5E3 build ... loud hum See pictures

[Doc Stitches]

This is my second 5E3 build.
290AX PT
1750E OT
Rec tube : GZ34S
Loud hum with all pots off and on.
Volume is VERY loud on 1 1/2.
Here are some photos....I think it's a wiring problem.
Thanks again
Doc

[52 Bill]

I don't see a ground reference for the filaments. Is there a center tap on the 6 volt winding or do you have a pair of 100 ohm resistors to ground?

[Doc Stitches]

This is my second 5E3 build.
290AX PT
1750E OT
Rec tube : GZ34S
Loud hum with all pots off and on.
Volume is VERY loud on 1 1/2.
Here are some photos....I think it's a wiring problem.[ATTACH=CONFIG]28492[/ATTACH][ATTACH=CONFIG]28493[/ATTACH][ATTACH=CONFIG]28494[/ATTACH][ATTACH=CONFIG]28495[/ATTACH][ATTACH=CONFIG]28496[/ATTACH][ATTACH=CONFIG]28497[/ATTACH][ATTACH=CONFIG]28498[/ATTACH][ATTACH=CONFIG]28499[/ATTACH]
Thanks again
Doc

Is there another resistor value I can use ?
....I am out of 100 ohm

[g1]

220 if you have them.

[Doc Stitches]

update

220 if you have them.

Thanks 52Bill and g-one...............much quieter, almost no hum with the 1/4 watt 100 ohm resistors.

However, now there is a very loud popping sound ( way too loud ), when I turn the volume pots on

and off and some popping with the standby switch. Other than that it sounds great.

thanks
Doc

[stokes]

The pop when turning the standby on is the first cap charging suddenly.The pots popping when turning is odd,are you sure its not more of a scratchiness?If so it could be a leaky cap feeding the pot.If you connect those two 100ohm resistors to the cathode of the power tube instead of ground it will further reduce any 60cycle hum from the heaters.

[g1]

Are you using some kind of switched pots? And if so, what function is the switch performing?

[Doc Stitches]

pots pop

The pop when turning the standby on is the first cap charging suddenly.The pots popping when turning is odd,are you sure its not more of a scratchiness?If so it could be a leaky cap feeding the pot.If you connect those two 100ohm resistors to the cathode of the power tube instead of ground it will further reduce any 60cycle hum from the heaters.

Not scratchiness......pop is just like the standby pop but louder ! The 2 volume controls are both on/off switches and volume

controls.... is this correct ? They both pop very, very loud, when I turn them off and on, as well as on and off. I will check for leaky

cap and connect the 100s to power tube.

thanks stokes

[Doc Stitches]

I don,t know much about the switches, but both are on/of as well as volume.

They are stamped A1M on the black plastic housing and stamped 0E2 on the metal housing.

[Tom Phillips]

...The 2 volume controls are both on/off switches and volume controls.... is this correct ? ...

The 5E3 circuit does not use switched pots. Having said that I can see by the photos you posted that the switches on your pots are not wired to anything. Since the switch built into a pot such as the ones you used is independent from the pot track you should theoretically have no pop when you switch the pot. You are just operating an unconnected independent switch. Perhaps your pots have a problem at the lower end of the pot track or perhaps the vibration created when the switch clicks is causing the pot wiper to jump and temporarily loose contact. Either way I'd say that those pots are lacking in quality.

If the amp works fine for you if you just never click the switch then you could go with that. Otherwise I think you could try normal un-switched pots.

Regards,
Tom

[Doc Stitches]

agreed

The 5E3 circuit does not use switched pots. Having said that I can see by the photos you posted that the switches on your pots are not wired to anything. Since the switch built into a pot such as the ones you used is independent from the pot track you should theoretically have no pop when you switch the pot. You are just operating an unconnected independent switch. Perhaps your pots have a problem at the lower end of the pot track or perhaps the vibration created when the switch clicks is causing the pot wiper to jump and temporarily loose contact. Either way I'd say that those pots are lacking in quality.

If the amp works fine for you if you just never click the switch then you could go with that. Otherwise I think you could try normal un-switched pots.

Regards,
Tom

I'm with you Tom.....I am ordering normal pots tonight.

I've never had this problem with my other builds/repairs.

Thanks to all for now................I'll update in about a week.

Doc

[Doc Stitches]

All is good in 5E3 land.

I'm with you Tom.....I am ordering normal pots tonight.

I've never had this problem with my other builds/repairs.

Thanks to all for now................I'll update in about a week.

Doc

The 2 100 ohm rs did the trick ...... along with the 3 standard pots.

Thanks to everyone.
Doc