PRS 408 pickup output

[Max Headroom]

@BlueSky, here are those pictures:

Very decent of you to help out by sharing his pictures.
Now hopefully someone can see if anything else glaringly obviously incorrect in there.

 

[Broseph]

wish I had my old 408 to compare...but that does not look original job - its not like PRS to leave a capacitor without some heat shrink wrap. Even their diagram depicts it.

 

[munyonm]

From my reading of the wiring diagram, I agree with @BlueSky's theory that the big yellow capacitor coming off of the switch is suspicious. From the wiring diagram, that should just be a wire from the 3-way switch to the terminal on the volume potentiometer, no third capacitor in the circuit. The other two capacitors look to be correct (at least in the correct location), but I would have at least slid some heat shrink on the legs of the 0.033 uF capacitor. This third capacitor is electrically 'in the way' of the pickups output to the volume potentiometer.

This would also explain there was no reading from the multi-meter. Depending on the circuit where it is used, a capacitor can be a treble bleed (like in a tone circuit) or it can be an energy storage device to smooth transients (which I guess is the same behavior, depending on if you are looking in the current domain or frequency domain), but I digress. If you are only trying to measure resistance, a capacitor is an open circuit, so no resistance would be measured.

Lastly, there would be some output because the vibrating string through the magnetic field of a guitar pickup is generating a small amount of electricity and that could make it's way through that capacitor, but it would be greatly stifled.

 

[Glide-bpm]

Yeah, that doesn't look like a good place for a cap!

 

[Rider1260]

My 408 ( Rosewood neck ) has been my #1 or 1a since I got it .
The pickups do have a different EQ , I call it "even" or "smooth" some would call it " flat " basically no hot spots to the EQ to my ears
I have never had the back plate off but here is mine , I would look at your ground on the tone pot it looks different.
the yellow cap ? is correct it on mine.
I would also contact PTC they can get you sorted.

I seem to remember not being able to measure mine at some point I will try again later.

It should sound like this ( I own the frost one )

IMG_8668 copy by
[url=https://flic.kr/p/2oDZ7GD]IMG_8667 copy by https://www.flickr.com/photos/152274366@N08/

 

[munyonm]

My 408 ( Rosewood neck ) has been my #1 or 1a since I got it .
The pickups do have a different EQ , I call it "even" or "smooth" some would call it " flat " basically no hot spots to the EQ to my ears
I have never had the back plate off but here is mine , I would look at your ground on the tone pot it looks different.
the yellow cap ? is correct it on mine.
I would also contact PTC they can get you sorted.

I seem to remember not being able to measure mine at some point I will try again later.

It should sound like this ( I own the frost one )

IMG_8668 copy by
[url=https://flic.kr/p/2oDZ7GD]IMG_8667 copy by https://www.flickr.com/photos/152274366@N08/

Interesting, your 0.033uF capacitor between your tone and volume potentiometers isn’t sleeved either. . .

 

[BlueSky]

My 408 ( Rosewood neck ) has been my #1 or 1a since I got it .
The pickups do have a different EQ , I call it "even" or "smooth" some would call it " flat " basically no hot spots to the EQ to my ears
I have never had the back plate off but here is mine , I would look at your ground on the tone pot it looks different.
the yellow cap ? is correct it on mine.
I would also contact PTC they can get you sorted.

I seem to remember not being able to measure mine at some point I will try again later.

It should sound like this ( I own the frost one )

IMG_8668 copy by
[url=https://flic.kr/p/2oDZ7GD]IMG_8667 copy by https://www.flickr.com/photos/152274366@N08/

Interesting. I have a DiMarzio Transition set in another of my guitars and that is also described as "flat" in terms of frequencies but it's a very responsive and juicy pickup, whereas my 408 is very -- here I go again -- "lifeless". No sustain, no harmonics, really terrible.
Maybe I just got a lemon, who knows? But I'd like to know more when you say you were "not being able to measure mine at some point". Can you measure the pickups now? If so, what have you done to change this?
Well, I'm sorry I go on about this, maybe there's nothing wrong with the guitar and it just isn't for me. But when I play it unplugged, it really rings and has sustain but when plugged it it just dies on me. Really weird.
Anyway, I'll take it to a luthier/tech in a few day, so any tips what could potentially be wrong are all appreciated. Many thanks to everyone who responded so far.
I've contacted PRS customer service. I haven't heard from them so far...

 

[Broseph]

Interesting to see such unsleeved caps bridging volume and tone pots. I never cracked my 408 open while I had it. The wiring appears similar in both guitars. My experience with the 408 was that neck pickup was where the money was at! The bridge was more hi fi for me compared the more vintage aspect of the neck pickup. But it remained resonant for me even plugged in. The output is pretty high volume wise. I ran the volume around 6-7 most times when I would have been on 7-9 on other PRS.

 

[Rider1260]

Interesting. I have a DiMarzio Transition set in another of my guitars and that is also described as "flat" in terms of frequencies but it's a very responsive and juicy pickup, whereas my 408 is very -- here I go again -- "lifeless". No sustain, no harmonics, really terrible.
Maybe I just got a lemon, who knows? But I'd like to know more when you say you were "not being able to measure mine at some point". Can you measure the pickups now? If so, what have you done to change this?
Well, I'm sorry I go on about this, maybe there's nothing wrong with the guitar and it just isn't for me. But when I play it unplugged, it really rings and has sustain but when plugged it it just dies on me. Really weird.
Anyway, I'll take it to a luthier/tech in a few day, so any tips what could potentially be wrong are all appreciated. Many thanks to everyone who responded so far.
I've contacted PRS customer service. I haven't heard from them so far...

