5E3 clone build has low level hum
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5E3 clone build has low level hum
I just completed 5E3 amp sounds great. However there is a low level hum that is present. When playing you can't hear it but in between tunes at a gig it is very annoying. I would like to cut that hum down. The hum starts when you turn up either volume single or double (both a little louder) and tone pot (treble, side) even more so. Installed on volume pot to V-2 pin 2 shielded wire (shield to pin1). Shielded wires on all jacks (shield to ground) and shielded wires from board to V-1 pin 7 shield to pin 8, and pin 2 shield to pin 1. There are no other hisses or other issues with the amp. Any assistance is appreciated. mazzbob@gmail.com Thanks everyone, Bob
Re: 5E3 clone build has low level hum
The champs aren't silent amps
You may have a noisey tube or questionable rectifier tube.
make sure you have a solid solder to all grounds and your wiring is short, and neat. wire placement can also play a part in this.
You may have a noisey tube or questionable rectifier tube.
make sure you have a solid solder to all grounds and your wiring is short, and neat. wire placement can also play a part in this.
My Daughter Build Stone Henge
Re: 5E3 clone build has low level hum
Yeah, before I connected it to the current limiter and powered it up I re-flow all the connections made sure they were good. I also have been moving the wires around with the chopstick to see if that has any effect but it does not. I did not use a copper ground buss or brass plate but have multiple star grounds in various locations. I have a friend that has a 5E3 which has about the same type hum as well This is my first 5E3 therefore it just maybe the way the amp is (I'm not sure) I have the center tap grounds in place from the PT but was wondering if the heater wires may be the cause of this hum and to install the virtual center tap using 2 100 ohm resistors. I have heard of 2 ways to do it one the the pilot light. Then read about installing them to power tube sockets connect a 100 ohm 1/2 watt resistor to pins 2 & 8, on the other power tube socket connect a 100 ohm 1/2 watt resistor to pins 7 & 8, I am not sure which is the way to go or even if this will work but I'll try it and see what happens. Has anyone completed this ?
Re: 5E3 clone build has low level hum
If your heater/filament circuit has no ground reference it is going to hum. There are a number of different styles for wiring the fliament harness, all of which work. Some people use zip/lamp cord, keeping the wires absoulutely parallel. The other two methods involve twisted pair. Fender style is up in the air, leaving the chassi floor for signal wires. Marshall style is tucked into the chassis fold. The point is to avoid coupling of the AC heater voltage with the signal wires. If you've done a poor job on the harness, that might actually be the problem. Post a picture here so we can see.
As for the artificial center tap, this is a necessity. The exception is when you've got a real center tap for that winding on the transformer -- you don't do both. It doesn't matter where you put the two 100 ohm resistors. They can be at the pilot light or at any tube socket. The ground is not part of the signal ground, so you can go directly to the chassis. Do this wherever it is convenient to do so.
Some people like to elevate the filament circuit by running the two 100 ohm resistors to the power tube cathode instead of ground. The 5E3, not being a high-gain amp, makes this a bit less of an issue. But that's my view of it and others will not only disagree, but tell you that you should always elevate the heaters. I'll say this much about elevating heaters, which is that it certainly couldn't hurt and if convenient, do it.
As for the artificial center tap, this is a necessity. The exception is when you've got a real center tap for that winding on the transformer -- you don't do both. It doesn't matter where you put the two 100 ohm resistors. They can be at the pilot light or at any tube socket. The ground is not part of the signal ground, so you can go directly to the chassis. Do this wherever it is convenient to do so.
Some people like to elevate the filament circuit by running the two 100 ohm resistors to the power tube cathode instead of ground. The 5E3, not being a high-gain amp, makes this a bit less of an issue. But that's my view of it and others will not only disagree, but tell you that you should always elevate the heaters. I'll say this much about elevating heaters, which is that it certainly couldn't hurt and if convenient, do it.
Re: 5E3 clone build has low level hum
Thanks, a lot for all your info, I got the trany's from triode electronics. It contains a green/yellow and red/yellow wires which go to ground. Which was done.
On my last build (I completed a 18watt) which I had first installed switchcraft jacks in the amp. I had to remove these and install the Marshall type input jacks as there was a hum. When I installed the Marshall style jacks the hum disappeared. I'm beginning to wonder in this 5E3, I know I wired the jacks in correctly (as I did with the 18 watt) no matter what I did with switchcraft jacks the 18 watt amp hummed. The hum stopped only when I replaced the jacks with the Marshall type, and I wired them same by the way. I always thought that was very weird but it worked.
