plz help: Tube pre unplayable noise (Olympic MKII)

[valaka]

Hi, I have Shift Line Olympic MKII (visually in perfect shape) for half a year and it began to behave weird recently. Sometimes when I play, the tone starts to dissappear in some weird noise. The noise is audible only when I send some signal (play note) into Olympic. Usually, the tone itself can be heard through the noise, but sometimes it totally dissappears together with the noise. After some time, it usually starts to work normally. Could the cause be the adapter? I use the original one, but its cable is sort of damaged. Or is it the tube? Or what? Please, help!

thanks

Noise:


The volume boost is when I turned the Gain knob up.

Photo of the tube (are those red/orange dots normal?):

 

[Rhinosonorous]

I'll check mine for orange dots tonight. Do you have a spare tube that you could put in to see if that solves it?

 

[valaka]

Thanks!

No spare tubes, unfortunatelly.

 

[Rhinosonorous]

No Dots on mine. Not sure if that means anything, but the sound dying like that sounds like it could be an issue with the tube.

 

[valaka]

So, I received a kind email from Oleg from Shift Line:

The distortion is most likely caused by Return jack. it mechanically commutates signal when loop is not in use and sometimes gets oxidized. This can be easily checked: next time you'll hear this distortion just plug any cable to the Return jack once and remove it - noise and distortion should go away immediately and the signal should get back to normal level.

If this is confirmed, please plug in and out any cable to this socket for few times - this should mechanically clean the contact and it should run good for years again. This problem never happens when loop is in use - so fo shows and recording you might want to shut the loop with patchcord to be 100% sure your sound will not be interrupted.

The red dots on tube are good, it's actual glowing from the heater filaments - indicating that power is applied to the tube and it's heated to the working condition.
Please let me know how it goes.
Regards,
Oleg

You know what happened? Ever since I received this advice, Olympic was operating flawlessly, so I wasn’t able to try it out . I’ll give you an update, when the sucker starts farting out again. (I call it sucker just because it plays games with me. Apart from that, it’s an awesome little preamp.)