Mine has plenty of sustain and harmonics , I would first try a new set of strings , mine loves new strings.
I have the pickups even with the rings.
Sorry won't be able to measure the pickups for a week or so ;(
The bridge pickup in mine is why I love it more output and push compared to the Narrow 408 that was in both positions of my Brushstroke 24 ( 24 fret pauls guitar )

 

[BlueSky]

Just got back from the tech and problem solved!
It was that big yellow capacitor between the switch and the volume pot. The tech took it out and soldered in a wire and - voilà - now the pickups measure 9.45k (bridge) and 8.47k (neck). And most important of all: the guitar came alive. Before it was lifeless and unresponsive and now it is juicy with lots of sustain. Will do some finetuning with the pickup heights tomorrow to get more note bloom but it already sings quite nicely.
The tech was only shaking his head when he saw that capacitor. Mind you, it was not a mod, it came like this from the factory. Whoever at PRS thought this was a good idea?
Many thanks to anyone who responded, especially to munyonm for putting up the pictures.

 

[Broseph]

great news - such an odd location for a cap like that. Glad it's fixed. 408s are great guitars

 

[Rider1260]

It would be interesting to know what the Cap does ?? , why its there ??

James Skitchy Zimmers ​

 

[BlueSky]

It would be interesting to know what the Cap does ?? , why its there ??

James Skitchy Zimmers ​

Well, I can tell you what it does. It kills the guitar's dynamics and tone. I see yours has one too. I'd strongly recommend removing it and replace it with a simple wire. You can always put it back if you prefer having it in but I doubt you would want that.
PRS customer support wasn't helpful at all.

 

[Glide-bpm]

Just got back from the tech and problem solved!
It was that big yellow capacitor between the switch and the volume pot. The tech took it out and soldered in a wire and - voilà - now the pickups measure 9.45k (bridge) and 8.47k (neck). And most important of all: the guitar came alive. Before it was lifeless and unresponsive and now it is juicy with lots of sustain. Will do some finetuning with the pickup heights tomorrow to get more note bloom but it already sings quite nicely.
The tech was only shaking his head when he saw that capacitor. Mind you, it was not a mod, it came like this from the factory. Whoever at PRS thought this was a good idea?
Many thanks to anyone who responded, especially to munyonm for putting up the pictures.

Awesome!!! I knew something had to be wrong for 408 pickups to sound lifeless!!! Some of my favorite guitar pickups!!!

 

[Herr Squid]

Just got back from the tech and problem solved!
It was that big yellow capacitor between the switch and the volume pot. The tech took it out and soldered in a wire and - voilà - now the pickups measure 9.45k (bridge) and 8.47k (neck). And most important of all: the guitar came alive. Before it was lifeless and unresponsive and now it is juicy with lots of sustain. Will do some finetuning with the pickup heights tomorrow to get more note bloom but it already sings quite nicely.
The tech was only shaking his head when he saw that capacitor. Mind you, it was not a mod, it came like this from the factory. Whoever at PRS thought this was a good idea?
Many thanks to anyone who responded, especially to munyonm for putting up the pictures.

It would either seem that the original PRS recipe for the guitar didn't jive for you, or that particular guitar was messed up. Either way it's great news that it came to life for you!

 

[BlueSky]

It would either seem that the original PRS recipe for the guitar didn't jive for you, or that particular guitar was messed up. Either way it's great news that it came to life for you!

It certainly didn't jive for me. I don't think it was messed up but delivered like that from the factory and I bought it new from a reputable store. PRS must have realised that cap was a bad idea because it's gone on the latest updated diagram. The tech said it sucked out all the tone.
Anyway, very happy now with the guitar. It's like day and night.

 

[Stephen J.]

I am glad you were able to find a solution that worked for you.

One of the characteristics of the 408 guitars was the balanced output level from the single/split/tapped (whichever it was) and the humbucker selections. Did the removal of the component alter that at all?

 

[László]

It certainly didn't jive for me. I don't think it was messed up but delivered like that from the factory and I bought it new from a reputable store. PRS must have realised that cap was a bad idea because it's gone on the latest updated diagram. The tech said it sucked out all the tone.
Anyway, very happy now with the guitar. It's like day and night.

It's great that you have it sounding the way you want!

 

[bodia]

Just got back from the tech and problem solved!
It was that big yellow capacitor between the switch and the volume pot. The tech took it out and soldered in a wire and - voilà - now the pickups measure 9.45k (bridge) and 8.47k (neck). And most important of all: the guitar came alive. Before it was lifeless and unresponsive and now it is juicy with lots of sustain. Will do some finetuning with the pickup heights tomorrow to get more note bloom but it already sings quite nicely.
The tech was only shaking his head when he saw that capacitor. Mind you, it was not a mod, it came like this from the factory. Whoever at PRS thought this was a good idea?
Many thanks to anyone who responded, especially to munyonm for putting up the pictures.

That’s awesome! And huge props to everyone that tried to help. Good job, gang.

 

[BlueSky]

I am glad you were able to find a solution that worked for you.

One of the characteristics of the 408 guitars was the balanced output level from the single/split/tapped (whichever it was) and the humbucker selections. Did the removal of the component alter that at all?

Removing that cap did not affect the balanced output. There is still the treble bleed cap on the volume pot, the .033uF tone cap and the 1.1k and 2.2k resistors for the tapped humbucker. Just like on the updated 408 wiring diagram.