5E3 Clone (HUM)Help

[Dmac252]

I recently came by a 5E3 Clone as part of a trade for some guitar work. It sorta worked but the wiring was hideous so I decided to rewire it. I de-soldered all the components and reterminated all of the old components except swapped the coupling caps for .022's . I replaced the transformers with the classicTone pair 40-18021 PT and the 40-18022 OT.

The amp certainly works and has good tone if you like the .022's anyway the reason for the post is that there is this annoying low constant hum. It doesn't sound to me like your typical 60 cycle but of course I am relatively new to putzing with amps. I have built several kits an have not needed to trouble shoot beyond verifying that I followed the wire diagram properly.

What I have done is install to grounding strips on on the tube side and one on the pots side and connected them together I did not use the chassis for my input of speaker out grounds I brought them to the GND strips the same with the pots. The green wire from the power chord is terminated on the strip as well and both strips are terminated to the lugs of the PT. Some photos below:

Any advice would be GREATLY appreciated


ORIGINAL WIRING:
[IMG:640:480]http://i838.photobucket.com/albums/zz308/dmac252/5E3start_zps75230460.jpg[/img]

New Wiring:
[IMG:768:1024]http://i838.photobucket.com/albums/zz308/dmac252/Mobile%20Uploads/AB707FC3-7FCA-488F-8DB1-ECEBA7938A21_zpsv71p2sql.jpg[/img]

[IMG:768:1024]http://i838.photobucket.com/albums/zz308/dmac252/Mobile%20Uploads/6D0CCA37-AF82-491F-B423-8B00AE87C29C_zpslvqbtd5j.jpg[/img]

[IMG:768:1024]http://i838.photobucket.com/albums/zz308/dmac252/Mobile%20Uploads/4EAF0BA3-DE75-41AE-B036-FED6D2312AEA_zps3ebr2uqv.jpg[/img]

[IMG:768:1024]http://i838.photobucket.com/albums/zz308/dmac252/Mobile%20Uploads/53122E4F-E750-44F1-A042-90451FED73B9_zpsqlj8jqhn.jpg[/img]

[cbass]

Does pulling out the preamp tube stop the hum

[ToneMerc]

Good info here......

http://www.aikenamps.com/index.php/grounding

TM

[Phil_S]

On V2, the heater wires are laying on the signal wires. The twist is non-existent, so there is no hum-cancelling going on there.
http://ax84.com/bbs/dm.php?thread=283738

Pratical stuff on grounding:
http://www.valvewizard.co.uk/Grounding.html

[Dmac252]

Does pulling out the preamp tube stop the hum

I will check this in the morning when I get back to the shop

Thanks

[Dmac252]

Good info here......

http://www.aikenamps.com/index.php/grounding

TM

Yea I read this and that was what prompted the double star attempt trying to avoid the floating ground loop stuff.

Thanks

[Dmac252]

On V2, the heater wires are laying on the signal wires. The twist is non-existent, so there is no hum-cancelling going on there.
http://ax84.com/bbs/dm.php?thread=283738

Pratical stuff on grounding:
http://www.valvewizard.co.uk/Grounding.html

The Heater pins are 4/5 & 9 yes ? the Green & Red wires they should be twisted more than the are? I can dress that up a bit more I guess every little bit helps.

Thanks

[vibratoking]

No need to get crazy and change the whole grounding scheme. These things work really well when the problems are fixed. I was to lazy to look much, but do you have the heaters artificially grounded?

[Dmac252]

No need to get crazy and change the whole grounding scheme. These things work really well when the problems are fixed. I was to lazy to look much, but do you have the heaters artificially grounded?

Not sure what you mean by that. Please explain

[ampgeek]

Your PT filament (6.3 VAC) secondary has 3 leads. Two go off to power the tube filaments. The last lead (usually green with a yellow stripe) is the center tap for other two leads. This is typically connected directly to ground.

Many filament secondary windings do not have a center tap. You can create an artificial center tap by running a 100 ohm resistor from each of the filament power leads directly to ground.

Where, if at all, did you connect your 6.3 VAC filament center tap lead?

The mishandling of the filament power supply wiring is a very, very common cause of 60 hz hum.

Fortunately, if is very easily corrected once a problem is identified!

Dave O.

[Dmac252]

Your PT filament (6.3 VAC) secondary has 3 leads. Two go off to power the tube filaments. The last lead (usually green with a yellow stripe) is the center tap for other two leads. This is typically connected directly to ground.

Many filament secondary windings do not have a center tap. You can create an artificial center tap by running a 100 ohm resistor from each of the filament power leads directly to ground.

Where, if at all, did you connect your 6.3 VAC filament center tap lead?

The mishandling of the filament power supply wiring is a very, very common cause of 60 hz hum.

Fortunately, if is very easily corrected once a problem is identified!

Dave O.

This PT 40-18021 has green/yellow which I connected to the ground as well as the red/yellow which is also connected to ground same location. Would it still be recommended for artificial ground

[Dmac252]

Your PT filament (6.3 VAC) secondary has 3 leads. Two go off to power the tube filaments. The last lead (usually green with a yellow stripe) is the center tap for other two leads. This is typically connected directly to ground.

Many filament secondary windings do not have a center tap. You can create an artificial center tap by running a 100 ohm resistor from each of the filament power leads directly to ground.

Where, if at all, did you connect your 6.3 VAC filament center tap lead?

The mishandling of the filament power supply wiring is a very, very common cause of 60 hz hum.

Fortunately, if is very easily corrected once a problem is identified!

Dave O.

This PT 40-18021 has green/yellow which I connected to the ground as well as the red/yellow which is also connected to ground same location. Would it still be recommended for artificial ground

OK if you look at photo 3 the filament power runs to the light bulb before the 6V6 where It has 1 100ohm resister terminating to ground. I assume that this would be the artificial ground, Yes?

[M Fowler]

Looks like you have both a filament center tap to ground and the two resistors off the pilot going to ground (artificial tap). The artificial tap needs to go.

[Dmac252]

Looks like you have both a filament center tap to ground and the two resistors off the pilot going to ground (artificial tap). The artificial tap needs to go.

Cool, 1st thing in the AM...

[Dmac252]

Looks like you have both a filament center tap to ground and the two resistors off the pilot going to ground (artificial tap). The artificial tap needs to go.

some updates
OK Removed the artificial tap - no if anything the hum sounds more familiar like 60 Hz.