5E3 help please

Adam Waldron · October 17th, 2007, 09:33 PM

Hey folks,

I recently picked up a 5E3 Deluxe built up from a Weber kit. Now, the amp sounds fantastic but I am plauged by what I think is low level motorboating.

The noise is there when all controls are set to zero. When I turn the amp up to operating levels of '3' or more, the amps natural hiss makes the motorboating practically inaudible. With a guitar plugged it, the noise is well and truly drowned out by the 60 cycle hum I am well used to with Fenders.

The problem is intermittant.

I was experiencing intermittant popping which eventually rendered the amp unplayable. This would occur when I'd play after the tubes the tubes got up to full operating temperature, but that has been sorted with a power tube change.

Hope someone can help, this problem has become frustrating and is driving me to distraction!

Cheers,

Adam

Natstrat79 · October 17th, 2007, 10:08 PM

I'll assume you are familiar with working with tube amps? If not take it to a tech. I suppose a few easy things to check would be how neat is the lead dress. Messy wiring could be part of the problem if this kit was built by an inexperienced builder. It sounds as if you're not the original builder. You might also download the schematic and layout from weber and see if you can track down any errors maybe a resistor of the wrong value in the B+ rail or something like that.

Dacious · October 17th, 2007, 11:33 PM

Try swapping the two leads that run to pin 3 of the power tubes. This might be difficult depending on how the amp is laid out. You might also just have bad connections on the filter caps. If this is the traditional Fender layout there is an underboard wire to the third cap. This is easy to partly dislodge when making the above-board connections.

Foreign Made · October 18th, 2007, 12:08 AM

Howdy Adam

I can't quite see how swapping the OT/pin3 leads will help as the 5E3 does not have a neg-feedback loop, I'd like to know more from "Dacious" on that one. I'm ever keen to learn.

But I'd suspect the filter-caps, good idea to check with the DDM that the -ve side of each in turn is zero resistance to earth/chassis, that'll check the under board connection without having to remove the board.

Upgrade them Weber supplied caps to Sprague Atoms in any case.

Also check that all the resistors in the power section read true.

And keep it old skool and raw!

Adios amigo.

zook · October 18th, 2007, 07:20 AM

Quote:

Originally Posted by Foreign Made

Howdy Adam

I can't quite see how swapping the OT/pin3 leads will help as the 5E3 does not have a neg-feedback loop, I'd like to know more from "Dacious" on that one. I'm ever keen to learn.

Agreed, this is not the issue

Quote:

But I'd suspect the filter-caps, good idea to check with the DDM that the -ve side of each in turn is zero resistance to earth/chassis, that'll check the under board connection without having to remove the board.

Upgrade them Weber supplied caps to Sprague Atoms in any case.

This would make no difference, the filter caps are fine as they are. Nothing magical about Sprague caps except the high proce.

Quote:

Also check that all the resistors in the power section read true.

Even a 20% difference wouldn't cause motorboating.

Quote:

And keep it old skool and raw!

Adios amigo.

I'd suspect lead dress. Move the wires about with a non conductive probe (I use a 1/4" dowell sharpened in a pemcil sharpener) and mpve the wires about gently while the amp is on (keep one hand in your pocket)

Winnie

Lance · October 19th, 2007, 07:42 AM

Zook's right on this. It's not tubes. You've got an occilation problem that probably due to how the wires were routed (dressed). There's a lot of pictures out there on 5E3 wiring. Compare your layout with the others and see if there's places where you've done it differently. Focus especially around the early preamp stage of the amp. On my amp, I literally copied the exact placement and twist that I saw in the pictures.

Chris Callahan · October 19th, 2007, 10:44 AM

I had a nasty hum in my homebrew/spare parts 5E3 that was fixed by moving the ground of the filter cap farthest from the input further away from the input.
I realize that's not your issue but it certainly pointed out to me how much the placement of a ground can affect the noise floor of the amp.

Adam Waldron · October 19th, 2007, 11:39 PM

Thanks for the responses and help thus far fellas.

I didn't build this amp.

No amount of poking or prodding with a chopstick changed the nature of or stopped this low level rapid 'put put'. No other odd noises were generated while having a real good poke around inside the amp.

What is interesting is that the amp doesn't do it immediately, it needs half a minute or so of warming up then the noise occurs.

Anyone have a link to a shot of ideal 5E3 lead dress?

Thanks,

Adam

JohnnyCrash · October 20th, 2007, 12:25 AM

Lead dress should be short (enough to get from one poijnt to the other). Any wires crossing it should be at a 90 degree angle. Solders should be shiny and none of them should be dull in color, if so they are cold solders and need to be resoldered or reheated.

Check all of the solders to make sure they're not cold solders OR poor connections.

BE VERY CAREFULL AS HIGH VOLTAGE IS PRESENT IN EVEN AN UNPLUGGED AMP.

