i luvmusic 2 said:

  Hi Mikelap,
    How much was the shipping and other charges?Thank!

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Shipping was $14.00 to Montreal total $54.00 U.S for a pair 

mikelap said:

  Shipping was $14.00 to Montreal total $54.00 U.S for a pair 

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Thanks!

Hi i luvmusic2,
 
The measurements depend on the reference point of the equipment used to test the tubes. Here is an example from a current Ebay listing:
If the tube was true NOS it should read 100% or even higher, for example 110%. The two readings correspond to the two triodes in a dual triode tube (in our case right and left channel if used as a driver). In this case the tube measures below acceptable in one channel.
If the tube has a life span of 3000 to 10000 hours I would not worry if the value is above good. You may have to turn up the volume slightly compared to a 100% tube.
In summary, you must ask what a "good" value is since each manufacturer is different.
 

General Mutual Transconductance (Gm) Test Results:​

44/56 Where the Minimum is: 50/50 and the NOS value is: 82/82
or
54/69% of what a NOS tube should test where the Minimum "good" value is 65%​

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mordy said:

  If the tube has a life span of 3000 to 10000 hours I would not worry if the value is above good. You may have to turn up the volume slightly compared to a 100% tube.
In summary, you must ask what a "good" value is since each manufacturer is different.

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Do you have a site you could link us to with tube life span specs or predictions?

mikelap said:

 

bbmiller said:

  https://www.vacuumtubes.net/RES%20Audio%20pages/5998.html what do you think of these?

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i bought a pair of Chathams from this seller.they work fine .

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Did you see all the brands on that page first and come to the Chathams decision by past experience or review or how?

bbmiller said:

  Did you see all the brands on that page first and come to the Chathams decision by past experience or review or how?

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Here is a nice review of 6AS7-type tubes.
 
http://the-key.enix.org/~krystal/review-tube-bottlehead.html
 
I have had good luck purchasing from www.vacuumtubes.net. That said, I have some doubt about the Mullard 6AS7's for $35. At that price, I am inclined to think they are Russian rebrands, similar to these:
 
http://www.ebay.com/itm/NOS-NIB-Mullard-USSR-6AS7G-Gray-Plate-UFO-Get-3-Mica-Vacuum-Tube-100-/121317136204?

Hi bbmiller,
 
It is difficult to predict tube life, but it seems to me that the octal tubes often were engineered for a life span of around 10,000 hours."The lifespan of the tube depends a great deal on its operating conditions. In other words, you can probably use up a 6SN7 in 2,000 hours or 10,000 hours, depending upon the choice of current and plate voltage. I think that a standard 6SN7 is rated for something less than 10,000 hours."
 
Seems that the smaller tubes such as the 6AK5 were engineered to last on average 3,000 hours. Various manufacturers made versions with longer lived heaters rated for 10, 000 hours. Amperex had PQ (Premium Quality) tubes, Mullard Millenium tubes, and GE Five Star tubes, the latter said to be good for 7,500 hours. Russian EV tubes are good for 5,000 hours and DR tubes for 10,000 hours. Russian tubes with suffix -i (6N6P-i) are supposed to last only 500 hours, but I think that means in a stressed environment inside an airplane and not in a home use amp.
 
Personally, being struck by the tube rolling bug, I cannot remember having a tube that I used up. If a tube stopped functioning it always was because of corrosion - a little scraping of the pins with a pen knife would restore it.
 
You can google individual tube types and see if you can find the life span mentioned.

gibosi said:

I have had good luck purchasing from www.vacuumtubes.net. That said, I have some doubt about the Mullard 6AS7's for $35.  

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Have you ever bought a 6AS7 from them you were satisfied with? Will they give you all the information on exactly what you're buying so you can research on review places like the one you link to? How where exactly would you get all the information from them if they will give it to you? Does it require it a dialogue with them?

bbmiller said:

  Have you ever bought a 6AS7 from them you were satisfied with? Will they give you all the information on exactly what you're buying so you can research on review places like the one you link to? How where exactly would you get all the information from them if they will give it to you? Does it require it a dialogue with them?

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I have not purchased a 6AS7 from them, as I do not have an amp that uses this tube. But of course, you can email them directly with your questions:
 
 sales@vacuumtubes.net
 
Whether or not you will be satisfied with their answers, I cannot say.

mordy said:

Personally, being struck by the tube rolling bug, I cannot remember having a tube that I used up. If a tube stopped functioning it always was because of corrosion - a little scraping of the pins with a pen knife would restore it.

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I do not know if there is some sort of view thread biased you bring to viewing a thread as lodges this one. But on this thread I have not run across people saying they are rolling tubes per vintage of recording. Do you do things like rolled tubes to listen to your favorite 60s or 70s recordings and have other tubes you use for modern recordings.
 
