[Cognomen]

Lucked out with a free junk box that included 6SN7GT: 3 GE top-heated "Christmas Tree" coin base 6SN7GTB and about half a dozen singles, none holy hyper but they are no longer cheap anyhow! A GE coin base occasionally sends a fairly loud crackle to my speakers, sounding sort of like a spark of amplified static electricity. I re-scraped the pins and made sure the tube was plugged in tight and restarted the amp. After the amp had played music for awhile, if my hand was an inch or so away from the tube, it crackled a few times. When I turned the volume to zero, and lightly touched the tube with a pencil, my speakers crackled. If I do not provoke a crackle, it will probably crackle twice within an hour of startup and then perform correctly for hours. I have removed it, and the replacement coin-base works correctly. My diagnosis is that the crackling tube is defective or wearing out. There's the concern that if a tube fails the wrong way in the LD MKIII, it can send 100+ volts downstream and destroy things so I sent the tube out to pasture. Is it time to throw away the "Christmas Tree?" I'm using the Little Dot as a preamp for a cap-coupled power amp. I'm wondering if a tube fails the wrong way if it might blow the capacitor or something (unless it would trip trip protect mode before that). Occasional crackles do not trip protect mode. I'm wondering if my assessment of things is likely correct or if there might be another way to try to solve the crackling. Before figuring out it was causing the crackle, it played music for about 25 hours so I suppose it is rather burned in. It was probably used anyhow. The GE coin base 6SN7GTB initially seemed to roll off bass and accentuate the mids. I've gotten used to them and like them, beautiful strings last night and competent reggae bass now. It will be interesting to hear the contrast when I roll different output tubes.

 

[JazzVinyl]

Somthin' bout RCA !

 

[mordy]

Lucked out with a free junk box that included 6SN7GT: 3 GE top-heated "Christmas Tree" coin base 6SN7GTB and about half a dozen singles, none holy hyper but they are no longer cheap anyhow! A GE coin base occasionally sends a fairly loud crackle to my speakers, sounding sort of like a spark of amplified static electricity. I re-scraped the pins and made sure the tube was plugged in tight and restarted the amp. After the amp had played music for awhile, if my hand was an inch or so away from the tube, it crackled a few times. When I turned the volume to zero, and lightly touched the tube with a pencil, my speakers crackled. If I do not provoke a crackle, it will probably crackle twice within an hour of startup and then perform correctly for hours. I have removed it, and the replacement coin-base works correctly. My diagnosis is that the crackling tube is defective or wearing out. There's the concern that if a tube fails the wrong way in the LD MKIII, it can send 100+ volts downstream and destroy things so I sent the tube out to pasture. Is it time to throw away the "Christmas Tree?" I'm using the Little Dot as a preamp for a cap-coupled power amp. I'm wondering if a tube fails the wrong way if it might blow the capacitor or something (unless it would trip trip protect mode before that). Occasional crackles do not trip protect mode. I'm wondering if my assessment of things is likely correct or if there might be another way to try to solve the crackling. Before figuring out it was causing the crackle, it played music for about 25 hours so I suppose it is rather burned in. It was probably used anyhow. The GE coin base 6SN7GTB initially seemed to roll off bass and accentuate the mids. I've gotten used to them and like them, beautiful strings last night and competent reggae bass now. It will be interesting to hear the contrast when I roll different output tubes.

Sometimes there are changes over time in the solder inside the octal pins leading to noise such as hiss, crackling or loud pops. The loud pops could damage headphone drivers so I usually first plug in a cheap headphone to make sure that nothing is wrong with a new tube - a blown driver could be expensive to replace in a good set.
I have had success (but not always) in eliminating noise by heating up each pin around 30 seconds with a 30W soldering iron. You just wait for the iron to warm up and then touch each pin for 30 seconds, working your way around the socket.

