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Post by Chris on Oct 11, 2015 13:48:36 GMT
Interesting...or not...depends... Changed out my 6SN7s yesterday just for the crack,cranked it up and hmmmm....somethings not right..  Thought at first a connection wasn't right so checked the Bluetooth receiver then the cable connections. No problem. Switched it all off then had a look at one of my Russian 6n8s(very good) and one had a sort of filler/sealant around the valve base that had degraded. Switched it out and BOOM back in action!  Not very interesting I know but that's a first for me. Sounded like a speaker not connected properly. Nice easy fix as well! |
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Post by John on Oct 11, 2015 13:52:29 GMT
At least easy to solve
Today I had to re-install the driver on the NAD took my awhile to figure out why I had no sound
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Post by Chris on Oct 11, 2015 14:01:02 GMT
That computer stuffs too much for me! Glad you got it sorted.
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Post by Deleted on Oct 11, 2015 18:11:23 GMT
I rely on computer stuff for some things but playing music as a main source no way hosay. If my Computer crashes in the studio there is no way i can play any music, This is true if this same things happens on stage. Same with computer based music i done fore, however i know that pretty much everytime i used my turntable it will not fail, has never failed in the 32 years ive used it.
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Post by John on Oct 11, 2015 18:14:59 GMT
Celebrate la difference!
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Post by Deleted on Oct 11, 2015 18:28:56 GMT
I found this circuit I did a few days ago to be excellent.  |
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Post by MartinT on Oct 11, 2015 21:35:13 GMT
I'm not very good with valve circuits, Colin, is that a long tailed differential pair?
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Post by Deleted on Oct 12, 2015 8:35:45 GMT
No
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Post by MartinT on Oct 12, 2015 8:53:01 GMT
Ok, I'm still not good at valve circuits then!
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Post by speedysteve on Oct 16, 2015 13:25:00 GMT
Never had a computer crash on any of the laptops I use for serving music. Totally reliable.
Ok the older one had a HD die but not while being used as music server;)
Grand father, father, son with the back ups.
I even have a backup HD in the shed that is well away from the house;)
Sometimes depending on design a valve may take out a passive but usually to replace all the passives in an amp is not too expensive...
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Post by canetoad on Oct 16, 2015 23:37:04 GMT
Ok, I'm still not good at valve circuits then!  |
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Post by Paul Barker on Oct 18, 2015 7:32:22 GMT
Russian 6n8s(very good) and one had a sort of filler/sealant around the valve base that had degraded. Switched it out and BOOM back in action! Not very interesting I know but that's a first for me. Sounded like a speaker not connected properly. Nice easy fix as well! Clearly that valve was not working. But not because you saw something different between the valve base and the glass (or metal) envelope. The seal is made where loose leeds are brought out of the envelope, not where the envelope sits in the base. Your idea is that the valve no longer contained a vacuum. But when a valve goes "gassy" as we call it, a white mist forms inside it and usually clouds the glass. This is nothing like the mirror looking getter flash. It is like a fog. When valves have expired there is not often a visible sign. Strange that it went from working to nothing at all. Might be filament broken (test with ohm meter) or a bad contact from the loose wire into the pin. Sometimes worth resouldering, depending on the value of the valve to you. I have resurrected a few Globe valves resouldering the pins. |
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Post by Chris on Oct 18, 2015 13:43:01 GMT
Cheers Paul,interesting answer. I did indeed think it was the vacuum away. These valves are pretty cheap so I just threw it away. Should really have opened it up to have a look round but there's not much to gain in doing that tbh. I had a spare handy so turned out it was no big deal. I also wouldn't describe it as nothing at all - best way I can think of to describe it is as if a speaker wire wasn't connected properly. Then you wiggle it and it kicks in...
Nothing else had changed though so took out the suspect and that did the trick.
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