Amp Whooshing Noise

[Metlupass2]

Sorry I'm putting this here cause the tech section gets no attention.


So I accidentally started up my Quick Rod last night for about 20 secs without having the speaker plugged in. I turned it off, plugged the speaker in, turned back on and it played fine last night.


Today I start it up and it makes this noise whenever I take it off standby. I'm a tube amp N00b so anyone know what this might be?

Thanks!

 

[LP Freak]

You done fucked it up.

 

[Whowantsamustache]

Nah it’s most likely a tube went. Probably a pre amp tube...or a power tube. People need tube testers.

 

[Metlupass2]

You done fucked it up.

Can you unfuck it up for me please sir?

 

[ChurchHill]

Does it fade away eventually? Definitely sounds like a tube, but there are several things it could be.

If replacing the tubes doesn't help, I'd take it to a tech. Might think about giving Scott Splawn a call or shooting him an email (see the Splawn website for contact info). I seriously doubt you're the only person who's ever done this (run it without a speaker) and he might be able to offer some advice.

 

[glpg80]

Bad pre-amp tube. It's not related to your cabinet disconnect issue. Transformers are fairly indestructible. 5 minutes without a load can cause problems, but 20 seconds is nothing that will cause harm.

 

[Metlupass2]

Does it fade away eventually? Definitely sounds like a tube, but there are several things it could be.

If replacing the tubes doesn't help, I'd take it to a tech. Might think about giving Scott Splawn a call or shooting him an email (see the Splawn website for contact info). I seriously doubt you're the only person who's ever done this (run it without a speaker) and he might be able to offer some advice.

Yeah about 10 secs just like in the video. I did sent Scott an email tonight. I just got the amp used the other day so not sure how old the tubes are.

Thanks guys. I'll try a preamp tube first.

 

[ChurchHill]

Cool. If it's fading away, almost definitely a tube. I'd think the transformer would be pretty unlikely, considering the duration. It could have damaged a resistor, but if it's fading like that, I doubt it.

Since the amp was used and you're not sure about the history of the tubes, I might want to consider replacing all of them, both preamp and power tubes, and getting it biased. Even if the tubes are still good, it never hurts to check the bias and make sure that the tubes haven't drifted too much since the last time it was biased.

As for tubes, I'm not sure what Scott's recommending these days, but I'm sure he'll tell you. I've got a Splawn Competition (50w QR minus the clean channel) and I had really good luck with the Mullard 12AX7s and maybe a JJ ECC803S for the PI. I used Gold Lion KT77s for power, but if you want to stick with EL34s, I've heard that the EH EL34s are pretty good and reliable these days, too. I think that's what Friedman are using these days.

Good luck and let us know what you find out!

 

[Metlupass2]

Thanks. The guy I bought it from told me he bought new tubes from Scott last year. They are the Splawn branded tubes Scott has on his online store.

 

[ChurchHill]

I think those look like Chinese tubes to me. Should be good sounding, but from what I've heard, they can be prone to failure, depending on how much QC they've been put through. Depending on how much playing time the power tubes have on them, they could be getting close to needing replacement, too. Not sure what year yours is, but mine's an '07 and has 525 volts on the plates, which can be pretty rough on power tubes. It's pretty likely they at least need to be biased again. Preamp tubes last longer, but even new ones can go bad.