Advice needed...

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TriodeLuvr
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Re: Advice needed...

Post by TriodeLuvr »

Just to clarify something I said earlier, here's a diagram to show what I meant regarding input stage grounding. I don't know why all the TW diagrams show the input jack grounded, but that's not how I would do it. For one thing, there's no reason to have signal and DC current from the cathode traveling on the shield conductor. Grounding at the cathode end eliminates that while still preventing a ground loop. Didn't want my earlier comment about the "floating" input jack to be misconstrued. It's not really floating, it just isn't grounded directly with a separate wire. :)

Image

About the transformers, you could experiment by covering each one with a tin can. Just slip the can(s) over the transformers and see what effect the shielding has on the hum. Aluminum might work (it depends on the nature of the field), but steel will offer a better test. Also be sure you have the tube shields in place for any work regarding hum. If this experiment proves beneficial, something more permanent can be fabricated. Don't forget what Josh said, too, about the pickups. The fact that it's clean without the guitar plugged in and when the guitar is at a distance from the amp might imply that this is mostly the fault of the guitar. There's nothing wrong with shielding the amp more effectively, but the guitar might be the final limit for reducing the noise.

Jack
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The4thWatcher13
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Re: Advice needed...

Post by The4thWatcher13 »

Hey guys, just a quick note on what I've been up to and some observations. Firstly I tried the shielded grid wire grounding scheme detailed by Jack. A shielded lead grounded at the jack and cathode only. The only ground connection for the jack being through the shield to the cathode ground. But it didn't work well at all. Probably because of the tube socket orientation, i.e. the cathode ground lead length from the grid pin's position. So I switched it back to the 18W lite2b scheme provided by Josh. I also went after my shop Strat with a vengeance to try to eliminate it as a potential source of my woes. All wiring and grounding was checked and cleaned up. The wiring scheme is that of a 1960's Fender Strat, schematic provided by Fender. Pretty basic. All cavities and pick guard are properly shielded and grounded. The results were good. But an interesting issues arises; (aside from another issue that I'll describe momentarily) the amp with the serviced guitar is very quiet at full vol and with guitar at full vol also, just the way I'd like it. Except, when the 5 way pickup selection switch is in positions 1, 3 & 5, it buzzes like usual!
I'm hoping someone has experienced this before and has some idea of what is going on. I feel like we're close.
The other issue is that there is a "flicking" sound from time to time when it is buzzing. That's the only way I can describe it. Like someone is flicking a few pages of paper. Not very loud, and not a tick, but a flick. I've tried different 12AX7 tubes as well lately with varying results. All were tested as good to very good. But some initiated or reinforced oscillations or possibly feedback of some kind. I stopped at that point, being a new "issue", and replaced the original NOS RCA 12AX7 and decided to revisit that occurrence later.
That's about it for now. I guess it wasn't a "quick note" but I do like to be as clear about things as I can. I'll be return to testing momentarily. One more thing: I've tried the tin can over the transformers deal and I don't think it helped at all. I also came up with an interesting contraption, seen below not "installed" just staged, as a potential trans shield. It's three modular light switch boxes muxed together! It fits perfectly and actually looks kinda cool. But again it doesn't seem to have any affect on the buzz. So I'm at a loss for the moment but I refuse to give up! Thanks again guys, I appreciate your help all the way.
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Re: Advice needed...

Post by JMPGuitars »

From your description, it sounds like you may have a bad solder connection. Could be in the guitar, and possibly a bad ground as well.

But if you have classic F*nder wiring, then it's also very likely that your wiring in your guitar is actually a ground loop. In positions 2 and 4, you should be hum cancelling, so you may not notice the noise as much. But as you said, in 1,3, and 5, you're not cancelling the hum, so you're quite likely enhancing the hum.

Show me a couple photos of the inside of your guitar.

Thanks,
Josh
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The4thWatcher13
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Re: Advice needed...

Post by The4thWatcher13 »

JMPGuitars wrote:
Wed 06/16/21 8:15 pm
Show me a couple photos of the inside of your guitar. Thanks, Josh
Man, I hate putting a new set of strings on, stretching them, tuning them, playing them and going, "..nice", and then cutting them off! :lol: Well,...I guess I hate the buzz more so...
(Note to self: take pics of the inside of everything and buy a BOX of strings next time!)
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Re: Advice needed...

