help with noise at startup volume turned down

[Zashoomin]

Hello,

The Crack with speedball that I have built measures completely fine but a couple seconds after I turn it on, the amp emits a hum for about a second or two and then stops.  It never hums again and the background becomes completely black.  Music plays perfectly fine through it and it seems as if all the measurements are correct.  Is there anyway to fix it as I have no idea what is causing this hum.

Thanks in advance. 

[jboehle]

Wait 10 seconds to plug your headphones in? 

[Zashoomin]

Haha I figured. 

[Hornet900]

Hello
 
well I made some progess . I think its something to do with the power tubes ..the 5998 tungsol and also the stock RCA 6080 ( rca 6080 with this tube the noise goes away after some time) ...the weird thing is both tubes works fine without the speedball installed.

I purchased 2 RCA 6AS7G (thanks jamie  and these tubes only make the noise while the amps warming up  . It goes away with 1 tube within 30 seconds ....the other tube the noise goes away within 20 seconds with volume up a bit  ..takes a bit longer for no noise with  volume at %0.

So I'm sending the tungsol back to  vacuumtubes.net

So does the speedball show up bad tubes more so than using a stock crack?  As its a shame as I really liked the tungsol sound when I 1st installed the speedball and the tunsol worked fine 1st 24hours .

Another thing is my tube sockets have came lose now , The big 8 pin , one of the solder tabs fell out the back  and the 9 pin socket is very lose  when the tube is installed .
The new audio note socket   bought is slightly a different size and the middle pin u cant attach the ground and led wires like the stock sockets 

[ghost_rider]

Hi,

I just installed the Speedball in my crack today. Was very excited. At first I played it with the supplied Chatham 6080WA and a Mazda 12AU7. I notice there was a noise at 0 volume and it goes to about 5mm travel of the volume knob. at about 4mm travel point it makes a pop sound and the noise goes away. But the noise goes away after about 3 minutes. Please note everything is stock in my setup.

But the bad news starts with the Tung Sol 5998. I have 2 NOS and 1 less than 3 hours used Tung Sol 5998. They worked great my stock crack, but with the speedball there is a bad noise, more like a humming noise. The noise is like something on 0 volume and then there is the the same pop at about 4-5mm travel and then then noise slightly changes alittle, it does not increase or decrease, just makes a small change in the note of the noise may be,and it stays like the till the very last of the volume nob and again there is another change at the final 5mm of the volume nob. I tried all three 5998s but all were the same

I checked the connections and they seem fine. All the tiny LEDs r glowing just fine. 1 thing is the LED does light up a few seconds after i plug in the amp, they dont light up instantly, takes may be 1-2 seconds to light up, the LEDs on speedball.

Please do let me know what to do. I am very confused

[Hornet900]

Hello ghostrider

I have exactly the same problem and been battling it for days,  Not yet fixed because I was thinking its bad tube so sent it back for a refund.
I've now ordered a newer chatham 5998 and I'm waiting for that to be delivered.

I upgraded to the speedball and my chatham 2399 made a bad noise.

what your saying makes me sad     I'm  hoping it would be fixed with a new tube >:

My Chatham 2399 (same as 5998 I've heard  ) went slightly quieter once I upped the volume past 5mm (still very loud ) and my noise is louder in the left channel ...I don't get the pop you have though.

Mine is weird as with the stock tube the amp was making the same noise at  power up 0% volume as the chatham did.... but if  I upped the volume with stock tube  past 5mm the noise would go away and be silent after 5 mins warm up at  0% volume. 
No problems.    Then I got hold of some more power tubes to try and all seemed fine  but all these tubes are the 6080 6AS7G  not the 5998 tubes.

With my chatham I had the same noise as the stock 6080 tube did at warm up 0% volume but upping the volume past 5 mm it would change the noise slightly and go a little quieter but  never go away and is still loud unusable.

Trying to find out what's wrong  I uninstalled the speedball and the tubes worked fine .... chatham works fine 

I swapped the 2 little pcb boards around no change, I even uninstalled the big pcb board and put back in the 3k resistors while keeping the 2 small boards installed that didn't fix it.
I was then thinking the speedball made the tubes work harder or something and shows a bad tube as a bad one,  ??

