The Acoustic Guitar Forum

Go Back   The Acoustic Guitar Forum > General Acoustic Guitar and Amplification Discussion > Electric Guitars

Reply
 
Thread Tools
  #1  
Old 06-16-2017, 06:19 PM
ChrisN ChrisN is offline
Registered User
 
Join Date: Jan 2017
Location: Seattle Area
Posts: 1,508
Default Tone Pots Question

I'm evaluating the Agile's electronics and find all vols/tones are linear taper 500k. I want audio taper in both, so will replace those.

I notice there's a .022uF capacitor on each tone pot, and I want to upgrade those, BUT what I see offered in the various assembled drop-in kits is the tone capacitor wired between the tone and volume pots, not wired just to the tone pot itself, as on my guitar.

I'm guessing the aftermarket guys are doing it correctly, but does anyone know why the two are wired differently, and how, being wired so differently, does each accomplish the job of affecting the tone??

Thanks for any guidance.

EDIT: More confusion - My RS Guitars drop-in kit has the cap wired to the tone pop and grounded to the top of the same tone pot, separate wire connecting the volume and tone pots - https://rs-guitarworks.myshopify.com...kit-long-shaft


This BCS kit, however, shows the cap wired between the vol and tone pots: http://bcsguitars.com/wp-content/upl...-Large-Add.jpg

What's happening?

Last edited by ChrisN; 06-16-2017 at 07:06 PM.
Reply With Quote
  #2  
Old 06-16-2017, 10:57 PM
clintj clintj is offline
Registered User
 
Join Date: Oct 2012
Location: Idaho Falls, ID
Posts: 4,267
Default

Electrically, they're equivalent. The cap carries treble frequencies to ground to do its job, they just changed where the ground connection physically is. There is a difference in wiring on the upstream side of the cap when you look at modern vs vintage wiring schemes, though.

Sent from my SM-G920V using Tapatalk
__________________
"You don't have to be great to start, but you have to start to be great." -Zig Ziglar

Acoustics
2013 Guild F30 Standard
2012 Yamaha LL16
2007 Seagull S12
1991 Yairi DY 50

Electrics
Epiphone Les Paul Standard
Fender Am. Standard Telecaster
Gibson ES-335
Gibson Firebird
Reply With Quote
  #3  
Old 06-16-2017, 11:26 PM
ChrisN ChrisN is offline
Registered User
 
Join Date: Jan 2017
Location: Seattle Area
Posts: 1,508
Default

Quote:
Originally Posted by clintj View Post
Electrically, they're equivalent. The cap carries treble frequencies to ground to do its job, they just changed where the ground connection physically is. There is a difference in wiring on the upstream side of the cap when you look at modern vs vintage wiring schemes, though.

Sent from my SM-G920V using Tapatalk
Thanks for the info re: "they're doing the same thing" - I've got to learn more about this stuff. I think I've got a handle on the vintage/modern thing (but would need to a/b soundwise before choosing, based on the differing opinions I've seen).
Reply With Quote
  #4  
Old 06-17-2017, 08:25 AM
BTF BTF is offline
Registered User
 
Join Date: Jul 2007
Posts: 1,324
Default

One advantage of soldering the tone capacitor to the back of the pot is that- if the tone pot nut should work loose- turning the tone pot won't destroy a relatively costly cap. It at worst may wind up or break a wire. If the cap is between the pots, you can conceivably tear the cap apart should you turn the pot casing.

Good luck.
Reply With Quote
  #5  
Old 06-17-2017, 09:14 AM
ChrisN ChrisN is offline
Registered User
 
Join Date: Jan 2017
Location: Seattle Area
Posts: 1,508
Default

Quote:
Originally Posted by BTF View Post
One advantage of soldering the tone capacitor to the back of the pot is that- if the tone pot nut should work loose- turning the tone pot won't destroy a relatively costly cap. It at worst may wind up or break a wire. If the cap is between the pots, you can conceivably tear the cap apart should you turn the pot casing.

Good luck.
Well, that makes sense. It might be that the guys grounding to the vol pot are showcasing the cap a little more. Thanks
Reply With Quote
  #6  
Old 06-21-2017, 02:10 PM
Big Band Guitar Big Band Guitar is offline
Registered User
 
Join Date: Mar 2017
Posts: 1,031
Default Bad practice

In the industrial electronics world soldering anything to the back of a pot is considered bad practice.

I have serviced industrial electronics for 39 years. I have seen 1000's of pots in circuits of all types. The only place I have seen the back of the pot soldered is in the musical instrument industry.

Getting enough heat to solder to the relatively massive back of the pot requires a lot of heat and if your not good at it the pot can be damaged. It also makes changing the pot a lot harder. Grounding the case is done through the mounting.
__________________
"My opinion is worth every penny you paid for it."

"If you try to play like someone else, Who will play like you". Quote from Johnny Gimble

The only musician I have to impress today is the musician I was yesterday.