On my last build (I completed a 18watt) which I had first installed switchcraft jacks in the amp. I had to remove these and install the Marshall type input jacks as there was a hum. When I installed the Marshall style jacks the hum disappeared. I'm beginning to wonder in this 5E3, I know I wired the jacks in correctly (as I did with the 18 watt) no matter what I did with switchcraft jacks the 18 watt amp hummed. The hum stopped only when I replaced the jacks with the Marshall type, and I wired them same by the way. I always thought that was very weird but it worked.
Re: 5E3 clone build has low level hum
Run the green/yellow (or green/white from the tranny specs) wire to the power tube cathodes to get some heater elevation. If it's coming from the heaters, that should cut quite a bit of it without having to add an artificial center-tap.mazzbob wrote:Thanks, a lot for all your info, I got the trany's from triode electronics. It contains a green/yellow and red/yellow wires which go to ground. Which was done.
Is the hum still present with nothing plugged in to the amp?On my last build (I completed a 18watt) which I had first installed switchcraft jacks in the amp. I had to remove these and install the Marshall type input jacks as there was a hum. When I installed the Marshall style jacks the hum disappeared. I'm beginning to wonder in this 5E3, I know I wired the jacks in correctly (as I did with the 18 watt) no matter what I did with switchcraft jacks the 18 watt amp hummed. The hum stopped only when I replaced the jacks with the Marshall type, and I wired them same by the way. I always thought that was very weird but it worked.
Matt.
Re: 5E3 clone build has low level hum
First of all 5E3's don't hum. I have owned many and still have a 57' Deluxe. It does not hum. It is very quiet until I hit a note, then it's a monster.
I suspect it is your grounding scheme or layout. Follow the original ground scheme and layout. It could be a power tube though, try a nice matched set. I use a 12ax7 in V1 for extra gain and it is still very quiet.
I suspect it is your grounding scheme or layout. Follow the original ground scheme and layout. It could be a power tube though, try a nice matched set. I use a 12ax7 in V1 for extra gain and it is still very quiet.
Re: 5E3 clone build has low level hum
Hi mazzbob
What billyz said. It probably your grounding or a bad tube. A bad tube is an easy fix - redoing your grounding is a bit more involved and is a bit of art and science and is harder to get right.
This article is a handy read for grounding
http://www.freewebs.com/valvewizard2/Grounding.pdf
Essentially - each ground return wire in your amp has the capacity to cause problems if it gets contaminated by ground return signal from another wire part of the ground return. Furthermore the 'high-current' ground return wires which come from the output tube end of the amp, have the capacity to wreak havoc on the 'low-current' ground return wires coming from the pre-amp end of the amp. Although we would like filter caps to work perfectly to dump AC to ground, the reality is that they can't, and their filtering action actually results in tiny AC micro-rises in ground potential on the grounded side of the cap (in much the same way that the earth is a big capacitor that has localised rises in ground potential in different places depending on a range of factors such as atmospheric conditions like lighting strikes, or power generation facilities like hydro dams and wind farms, which 'pull-up' the ground potential in vicinity etc). In the amp, the high-current ground return wires have bigger AC micro-rises in ground potential which can cause 'backwobble' to get into the lower-current ground return paths, which the pre-amp filter cap(s) is/are riding on, which in-turn introduces a hum into the pre-amp signal because the pre-amp filter ground reference is not constant but is instead wobbling up and down (because of the AC micro-rises in ground potential).
The goal here is to un-contaminate the ground return paths in your amp from each other by keeping them separate as much as possible up to the single point where they all need to meet.
You may need to try different arrangements for organising your ground return paths to get the most optimal situation for your amp. I find that a split-ground scheme can help if you are using an ally chassis, but a brass grounding plate is maybe better if you are using a steel chassis. It helps to have individual/separate wires from each ground return point going to the common ground return point. If you start to share ground return wires, then those two ground returns have the capacity to interact, which is where problems begin. JM2CW
What billyz said. It probably your grounding or a bad tube. A bad tube is an easy fix - redoing your grounding is a bit more involved and is a bit of art and science and is harder to get right.
