Hollowbody w/ Archtop PUs - Volume control treble rolloff is too much

[68TwinReverb]

Hi All,

This is my first post about my first PRS. I came into a 2005 PRS Hollowbody Spruce with the Archtop pickups and absolutely love the guitar except for one annoyance. The treble rolloff on the volume pot when the volume is turned down, even slightly, is waaaayyyy too much. Instantly muffled - it doesn't even sound like the same guitar.

I'm guessing this could be due to a volume pot that is under spec'd and potentially needs to be replaced. Any suggestions here?

What are the original specs for the pots? Would a pot testing at 400-450k exhibit these symptoms with the Archtop pickups?

 

[garrett]

Those didn't come with a treble bleed cap, so that's to be expected irrespective of pot value. They'll be 500k pots, but PRS has a wide tolerance. I have one that measures 400k.

When I had a HBII, I put in a 220nf cap and it was a great difference. PRS typically use a 180pf cap. The higher the cap value, the more treble when you roll off the volume.

 

[68TwinReverb]

Thanks! That's helpful to know... I assumed that there was no treble bleed cap and was hoping to avoid altering the inherent tone too much. Did the 400k pot impact the treble rolloff in your experience?

 

[garrett]

The 400k one I had was the tone control, so I'm not sure. I modded the guitar within a few days of buying, so I didn't spend much time with it anyway.

I guess the guitar might overall sound a little darker overall due to the lower resistance value, but I haven't tested that sort of thing.

I found the 220nf treble bleed cap perfect in my HBII. I don't think treble bleeds impact anything with the volume on 10, and it's not an overwhelming value when you roll it back. I found the Archtop pickups surprisingly round sounding for the low resistance, so it was a game changer keeping that top end.

 

[jimfisher]

I had a 180 pf cap put on my HB Spruce's volume pot years ago and it made a lot of difference, I'll bet the 220 would be even better.

 

[RickP]

These videos were interesting as far as demonstrating how you can try multiple values of capacitors in your bleed before soldering them in. Everything here (especially the guitar tone!) isn’t gospel, but does give a good example and demo if you’ve never done this. I’ll be doing this on both of my HB-S guitars before long!

 

[68TwinReverb]

I hate dealing with wiring on a hollowbody guitar (any of them) but I'm curious to see what the spec of the volume pot is and wonder if replacing it with a higher value would solve the problem - although, from what it sounds like, this is a common issue with this guitar and those pickups.

I was considering replacing the pickups with some Ron Ellis humbuckers but may wait/opt-out of doing that if I can get this treble issue worked out.

I'm going for a kind of Trey Anastasio tone with this guitar and I can get close with the Archtop pickups at full-on volume but I'm missing the snappy cleaner tones with the volume rolled off.

 

[68TwinReverb]

Tangentially, can the Archtop pickups be coil tapped? Figure I might as well look into installing a push-pull coil tap if I'm going through the pain of getting the electronics out.

 

[garrett]

I hate dealing with wiring on a hollowbody guitar (any of them) but I'm curious to see what the spec of the volume pot is and wonder if replacing it with a higher value would solve the problem - although, from what it sounds like, this is a common issue with this guitar and those pickups.

I was considering replacing the pickups with some Ron Ellis humbuckers but may wait/opt-out of doing that if I can get this treble issue worked out.

I'm going for a kind of Trey Anastasio tone with this guitar and I can get close with the Archtop pickups at full-on volume but I'm missing the snappy cleaner tones with the volume rolled off.

Tangentially, can the Archtop pickups be coil tapped? Figure I might as well look into installing a push-pull coil tap if I'm going through the pain of getting the electronics out.

Yeah it ain't no fun working on hollow body guitars. Good thing about a PRS Hollowbody is there's no center block, so it's easy to pull all the guts out through the bridge pickup hole. Much better than wiggling everything through the f-hole like on a 335 type.

Putting in a higher value pot won't help your problem. That treble loss is a byproduct of wiring the tone control to the input of the volume pot. That's where the treble bleed comes in to compensate for that treble loss. Or you can go with "50's wiring" which has its own set of trade-offs.

And no, you can't tap the Archtop pickups without some major surgery. They are single conductor pickups.

 

[68TwinReverb]

So for better or worse, I've got my HBII Archtop apart.

I cannot get both circuit boards out - only the large one with the jacks mounted on it.

My questions is: where would I install the treble bleed pot?

Usually I believe it goes on the volume control but in this case the volume control is connected to the circuit board and not the tone pot directly. I could also mount it on the tone pot I suppose. Will mounting it on the volume pot mess with the tone coming from the piezo pickup?

 

[Lacire]

I cannot get both circuit boards out - only the large one with the jacks mounted on it.

This was discussed here on the forum before, if memory serves me correct after removing the bridge pickup the other circuit board comes out through the opening In the top.

 

[garrett]

So for better or worse, I've got my HBII Archtop apart.

I cannot get both circuit boards out - only the large one with the jacks mounted on it.

My questions is: where would I install the treble bleed pot?

Usually I believe it goes on the volume control but in this case the volume control is connected to the circuit board and not the tone pot directly. I could also mount it on the tone pot I suppose. Will mounting it on the volume pot mess with the tone coming from the piezo pickup?

A treble bleed always goes on the volume pot from the left outside lug (as viewed from the bottom of the pot) to the center lug.

 

[Lacire]

Here‘s the link. Second PC board comes out through the top after removing the bridge pickup.

Have any of you removed a Piezo from an HB?

I've almost got my SC HB broken down for a bit of work but can't figure out how to get the last circuit board out. The one with the switch & volume pot attached to it. The board itself seems to be able to fit thru either of the rectangle ports but the switch & pot prevent it from passing thru...

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