It could be a few things, including bad solders or crappy tubes... sometimes a heated tube even makes solders sort of looser (heat expands, etc) and I've experienced this myself in my early days of amp building.

Read up on safety FIRST, then get a soldering iron and start up on looking for the usual trouble spots.

Adam Waldron · October 21st, 2007, 11:28 AM

Hey folks,

Thanks for the safety warnings. I am new to working on tube amps but did a lot of reading before going in. I check and check again with a DMM, and discharge the caps if needed.

The saga continues, I have spent a lot of this weekend fiddling with the amp. Many hours checking stuff with the DMM, and poking and prodding. I have been right through the circuit with a chopstick. Some of the junctions generated crackles when prodded. I have re-flowed the soldering on much of the tagboard.

Checked all grounds, checked all underboard wiring. All checks out ok. Voltage on the tubes is right on.

What now has me perplexed is today I discovered two different sets of symptoms depending on which pair of power valves are in the amp!

Reflektors:
Amp is silent at idle - no popping, rustling or crackling. Popping is generated when a loud chord is played, and stops sometime after decay. Amp settles down to quiet again.

AELs:
Popping at idle, crackling, rustling. I did witness visible arcing on the plate of one tube. Crank the amp and the guitar, play it, sounds great, noises are drowned out. Amp is playable, but is a noisy little bugger at idle.

I have swapped between the two sets of power tubes numerous times, the symptoms are fully repeatable in each instance!!

Anyway, I have a new set of TungSols on the way. Will see how they fare.

Cheers,

Adam

jjmantele · October 21st, 2007, 07:15 PM

Sounds like a few problems. I would try replacing the cathode resistor on the power tubes and tossing the arcing tube in the trash.

Adam Waldron · October 30th, 2007, 10:12 PM

Well, the TungSols are in. I have also desoldered and resoldered a number of dodgy looking joints. Had a real good look around. All tidy now.

The amp is functioning perfectly. No pops, no noises, no motorboating, quiet at idle. Just pure tone. The TungSols are loud and just sing. Loads of bottom end, first time I have heard the cabinet shake like this.

Great sustain, note bloom and touch sensitivity.

Cheers,

Adam

October 17th, 2007, 09:33 PM	#1 (permalink)
Adam Waldron Tele-Holic Join Date: Mar 2003 Location: Adelaide, Australia Posts: 607	5E3 help please Hey folks, I recently picked up a 5E3 Deluxe built up from a Weber kit. Now, the amp sounds fantastic but I am plauged by what I think is low level motorboating. The noise is there when all controls are set to zero. When I turn the amp up to operating levels of '3' or more, the amps natural hiss makes the motorboating practically inaudible. With a guitar plugged it, the noise is well and truly drowned out by the 60 cycle hum I am well used to with Fenders. The problem is intermittant. I was experiencing intermittant popping which eventually rendered the amp unplayable. This would occur when I'd play after the tubes the tubes got up to full operating temperature, but that has been sorted with a power tube change. Hope someone can help, this problem has become frustrating and is driving me to distraction! Cheers, Adam

October 17th, 2007, 11:33 PM	#3 (permalink)
Dacious Friend of Leo's Join Date: Mar 2003 Location: Godzone Posts: 2,612 35 Photos	Try swapping the two leads that run to pin 3 of the power tubes. This might be difficult depending on how the amp is laid out. You might also just have bad connections on the filter caps. If this is the traditional Fender layout there is an underboard wire to the third cap. This is easy to partly dislodge when making the above-board connections. __________________ My other Telecaster is a Thinline The Tele Bible, Ch 1, v 10 Love thy Telecaster, covet not thy neighbour's Strat!

October 19th, 2007, 07:42 AM	#6 (permalink)
Lance Friend of Leo's Join Date: Mar 2003 Posts: 2,180	Zook's right on this. It's not tubes. You've got an occilation problem that probably due to how the wires were routed (dressed). There's a lot of pictures out there on 5E3 wiring. Compare your layout with the others and see if there's places where you've done it differently. Focus especially around the early preamp stage of the amp. On my amp, I literally copied the exact placement and twist that I saw in the pictures. __________________ Lance "not very good...but I make up for it by playing loud"

October 19th, 2007, 10:44 AM	#7 (permalink)
Chris Callahan Tele-Meister Join Date: Nov 2006 Location: Tucson AZ Age: 44 Posts: 416	I had a nasty hum in my homebrew/spare parts 5E3 that was fixed by moving the ground of the filter cap farthest from the input further away from the input. I realize that's not your issue but it certainly pointed out to me how much the placement of a ground can affect the noise floor of the amp. __________________ Chris

