Rabbit
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Post by Rabbit on Jun 12, 2017 20:54:48 GMT
It's funny, but for some, this is the beauty of tubes; being able to 'tweak' the sound but for me it's also their weaknesses that can be annoying in that they deteriorate slowly as soon as you start using them so that you're unaware of how bad a tube might be even at close to the end of its life. You can get very accustomed to the sound and accept it as fine until it's really obvious.
Also, the subjective nature of listening to different tubes and going on 'taste' can lead to serious cases of 'tubitis' where the listener buys a shopload of the things in an attempt to 'better' their amp subjectively and it's such hit and miss activity!!
I used a tube in my Ember until it was so noisy that it sounded like a poor fm radio station hissing. I didn't really notice if I'm honest, until the very end and realised that I had been lostening through the snow. It was a nice tube as well ... an Orange Globe.
Hiss is a strange thing because we seem to have the ability to turn it off and hear through it without realising, I think.
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Post by lobalwarming on Jun 12, 2017 22:41:01 GMT
At least you were listening to vintage hiss. It's much more pleasing than modern 21st century hiss. LOL!
As string instrument player, I know too well the sounds of deteriorating strings. And the brief sweet hours after break-in of optimum tone. I hope to approach tube rolling with a zen-like appreciation of the impermanence of all things. Especially my bank balance. ;-)
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Post by lobalwarming on Jun 12, 2017 22:50:31 GMT
Nope didn't envison that. I did expect a lot of exotic tubes that would be used using adapters though. A problem with tubes is that there is no single (or combination) of certain parameters that quarantees a certain sound. Yes, you can calculate gain and even frequency response etc but it is hard to predict how much 2nd harmonics the tube will generate under certain conditions. No clear correlation to perceived SQ and specs exist so hard to say what one will have to be looking for in tubes. You could even use pentodes (in triode config) using adapters etc. This way one could add lots more suited tubes when you have an adapter that accomodates for 2 pentodes for instance. The fun part of the Ember (and other G1217 amps) is the very wide range of currents and heaters that can be used. How the sound will turn out is partly science and partly subjective. Pentodes? Adapters? Can we call Jeremy? Experimentation is a big part of the appeal of tube rolling for me - tweaking to suit our own personal taste. Headphone listening for pleasure only needs to please one set of ears. And the eager ears of some internet forums. ;-) |
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Post by starence on Feb 8, 2018 6:38:58 GMT
Hey guys, tube rolling noob here. When you're shopping for tubes, how do you determine whether they're "high gain" or not?
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Post by lobalwarming on Feb 8, 2018 7:09:40 GMT
You look for the tubes with the volume control that goes to 11  Or you find out using the sensible way by looking up the tube type. Although type naming scheme sometimes seem less than sensible. For example in the 12Ax7 family there is: 12AX7 - amplification factor: 100 - highest gain tube in the family - (Great for guitar amps, for hybrid headphone amps, not so much) 12AT7 - amplification factor: 60 - medium high gain 12AY7 - amplification factor: 45 - medium gain 12AU7 - amplification factor: 19 - medium low gain The 6DJ8/6922 have an amplification factor of 32. The much loved 6SN7/12SN7 family an amplification factor of 20. If you want to look up other tubes, can download data sheets from here: www.r-type.org/search.phpWhat is the tube type you're looking at and what amp do plan to roll it in? |
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Post by starence on Feb 10, 2018 7:44:46 GMT
I looked up the 12BH7 data sheet, and it seems like it will work with either a 6V or 12V heater. I wonder which setting would be better to use.
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solderdude
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measureutternutter
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Post by solderdude on Feb 10, 2018 16:08:11 GMT
I looked up the 12BH7 data sheet, and it seems like it will work with either a 6V or 12V heater. I wonder which setting would be better to use. It should be set at 12V. (the 12 in 12BH7 is the indicator) In this case both heaters work as expected and get 6V. On 6V setting both heaters get just 3V and do not heat up properly. Takes more time to reach a working temperature where the cathode starts to emit electrons. It is possible the tube heaters work just enough at 3V but is far from a desirable situation. |
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Post by starence on Feb 11, 2018 13:37:43 GMT
Thanks guys. Does turning your amp off and on frequently shorten the life of the tubes? Like should you turn the amp off if you're not going to be using it for an hour or two, or will that cause more wear on the tube than leaving it on?
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solderdude
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Post by solderdude on Feb 12, 2018 10:06:28 GMT
When not using it for one or two hours it may be best to leave it on.
It takes time for tubes to reach optimal working temperature/conditions.
This takes about 10 mins so when not using it for 1 or 2 hours you can leave it on.
For more than a few hours or not sure to come back and use it again in a short time period it may be best to switch it off.
No need to keep it on 24/7.
Only when using tubes that flash brightly on start-up and then glow softly tube life may be affected.
When the tubes light up slowly lifespan will not be affected.
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Post by starence on Mar 29, 2019 16:02:38 GMT
What does it mean when it's not possible to set the bias low enough for a tube? I bought a 12AT7WC that seems to be in good condition, but no matter how low I set the bias on my Sunrise 3, it's apparently still too high. Is the tube simply not compatible with my amp?
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solderdude
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Post by solderdude on Mar 29, 2019 18:11:38 GMT
It looks like the tube cannot supply enough current.
The range in which the SR3 can be set is very wide.
The 12AT7 is designed to work on a very high voltage and designed for RF radio amplification.
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Post by starence on Mar 29, 2019 20:16:45 GMT
Thanks for the response. Is it bad to keep turning the bias trimmers past the point where they start clicking?
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Post by starence on Mar 30, 2019 1:11:09 GMT
I guess I can answer my own question this time. There's no point in going past where it starts clicking, that's the limit of how far it can be adjusted. After letting the tube burn in for several hours, I've actually got the bias dialed in well enough, it's still slightly high on one side though.
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solderdude
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Post by solderdude on Mar 30, 2019 5:59:58 GMT
Thanks for the response. Is it bad to keep turning the bias trimmers past the point where they start clicking? Nope... just don't keep on turning them after you heard a few clicks or so. The bias being slightly on the high side isn't a problem unless you use insensitive headphones and drive these loud and the sound distorts. |
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