Vox Ac15 C1 - valve problem (I think)

easter12

My AC15 C1 has started to crackle when I first turn it on.

The crackling sound stops after 10/15 seconds and then the amp is absolutely fine. 

Has anyone ever had the same problem?

I'm not technically great with amps but a few friends have said it might be the valves.
The power/output valves maybe?
Any advice?

Here's a quick youtube vid of the sound it makes when i turn the amp on:
https://youtu.be/FEdEkPaWT4M

Thanks for any help

ICBM

Hard to tell, but a valve is a possibility - not necessarily power, and not necessarily faulty but possibly making a poor contact with the socket.

Does it do the same if you use the standby switch on power-up and then switch to fully on, or not? Does it do it if you later put the amp on standby, wait a few minutes, then back to fully on?

ecc83

"We" had a batch of EL84s that made a quiet "rustling" sound for 20 secs to a minute at switch on. After a few on/off cycles they stopped doing it. I just left the amps on all day and then next day they were fine. The next batch of valves didn't do it as I recall.

Modern valves are ***t you see.

Dave.

easter12

ICBM said:

Hard to tell, but a valve is a possibility - not necessarily power, and not necessarily faulty but possibly making a poor contact with the socket.

Does it do the same if you use the standby switch on power-up and then switch to fully on, or not? Does it do it if you later put the amp on standby, wait a few minutes, then back to fully on?

Yeah it does still do it when I put it on Standby first and then put it fully on. It's not as loud though. Would that be significant? Thanks for your help 

Philtre

ecc83 said:

"We" had a batch of EL84s that made a quiet "rustling" sound for 20 secs to a minute at switch on. After a few on/off cycles they stopped doing it. I just left the amps on all day and then next day they were fine. The next batch of valves didn't do it as I recall.

Modern valves are ***t you see.

Dave.

JJ's?

easter12

ecc83 said:

"We" had a batch of EL84s that made a quiet "rustling" sound for 20 secs to a minute at switch on. After a few on/off cycles they stopped doing it. I just left the amps on all day and then next day they were fine. The next batch of valves didn't do it as I recall.

Modern valves are ***t you see.

Dave.

Thanks for your input I can try leaving the amp on for a good few hours and then see if that makes a difference. I have used it in the past though so it's not like the valves have not been used for long periods of time.