I only had 1 chatham 2399 (5998)  so thought it was bad,   

The tube was fine 1st time I used it with the speedball though ..  second time I powered  up the noise started.


at first I was thinking its a ground wire as when I touched my headphone cable or the headphone socket it would go quieter stock tube (It still does this and my headphone cable is very old 1st gen HD600 even thinner than current hd600s cable ..
Then more testing with the stock tube installed i found that the  white middle wire on the volume pot that goes to the tube socket  touching this wire the noise would change or go away , (still 6080 tube)
So i fixed this white wire seemed  better but this was with the amp still warming up so I dont know if this was even a problem I was confused  ( no difference with the chatham)

weird thing is If I unplugged my headphones and waited 30 mins 1 hour the with the chatham the noise would go away but only if the volume was at max No change at all other volume.

I'll update you when I get the new tube ghostrider ,  I hope it works as I spent alot of money now! on tubes testing and stuff also I ordered a load new parts from bottlehead as i want to rebuild the amp ...Really want the 5998 to work as it sounded brilliant with the speedball installed 1st time ....so much better than the other tubes I have.

I thought without the speedball the 5998 didn't sound that good 

Good luck ghostrider 

[Hornet900]

And another thing about the LEDs  glowing

When I first installed the speedball and was testing the voltage  I noticed that the leds glowed up faster than they do now. ( I swear I remember them glowing faster than they do now)
The 2 little boards glow 1st followed by the big board now... If thats any help information?

[ghost_rider]

Bump guys

Here are my volt checks (With Tung Sol 5998 and Mazda 12Au7)

Terminal            Volt
1-------------------77.4
2------------------167.1
3---------------------0.1
4------------------166.4
5--------------------85.4
6----------------------0.1
7--------------------88.5
8------------------------0
9--------------------72.6
10--------------------0.4
11----------------------0
12----------------------0
13-----------------165.8
14----------------------0
15-----------------184.6
20----------------------0
21------------------204

I am running it on 220V AC.

Somebody help

[ghost_rider]

And another thing about the LEDs  glowing

When I first installed the speedball and was testing the voltage  I noticed that the leds glowed up faster than they do now. ( I swear I remember them glowing faster than they do now)
The 2 little boards glow 1st followed by the big board now... If thats any help information?

Yes exactly the same happens with me. The two small one glows and then the big one.

Man I am very scared. I had so spend a fortune on the 3 NOS Tung Sols. If they dont work its an all budget blown nightmare for me

[fullheadofnothing]

If the noise goes away after 3 minutes, as you state, then it is the sound the tube makes as it warms up. Simply turn on your amp and wait a bit before listening.

If it a noise that a tube makes constantly, then it is a noisy tube. Replace it. NOS is not a guarantor of anything, there are noisy NOS tubes and there are tubes that have been sitting dead in boxes for years.

The low voltage at terminal 9 is suggesting that there is something wrong with the 5998. Are your voltages in spec with the stock tubes?

[ghost_rider]

Hello ghostrider

I have exactly the same problem and been battling it for days,  Not yet fixed because I was thinking its bad tube so sent it back for a refund.
I've now ordered a newer chatham 5998 and I'm waiting for that to be delivered.

I upgraded to the speedball and my chatham 2399 made a bad noise.

what your saying makes me sad     I'm  hoping it would be fixed with a new tube >:

My Chatham 2399 (same as 5998 I've heard  ) went slightly quieter once I upped the volume past 5mm (still very loud ) and my noise is louder in the left channel ...I don't get the pop you have though.

Mine is weird as with the stock tube the amp was making the same noise at  power up 0% volume as the chatham did.... but if  I upped the volume with stock tube  past 5mm the noise would go away and be silent after 5 mins warm up at  0% volume. 
No problems.    Then I got hold of some more power tubes to try and all seemed fine  but all these tubes are the 6080 6AS7G  not the 5998 tubes.

With my chatham I had the same noise as the stock 6080 tube did at warm up 0% volume but upping the volume past 5 mm it would change the noise slightly and go a little quieter but  never go away and is still loud unusable.

Trying to find out what's wrong  I uninstalled the speedball and the tubes worked fine .... chatham works fine 

I swapped the 2 little pcb boards around no change, I even uninstalled the big pcb board and put back in the 3k resistors while keeping the 2 small boards installed that didn't fix it.
I was then thinking the speedball made the tubes work harder or something and shows a bad tube as a bad one,  ??