Also do you have a system of marking your tubes for left and right channels before you remove them. Is there a marker that will withstand the heat tubes make?
 
Is there a premium contact cleaner recommended by the people on this thread? I mean something like the old spray tuna cleaner you used when televisions had those click to change channels tuners?

David and Goliath?.... Read on!...
 

 
Guys...just when I thought I was done with mind-blowing moments in this rolling game, I thought (for a laugh) I'd pop in the cheapo 6HM5s, in place of the C3GSs....and SHOCK, AMAZEMENT, BEWILDERMENT...final proof that the traditionally-held "wisdom" re the power tubes having only slight influence on the final results is TOTALLY WRONG - dare I even say it?!
 
What hit my ears left me dazed, to say the least...expecting to go 'yeuch', I was not prepared for a sound that wasn't actually far off the C3GS's. They never sounded like this with the 6N30P-DRs.
 
As I am still reeling from the shock, I will have to end here and have a treble espresso (or equivalent). These 6AS7Gs are truly amazing tubes, and have rewritten the book, lol!
 
So what will the Tesla E88CC (gold grids & pins) do? Probably have me shooting myself!! . Will keep you posted...

bbmiller said:

  Did you see all the brands on that page first and come to the Chathams decision by past experience or review or how?

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Yes i saw all the tubes on that page the Chatham tubes seem to be well regarded and for $20.00 each that as much as i want to pay theres the Tung Sol 5998 at $85.00 each that are supposebly better but i probably wouldnt ear the difference anyway. So i only have the affortable 6AS7G tubes like the  Chathams, RCA, and Russian equivalent 6SN5S that are cheap but decent.

mikelap said:

 

bbmiller said:

  Did you see all the brands on that page first and come to the Chathams decision by past experience or review or how?

Click to expand...

Yes i saw all the tubes on that page the Chatham tubes seem to be well regarded and for $20.00 each that as much as i want to pay theres the Tung Sol 5998 at $85.00 each that are supposebly better but i probably wouldnt ear the difference anyway. So i only have the affortable 6AS7G tubes like the  Chathams, RCA, and Russian equivalent 6SN5S that are cheap but decent.

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Please bear with me I am trying to understand this tube rolling stuff are you saying you own at least three pairs 6AS7G tubes or their equivalent and are rolling them for some purpose? I mean per headphones or per type of music or per vintage of recording or per something else?

hypnos1 said:

  David and Goliath?.... Read on!...
 

 
Guys...just when I thought I was done with mind-blowing moments in this rolling game, I thought (for a laugh) I'd pop in the cheapo 6HM5s, in place of the C3GSs....and SHOCK, AMAZEMENT, BEWILDERMENT...final proof that the traditionally-held "wisdom" re the power tubes having only slight influence on the final results is TOTALLY WRONG - dare I even say it?!
 
What hit my ears left me dazed, to say the least...expecting to go 'yeuch', I was not prepared for a sound that wasn't actually far off the C3GS's. They never sounded like this with the 6N30P-DRs.
 
As I am still reeling from the shock, I will have to end here and have a treble espresso (or equivalent). These 6AS7Gs are truly amazing tubes, and have rewritten the book, lol!
 
So what will the Tesla E88CC (gold grids & pins) do? Probably have me shooting myself!!

. Will keep you posted...

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OK...it's official...I'm gonna shoot myself!
 
Having just recovered, thanks to good ol' caffeine, my mind has at last totally blown...the reason...:
 

 
With the Teslas in the driving seat I'm once again in a mortifying stupor...this is just crazy! These 6AS7Gs take otherwise very good tubes to an entirely new level. On preliminary listening there is now only the slightest difference between the sound from the Teslas and that from the wonderful C3GS. Will need much more testing yet, but it's so close that I cannot really put my finger on the actual differences...perhaps the C3GS does things with a little more delicacy is all I am getting at present. But overall, if the 6AS7Gs had been in place way back then, I would have saved myself a lot of money...aah, this rolling game lol!
But, of course, these E88CCs have to be adapted - no commercially- made ones available, I think.
 
And so the saga continues...oh my poor head hurts! .

Hi bb,
 
IMHO tube rolling involves finding the tubes or combinations thereof that sound best in your system. The sound signature will affect all music you are playing. There is a consensus what the best tubes are, and within these top tier tubes you have to pick what your personal preference is.
 
It's not about a certain tube being better for hard rock and another for classical music. It's about a tube/tube combination that makes everything sound right, albeit there are subtle differences between the best sounding ones. (I personally feel that octal tubes match very well with old 78 recordings. However, it could just be the difference between analog and digital recordings.)
 
Please note that the price of the tube is not related directly to how good it sounds. There are many lesser known inexpensive tubes that beat the hyped up expensive alternatives. In addition, the same tube can cost $5 from one seller, and $35 from another seller - caveat emptor.