help with noise at startup volume turned down

[Doc B.]

All of this talk about touching the cable and moving the cable is really taking away the idea that there is a problem with the tubes. It sounds like your signal grounding connection is not 100% somewhere between the headphone jack and the volume pot.

[Hornet900]

yeah but this is what I'm experiencing....   And I would of thought the noise would of been there when i uninstalled the speedball boards ..which it was not .....perfect with  no speedball

[Doc B.]

I suggest checking the solder joints of the black wire that connects from the volume pot to the two tabs of the head phone jack and also the connections of the two black wires on the upper and lower tabs of the volume pot. I would also check that somewhat gnarly connection of black wires on the center tab of the t strip by the nine pin socket. All those connections need to be really low impedance, i.e., soldered really well and they all have to do with grounding the various components talked about in this thread.

[tdubl07]

Guys for what it's worth I recable all my headphones in canare starquad 4e5c not for sound but because I think it looks and feels much better than stock cables and it has terrific shielding. That being said I have had the zero volume hum with all tubes and a persistent hum all the time with my 5998. It's not the pot as I have changed that to a PEC. Hornet sounds like he has the zero volume hum and perhaps another issue causing the buzz. Ive tried different cans as well. 990 pros and T90s, same problem.

[ghost_rider]

I suggest checking the solder joints of the black wire that connects from the volume pot to the two tabs of the head phone jack and also the connections of the two black wires on the upper and lower tabs of the volume pot. I would also check that somewhat gnarly connection of black wires on the center tab of the t strip by the nine pin socket. All those connections need to be really low impedance, i.e., soldered really well and they all have to do with grounding the various components talked about in this thread.

Hi Doc,

I did check my ground point impedance and all if was pretty low. So i think my grounding is fine, the problem seems to be somewhere else

[Paul Birkeland]

A loose connection may measure just fine with your meter, but once you flip the chassis plate over, jiggle the plate, and plug in headphones, the connection may be compromised again.

Reheating all your solder joints is free, I'd give it a try before anything else.

[ghost_rider]

A loose connection may measure just fine with your meter, but once you flip the chassis plate over, jiggle the plate, and plug in headphones, the connection may be compromised again.

Reheating all your solder joints is free, I'd give it a try before anything else.

I did try poking all the connections with a lolly stick and none of them were loose. Still i will give it a try, just to be sure

[Hornet900]

I just tried a Brimar 12BH7 tube and its still got the noise at 0% volume, Amps been on for 30 mins     And It sounds rubbish waste of money

The Noise is maybe  a little louder with this tube and still touching my headphone cable changes the tone of the noise ...I've ordered a new HD650 cable should have it next week ..Cant see that fixing it as I've  tried another pair of headphones ....I  needed a new cable anyway.

But yesterday I had the amp on for a long time and it went silent at 0% volume after an hour or 2!  But still if I moved the headphone cable about it would come back ...
I could make it go silent though!

i also installed new headphone jack socket yesterday with no change.
Will have another 5998 on wednesday

[Paul Birkeland]

Try moving the ground wire leaving the headphone jack and heading to the volume pot so that it's not on top of the 9 pin socket.

[Hornet900]

Hello Paul thanks for the tip  I already rerouted that wire with my troubleshooting, I did rerouted that wire around the front like I've seen other  people do  their builds.
The amps been on for an hour now and its silent again at 0%.
Its must be something to do with the 5998 tubes I've had and I'm unlucky   

though it makes the noise with the other tubes at startup but goes much quicker with them  , With the mulllard 6080 it goes in 10 seconds 0% and the 2 RCA 6AS7G tubes it stays for a few mins then silent and the stock tube takes bit longer .
All the tubes make the same type of noise at startup even if the volume up but goes in 5 seconds max with the volume up.. just  turning the volume down the noise is there longer with different tubes and the 5998 takes the longest for it to go.

Its just messing with my cable thats freaking me out because the noise changes. ( it happens with all the tubes when the noise is there 0% playing with the cable)
And the really noisy 2399 tube I had with all volumes was ok when I uninstalled the speedball. 
Its Always the same type of noise.

I've ordered new parts for my amp and will be rebuilding it, but stupid me I've only got the parts for the stock crack but I'll see how I go with that 1st

Thanks...
Its still silent     sounds great 
 

 

[Paul Birkeland]

I've ordered new parts for my amp and will be rebuilding it, but stupid me I've only got the parts for the stock crack but I'll see how I go with that 1st

What do you plan to do differently?

[Hornet900]

Nothing really    Just  reflowing all the joints made my amp look bit messy doesnt look as nice now   and On the big power tube socket 1 of the solder tabs fell out the bottom when I  removed and replaced the wire. I soldered a little bit on it and put it back in , The big tube wont go all the way down now on 1 side,  I had the noise before I did this.
I've replaced loads of the wires   ....the little tube socket is  also bit wobbly now.

Mostly I want to polish both sides of the top plate and clean clear coat the bell housing
and I thinking about running the amp without the speedball for a while

Thanks 

I

[Hornet900]

Number 4  5998 tube  arrived.

Also has the noise at 0% volume,  amps been on 30 mins ... noise not gone away at 0% volume ...with the volume turned up past 5mm its silent. 
took about 2 mins to be dead silent with volume turned up..longer than my other 5998 tubes.
 
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[Stanshall]

Just seen that this is mentioned elsewhere and is standard amplifier warm-up behaviour.

[tdubl07]

No, the zero volume hum never goes away that some of us are getting. Even after all day usage. I've resolved myself to never turn it that low and no issues.