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I've not seen any metal bases with yellow print.All the ones I've seen have had either black or green print
For tubes, never say never.
Granted, this tube isn't labeled 'Sylvania' - but I have seen one Sylvania metal base with yellow labels. Just one. Unfortunately I do not have a photo of that tube.
__________________
Curator of The Reference 6SN7 Thread : GO HERE!!
Author of The New & Improved™ Tube FAQ for Newbies! : GO HERE!!
>>NEW!! JUST IN!!<< Author of the The 6SN7 Identification Guide : NOW HERE!!
"Life without music is an error - Nietzsche"
I keep my PROFILE updated religiously - YOU should too!
I have a friend who worked for RCA and has multiple patents, though he was the inventer and RCA has the patent, on tubes. He designed and got the ball rolling on many tubes. I never thought to ask him about what he may know about the black and grey glass tubes but I will pose this to him. It is funny because many of the "new" circuits using tubes you read about and are brought forth as something just thought of are not. I have brought many of these designs to his attention and he always recognizes them.
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John aka Jam and Jama Photo gallery at:www.pbase.com/jamato8
The one constant in life is change, so will that change?
Feel with your own heart, see with your own eyes and hear with your own ears. Sand is sand no matter where it is found. Listening to: The Greatful Dead, The Closing of Winterland 1978, Fillmore West 1969, Lucinda Williams Favorite headphone: Ultrasone Ed. 9 #1010 Listening to: Predator- an exceptional portable, Woo 6 Modified-pseudo dual PS, iBasso D2 Boa, the new Xin Reference Portable amp ratings: *1. a. Xin Reference 12,000uf, b. RSA Predator*2. iBasso P2 *2. Micro IV*3. Mini IV *3. SR71 *4. D1 iBasso upgraded amp *5. iBasso P1 (upgraded opamps) *6. C & C Box (good decay, tilted up high frequency, slightly synthetic) *8 iBasso T1 *9. iBasso T2*10. XTRA X-1 (warm not neutral, very musical) *11. LD M+ These amps are enjoyable to listen to and present a slightly different interpretation of the musical signal. Portable monitor ratings: *1. PortaPros, KSC35 (modified-a great value) *2. Amadana P-117 bamboo *3. UM2 (respond to top quality amplification but I don't enjoy their sound) *4. OVC 8+ Source: iRiver H130,140, D303 optical out, D-EJ955, D-EJ1000, D-EJ2000, 25s, 25, D-303, D-777 and others (optical out if available) Digital Conversion: Altoid tin Monica Dac I, Altoid tin Monica II Asynchronous Reclocking Dac. Headphone Amplifiers: iBasso D1, IV Micro, IV Mini, Xin Reference, SM3B, SuperMacro V LE, SM3 V6 Xin (IV all switches), XRTA X-1, LD Micro +, LD Micro Tube, C&C Box, iBasso P1, P2, D1, D2, Woo 3 Modified-Siemens 6922 driver, 7236 power tube, Woo 6 Modified Pseudo dual PS - Headphones: Ultra Ed. 9, HD650, Ultrasone 750, HFI780, PortaPro modified, KSC35, Equation RP-21, Westone UM2
"I have a friend who worked for RCA and has multiple patents, though he was the inventer and RCA has the patent, on tubes. He designed and got the ball rolling on many tubes. I never thought to ask him about what he may know about the black and grey glass tubes but I will pose this to him."
It would be great to document the real story from the "old timers" who made the tubes and find out why things were done a certain way. In both the manufacture and marketing methods used. I'm sure they just didn't use black/grey glass because it looked sexier.
National Union (NU) gray glass 6SN7GT with rectangular top mica is the same with RCA grey glass which is the same as RCA VT-231
Look again -
There is no rectangular mica on a true NU grey glass. It is round. The mica spacers are also square, in contrast to the rectangular ones on both RCA variations.
When you have enough experience with tubes you will realise that labels can mean nothing - I've seen tubes that were clearly RCA labeled NU.
__________________
Curator of The Reference 6SN7 Thread : GO HERE!!
Author of The New & Improved™ Tube FAQ for Newbies! : GO HERE!!
>>NEW!! JUST IN!!<< Author of the The 6SN7 Identification Guide : NOW HERE!!
"Life without music is an error - Nietzsche"
I keep my PROFILE updated religiously - YOU should too!
Just a quick couple of questions on the RCA 6SN7GTA.
I've got a single pair of these tubes which actually seem like a very nice 6SN7 variant. They have two side getters, directly opposite each other and at right angles to the plates (meaning, you can look at the flat side of the plates, but the gap between the plates if you're looking at the edge is obscured by the getters). Why two getters?
Also, what's up with this tube? Seems like RCA made 6SN7GTs for quite a while, made the GTAs for a very short time, and then moved right into GTBs. Is my perception correct?
Thanks,
Stuart
__________________
Stuart Hall
(sturob@swbell.net)
(sturob@onebox.com)
I've got a single pair of these tubes which actually seem like a very nice 6SN7 variant. They have two side getters, directly opposite each other and at right angles to the plates (meaning, you can look at the flat side of the plates, but the gap between the plates if you're looking at the edge is obscured by the getters). Why two getters?
the question should be - why not?
Actually, no one outside of the engineers/designers behind that tube will likely know the answer to that question. I suppose the best answer for now would be: because they can.
Originally Posted by sturob
Ilso, what's up with this tube? Seems like RCA made 6SN7GTs for quite a while, made the GTAs for a very short time, and then moved right into GTBs. Is my perception correct?
Yep - 100% correct. GTAs were never very popular and were quickly superceded by the better-rated GTB. My understanding is that GTAs took time to succeed the GT type (much like how leaded petrol was phased out in favour of unleaded), and by the time the phaseout of GT was complete, GTBs were already on the market. Kinda like how we all jumped from CD to VCD while leaving LD on the wayside.
__________________
Curator of The Reference 6SN7 Thread : GO HERE!!
Author of The New & Improved™ Tube FAQ for Newbies! : GO HERE!!
>>NEW!! JUST IN!!<< Author of the The 6SN7 Identification Guide : NOW HERE!!
"Life without music is an error - Nietzsche"
I keep my PROFILE updated religiously - YOU should too!
Why not indeed. They look like a lot of work; I guess I'm not surprised the GTBs succeeded them so quickly. There seem to be a ton of Sylvania GTAs, but not so many RCA GTAs. Doing both of those getters, flashing both sides, blah blah, lots of extra time/expense if it's not "needed."
They are a nice tube/valve, though.
Stuart
__________________
Stuart Hall
(sturob@swbell.net)
(sturob@onebox.com)
Linear Mode