I only had 1 chatham 2399 (5998)  so thought it was bad,   

The tube was fine 1st time I used it with the speedball though ..  second time I powered  up the noise started.


at first I was thinking its a ground wire as when I touched my headphone cable or the headphone socket it would go quieter stock tube (It still does this and my headphone cable is very old 1st gen HD600 even thinner than current hd600s cable ..
Then more testing with the stock tube installed i found that the  white middle wire on the volume pot that goes to the tube socket  touching this wire the noise would change or go away , (still 6080 tube)
So i fixed this white wire seemed  better but this was with the amp still warming up so I dont know if this was even a problem I was confused  ( no difference with the chatham)

weird thing is If I unplugged my headphones and waited 30 mins 1 hour the with the chatham the noise would go away but only if the volume was at max No change at all other volume.

I'll update you when I get the new tube ghostrider ,  I hope it works as I spent alot of money now! on tubes testing and stuff also I ordered a load new parts from bottlehead as i want to rebuild the amp ...Really want the 5998 to work as it sounded brilliant with the speedball installed 1st time ....so much better than the other tubes I have.

I thought without the speedball the 5998 didn't sound that good 

Good luck ghostrider 

Thanks for all the info Hornet. really really really appreciate it

I just tried your idea on poking the white wires but nothing happened on the 6080WA tubes

Here are my volt checks (With Chatham 6080WA and Mazda 12Au7)

Terminal            Volt
1-------------------85.9
2------------------165.8
3---------------------0.0
4------------------165.5
5--------------------85.3
6------------------------0
7------------------105.5
8------------------------0
9------------------105.4
10----------------------0
11----------------------0
12----------------------0
13-----------------165.1
14----------------------0
15-----------------184.2
20----------------------0
21-------------------203

I am running it on 220V AC.


Another odd thing I noticed is when the volume is near 0 and the buzzing is there with the 6080WA. That time if I measure voltage on terminal 1 or terminal 5, in both it shows 85V and the noise totally dispersers as long as I am holding the volt meter there.

[ghost_rider]

If the noise goes away after 3 minutes, as you state, then it is the sound the tube makes as it warms up. Simply turn on your amp and wait a bit before listening.

If it a noise that a tube makes constantly, then it is a noisy tube. Replace it. NOS is not a guarantor of anything, there are noisy NOS tubes and there are tubes that have been sitting dead in boxes for years.

The low voltage at terminal 9 is suggesting that there is something wrong with the 5998. Are your voltages in spec with the stock tubes?

Hi, Thanks for the reply. I also posted the voltage checks with the 6080WA tube for comparing.

But all the 3 tubes does the same noise and all of there were tested and guaranteed by the seller (Billington Export Ltd). Please do let me know should I do now to make it work. These three tubes cost me a fortune so do let me know if i should return all three of them or can i fix the amp somehow?

[ghost_rider]

Adding up another thing.

The noise on 5998 (if volume set to high) disappears when I am checking voltage on terminal 2. It makes some poping sound but then goes completely silent as long im measuring the terminal 2. 

[ghost_rider]

If the noise goes away after 3 minutes, as you state, then it is the sound the tube makes as it warms up. Simply turn on your amp and wait a bit before listening.

If it a noise that a tube makes constantly, then it is a noisy tube. Replace it. NOS is not a guarantor of anything, there are noisy NOS tubes and there are tubes that have been sitting dead in boxes for years.

The low voltage at terminal 9 is suggesting that there is something wrong with the 5998. Are your voltages in spec with the stock tubes?

I tried another tube and now the volts were

85.1 at 1
155.6 at 2
93.7  at 7‏
87.5 at 9

Still there was that buzzing. I kept it on for 15 mins and the noise was there. same with all 3 tubes.

I used the other (the one u said bad) 5998 with stock crack and it sounded great

[ghost_rider]

I tested with Speedball Crack with another tube.

Its a "6H5C SVETLANA (EQUIVALENT TO 6AS7G)". The sound isnt that good but its the least noisy tube with crack. What I mean by that is it still have that initial warming up humm/noise at 0 volume but it fades away in over a minute if the amp is playing and then does not return.

Only my 5998s are causing the problem. Still waiting for some solutions on them I will be going back to my university in 3 days for a semester and I cant take the crack, feels bad if i have to leave it like this