# Is my Ycs90 cooked?



## Zifnab (Dec 1, 2017)

This may be a bit long, but bear with me please, I'm not so technical.

So last night I went to the studio to jam with the band, and I turned my Traynor YCS90 on. As I was firing up the computer I noticed a single crackle noise come out of the speakers. I thought it was odd and let it sit while I fired up the iMac. I grabbed my explorer off the wall and plugged it in then hit the standby switch on the amp. I was greeted with a loud popping noise from the speakers. This amp has never made more than the slightest noise coming off standby. It makes the same noise without anything plugged into the input jack. All the tubes are glowing but one of the power tubes (5881/6L6) is about 3 times brighter than the others. All 4 power tubes turn blue when the amp is switched off standby. The amp will play my guitar through it ( I strummed the strings while it was on the wall). After about 5 more minutes of being off standby, it made the loudest, most terrible noise I have ever heard come out of an amp. It sounded like electrical interference, ggggzzztttbbbzzztttt (pretty good description eh?) It does not make the noise when in standby but will crackle a bit. 

I don't know the first thing about what goes on inside an amp to make it make the sounds it makes, so I need a bit of help. I have had the amp for about 5 years and have never changed the tubes....I've never had an issue where I noticed any drop in volume or sound quality. Can this be caused by a bad tube? I tried gently tapping on the tubes with the back of a sharpie, and I did not notice any change with everything turned on. The Ggggggzzzbbbttzztt comes after about 2 mins off standby. It should be noted that it does not make the noise with the master volume turned right off, and it will make the noise on both 25 and 90 watt settings.


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## dtsaudio (Apr 15, 2009)

Very likely bad 6L6. The one that is glowing brighter, is it just filament or the large metal plates?
If the plates, it is called red plating and is probably the death of that tube. That could be the tube or something ahead of that tube. The noise is quite likely a short internal to a tube.
Blue glow is nothing to worry about.


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## Scottone (Feb 10, 2006)

how close was your Mac to the amp? Some amps seem to be sensitive to signals emitted from iPhones and laptops. I had this issue with a PRS amp...couldn't keep my phone anywhere near it.


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## Scotty (Jan 30, 2013)

Scottone said:


> how close was your Mac to the amp? Some amps seem to be sensitive to signals emitted from iPhones and laptops. I had this issue with a PRS amp...couldn't keep my phone anywhere near it.


Interesting, I have an old receiver that makes a horrible racket for about 5 seconds when I turn it on. Ipad or Iphone sitting right there. Although, the receiver is solid state...so, maybe its just a POS

Hope I did not hijack. 

Watching with interest actually. I have A ycS90 also


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## dtsaudio (Apr 15, 2009)

Usually when cellphone or other wifi device is causing the noise, it is a higher pitched noise, and not real loud. This definitely sounds like a shorted tube.


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## Scottone (Feb 10, 2006)

dtsaudio said:


> Usually when cellphone or other wifi device is causing the noise, it is a higher pitched noise, and not real loud. This definitely sounds like a shorted tube.


You're probably right....I find that these problems are tube related about 90% of the problem.


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## Zifnab (Dec 1, 2017)

The iMac is in a different room, and has been there since we built the studio. The amp has never made any noise at all before. Should I replace just the power tubes? Or all 7?


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## dtsaudio (Apr 15, 2009)

Sometimes the vibration of the speaker can cause the small signal tubes to loosen up and cause noise, however the most likely cause is the power tubes. Start with those.


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## copperhead (May 24, 2006)

Replace the power tubes 
If you don't have a spare 6l6/5881 kicking around to test .


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## Zifnab (Dec 1, 2017)

Thanks for the input peoples. I do not have any spare tubes, I have never had to replace any and this is the only tube amp I have ever owned. I will get some on order and see what goes down. Oh, whats the best place to order some or suggestions on what type? We mainly play rock.


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## Scotty (Jan 30, 2013)

Traynor YCS90 Amplifier - Tube Replacement Sets


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