McCarty 594 Volume Pots

Tedd Caldwell

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I own a 2017 PRS McCarty 594. Love it except for one thing. When I roll off the volume knob, even just a little, the tone of the guitar changes pretty drastically and not in a good way. Dull, lifeless, dark and muddy would be a few choice descriptors.

Anyone had any luck upgrading the volume pots such that the volume can be rolled back and the tone remains the same?

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ViperDoc

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Seconded. A treble bleed mod is all you need. You can even clip it in place to test your preferred value, it's easy. PRS stock value is a 180 pF ceramic cap. The "Golden Age mod" from Stewmac also places a resistor in parallel with a 1 nF cap which keeps a lot more treble and tends to keep the volume louder on the upper part of the pot sweep, IIRC.

See here for the location:

golden-age-treble-bleed-circuit.jpg
 

garrett

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The PRS treble bleed cap works well. It's just a 180pf cap wired to the input and output lugs of the volume pots. I don't recommend going with a value much higher than that with humbuckers. In my experience it makes the tone too bright when when you roll the volume down.

On mine, I just moved a few wires around to convert it to 50's LP style wiring and that made it perfect. This is the way the 594 should be, IMO.

gibson-20wiring-20-20modern-20vs_-2050s-jpg.201062
 

LSchefman

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That's a beautiful guitar!

I've been able to keep high frequencies more intact when I use the volume controls by paying close attention to cable capacitance and using a buffer to preserve high frequencies. I think cable capacitance is underrated. It affects high frequency signals as much as the resistance in a volume pot. This is the case regardless of whether you mod the guitar's cap.

Forgive me if you already know all the following stuff. I mention it because lots of players don't. I've reached these conclusions after 30-plus years of studio work.

A low capacitance cable will preserve high frequencies over a longer run than a higher capacitance cable, and you can hear it. The lowest capacitance cables I've found are the Van Damme XKE (22 pF per foot) that PRS offers as its higher end OEM cable, Sommer Spirit LLX (16pF per foot), and Gotham GAC-1 Ultra-Pro (21 pF per foot). You might not be able to hear the difference between 22 pF and 16 pF in a 15-20 foot cable, but you will hear the difference between that cable and a 40-50 pF or higher capacitance in a cable of the same length.

Compared to a Mogami or Canare cable, with capacitances of 40-50 pF per foot - incidentally, these are also very fine cables, I'm not knocking them - an 18 foot low capacitance cable like the ones I mentioned above will not rob your high frequencies as quickly. Alternatively, you can have longer runs with less signal loss.

The reason cable capacitance is measured referencing length is that every foot of cable adds to the cable's capacitance. The longer the cable, the greater the high frequency loss.

All you have to do to prove how cable capacitance affects your signal is take a very short cable, like a one-foot pedal connector, and plug the guitar into the amp with it. You'll undoubtedly hear hear a brighter signal; in fact, you might find it too bright!

If you're using a pedalboard, a high quality buffer is a great high frequency preservation device. Here I'm not talking about the inexpensive buffers thrown onto Boss pedals. A good buffer is a different thing. Once the signal hits the buffer, the high frequencies are preserved because the signal is converted from high to low impedance by its circuit.

The beauty of a buffer is that the cable following the buffer is far less of a problem, and the capacitance of the cable following the buffer doesn't noticeably affect the signal, except that a good cable rejects noise and is mechanically more robust. Use the higher capacitance cables from pedalboard to amp, or to amp switcher, no problem after the buffer.

I've migrated from using 20 foot cables to 10 and 15 footers. Every little bit helps.

Point is that this aspect of high frequency preservation has lots of factors.
 

Goodsal

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My experience with the 594 was that the volume knobs are very sensitive. I found the useful range to be between 8 and 10. I could set the volume at 8 and get good clean up and then turn it to 10 and get much more gain. If I went below 7 it was all mud.
 
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LSchefman

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My experience with the 594 was that the volume knobs are very sensitive. I found the useful range to be between 8 and 10. I could set the volume at 8 and get good clean up and then turn it to 10 and get much more gain. If I went below 7 it was all mud.

They are sensitive, but using the above technique, I routinely run mine at 4-6 for cleaner tones. I suppose we're all different, but that's my experience.
 

Mosswalker

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I had a similar experience with my 594 -- struggled with how lifeless the tone got with volume knobs below 10. Finally I found what has turned out to be the perfect solution for me: set the amp up for the volume knobs on 8. For my amp this means higher on the master volume and pushing the treble fuller than I would normal. I also use a Earthquaker Tone Job pedal always on as a slight boos and EQ to add clarity.

I can't say how much more I love this guitar playing this way. The tone blooms from the louder amp and I play softer and clearer. The overall volume is about the same-- though remember amps don't generally sound that good at whisper volumes. Now I can roll up to ten and get the boost I expected. I learned this from a few videos explaining it by David Grissom and Tim Pierce, both who are very into using the volume knob. This is just vintage guitar and amp 101, really.
 

LSchefman

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I had a similar experience with my 594 -- struggled with how lifeless the tone got with volume knobs below 10. Finally I found what has turned out to be the perfect solution for me: set the amp up for the volume knobs on 8. For my amp this means higher on the master volume and pushing the treble fuller than I would normal. I also use a Earthquaker Tone Job pedal always on as a slight boos and EQ to add clarity.

I can't say how much more I love this guitar playing this way. The tone blooms from the louder amp and I play softer and clearer. The overall volume is about the same-- though remember amps don't generally sound that good at whisper volumes. Now I can roll up to ten and get the boost I expected. I learned this from a few videos explaining it by David Grissom and Tim Pierce, both who are very into using the volume knob. This is just vintage guitar and amp 101, really.

Yup. You are so right!
 

vchizzle

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Personal preference for sure. I think I prefer the way the volume knob responds more with the former typical treble cap PRS used. I suspect this change is a more vintage style appeal maybe? Thing is, I've grown very accustomed to the way the volume control on the rest of my PRS respond, that the way the 594 volumes respond, it feels/sounds a bit foreign. I'll have to decide if I want to throw a cap in my 594.
 

Alnus Rubra

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Personal preference for sure. I think I prefer the way the volume knob responds more with the former typical treble cap PRS used. I suspect this change is a more vintage style appeal maybe? Thing is, I've grown very accustomed to the way the volume control on the rest of my PRS respond, that the way the 594 volumes respond, it feels/sounds a bit foreign. I'll have to decide if I want to throw a cap in my 594.

Are you saying you want to bust a cap up it’s cavity?!:confused:;)
 

Tone-y

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Any downside to the treble bleed mod?
Can change the taper of the volume meaning it's harder to get a smooth progression from nothing. Probably only a problem if you do a lot of volume swells
 
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