Loosing highs with mojo blender control

[the great waldo]

Hi All

I just had a customer call back saying that he thought he was loosing some of the high end on his strat pups when the blender was turned out of circuit. He likes the tones with the blender wound in. Has anyone any ideas on bringing the brightness back. Maybe making the blender 500k instead of 250k might help. If David Sheperd is browsing he can drop an opinion or anyone else for that matter.

Cheers

Andrew

[David Schwab]

Do you mean he loses highs when he's not mixing the bridge pickup in with the neck? That's kind of obvious, right? It's brighter with the bridge pickup mixed in.

Or are you saying the neck pickup is not as bright as it used to be? Maybe he forgot what the neck pickup sounded like on its own.

The blender pot is not wired to ground, so a 500K pot wont change anything. It's apparently a "no load" pot, so it's out of the circuit when you have it on zero.

[the great waldo]

Hi David

I spoke with the customer just now and he says he thinks the guitar with the normal strat setting does´nt seem to be as bright as before without the blender fitted, he´s got an srv strat with texas specials in which he says sounds mega bright in comparison. He´s going to bring both in next week so I can check out the difference and maybe try a 500 k vol control to se if it makes any difference or just wire a push pull pot to get the bridge neck combination. You could well be right that he´s forgotten the sound before and is expecting the guitar to sound the same as his srv strat. I´ll post when I find out.
Cheers

Andrew

[David Schwab]

He's going to bring both in next week so I can check out the difference and maybe try a 500 k vol control to se if it makes any difference or just wire a push pull pot to get the bridge neck combination.

You are missing the point on how this works. It's not wired up like a volume control. The pot is not connected to ground. It's series resistance and only affects the bridge pickup, not the neck or middle. The pot is a "no load" pot that disconnects the bridge pickup from the neck when on zero. When on zero it is not in the circuit at all. So it can't affect the tone of the neck pickup unless it was wired up wrong.

If you replace the blender pot with a 500K, you will always have some bridge pickup bleeding into the neck pickup.

If the circuit is wired up correctly then your customer just likes the neck pickup brighter and forgot what it sounded like. So the fix would be replace the neck pickup with something brighter, or just leave some bridge dialed in. That wont hurt anything.

You can also wire up the blender so when it's off, some of the bridge pickup is bleed through a small value cap (like 0.005µF) and a resistor or better yet, a trim pot. This will add some highs from the bridge into the neck even when the blender is off.

[the great waldo]

Hi David

We are going to try a 500k on the vol to see if it brightens up the tone for all the pups. I realize that the blender is not wired as a vol control just as a series resistance (the neck and bridge pup are both wired to the pot and the resistance works on which pup is selected by the selector, in the bride position the the neck pup is dialled in and in the neck position the bridge pup is dialled in) I think basically the problem is that the customer has one guitar that sounds different from the other and as you say he´s probably forgotten the sound he had.

Cheers

Andrew

[Rick Turner]

A better variety of blend pot acts like a straight ahead volume control for each pickup using a ganged dual pot with one section working from full counterclockwise up to full on at the half-way point detent and the other section working in reverse. In the middle position, both pickups are full on (plus the load of the pot). The net effect on loading is like having two volume controls in line...in other words the resistance load on the pickup is 250K if you're using 500 K volume and blend. Of course, tone controls will change that. I get the pots from All Parts, and they work great. Yes, bump up to the higher value for the least load. Then use a push/pull volume control and use it to bypass itself when the knob is pulled up. That will take the volume control load out of the circuit. Ditto on tone controls...try either no-load pots or push-pulls with bypass.

[the great waldo]

A better variety of blend pot acts like a straight ahead volume control for each pickup using a ganged dual pot with one section working from full counterclockwise up to full on at the half-way point detent and the other section working in reverse. In the middle position, both pickups are full on (plus the load of the pot). The net effect on loading is like having two volume controls in line...in other words the resistance load on the pickup is 250K if you're using 500 K volume and blend. Of course, tone controls will change that. I get the pots from All Parts, and they work great. Yes, bump up to the higher value for the least load. Then use a push/pull volume control and use it to bypass itself when the knob is pulled up. That will take the volume control load out of the circuit. Ditto on tone controls...try either no-load pots or push-pulls with bypass.

Hi Rick

I had the customer in today and will be trying a 500k pot for the volume. I think the blenders putting him off because he´s got a pushpull for the pup switch in his srv strat. He´ll drop the guitars by next week for me to check out.
I liked your comments on it´s all in the hands on your other post. I´ve been repairing guitars and making when time allows since 1976. my moto is good player bad guitar= good music, bad player good guitar=bad music !

[Rick Turner]

Ry Cooder had me put in 1 meg pots on a couple of guitars for even less loading. Of course the taper gets weird and you lose highs faster when turning the volume pot down, but for him it was either all the way up or all the way off. Could have used a standby switch.

[David Schwab]

Ry Cooder had me put...

Rick, have you considered writing a book? I bet you have some great stories!