October 19th, 2007, 11:39 PM	#8 (permalink)
Adam Waldron Tele-Holic Join Date: Mar 2003 Location: Adelaide, Australia Posts: 607	Next installment Thanks for the responses and help thus far fellas. I didn't build this amp. No amount of poking or prodding with a chopstick changed the nature of or stopped this low level rapid 'put put'. No other odd noises were generated while having a real good poke around inside the amp. What is interesting is that the amp doesn't do it immediately, it needs half a minute or so of warming up then the noise occurs. Anyone have a link to a shot of ideal 5E3 lead dress? Thanks, Adam

October 17th, 2007, 10:08 PM	#2 (permalink)
Natstrat79 Tele-Meister Join Date: Jul 2007 Location: Iowa Posts: 152	I'll assume you are familiar with working with tube amps? If not take it to a tech. I suppose a few easy things to check would be how neat is the lead dress. Messy wiring could be part of the problem if this kit was built by an inexperienced builder. It sounds as if you're not the original builder. You might also download the schematic and layout from weber and see if you can track down any errors maybe a resistor of the wrong value in the B+ rail or something like that.

October 18th, 2007, 12:08 AM	#4 (permalink)
Foreign Made Tele-Meister Join Date: May 2006 Location: on the floor, drunk; in New Zealand Posts: 152	Howdy Adam I can't quite see how swapping the OT/pin3 leads will help as the 5E3 does not have a neg-feedback loop, I'd like to know more from "Dacious" on that one. I'm ever keen to learn. But I'd suspect the filter-caps, good idea to check with the DDM that the -ve side of each in turn is zero resistance to earth/chassis, that'll check the under board connection without having to remove the board. Upgrade them Weber supplied caps to Sprague Atoms in any case. Also check that all the resistors in the power section read true. And keep it old skool and raw! Adios amigo.

October 20th, 2007, 12:25 AM	#9 (permalink)
JohnnyCrash Poster Extraordinaire Join Date: Mar 2005 Location: Lost Angeles and Orange County Posts: 7,128	Lead dress should be short (enough to get from one poijnt to the other). Any wires crossing it should be at a 90 degree angle. Solders should be shiny and none of them should be dull in color, if so they are cold solders and need to be resoldered or reheated. Check all of the solders to make sure they're not cold solders OR poor connections. BE VERY CAREFULL AS HIGH VOLTAGE IS PRESENT IN EVEN AN UNPLUGGED AMP. It could be a few things, including bad solders or crappy tubes... sometimes a heated tube even makes solders sort of looser (heat expands, etc) and I've experienced this myself in my early days of amp building. Read up on safety FIRST, then get a soldering iron and start up on looking for the usual trouble spots.

October 21st, 2007, 11:28 AM	#10 (permalink)
Adam Waldron Tele-Holic Join Date: Mar 2003 Location: Adelaide, Australia Posts: 607	The latest Hey folks, Thanks for the safety warnings. I am new to working on tube amps but did a lot of reading before going in. I check and check again with a DMM, and discharge the caps if needed. The saga continues, I have spent a lot of this weekend fiddling with the amp. Many hours checking stuff with the DMM, and poking and prodding. I have been right through the circuit with a chopstick. Some of the junctions generated crackles when prodded. I have re-flowed the soldering on much of the tagboard. Checked all grounds, checked all underboard wiring. All checks out ok. Voltage on the tubes is right on. What now has me perplexed is today I discovered two different sets of symptoms depending on which pair of power valves are in the amp! Reflektors: Amp is silent at idle - no popping, rustling or crackling. Popping is generated when a loud chord is played, and stops sometime after decay. Amp settles down to quiet again. AELs: Popping at idle, crackling, rustling. I did witness visible arcing on the plate of one tube. Crank the amp and the guitar, play it, sounds great, noises are drowned out. Amp is playable, but is a noisy little bugger at idle. I have swapped between the two sets of power tubes numerous times, the symptoms are fully repeatable in each instance!! Anyway, I have a new set of TungSols on the way. Will see how they fare. Cheers, Adam

October 21st, 2007, 07:15 PM	#11 (permalink)
jjmantele Tele-Holic Join Date: Aug 2003 Location: New Jersey Posts: 850	Sounds like a few problems. I would try replacing the cathode resistor on the power tubes and tossing the arcing tube in the trash. __________________ JJman If it says "Vintage" on it -it isn't.

October 30th, 2007, 10:12 PM	#12 (permalink)
Adam Waldron Tele-Holic Join Date: Mar 2003 Location: Adelaide, Australia Posts: 607	5E3 amp is sorted! Well, the TungSols are in. I have also desoldered and resoldered a number of dodgy looking joints. Had a real good look around. All tidy now. The amp is functioning perfectly. No pops, no noises, no motorboating, quiet at idle. Just pure tone. The TungSols are loud and just sing. Loads of bottom end, first time I have heard the cabinet shake like this. Great sustain, note bloom and touch sensitivity. Cheers, Adam