the cap I should use. The cap will be installed on the two tabs NOT connected to grnd. It really works good. Again, it changes from amp to amp.

[dg]

Re: Treble roll off problem on 1990 USA Fusion

One other thing to consider: the Model 6 used 25k pots, not 250k, as part of the famous Jackson Low Impedence Electronics. 25k pots are (were) pretty commonly used in active systems. This may explain why there was no noticeable roll off of highs.

[Cleveland Metal]

Re: Treble roll off problem on 1990 USA Fusion

[img]/images/graemlins/idea2.gif[/img] yep... [img]/images/graemlins/grin.gif[/img]