This article is a handy read for grounding
http://www.freewebs.com/valvewizard2/Grounding.pdf
Essentially - each ground return wire in your amp has the capacity to cause problems if it gets contaminated by ground return signal from another wire part of the ground return. Furthermore the 'high-current' ground return wires which come from the output tube end of the amp, have the capacity to wreak havoc on the 'low-current' ground return wires coming from the pre-amp end of the amp. Although we would like filter caps to work perfectly to dump AC to ground, the reality is that they can't, and their filtering action actually results in tiny AC micro-rises in ground potential on the grounded side of the cap (in much the same way that the earth is a big capacitor that has localised rises in ground potential in different places depending on a range of factors such as atmospheric conditions like lighting strikes, or power generation facilities like hydro dams and wind farms, which 'pull-up' the ground potential in vicinity etc). In the amp, the high-current ground return wires have bigger AC micro-rises in ground potential which can cause 'backwobble' to get into the lower-current ground return paths, which the pre-amp filter cap(s) is/are riding on, which in-turn introduces a hum into the pre-amp signal because the pre-amp filter ground reference is not constant but is instead wobbling up and down (because of the AC micro-rises in ground potential).
The goal here is to un-contaminate the ground return paths in your amp from each other by keeping them separate as much as possible up to the single point where they all need to meet.
You may need to try different arrangements for organising your ground return paths to get the most optimal situation for your amp. I find that a split-ground scheme can help if you are using an ally chassis, but a brass grounding plate is maybe better if you are using a steel chassis. It helps to have individual/separate wires from each ground return point going to the common ground return point. If you start to share ground return wires, then those two ground returns have the capacity to interact, which is where problems begin. JM2CW
Re: 5E3 clone build has low level hum
+1 good information, is your pre-amp grounded on the same lug as your center taps/filter caps? I prefer to ground with a bus on the back of the pots for all the preamp/board grounds. Grounds for the filter caps should not be on this bus.
Even a small hum in the pre-amp starts amplifying that hum through the gain stages and you end up with a pretty large hum. The 5e3 I built doesn't hum very much if at all. The only time I've had hum problems with it were at some very old clubs with what I think are suspect grounds at the outlet. I run a 12ax7 as well for V1, it gives less headroom, but man dimed its a monster playing pretty much any classic rock and roll you want to do.
I wish you luck on finding it, I'd bet if you work over your ground scheme you'll have success. It's been my experience (and its limited I'll admit, I'm not a full time amp tech, just what I've observed on the various Forums and my own experience) that people always want to blame heaters for any sort of hum.
If you route the wires well and don't run parallel with signal wires they are usually not a source of the problem, some guys I've seen don't even twist them and don't get a heater induced hum. Just an observation.
Regards,
RD
Even a small hum in the pre-amp starts amplifying that hum through the gain stages and you end up with a pretty large hum. The 5e3 I built doesn't hum very much if at all. The only time I've had hum problems with it were at some very old clubs with what I think are suspect grounds at the outlet. I run a 12ax7 as well for V1, it gives less headroom, but man dimed its a monster playing pretty much any classic rock and roll you want to do.
I wish you luck on finding it, I'd bet if you work over your ground scheme you'll have success. It's been my experience (and its limited I'll admit, I'm not a full time amp tech, just what I've observed on the various Forums and my own experience) that people always want to blame heaters for any sort of hum.
If you route the wires well and don't run parallel with signal wires they are usually not a source of the problem, some guys I've seen don't even twist them and don't get a heater induced hum. Just an observation.
Regards,
RD
Re: 5E3 clone build has low level hum
Excellent read on good grounding schemes from Tubeswell. I laugh at the British view of American vintage amp designs though, ha ha.
Re: 5E3 clone build has low level hum
Nothing weird about it. The Switchcraft type jack has the metal sleeve making contact with the chassis. This is quite possibly the source of a ground loop. IMO, it is always better to insulate your jacks from the chassis.mazzbob wrote:On my last build (I completed a 18watt) which I had first installed switchcraft jacks in the amp. I had to remove these and install the Marshall type input jacks as there was a hum. When I installed the Marshall style jacks the hum disappeared. I'm beginning to wonder in this 5E3, I know I wired the jacks in correctly (as I did with the 18 watt) no matter what I did with switchcraft jacks the 18 watt amp hummed. The hum stopped only when I replaced the jacks with the Marshall type, and I wired them same by the way. I always thought that was very weird but it worked.
Read up on how to run a proper ground scheme. It is not random. There is more than one method. It is one of the keys to a hum-free amp.
Re: 5E3 clone build has low level hum
Good read guys.
I never isolate my jacks and rarely use cliff jacks either.
Question to OP
Does the amp hum with no guitar plugged in?
Have you check the guitar itself and the cord being used?
Also the line noise at the wall receptacle the amp is plugged into is it clean?
If you have followed a good ground layout the amp should be quiet.
I never isolate my jacks and rarely use cliff jacks either.
Question to OP
Does the amp hum with no guitar plugged in?Have you check the guitar itself and the cord being used?
