Advice needed...

Forum to discuss amp circuits besides the 18 Watters and their ilk.

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The4thWatcher13
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Re: Advice needed...

Post by The4thWatcher13 »

The4thWatcher13 wrote:
Sun 06/20/21 5:50 pm
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 during no play passages and seems to stay 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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Re: Advice needed...

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The4thWatcher13 wrote:
Sun 06/20/21 5:50 pm
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!
I don't think those pickups sound great. You should see if you can get access to a guitar with humbuckers or noiseless singles and see how it sounds. The noise in context with the playing isn't overbearing in the recording, but you should try something with better pickups to rule out the amp. I wouldn't tinker with the amp until you can try another guitar, or better pickups in that guitar.

Thanks,
Josh
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Re: Advice needed...

Post by The4thWatcher13 »

JMPGuitars wrote:
Sun 06/20/21 6:03 pm
The4thWatcher13 wrote:
Sun 06/20/21 5:50 pm
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!
I don't think those pickups sound great. You should see if you can get access to a guitar with humbuckers or noiseless singles and see how it sounds. The noise in context with the playing isn't overbearing in the recording, but you should try something with better pickups to rule out the amp. I wouldn't tinker with the amp until you can try another guitar, or better pickups in that guitar. Thanks, Josh
Well the guitar I've been using is my "Franken-shop" guitar, a '93 Squire that I've been trying to make into as much of a "silk purse" as possible. I've got a second tho, a '16 Strat Elite, that is doing the exact same thing as the Squire. The wiring is a bit more complicated but some switch positions are noisier than others and the overall buzz level is disheartening. And this guitar has third or fourth gen noiseless pickups. I haven't had it open yet but it needs new strings so I'm gonna crack it tonight just to make sure everything is everything. So considering that it behaves in the same fashion as the other I'm assuming it's the amp. I still have Phil's timely warning ringing in my ears about transformer proximity and or orientation. But no shielding efforts have resulted in a solution so far. Other observations: as mentioned before there is sometimes a "flick flick...flick flick flick" sound that comes through the amp. It usually doesn't last long but it's weird. So I think there might be other things going on here. Either way I'm in it to win it. Thanks Josh
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Re: Advice needed...

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The4thWatcher13 wrote:
Sun 06/20/21 8:27 pm
Well the guitar I've been using is my "Franken-shop" guitar, a '93 Squire that I've been trying to make into as much of a "silk purse" as possible. I've got a second tho, a '16 Strat Elite, that is doing the exact same thing as the Squire. The wiring is a bit more complicated but some switch positions are noisier than others and the overall buzz level is disheartening. And this guitar has third or fourth gen noiseless pickups. I haven't had it open yet but it needs new strings so I'm gonna crack it tonight just to make sure everything is everything. So considering that it behaves in the same fashion as the other I'm assuming it's the amp. I still have Phil's timely warning ringing in my ears about transformer proximity and or orientation. But no shielding efforts have resulted in a solution so far. Other observations: as mentioned before there is sometimes a "flick flick...flick flick flick" sound that comes through the amp. It usually doesn't last long but it's weird. So I think there might be other things going on here. Either way I'm in it to win it. Thanks Josh
Standing by...
Ah, okay. If you have a guitar with noiseless pups doing the same thing, then it's time to inspect the amp.

Unfortunately, if it is the transformers causing the noise, it could be their physical position contributing to it. The relationship between the transformer position from one transformer to the next is very sensitive. Usually when working with a new design, it's best not to mount the transformers completely until you know how they will behave.

The other thing to consider is that PTP builds are often much harder to deal with noise issues. You need to consider your lead dress, and the position of everything in the amp.

What does it sound like if you have the amp on, with no guitar or instrument cable plugged in? What does it sound like when the cable is plugged in?

Thanks,
Josh
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Re: Advice needed...

Post by TriodeLuvr »

It's not the transformers. The shielding (copper tape and/or steel boxes) would have made a significant difference if that was the case.
there is sometimes a "flick flick...flick flick flick" sound that comes through the amp. It usually doesn't last long
Do you mean it goes away after the amp warms up? Tubes and coupling caps can both do something similar. I'd like to hear it.

Jack
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Re: Advice needed...

