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i want to quiet the amp some...it doesn't hum bad...but want to quiet it a bit...

i did the chop stick probe thing...the only thing i noticed is that when touching the wires at pin 2 and pin 3 on V1 i get a popping-like sound...

the other thing is...i put the cap in on the boost to give it a bit my dirt like on the sIII...but i noticed that the hum is louder when it is on...

i know a little...but...i'm looking for some thoughts...thanks all!

Thoughts...

Elevate the heater center tap
Using a hum balance pot on the heaters
Shield grid wires that aren't already shielded.
Keep needs short and direct (pay attention to the grids).
Make sure all grounds are tight and clean. Also keep ground wires short.
Swap tubes to find quietest tubes

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You might resolder the wires at pin 2 and pin 3 on V1. Push all heater wires tight to chassis and away from any low level preamp signal wires. Loop any preamp wires over the heater wires. Shorten leads.
Last effort would be to elevate the heater or add a hum pot.
kurtlives is correct tho, try to find the quietest tubes by swapping them around. That will make a difference.

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Stephen
Web: www.trinityamps.com. Facebook: facebook.com/trinityamps. Twitter: @trinityamps

one thing I am going to try one day is to install some kind of metal shield over the bottom of the chassis..I know on my old traynor yba1 it make quite a bit of difference.

i understand the last four...i've got a little shielded cable left so i can do this...if i did this for the boost switch leads as well...where would be the best place to ground it? just drill a new hole or tie it in somewhere?

the first two...i'm a little lost on...can you explain? perhaps an illustration?

That's a very good suggestion.

Get a sheet of aluminum flashing from Home Depot and cut it to size by scoring it with a box knife. Works great in a pinch! Sandwich it between the cabinet and the chassis.

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Stephen
Web: www.trinityamps.com. Facebook: facebook.com/trinityamps. Twitter: @trinityamps

sorry...just a bump so i can understand this...

http://www.valvewizard.co.uk/heater.html
Read the part on DC elevation

Hum pot just replaces the CT or two 100R resistors. Heater windings go to either side of a 200R pot. Wiper goes to ground. Adjust the pot for lowest hum (Best balance on heater windings).

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forgive me...i'm reading a lot here...i think i am following most...but here starts the questions...

1. more of an observation than a question...revisiting the wiring...i am thinking my heater wiring past the Power tubes needs to be re-done...not quite as tight as the rest of the pictures i've seen online...this is the first picture...i'm going to have to track down some new wire...i don't have any left...or...should it all be redone?

2. i'm following your schematic for the heater balance pot...so...i take a 2W 200k pot...and tie into the heaters...then...you said send it to ground...which would be presumable a close tie in...why, may i ask, did you take it to pin 8 of the power tubes in your 20W?
http://i0.wp.com/pdfelectronics.com/wp- ... atic_0.jpg?

3. elevate the centre tap...ok...so right now...the centre tap is wired to the terminal strip and goes nowhere...the 0V green w/yellow stripe...if i understand that 'the valve wizard' site is saying...if i actually ground that wire...it should help with the hum? can it be tied into the 'power ground' lug or should it have its own? (revisiting my amp...that wire is already grounded...as per the schematic to the power ground lug)

Addendum...the only thing different about my centre tap being grounded...I out my bleed resistor on the same lug...

1. That's more than tight enough

2. 2W 200R (ohms) not 200K! Yes you got it right there. I took the wiper to pin 8 of the power tubes becaue that is heater elevation. The wiper of the pot is the same as the centre tap here. And just like can take the CT to a voltage for heater elevation you can take the wiper of the pot to a voltage (cathode voltage of output tubes) for heater elevation.

3. The green/yellow wire should already be grounded if your amp is built stock. For heater elevation you take that green/yellow to a voltage for heater elevation.

I think the fact that I added a hum balance pot is throwing you off here.

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thanks!

so...if my heaters are ok...this weekend when i get a chance, i'll through some shielded wire in for some leads...make some new ground lugs for them too...

i'll then move the tubes around...and then barring that...i'm try the hum pot...

i think this is what confused me...b/c you mentioned replacing the centre tap...but that stills stays grounded...

i think i follow with the balance pot now too...*think*...heaters to the pot, wiper to pin 3 on a power tube...should reduce some hum

i found the main culprit...the switch for my cascade is toast...is it just a simple DPDT switch?

Should be. 6 lugs would be a DPDT

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ok...so...i replaced the switch...i have resoldered turrents...

i have taken input wires off and tied outside and the hum gets MUCH worse, on both sides...
i have shortened the grid resisters to be as short as i can get them...
i have used a jumper cable to check all my grounds (connected to the turret and then to chassis)
i pulled V3 and the noise died...which means it is in the pre-amp...I am running Tungsols...i've heard that maybe i shouldn't be...

heres a clip of the noise...this is with the VRM at 3oclock, as well as gain and both volumes...you can also hear the ac hum...at 120hz...(i grabbed my guitar and it works out to a B)
https://www.dropbox.com/s/iuye0edyc3weo ... %20002.3ga

i would appreciate some insight...thanks!

What is *.ga file. Does not play ! nm you recorded with your phone?. Can you convert it to mp3. And where on this planet are you

Ontario...why?

Ill find a way to convert it tomorrow...my vlc player on my computer plays it fine...recorded it on my sIII...

https://www.dropbox.com/s/rtsumfngyj0z5bu/Voice_002.mp3

here it is as an mp3...

Are you talking about the hiss or shhhhhhhhhh

Or about the faint hmmmmmmmm in the back ground

one other question was there a peddle pluged in at the time


And was just oneeatering how close you are

here are some some guts shots...

https://www.dropbox.com/s/lx0akegia9...712_064758.jpg

https://www.dropbox.com/s/esy02pr1cs...712_064901.jpg

https://www.dropbox.com/s/oo4k0xrd25...712_064811.jpg

https://www.dropbox.com/s/jxrk5xmwwt...712_064805.jpg

it was prettier...but in try to track this down i've re-wired a couple wires...

to re-interate...nothing is plugged into the jacks...the phone was about 8" from the cab and VRM and vol/gains at 3 oclock

and i am talking about both of those noises...the hiss right now is whats driving me nuts...

if 'oneatering' is wondering...its kingston...

i appreciate the help guys!