6sn7's crackle on start up

skite30 · « **on:** 13 Oct 2012, 01:44 pm »

I have a nice pair of sylvania gtb's when i first turn on my amp they make a kind of crackle popping noise. They do it just once. After that they are very quiet and sound great. I have several other pairs and none of them do this. Is this a problem?

dminches · « **Reply #1 on:** 13 Oct 2012, 02:54 pm »

Is the sound more of a pinging noise? I get that with my 6SN7s. It is likely the sound of the tube heating up. If it goes away and the tubes sound and test nicely I wouldn't worry about it.

kevin360 · « **Reply #2 on:** 13 Oct 2012, 03:24 pm »

I suspect that it's precisely as the OP described it – a bit of snap, crackle and pop as the condensate on the grid is destroyed. After the device is switched off, the tube will cool and the material that the getter doesn't exactly get will settle on the grid. When power is applied again, that weak short path will rapidly fail with some unsettling noises. I don't think it will ever 'work itself out', but it's not signaling impending doom.

skite30 · « **Reply #3 on:** 13 Oct 2012, 06:19 pm »

It is definitely not a ping. Pop crackle the only apt description. I dont know how they test but they are very quiet and sound great otherwise. No noise when turning off. Its the whole impending doom thing i am trying to avoid. I have lots of 6sn7's but only 1 pair of 300b's. thanks for ur help

Elizabeth · « **Reply #4 on:** 13 Oct 2012, 06:24 pm »

Basic 101 on tubes is mute for a few minutes at startup. Period.
Then you do not worry about startup noises, which are natural. and every tube different too.

Quiet Earth · « **Reply #5 on:** 13 Oct 2012, 06:59 pm »

Do the tubes make the "pop crackle" noise by themselves, or does the "pop crackle" noise come through the speakers?

If the noise is coming from the tube itself and not out of the speaker, is there sparking in the tube associated with the noise? (Try it in the dark to verify)

What is the make and/or model of the component that the tubes are in?

kevin360 · « **Reply #6 on:** 13 Oct 2012, 07:06 pm »

If it's what I mentioned, the sound will be heard from the speakers. If the sound is coming from the tubes, that's a different story altogether - as is the urgency of redressing the issue.

I'd bet a paycheck it's the former.

skite30 · « **Reply #7 on:** 13 Oct 2012, 07:31 pm »

The sound comes out of the speakers. I havent noticed any visual sparking or noise from the tubes . I will watch it tonight to make sure. It is a Triode Electronics TRV - a300se. Uses 2 6sn7 and 2 300b's.

SteveFord · « **Reply #8 on:** 13 Oct 2012, 07:46 pm »

Way to go - you could have just bought new tubes with Kevin's paycheck.
Honesty is not ALWAYS the best policy.

FullRangeMan · « **Reply #9 on:** 13 Oct 2012, 08:19 pm »

Quote from: skite30 on 13 Oct 2012, 01:44 pm

I have a nice pair of sylvania gtb's when i first turn on my amp they make a kind of crackle popping noise. They do it just once. After that they are very quiet and sound great. I have several other pairs and none of them do this. Is this a problem?

Putz, seems your amp is not heating the tube before delivery the hi voltage supply(B+) to the grid and plate of the tube, it is not a good thing.
May occour short tube life, of a flash as in the begining of this video(at 8 seconds):
http://www.youtube.com/watch?v=NPc8JN9mbDE&feature=related

When a cold tube receive the hi voltage supply strange things happen.

I think a good delay for heating a tube(cathode) is 20 minutes, after it the tube is hot and suited to receive the grid and B+ supplies.

So at this point is need more a time to the grid and plate stabilize after receiving the energy, resulting in around 40 minutes of cooking to listening.

medium jim · « **Reply #10 on:** 13 Oct 2012, 08:55 pm »

Paycheck, Kevin is retired! Get some contact cleaner and clean the tube sockets, reseat the tubes and use tube dampers. If the tube(s) sound good, then chances are they are. That said, test the tubes

Jim

p.s. Could be a grid short in one of the output tubes.

SteveFord · « **Reply #11 on:** 13 Oct 2012, 09:31 pm »

Come to think of it, he didn't mention just how large that paycheck would be.
Isn't there a candy bar called a Paycheck?