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JMPGuitars wrote:
Sun 06/20/21 9:46 pm
Ah, okay. If you have a guitar with noiseless pups doing the same thing, then it's time to inspect the amp.
Unfortunately, if it is the transformers causing the noise, it could be their physical position contributing to it. The relationship between the transformer position from one transformer to the next is very sensitive. Usually when working with a new design, it's best not to mount the transformers completely until you know how they will behave.
The other thing to consider is that PTP builds are often much harder to deal with noise issues. You need to consider your lead dress, and the position of everything in the amp.
What does it sound like if you have the amp on, with no guitar or instrument cable plugged in? What does it sound like when the cable is plugged in? Thanks, Josh
When the amp is turned on with no cable inserted there is no noise or sound whatsoever until you turn the amp volume to "10", and even then you have to put your ear up the the speaker to hear a very soft low frequency hum. When a guitar is plugged in it works like this:
Single pickup switch positions only
Guitar on 5 and the amp on 10 = bad buzz
Guitar on 10 and the amp on 5= bad buzz
Guitar on 5 and the amp on 5 = low, acceptable buzz; 1/2 vol. :evil:
Dual coil switch positions:
Guitar on 10 and amp on 10 = the expected soft, quiet "airy" amp sound. All other guitar and amp levels produce no discernible buzz.

Unfortunately I don't have a guitar with humbuckers but I might be able to borrow one if it's really necessary. If things were a little better around here this would be more than enough reason to have me out at the store scoping Les Paul's or SG's! :D
Thanks Josh!
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Re: Advice needed...

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The4thWatcher13 wrote:
Mon 06/21/21 2:58 pm
When the amp is turned on with no cable inserted there is no noise or sound whatsoever until you turn the amp volume to "10", and even then you have to put your ear up the the speaker to hear a very soft low frequency hum. When a guitar is plugged in it works like this:
Single pickup switch positions only
Guitar on 5 and the amp on 10 = bad buzz
Guitar on 10 and the amp on 5= bad buzz
Guitar on 5 and the amp on 5 = low, acceptable buzz; 1/2 vol. :evil:
Dual coil switch positions:
Guitar on 10 and amp on 10 = the expected soft, quiet "airy" amp sound. All other guitar and amp levels produce no discernible buzz.

Unfortunately I don't have a guitar with humbuckers but I might be able to borrow one if it's really necessary. If things were a little better around here this would be more than enough reason to have me out at the store scoping Les Paul's or SG's! :D
Thanks Josh!
It sounds like you do need to try a guitar with humbuckers, though the noiseless pups shouldn't have the buzz...but they say F*nder on them, so I won't expect them to live up to anything. ;)

I meant to plug a cable in with nothing attached. Or alternatively you could disconnect the shunt to ground on the input jack and hear what kind of noise the amp makes with nothing plugged in, but the input not grounded out.

Thanks,
Josh
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Re: Advice needed...

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JMPGuitars wrote:
Tue 06/22/21 6:15 am
It sounds like you do need to try a guitar with humbuckers, though the noiseless pups shouldn't have the buzz...but they say F*nder on them, so I won't expect them to live up to anything. ;)
I meant to plug a cable in with nothing attached. Or alternatively you could disconnect the shunt to ground on the input jack and hear what kind of noise the amp makes with nothing plugged in, but the input not grounded out. Thanks, Josh
Hey guys! My "filaments" haven't dimmed just yet and I'm still here. I just had to deal with some stuff around here that couldn't wait any longer. I did what Josh asked and plugged in a cable, turned the amp on and there was the expected buzz even without touching the tip of the cable. The odd thing was that if I moved the unplugged cable end around the amp I could sort of get an idea what the shape of the electromagnetic field was. I decided to completely wrap the isolation transformer in shielding and that did help a tad. Another odd thing was that the most quiet place for the bare end of the cable was the dead center of the top of the amp, right in between the two transformers and the tubes! Interesting. Anyway, I almost went out and bought a guitar with humbuckers last weekend but I accidentally transferred money to the wrong account by mistake and had to wait until this week to remedy it. :oops: I took that as a sign and decided I'm going to borrow a guitar from a friend to see how it behaves with a dual coil guitar. When I do that I'll be back with a report. Thanks again for all your help and I hope things are well for you all. M
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Re: Advice needed...

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The4thWatcher13 wrote:
Thu 07/01/21 8:00 pm
I did what Josh asked and plugged in a cable, turned the amp on and there was the expected buzz even without touching the tip of the cable.
This can be useful as a sensitive probe to determine the location of AC fields (as you discovered), but it doesn't help much in determining whether those fields are excessively strong. There are just too many things that affect the amplifier's response to the open cable. It might be more meaningful if the far end of the cable was terminated with a resistor approximately equivalent to the impedance of the pickups, but even that doesn't necessarily create a useful reference. The only real reference available to the average person is a known-good guitar (which you're pursuing) or second best, a known-good amplifier.
I decided to completely wrap the isolation transformer in shielding and that did help a tad.
None of the experiments you've done point to the amp or the transformers as the culprits. Just the opposite, in fact. If shielding the transformers doesn't create a significant difference, they're not the problem. Also, about something you said earlier, don't worry about shields on the output tubes. They're mostly self-shielding because the anodes encircle the other components. Whatever small AC voltage might be induced on the anodes from an external source is working against the anode resistance, the load impedance, and is additionally stepped down by the ratio of the output transformer.

