help with noise at startup volume turned down

[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  ;D ( 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  ;D

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  ;D ( 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  ;D

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

 

[Paul Birkeland]

The 5998 does not have the high strength heater to cathode insulation that the 6080 and 6AS7 do.  Consequently, when you exceed the 100V heater to cathode voltage limitation, there is the possibility that the tube will make some noise while operating.

One way to check to see if this is an issue is to plug a 12BH7 into the amp with the stock circuit.  This will drop the grid bias on the 5998 significantly, and lower the cathode voltage at the same time.  If this solves the noise issue, then there are approaches that can be implemented to account for this.

-PB

 

[Paul Joppa]

PB is exactly right. Remember, the circuit was designed for the 6080 or 6AS7, which have unusually high heater-cathode voltage ratings of +/-300v. Most tubes, including the 5998, are at most +/-100v.

 

[tdubl07]

Hi guys, I was following this thread today because I as well got a 5998 in the other night, and had the loud hum going on as well. This is with the stock 12au7 also. So I'm very glad it's something as simple as a different tube up front. With my 6080 in, no humming at all and the amp sounds glorious with the speedball. Thanks for the helpful insight PB and Paul.

 

[ghost_rider]

The 5998 does not have the high strength heater to cathode insulation that the 6080 and 6AS7 do.  Consequently, when you exceed the 100V heater to cathode voltage limitation, there is the possibility that the tube will make some noise while operating.

One way to check to see if this is an issue is to plug a 12BH7 into the amp with the stock circuit.  This will drop the grid bias on the 5998 significantly, and lower the cathode voltage at the same time.  If this solves the noise issue, then there are approaches that can be implemented to account for this.

-PB

PB is exactly right. Remember, the circuit was designed for the 6080 or 6AS7, which have unusually high heater-cathode voltage ratings of +/-300v. Most tubes, including the 5998, are at most +/-100v.

Thanks PB and Paul. But the thing is I cant check with a 12BH7 now

Let me explain my situation a little. I am from Bangladesh and I study in the UK. I was at home now for easter and in here i got the crack and built it. The problem is I cant find any tubes within few thousand miles of my home country and the post office is not very delicate so getting off ebay is also not an option. Therefore what I did was when coming back to home from UK,I bought 3 5998s,2 mazda 12au7,1 westingstone 12au7 and a Svetlana 6H5C. The reason I got so many of them is cause getting a tube in uk is alot easier than getting one in bangladesh. I am leaving in 3 days for 4 months (another semester). The crack will be left home because of its size and weight.

I can bring some 12BH7s next time when I come back home but I was thinking is there any other problems that might have happened here? Like if I have soldered something wrong in the board (which is highly unlikely cause I double checked everything) Or any errors from my end? Because from I have read is that the 5998 is a very very common and proffered tube for the crack and also with speedball. So many people is running a 5998 in there crack+speedball system. Are all of them using the 12BH7s? Do they also face the same problem with 12au7s? Or is it just me and "Hornet900"?

I guess im getting too worried about the speedball but see I was really really excited about it. So much excited that I already started saving up for the S.E.X or Stereomour for a small speaker setup for my room So you can understand when this bad hum comes with all 3 tubes,how i feel  :'(

I will order some 12BH7s in a week but in the meantime do let me know if there are anything els I can check? Just to be sure that there is no problems/errors/mis-solders from my side and the amp is built right,now all it will need is a 12BH7.

Thanks everybody for the help.

Ghost_rider

 

[Paul Birkeland]

It's just a matter of how lucky you are.  A lot of 5998's work fine, some do not, and this operation will depend a bit on how strong the 12AU7 is that's used in conjunction with the 5998.

If the amp works well with your Svetlana tube, but not with the 5998, that would point to an insulation issue in the tubes themselves.

 

[ghost_rider]

It's just a matter of how lucky you are.  A lot of 5998's work fine, some do not, and this operation will depend a bit on how strong the 12AU7 is that's used in conjunction with the 5998.

If the amp works well with your Svetlana tube, but not with the 5998, that would point to an insulation issue in the tubes themselves.

I just found something very stupid that i think I did. I was looking at speedball update guide and i noticed a 270k Ohm resister at the terminal 12U and 13U. But I remember I only attached the capacitor there. On my inspection I saw that I really dont have a resistor installed on my 12U and 13U. I was shocked as how did i miss it and it never came up in my volt checks.

Anyways the wierd thing is I have holes on both the terminal 12U and 13U but no resistor there (I usually filled the holes with solder.)

I am gona get a 270k Ohm 1W resistor first thing tomorrow and try to connect it and pray it works  :-[

It feels like a beacon of hope cause a wire is going from terminal 13 to power tubes 2 ports and then to terminal 2. And when I connected my Volt checker to terminal 12 and 2,the noise did vanish for a while.

Do you think it might work?  :-\

 

[Hornet900]

One way to check to see if this is an issue is to plug a 12BH7 into the amp with the stock circuit.  This will drop the grid bias on the 5998 significantly, and lower the cathode voltage at the same time.  If this solves the noise issue, then there are approaches that can be implemented to account for this.

-PB

Hello
I'm going to buy some more tubes so I'll get a 12BH7 now

What are the changes to the amp you are talking about Paul to make it work with 5998 ?

 

[fullheadofnothing]

The 270KΩ resistor is there to bleed off the voltage from the power supply. DO NOT RUN YOUR AMPLIFIER WITHOUT IT!!!!!!

 

[ghost_rider]

The 270KΩ resistor is there to bleed off the voltage from the power supply. DO NOT RUN YOUR AMPLIFIER WITHOUT IT!!!!!!

I totaly forgot to put that one in. I dont know how it happened. 

I will get one tomorrow and install it. Do you think it might solve my problem?

 

[ghost_rider]

I just installed the 270K 1W resistor on the terminal 12U and 13U. Sadly nothing changed

There is still the warm up noise/hum when using the 6080WA for first 5mins at 0 Volume and Noise/hum on all volume levels with Tung Sol 5998 There are still some pop sounds when I increase volume from 0 to 5mm. The Noise/hum is louder on the left side than the right side.

What should I do now??