Nice find!
bcowen
Headphoneus Supremus
FWIW, bogey for a 12AT7 is around 4000, which would make more sense with the Hickok minimum being about 60% of that. Makes the readings you're getting even worse though (as they relate to NOS values). Sorry to rain even harder on the parade....
bcowen
Headphoneus Supremus
I've replaced a number of 6DJ8's over the years. Only a couple outright failed (as in no sound), but the others became noisier than hell and/or started losing dynamics and became rather dull sounding. Testing showed the GM had fallen well below minimum. Those are the only tubes that I've "worn out" per se...I've had a few random failures with other tube types, but I chalk that up to a flaky/marginal tube rather than failure from high usage.I am still curious what other's have to say, in regards to @billerb1's question about backups. It would be very helpful for me to know, if anyone has ever even had to use a backup or had a tube die on them? From past experience and then the one I had this morning, I am thinking my tube going bad was just a fluke. I am trying to convince myself I don't need backups, and if none of you have ever had to use one, then that's hopefullyenough to convince my OCD to stop wasting time and money
You guys have already taught me I don't need to wait 40 minutes between tube rolls, which has been a game changer. So, I am looking forward to what you have to say about the backups. It would be amazing to not have to worry about that too!
TK16
Headphoneus Supremus
You sure on the Hickok 752 roll chart 3,000 was NOS? At least the 1 on my tester. Thanks a bunch on the piling on about my 455's.FWIW, bogey for a 12AT7 is around 4000, which would make more sense with the Hickok minimum being about 60% of that. Makes the readings you're getting even worse though (as they relate to NOS values). Sorry to rain even harder on the parade....
Edit
Checked my 752 .pdf and it only has minimum of 625x4=2,500 with no NOS values. Never buying from that seller again.
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bcowen
Headphoneus Supremus
Yup, your 752 and my 752A use the same data with 'minimum good' values rather than NOS. General rule of thumb across most vintage tester manufacturers is the minimum value is approximately 60% of average NOS, and the NOS value in a couple tube data sheets I looked at is 4000 for a 12AT7 (with 100v to the plates). 60% of that is 2400 which corresponds decently with Hickoks minimum of 2500. So at test values of 3000/triode, that one tube you have is about 75% of NOS.You sure on the Hickok 752 roll chart 3,000 was NOS? At least the 1 on my tester. Thanks a bunch on the piling on about my 455's.
Edit
Checked my 752 .pdf and it only has minimum of 625x4=2,500 with no NOS values. Never buying from that seller again.
Apologies again for the party poopin', but please remember the calculations above required math which took me 3 hours and gave me a splitting headache and I kind of share your pain a little somewhat.
TK16
Headphoneus Supremus
Was thinking about lowering the bias dial lower than 14 until I get the numbers I want.Yup, your 752 and my 752A use the same data with 'minimum good' values rather than NOS. General rule of thumb across most vintage tester manufacturers is the minimum value is approximately 60% of average NOS, and the NOS value in a couple tube data sheets I looked at is 4000 for a 12AT7 (with 100v to the plates). 60% of that is 2400 which corresponds decently with Hickoks minimum of 2500. So at test values of 3000/triode, that one tube you have is about 75% of NOS.
Apologies again for the party poopin', but please remember the calculations above required math which took me 3 hours and gave me a splitting headache and I kind of share your pain a little somewhat.
jonathan c
Headphoneus Supremus
Which raises the GE conundrum: If a GE tube goes bad, it clearly is not a great loss. But can a GE tube go bad when it is already bad? Can one tolerate considering degrees of dreckness?…
They fixed the amp which required a new main board but wouldn't do anything about the headphones or the expensive tubes it killed. To say I wasn't best pleased would be an understatement...
Considering they still haven't replied about sorting out my faulty tube I am not sure I would have much faith in them actually reading the note and fulfilling that request.
Dude! I would be knocking down their door! Seriously, I can't believe they have not got you fixed up yet. I am loosing faith with Langrex, reading these last couple of post.
I emailed them for the 3rd time this morning as a reply to the original order confirmation so hopefully that one might get through...Dude! I would be knocking down their door! Seriously, I can't believe they have not got you fixed up yet. I am loosing faith with Langrex, reading these last couple of post.
Is there anyone in the UK that would be able to test them for me just to confirm my eventual replacement is actually measure as NOS?
Keeping it real, I just rolled in a new tube and damn this is another killer one! @TK16 I see you have this tube at the number 9 spot, and it ranks quite a bit higher for me. The Copenhagen ECC81 Angled D Getter 51' with bottom code TKB, has a freaking killer midrange. The tone, texture, timbre, and inner detail in the mids is stunningly lifelike, and the delicate touch of the notes is magic. I am hearing guitars and vocals as if they were in the room with me, and this tube has the "Thereness" factor in full affect. For acoustic music this tube is insanely good. Still burning it in, but so far it's all about the very involving mids with this tube and I am loving how it pairs with my ZMF's and their very involving mids. I have had this tube for a while now just sitting in storage, and after loosing my Lorenz ECC81 Foil D yesterday, I decided it was time to give it a go, as I like to have 3 driver tubes in rotation to keep things fresh. I have to say with what I am hearing so far, it has easily made the cut and will be put into rotation. This tube is more of a specialist in that it is all about the very unique and involving midrange that is clear and natural sounding, and for acoustic music (especially guitar and vocals) this tube is fantastic and has some tube magic that only the older "top tier" tubes can produce.
Happy Friday my friends!
This tube is more of a specialist in that it is all about the very unique and involving midrange that is clear and natural sounding, and for acoustic music (especially guitar and vocals) this tube is fantastic and has some tube magic that only the older "top tier" tubes can produce.Happy Friday my friends!
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Anyone watch the most recent Mike Moffat video? Right at the beginning he says the 12A_ _ family of tubes are garbage. I am guessing he has never heard the tubes we are using. 
A statement like that is just ridiculous!
A statement like that is just ridiculous!
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He's clearly just trying to drive the price down...Anyone watch the most recent Mike Moffat video? Right at the beginning he says the 12A_ _ family of tubes are garbage. I am guessing he has never heard the tubes we are using.
Brilliant! I am so glad he said that, now that you mentioned it.
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It's like
"Oh, you're using ghetto 12A* trash in your hyper-nirvana-class audio chainz!? Here, let me help you..."
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