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The4thWatcher13 wrote:
Thu 06/17/21 8:07 pm
JMPGuitars wrote:
Wed 06/16/21 8:15 pm
Show me a couple photos of the inside of your guitar. Thanks, Josh
Man, I hate putting a new set of strings on, stretching them, tuning them, playing them and going, "..nice", and then cutting them off! :lol: Well,...I guess I hate the buzz more so...
(Note to self: take pics of the inside of everything and buy a BOX of strings next time!)
Seriously? I find restringing to be a very satisfying time 💅
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Re: Advice needed...

Post by The4thWatcher13 »

Bieworm wrote:
Fri 06/18/21 7:30 am
The4thWatcher13 wrote:
Thu 06/17/21 8:07 pm
JMPGuitars wrote:
Wed 06/16/21 8:15 pm
Show me a couple photos of the inside of your guitar. Thanks, Josh
Man, I hate putting a new set of strings on, stretching them, tuning them, playing them and going, "..nice", and then cutting them off! :lol:
Seriously? I find restringing to be a very satisfying time 💅
Yeah, I can agree, but It's the whole putting them on and cutting them off again pretty much right away due to not having done the electrics right part that's a bummer. But then I get to put new ones on again, and we're back to satisfaction! :)
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Re: Advice needed...

Post by JMPGuitars »

The4thWatcher13 wrote:
Fri 06/18/21 11:38 am
Yeah, I can agree, but It's the whole putting them on and cutting them off again pretty much right away due to not having done the electrics right part that's a bummer. But then I get to put new ones on again, and we're back to satisfaction! :)
Don't rush to put them back on. I'm likely to suggest you change some things. ;)
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Re: Advice needed...

Post by The4thWatcher13 »

Well, here we go. Pics of the inside of the Squire. I immediately see something that may be suspect in light of Josh's statements. That being the bridge ground, which is soldered to the shielding inside the pickup cavity.
Don't know why I did that, it was years ago. I'm assuming not a good idea when the jack cavity is grounded to the main cavity and the bridge ground goes to the Vol pickup anyway. This is dual conductivity copper tape, by the way, and the entire shield is "connected". And thanks for warning me about re-stringing right away. I'm in standby mode, bro. Let me know if you need better pics. Thanks Josh!
PS. the blue wire (jack ground) and the bridge ground wire (black) aren't connected to the vol pot at the moment)
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Re: Advice needed...

Post by JMPGuitars »

Cut those black wires out that do nothing besides connecting the pots to each other. That's your biggest ground loop. The shielding is already connecting them to each other.

I would connect your output ground and the bridge ground to the same point, preferably on the volume pot, but doesn't have to be.

Thanks,
Josh
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Re: Advice needed...

Post by The4thWatcher13 »

JMPGuitars wrote:
Fri 06/18/21 4:09 pm
Cut those black wires out that do nothing besides connecting the pots to each other. That's your biggest ground loop. The shielding is already connecting them to each other. I would connect your output ground and the bridge ground to the same point, preferably on the volume pot, but doesn't have to be. Thanks, Josh
Oh man, in regard to that ground lead from pot to pot, I didn't stop to think that the 60's & 70's Strats didn't have shielding and therefore needed the ground lead! :oops: Taking it out now. Can testing for the results of the current repair be tested without strings? Are there other common "stringless" tests that folks do to avert having to waste a pair of strings when they're doing electrical mods or repairs?
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Re: Advice needed...

Post by The4thWatcher13 »

Okie dokie, I think I have reasonable excuse to be excited. I made the changes Josh stated and voila, with the guitar (stringless) on "10" and the amp on "10" I can truly say it's dead quite. No buzz no proximity EI and yes, I tapped the pickups to make sure it was on! :lol: I think it's safe to restring it unless Josh has some Jedi tricks up his sleeve for me!
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Re: Advice needed...

Post by JMPGuitars »

It sounds like you're ready to rock. Record a demo. With strings. ;)
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Re: Advice needed...

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JMPGuitars wrote:
Sat 06/19/21 7:16 am
It sounds like you're ready to rock. Record a demo. With strings. ;)
Argh! I'm not ready to rock! :cry: After putting strings back on the same situation presents itself. Serious buzz on single coil switch positions, no buzz on dual coil. I replaced the bridge ground lead so it's only connected to Vol pot. And the jack ground is soldered to the Vol pot as well.
Please tell me if the following is OK: the shielding inside the jack well is grounded to the pickup cavity via soldered wire. Which is the way it's always been. But the pickup cavity shielding is now only connected to the common ground by a physical connection to the shielding on the rear of the pick guard when screwed down. Seeing that we were attempting to eliminate potential ground loops, as stated above, I replaced the bridge ground lead with one only connected to the Vol pot. In the pic above you can see how it was originally soldered to the pickup cavity on it's way to the Vol pot.
(I know it can be hard to help someone when they're changing things, without prompting, that may or may not make a difference; I'll try to restrain myself further. Apologies)
Audio sample of selector switch below.
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Re: Advice needed...