 

[TrollDragon]

Lucked out with a free junk box that included 6SN7GT: 3 GE top-heated "Christmas Tree" coin base 6SN7GTB and about half a dozen singles, none holy hyper but they are no longer cheap anyhow! A GE coin base occasionally sends a fairly loud crackle to my speakers, sounding sort of like a spark of amplified static electricity. I re-scraped the pins and made sure the tube was plugged in tight and restarted the amp. After the amp had played music for awhile, if my hand was an inch or so away from the tube, it crackled a few times. When I turned the volume to zero, and lightly touched the tube with a pencil, my speakers crackled. If I do not provoke a crackle, it will probably crackle twice within an hour of startup and then perform correctly for hours. I have removed it, and the replacement coin-base works correctly. My diagnosis is that the crackling tube is defective or wearing out. There's the concern that if a tube fails the wrong way in the LD MKIII, it can send 100+ volts downstream and destroy things so I sent the tube out to pasture. Is it time to throw away the "Christmas Tree?" I'm using the Little Dot as a preamp for a cap-coupled power amp. I'm wondering if a tube fails the wrong way if it might blow the capacitor or something (unless it would trip trip protect mode before that). Occasional crackles do not trip protect mode. I'm wondering if my assessment of things is likely correct or if there might be another way to try to solve the crackling. Before figuring out it was causing the crackle, it played music for about 25 hours so I suppose it is rather burned in. It was probably used anyhow. The GE coin base 6SN7GTB initially seemed to roll off bass and accentuate the mids. I've gotten used to them and like them, beautiful strings last night and competent reggae bass now. It will be interesting to hear the contrast when I roll different output tubes.

Since your not feeding into a DC power amp you should be fine. I would do as mordy suggests and resolder the pins on that tube.

 

[Cognomen]

Sometimes there are changes over time in the solder inside the octal pins leading to noise such as hiss, crackling or loud pops. The loud pops could damage headphone drivers so I usually first plug in a cheap headphone to make sure that nothing is wrong with a new tube - a blown driver could be expensive to replace in a good set.
I have had success (but not always) in eliminating noise by heating up each pin around 30 seconds with a 30W soldering iron. You just wait for the iron to warm up and then touch each pin for 30 seconds, working your way around the socket.

Hi, Yes I used inexpensive headphones to test them but not for long since seemed ok until every once in awhile there was a crack/pop. Thank you for the solder idea. It got rid of the crackle/pop when my hand was near the tube but not if lightly touched with a pencil. Tried resoldering and it didn't fix things, probably will have better luck next time.

 

[Cognomen]

I'm enjoying listening to a free pair of used Tung-Sol D getter 5687. Over the last few weeks, I've explored a new facet of the hobby: junk boxes of tubes. I have been persistent. Last week I was probably very lucky when I got over 1,500 free used tubes listed on Craigs. I have spent days sorting while listening and have found about 30 cosmetic pairs of interest, adapters (or breadboards) needed. I also found about a dozen single triodes of interest such as 6SN7. I also found more than a dozen cosmetic pairs of 7 pin minis widely auditioned on this forum that have not been nominated as best or close to it. I've also found some tubes that might prove useful with different tube gear. I have not found anything that is very expensive. While I sorted through all the tubes for fun to see what I'd discover, I'm probably saving $15-$20 per hour versus buying the tubes on eBay or from a dealer. If bought the tubes they would be tested NOS while mine are used and worth less and some might not work; however, I'm guessing I probably will not listen to quite a few of them so long that they wear out - used is probably fine, hence the idea of saving $15-$20 per hour! If I had a tube tester, I am guessing I could earn about $10 per hour selling used tubes I got for free on eBay until my limited stock of re-used packing materials and small boxes was exhausted.

Typically I see Craigs and Facebook Markeplace listings for 50-200 tubes priced at $1-$2 per tube that languish for weeks and disappear. Did they sell or did the seller give up? I have a hunch that sellers do not realize that potential buyers may be hobbyists that can only use a small subset of the tubes and that resellers and dealers are in general not interested. Hobbyists have the option of buying tested nos tubes and paying less for shipping than driving an hour+- across town for who knows exactly what. While it has been fun, I may have been very lucky, and am not sure I will be in the junk box business much longer.

 

[barbazz]

That's something you don't often (if at all) see in Europe. I can see myself having lots of fun browsing through 1500 tubes, for sure.

I'm intrigued about your 5687 usage. Are you using them in a Little Dot? With 12.6V/0.45A they are way out of LD specs.

EDIT: Way out of spec for my LD 1+ I guess you are using them as power tubes.

 

[Cognomen]

That's something you don't often (if at all) see in Europe. I can see myself having lots of fun browsing through 1500 tubes, for sure.

