Rabbit
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Post by Rabbit on Dec 29, 2015 14:43:09 GMT
I found a dodgy valve today on my Ember. It's been on there a while. The giveaway was a weird rustle sound every now and then. I could only hear it during quiet pieces and sounded like someone in the audience opening a sweet packet. At first, I thought it was a performer or audience member until the music stopped and I heard it clearly. Sound was fine, just a hint of a rustle. Changed the valve to a 6n23eb as sent to me tested!!! I pinged the side of the Ember and it rang like a bell. Only in one ear though. Put in another 6n23eb as tested ..... It rings as well. So I thought 'Blow the 6n23s and stuck in another one that I like ... Jan Philips. No ringing. Dead quiet no matter how much I ping. Perhaps that's why I've always like the Jan Philips valves. So check yer valves. They don't all ring. Do the ping test!!!!! Then with no music, turn up the volume and listen for hissing.......
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Post by jhelms on Dec 29, 2015 18:00:58 GMT
The rustling sound can be from: - So microphonic that the slightest movement of a headphone cable causes noise (definitely toss these) - When a tube gets super weak / past its life, they can do all sorts of odd things. Noises, clicks, rustling sounds. They will basically start to sound like the bias is way off - As the tube heats up, the grid wires can make noises. Ticks, clicks, hiss. This generally goes away on these tube types ones the tube has warmed up. Microphonics (depending on level and severity) do not indicate a bad tube. Almost all tubes are microphonic to some point - it is in their nature. They can test excellent with a lot of life and sound just as good as one with low to virtually no microphonics. However in home audio where heavier bass / higher spl can ring the tube - this STINKS. But in headphone amplifiers, no biggie. So in short, I would not toss a tube just because it rings if you tap on it. But if it does while you type on your keyboard and the amp is on your desk, then TOSS IT Certain series of tubes are HIGHLY prone to microphonics. Such as the 6n23p. I would say 8-9 out of 10 will audibly ring in some fashion. Same with many 6dj8's. It is the exception rather than the rule to find one that is not audibly microphonic. You really start to see it is luck of the draw or more tube type dependent when you have large qtys of NIB/NOS tubes and test each one, including microphonics testing. Get into certain tubes like 5814wa's, 6189WA's and such that were built millspec / beefed up internals and tighter tolerances and they are usually very resilient to microphonics. Not perfect, but I find the majority are dead to a tap on the glass.
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Rabbit
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Post by Rabbit on Dec 29, 2015 18:07:56 GMT
If I blew on mine, it would ring Jeremy!! Like a bell, just in one ear.
I liked the sound of the 6n23s generally, but noticed the rustling bag effect and then discovered the ringing which in the tired one was appalling and the replacement actually was too far off. If I tapped onto the desk top, it went.
These Jan Philips that I have are pretty dead. Not bad sounding either really.
Hope you had a good Christmas and weren't too busy!!!
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Post by jhelms on Dec 30, 2015 1:40:05 GMT
Ohhh yeah... that is a bad one. Some you can virtually play like a violin HA! They sing when barely touched. I have quite a full jars full of ones like that. For some dumb reason I find them nice decorations Philips made some great tubes. Even their late production 80's ECG tubes were top notch stuff. Build quality and tolerances seem excellent all around. Smart choice! Christmas was great - spent a lot of time with the family. Busy as always Hope yours was great and well spent - hard to fathom 2015 is already over. Here is to 2016!
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Post by techboy on Dec 30, 2015 5:27:39 GMT
With the right valve the Ember is dead quiet.
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Rabbit
Administrator
Posts: 7,087
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Post by Rabbit on Dec 30, 2015 8:40:49 GMT
Really? I never knew that.
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