Elizabeth may be right - my preamps all have a mute feature for 20 or 30 seconds.

medium jim · « **Reply #12 on:** 13 Oct 2012, 09:47 pm »

Steve:

I always turn on my preamp then amps and then the turn off the amps then preamp. Most preamp circuits delay heating the preamp tubes or soft start them to avoid flashing them which reduces their life.

Jim

skite30 · « **Reply #13 on:** 13 Oct 2012, 11:33 pm »

The amp is actually a integrated with solid state rectification. Takes about 20 seconds after turning it on before sound comes out. It does not have a mute switch. Been a long time since i heard the word putz. Thanks

SteveFord · « **Reply #14 on:** 14 Oct 2012, 12:00 am »

The sound is being muted when it's warming up and then it crackles, is that correct?
I don't believe that Fullrangeman is fluent in Yiddish so I wouldn't take offense.

kevin360 · « **Reply #15 on:** 14 Oct 2012, 12:06 am »

Quote from: skite30 on 13 Oct 2012, 11:33 pm

Been a long time since i heard the word putz. Thanks

I fail to see how you've earned such a reference. Your question is a valid one and your original post gave some clues that have apparently been missed. You are already completely aware of where the problem lies. (You only have the issue with one set of your 6SN7s. We are, therefore, discussing an issue with a front end tube.) If it's what I suspect, then I'm not sure what could be done about it.* Depending on how muting is implemented, it would likely make no difference with this issue anyway.

---

I'm only semi-retired. I still work a low pressure (hence, low paying) job 3 days a week. I need money for music and whatnot. When I fully retire, I want to be sure I have enough money to feed my habit.

* Of course, there is the course of action which places that pair of tubes in the 'no longer used' drawer. Hey, maybe that pair of tubes would be candidates for a cryo experiment. Can the tube be rescued by being operated and then allowed to cool upside down, then hit with a deep freeze? I have no idea if there is any chance that such a procedure could be effective, but it wouldn't be expensive to do and if it yielded positive results (in a way which is incontrovertible by way of its lack of subtlety), that would be really cool. I'd do it just for the fun of it (but I'm definitely not telling you that you should do this - probably just a crazy idea).

SteveFord · « **Reply #16 on:** 14 Oct 2012, 12:16 am »

Fullrangeman is from South America - I'm sure that some wisenheimer told him that putz means friend or something along those lines.

medium jim · « **Reply #17 on:** 14 Oct 2012, 12:28 am »

Quote from: kevin360 on 14 Oct 2012, 12:06 am

I fail to see how you've earned such a reference. Your question is a valid one and your original post gave some clues that have apparently been missed. You are already completely aware of where the problem lies. (You only have the issue with one set of your 6SN7s. We are, therefore, discussing an issue with a front end tube.) If it's what I suspect, then I'm not sure what could be done about it.* Depending on how muting is implemented, it would likely make no difference with this issue anyway.

---

I'm only semi-retired. I still work a low pressure (hence, low paying) job 3 days a week. I need money for music and whatnot. When I fully retire, I want to be sure I have enough money to feed my habit.

* Of course, there is the course of action which places that pair of tubes in the 'no longer used' drawer. Hey, maybe that pair of tubes would be candidates for a cryo experiment. Can the tube be rescued by being operated and then allowed to cool upside down, then hit with a deep freeze? I have no idea if there is any chance that such a procedure could be effective, but it wouldn't be expensive to do and if it yielded positive results (in a way which is incontrovertible by way of its lack of subtlety), that would be really cool. I'd do it just for the fun of it (but I'm definitely not telling you that you should do this - probably just a crazy idea).

Kevin:

A grid short in one or more of the output tubes can cause noise or crackling in the preamp or driver tubes...this could very easily be the issue. The OP should (if ne hasn't already) try another set of 6SN7's to see if the crackling is still present.

Jim

skite30 · « **Reply #18 on:** 14 Oct 2012, 02:34 pm »

I watched for sparks last nite and there werent any. The crackle happens at about 8
Seconds and sounds start at about 20 seconds. All I was asking is if this situation is a doomsday scenario. If the tubes didnt sound so good they would have been in the trash can by now.
Thanks again

FullRangeMan · « **Reply #19 on:** 14 Oct 2012, 07:43 pm »

Quote from: SteveFord on 14 Oct 2012, 12:16 am

Fullrangeman is from South America - I'm sure that some wisenheimer told him that putz means friend or something along those lines.

I apologize any bad pun that might have occurred. I have to stop using this term.
It is a slang in Portuguese that means ''damn''.