I think you're on the right path now, and a guitar that's less sensitive to this will almost certainly resolve the issue.

Jack
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Re: Advice needed...

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Thanks, Jack. I'm trying really hard to find an excuse to buy a Les Paul. Maybe not a Gibson, which I certainly would like, but definitely a dual coil axe. There is some nice stuff out there to be had and I've found taking your time searching can really pay off in the end! (yes, I've been looking,..a lot!) :D I've got a buddy that's one of the local guitar/tech Gods and he said "dude, those are the Single Coil Blues! Not much you can do about it. Been a problem since the beginning."
So, yeah, you can only do what you can do. But I'll keep at it.
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Re: Advice needed...

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The4thWatcher13 wrote:
Fri 07/02/21 10:12 pm
Thanks, Jack. I'm trying really hard to find an excuse to buy a Les Paul. Maybe not a Gibson, which I certainly would like, but definitely a dual coil axe. There is some nice stuff out there to be had and I've found taking your time searching can really pay off in the end! (yes, I've been looking,..a lot!) :D I've got a buddy that's one of the local guitar/tech Gods and he said "dude, those are the Single Coil Blues! Not much you can do about it. Been a problem since the beginning."
So, yeah, you can only do what you can do. But I'll keep at it.
I'm not a big fan of Gibson quality control (at all really, since there isn't any). I do like my CS-356 a lot, but it's the best guitar they ever made. I don't like that I'm paranoid about the headstock deciding to spontaneously combust.

PRS makes better LPs than Gibson does, including their S2 and SE models if you're on a budget. If you buy an SE, you could swap out the pickups for anything you want.

ESP/LTD also makes good LP shaped guitars (specifically the EC-1000 models), but don't get EMG pickups, they're 1 trick ponies, and not awesome. I guess you could swap those out too if you get a good deal. ;)

Thanks,
Josh
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Re: Advice needed...

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JMPGuitars wrote:
Sat 07/03/21 9:32 am
I'm not a big fan of Gibson quality control (at all really, since there isn't any). I do like my CS-356 a lot, but it's the best guitar they ever made. I don't like that I'm paranoid about the headstock deciding to spontaneously combust.
*PRS makes better LPs than Gibson does, including their S2 and SE models if you're on a budget. If you buy an SE, you could swap out the pickups for anything you want.
*ESP/LTD also makes good LP shaped guitars (specifically the EC-1000 models), but don't get EMG pickups, they're 1 trick ponies, and not awesome. I guess you could swap those out too if you get a good deal. ;) Thanks, Josh
Thanks for the info, Josh. I looked up that CS-356. That guitar costs more than some of the cars I've had! It's a real beauty tho. 8)
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Re: Advice needed...

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The best les Paul I had was a 2004 PRS singlecut. Although it was a superb instrument I sold it year later for it didn't suit me lookwise. It's too clean and posh.. I like simple and oldskool. That jazzmaster I built is my thang! It sports a P90 in the bridge.. It's somewhat noisy but perfect.
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Re: Advice needed...

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The4thWatcher13 wrote:
Sat 07/03/21 1:51 pm
Thanks for the info, Josh. I looked up that CS-356. That guitar costs more than some of the cars I've had! It's a real beauty tho. 8)
Lol, yeah, that's one of the reasons the Epiphone AlleyKat I replaced all the hardware/electronics on gets more use. ;)

That, and the DiMarzio pickups I put in it sound better than anything I've ever heard from Gibson.
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Re: Advice needed...

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Well, I went an did it. It took me three months but a deal came by and I pulled the trigger! So now I'm the proud owner of a 2012 "R-body", Les Paul Standard Plus Premium, or something like that. Slightly modified with Reverend Rail Hammer pickups, Grover locking tuners and Tone Pro jack. The rest is Switch craft and Alpha.
Hooked it up to my little amp and voila, no hum what so ever. And it sounds pretty darn good and it's loud! I have the amp plugged into a Fender Blues Jr. cab with no amp that I use for, whatever, and the amp has a fair bit of growl through the 12"in. speaker. I can't do a recording right now but will in the near future. I'm every appreciative to all here who've helped me this far. Some tweaks may be needed in the future but we'll see. I'll have to let a few of my buddies play it and see what they say. A proper head case is in the making as well currently also. I think it's a little heavy on the low freq throughout the range of the tone control but it may just be the p'ups. I'll have to listen more critically later. Tonight it's all about fun and gratitude!
Thanks again,
Mark
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