Also the line noise at the wall receptacle the amp is plugged into is it clean?
If you have followed a good ground layout the amp should be quiet.
Re: 5E3 clone build has low level hum
I had a 5E3 build that hummed quite a bit, and I spent hours on redoing the grounding with no improvement. When I changed the jacks to isolated ground jacks (Cliff type), the amp became nearly silent. It may not be the only way to go, but it is sure an easy way to go.
Re: 5E3 clone build has low level hum
Not much to add that the others haven't mentioned, but i do agree with billz and the others. Grounding can be very weird in some amps.Phil_S wrote:Nothing weird about it. The Switchcraft type jack has the metal sleeve making contact with the chassis. This is quite possibly the source of a ground loop. IMO, it is always better to insulate your jacks from the chassis.mazzbob wrote:On my last build (I completed a 18watt) which I had first installed switchcraft jacks in the amp. I had to remove these and install the Marshall type input jacks as there was a hum. When I installed the Marshall style jacks the hum disappeared. I'm beginning to wonder in this 5E3, I know I wired the jacks in correctly (as I did with the 18 watt) no matter what I did with switchcraft jacks the 18 watt amp hummed. The hum stopped only when I replaced the jacks with the Marshall type, and I wired them same by the way. I always thought that was very weird but it worked.
Read up on how to run a proper ground scheme. It is not random. There is more than one method. It is one of the keys to a hum-free amp.
put the cathode resistor and cap on its own ground. Put the power filters on their own ground away from other grounds.
Sometimes moving one ground can make the amp quiet as a mouse.
I know some of this may sound crazy but its very true. Try to put the amp into sections on your grounds. Pots and input jack and few preamp grounds together. Put the power section to its own ground,and also single own ground the cathode spot. See if it helps or changes.
IF you move one ground and it makes it quiet, just leave it!
Re: 5E3 clone build has low level hum
Well, now that Ritchie opened this line of thought...one way of doing the grounds is with a buss ground. "Buss" if s techie name for a piece of bare wire. Buss gournds are easy to do on turret/eyelet boards -- run them along one edge of the board from the V1 cathode to the last PI ground.
Gather the grounds by section and attach them to the buss in groups, from lowest potential to highest potential. The V1/input is the lowest and the PI is the highest. Power amp doesn't get grounded on the buss.
A section ends with the cathode of a tube. Just draw the line there. So the first section goes from the input jack to the first cathode, and so on down the line. Frequently one filter cap supplies 2 or more plates. That means you group all those as if they are one section. For example, you may see on the low potential end, V1 and V2 supplied by one filter cap/B+ node -- that's four plates and four cathodes, all treated as one group, including the filter cap ground. At the PI end of the buss, run one wire to the chassis ground where you have the PT center tap. All other high potential grounds in the power section (filter caps, cathodes, whatever else I didn't mention) go to the chassis ground.
FWIW (not much) I don't agree with the guys who want to ground the buss near the input jack. However, if it works and it floats your boat, I guess it's OK. My view is that it requires the use of the chassis itself to make the connection to the main ground point. The chassis is a shield, not part of the circuit and shouldn't be used in that fashion.
The filament ground isn't part of the amplifier circuit, so it gets ist's own chassis ground, whether a PT CT or a pair of 100 ohm resistors. The power tube cathode elevation trick is a favorite among some as the ideal spot to ground the filament string.
Gather the grounds by section and attach them to the buss in groups, from lowest potential to highest potential. The V1/input is the lowest and the PI is the highest. Power amp doesn't get grounded on the buss.
A section ends with the cathode of a tube. Just draw the line there. So the first section goes from the input jack to the first cathode, and so on down the line. Frequently one filter cap supplies 2 or more plates. That means you group all those as if they are one section. For example, you may see on the low potential end, V1 and V2 supplied by one filter cap/B+ node -- that's four plates and four cathodes, all treated as one group, including the filter cap ground. At the PI end of the buss, run one wire to the chassis ground where you have the PT center tap. All other high potential grounds in the power section (filter caps, cathodes, whatever else I didn't mention) go to the chassis ground.
FWIW (not much) I don't agree with the guys who want to ground the buss near the input jack. However, if it works and it floats your boat, I guess it's OK. My view is that it requires the use of the chassis itself to make the connection to the main ground point. The chassis is a shield, not part of the circuit and shouldn't be used in that fashion.
The filament ground isn't part of the amplifier circuit, so it gets ist's own chassis ground, whether a PT CT or a pair of 100 ohm resistors. The power tube cathode elevation trick is a favorite among some as the ideal spot to ground the filament string.