No tubes, No capos, No Problems.
Reply With Quote
  #7  
Old 06-21-2017, 03:13 PM
ChrisN ChrisN is offline
Registered User
 
Join Date: Jan 2017
Location: Seattle Area
Posts: 1,508
Default

Quote:
Originally Posted by Big Band Guitar View Post
In the industrial electronics world soldering anything to the back of a pot is considered bad practice.

I have serviced industrial electronics for 39 years. I have seen 1000's of pots in circuits of all types. The only place I have seen the back of the pot soldered is in the musical instrument industry.

Getting enough heat to solder to the relatively massive back of the pot requires a lot of heat and if your not good at it the pot can be damaged. It also makes changing the pot a lot harder. Grounding the case is done through the mounting.
That also makes sense. I noticed in the "diy" vids I watched it seemed they went very quickly - held wire against the pot's top and basically melted solder so it would surround the wire and called it good. They didn't spend any time heating the pot's top, from what I could see, so that makes me question how good a ground it is and how long it'll stay attached.

Separately, while one vid showed a guy (John Cooper's excellent vids) roughing the pot back with sandpaper, another vid said "don't do that - the backs are coated with [tin or solder, or something] that facilitates the soldering process, and sanding takes that away.
Reply With Quote
  #8  
Old 06-21-2017, 07:44 PM
clintj clintj is offline
Registered User
 
Join Date: Oct 2012
Location: Idaho Falls, ID
Posts: 4,267
Default

Some pots won't accept solder unless the surface layer is scraped. I've had good luck with CTS pots and not scraping being successful.

Guitar pots get soldered since they're mounted to wood, and grounding via that mechanical connection won't work. As far as actual technique, just making a solder puddle won't make a lasting connection. You can usually break the connection with a sharp poke with a chopstick or a tug. I use an 85W iron set to 650F with a 1/4" chisel tip. Takes a few seconds to get the target area good and hot, a couple of seconds to flow solder, and it's good to go. If the surface of a solder joint is shiny and concave, that's a good sign.

Last tip: set the pots to the zero position before soldering, so if you overheat something and create a dead spot it's at the least used setting.

Sent from my SM-G920V using Tapatalk
__________________
"You don't have to be great to start, but you have to start to be great." -Zig Ziglar

Acoustics
2013 Guild F30 Standard
2012 Yamaha LL16
2007 Seagull S12
1991 Yairi DY 50

Electrics
Epiphone Les Paul Standard
Fender Am. Standard Telecaster
Gibson ES-335
Gibson Firebird
Reply With Quote
  #9  
Old 06-21-2017, 11:22 PM
ChrisN ChrisN is offline
Registered User
 
Join Date: Jan 2017
Location: Seattle Area
Posts: 1,508
Default

Quote:
Originally Posted by clintj View Post
Some pots won't accept solder unless the surface layer is scraped. I've had good luck with CTS pots and not scraping being successful.

Guitar pots get soldered since they're mounted to wood, and grounding via that mechanical connection won't work. As far as actual technique, just making a solder puddle won't make a lasting connection. You can usually break the connection with a sharp poke with a chopstick or a tug. I use an 85W iron set to 650F with a 1/4" chisel tip. Takes a few seconds to get the target area good and hot, a couple of seconds to flow solder, and it's good to go. If the surface of a solder joint is shiny and concave, that's a good sign.

Last tip: set the pots to the zero position before soldering, so if you overheat something and create a dead spot it's at the least used setting.

Sent from my SM-G920V using Tapatalk
That tipset's a keeper. Thanks
Reply With Quote
  #10  
Old 06-22-2017, 07:05 AM
LSemmens LSemmens is offline
Registered User
 
Join Date: Aug 2016
Location: Riverton South Australia
Posts: 1,667
Default

I would also suggest, ChrisN, if you not had much experience with soldering, practise on something that does not matter if you stuff it up first. Learn how to solder properly or you could end up with random problems down the road. I'm talking dry joints and the like.
__________________
Maton CE60D
Ibanez Blazer
Washburn Taurus T25NMK
Reply With Quote
  #11  
Old 06-22-2017, 07:53 AM
ChrisN ChrisN is offline
Registered User
 
Join Date: Jan 2017
Location: Seattle Area
Posts: 1,508
Default

Quote:
Originally Posted by LSemmens View Post
I would also suggest, ChrisN, if you not had much experience with soldering, practise on something that does not matter if you stuff it up first. Learn how to solder properly or you could end up with random problems down the road. I'm talking dry joints and the like.
My soldering experience is limited to wiring, nothing solid, so that's good counsel in my case.
Reply With Quote
Reply

  The Acoustic Guitar Forum > General Acoustic Guitar and Amplification Discussion > Electric Guitars

Thread Tools





All times are GMT -6. The time now is 01:48 PM.


Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2024, vBulletin Solutions Inc.
Copyright ©2000 - 2022, The Acoustic Guitar Forum
vB Ad Management by =RedTyger=