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I'm a tube novice. I bought my first tubed component, the SP9 Mk III used, and it performed well for well over a year. The seller said the tubes might last about that length of time. At some point, it stopped working while it was in operation and a tiny puff of smoke rose from the vent. I don't know what happens when a tube fails. I haven't opened the unit, but I'm wondering first, if that's normal and second, if I could tell by inspecting it if it is a matter of replacing the tubes. I'm not really in the financial position to send it off to ARC at the moment. Is is safe to order replacement tubes and try it? If so where and what brand do you recommend?
Follow Ups:
I've had mine for nearly twenty years and the only problem I suffered early on was the failure of an IC in the start up muting circuit. It simply wouldn't unmute.I agree with others that a puff of smoke is likely a resistor failure which shouldn't be terribly expensive to repair. Tubes are said to last for 5000 hours and the factory tube is the Electro Harmonix 6922 easily found at numerous tube vendors. I've yet to see a small signal tube go poof (big outputs, yes)!
I use the longer life 7308 variation.
edit: I would really recommend having ARC take a look.
Edits: 03/09/15
A resistor has probably smoked and burned out. There are a lot of solid state sand elements that could have smoked too. You need to refer to a competent repairman. This is not a tube problem! It is more likely a solid state self destruct problem but don't think that everything is lost. It may be simple. Have faith! Ray
"...the fool doth think he is wise but the wise man knows himself to be nothing but a fool." Will Shakespeare
Thank you for your responses. I did open the unit to do a visual inspection and looked at the tubes, which seen to be original as they are hand numbered for position as ARC does. They looked fine and I see no signs of burn or smoke anywhere.
Ok, so may I ask you Chip647, would you recommend dealing with ARC for the repair? I checked around the web and found a Soundsmith, which is authorized and apparently had a solid reputation, but the maximum repair for a high end preamp is $1250, and they don't notify you unless it would exceed that. That's about what I paid for the unit. It sounds like my issue is fairly simple, just wondering what kind of bill to expect.
You'll need to remove the bottom and inspect that side as well.
Also check the fuse.
Taking pictures and uploading may help us narrow down problem.
Hang in there!
Jonesy
"I know just enough to get into trouble. But not enough to get out of it."
I will check the underside and the fuse. I forgot all about the fuse. It would be wonderful if it was just a fuse replacement.
If you have to send it to a tech, have the coupling and output caps upgraded (I used Vcaps in my SP14) . The tubes in the SP9 are for the phono stage, if that is important to you use the best you can find (think Amperex, Telefunken, or Seimens). If you use it as a line stage only then use Sovtec. These preamps respond to a high end fuse (I didn't believe it until I heard it) and a better power cable.
Maybe your little problem will get you a better preamp.
Find a local repair tech. A puff of smoke is an electrical failure beyond a bad tube.
When tubes wear out, they start to sound kinda bad, then worse, then so bad that you know something is wrong. It could take over 1000 hours to go through the downward progression.
The smoke means that a resistor or capacitor or a transistor caught fire. A shorted tube may be the cause, or it may not. Either way, a new tube will not fix it. When tubes fail, any issue with the tube stays within the glass envelope. Only if the tube shatters would you get any smoke from the tube. Unfortunately, you are going to have to have someone repair it.
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