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The4thWatcher13 wrote:
Sat 06/19/21 6:06 pm
JMPGuitars wrote:
Sat 06/19/21 7:16 am
It sounds like you're ready to rock. Record a demo. With strings. ;)
Argh! I'm not ready to rock! :cry: After putting strings back on the same situation presents itself. Serious buzz on single coil switch positions, no buzz on dual coil. I replaced the bridge ground lead so it's only connected to Vol pot. And the jack ground is soldered to the Vol pot as well.
Please tell me if the following is OK: the shielding inside the jack well is grounded to the pickup cavity via soldered wire. Which is the way it's always been. But the pickup cavity shielding is now only connected to the common ground by a physical connection to the shielding on the rear of the pick guard when screwed down. Seeing that we were attempting to eliminate potential ground loops, as stated above, I replaced the bridge ground lead with one only connected to the Vol pot. In the pic above you can see how it was originally soldered to the pickup cavity on it's way to the Vol pot.
(I know it can be hard to help someone when they're changing things, without prompting, that may or may not make a difference; I'll try to restrain myself further. Apologies)
Audio sample of selector switch below.
Remove the shielding from the jack well. Check for continuity between the bridge and the pots (keep the guitar closed, just check under the knobs). There should be continuity between the bridge and tuners, and the jack plate and bridge as well. Assuming that's all good, make another recording in a buzzy position, and touch the strings, and let go of the strings a few times.

After you make the string-touching/not touching recording, just play a little and see how it sounds on the recording also. A big question is the difference between playing volume and the guitar noise.

It's quite likely you simply have slightly noisy pickups, and that noise is being amplified. What I heard in that recording doesn't sound terrible, though I'm not a fan, so I only use noiseless pickups. Lace and DiMarzio make my favorites (I'm a dealer for both, and a few other brands), but the lead time on getting anything from DiMarzio right now is cuckoo. I ordered stuff in November, and I think April, and I'm still waiting on both orders.

Thanks,
Josh
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Re: Advice needed...

Post by The4thWatcher13 »

JMPGuitars wrote:
Sun 06/20/21 7:51 am
Remove the shielding from the jack well. Check for continuity between the bridge and the pots (keep the guitar closed, just check under the knobs). There should be continuity between the bridge and tuners, and the jack plate and bridge as well.

Shielding and connecting lead has been removed from the jack cavity. There is continuity between the bridge, jack plate, tuners and all pots.
JMPGuitars wrote:
Sun 06/20/21 7:51 am
Assuming that's all good, make another recording in a buzzy position, and touch the strings, and let go of the strings a few times. After you make the string-touching/not touching recording, just play a little and see how it sounds on the recording also. A big question is the difference between playing volume and the guitar noise.
Recording provided below. There is no noticeable change in the buzz when the strings are muted and when they're not. While I'm playing the buzz can still be heard at a constant level. I'll note again that regardless of where I stand in the room the buzz fades to a basically unnoticeable level when I'm standing in front or to the side of the speaker on a 45 deg. axis to the speaker. (that is at 2:00 or 8:00 so to speak) Shields are on V1 & V2. I've only got one EBY TS10U03 shield that'll fit the 6CU5 tubes but haven't been able to find another one anywhere.
JMPGuitars wrote:
Sun 06/20/21 7:51 am
It's quite likely you simply have slightly noisy pickups, and that noise is being amplified. What I heard in that recording doesn't sound terrible, though I'm not a fan, so I only use noiseless pickups. Lace and DiMarzio make my favorites (I'm a dealer for both, and a few other brands), but the lead time on getting anything from DiMarzio right now is cuckoo. I ordered stuff in November, and I think April, and I'm still waiting on both orders. Thanks, Josh
You may be right about the pickups. I bought them from a guy on Craigs years ago. They came in the Fender box et, al. I compared them to images online and I think they're the real deal, tho this may be why the guy sold 'em! Thanks again Josh!
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