I'm intrigued about your 5687 usage. Are you using them in a Little Dot? With 12.6V/0.45A they are way out of LD specs.

EDIT: Way out of spec for my LD 1+ I guess you are using them as power tubes.h

Yes, as power tubes on adapters. Page 585 lists double triodes including 5687 that can be used as power and driver tubes in LD MK1 - MKIV. While 5687 as a driver would require an external power supply, some of the double triodes do not. When used as drivers. I believe most people made their own adapters or used breadboards and tube test sockets. In the backpages I recall a post where a listener who had rolled oodles of triode-strapped pentodes exclaimed that in his experience double triodes as drivers are on average a leap forward in terms of sound quality. Is it a coincidence or not that the 6HM5 is a triode? There are posts about .6Ah 6SN7 as solid driver and power tube upgrades (adapters needed and external power if used as a driver). It's an audio tube that was created by combing two .3Ah 6J5 triodes; if deployed as a driver external power not needed and regular adapters needed rather than one that can "plug one tube into 2 sockets." I wonder if there are any more double triodes like that. I find the .4Ah Ultron Special Quality 6BQ7A as a power tube provides nice euphonic extended treble, nice euphonic mids and very competent bass, good amount and distinctions between notes and not boomy. I have a hunch that with an adapter it has the potential for excellence as a driver. It's .4Ah draw when deployed as a power tube is perhaps not well-suited for low-z cans and some listeners' preferences.

 

[triod750]

I wonder if there are any more double triodes like that.

6C5/6C5G/6C5GT/G can be used in the same adapter as 6J5 type tubes and are on par with 6J5 in my experience. The all metal 6J5/6C5 tubes are usually cheaper and with good sound quality. You don't need NOS tubes. Used tubes have a long life left, mostly. Don't expect them to fail on you or to sound worse in any way.
But they are single triodes, of course, and a lot of people favour singles for sound quality compared to their double triode brethrens.

 

[barbazz]

if deployed as a driver external power not needed and regular adapters needed rather than one that can "plug one tube into 2 sockets."

Or you can build a Christmas Tree like me

These are Novosibirsk 6S2S, the Soviet version of the 6J5GT. As @triod750 mentioned, you can also use the 6C5 family of tubes. I have a pair of almost 80-year-old VT-65 Ken-Rad's that, in a blind test, I'm pretty sure I wouldn't distinguish from the 6HM5.

There are literally hundreds of triodes that can be used in Little Dot. For some of them, there are off-the-shelf adapters; for others, you'll need to build a specific one.

Here's the list of families I found compatible for drivers (6,5V, <= 450mA):
2C22, 37, 3A/167M, 437A, 5842, 6AC5G, 6AC5GT, 6AE5GT, 6AF4, 6AM4, 6AQ4, 6C2, 6C5, 6C8P, 6CW4, 6DS4, 6ER5, 6ES5, 6F12, 6F5, 6FQ5, 6GK5, 6HM5, 6HQ5, 6J4, 6J5, 6J5G, 6J5GT, 6K5G, 6K5GT, 6K5MG, 6L5G, 6P5G, 6S3P, 6S45P, 6SF5, 6T2, 7245, 7586, 76, 7895, 7A4, 7B4, 8556, 8627, 8628, 8808, 9002, A2521, A2599, CV5112, CV6, E20C, E88C, EC52, EC80, EC8010, EC8020, EC86, EC866, EC88, EC88C, EC90, EC92, EC97, NY67

 

[barbazz]

Since we are on the subject, did anyone try to use triode-pentodes, like ECF82? I mean strapping the pentode and using it like a double triode? Is this possible or just wishful thinking?

 

[Cognomen]

Since we are on the subject, did anyone try to use triode-pentodes, like ECF82? I mean strapping the pentode and using it like a double triode? Is this possible or just wishful thinking

I don't recall anyone posting about using double pentodes, dissimilar double triodes, or dissimilar double pentodes or triode pentodes or double compactrons. While the latter have "a bizillion pins," sometimes some of them are not connected to anything inside the tube and the tube is a double rather than a triple or its triple section is a diode that one would not connect. Supposedly some provided mono tv audio all in one tube. Is there a compactron with double power (output) tube capability plus a single driver, an all-in-one tube for one channel of the Little dot MKIII? I don't recall seeing some additional bases for some of the types of tubes mentioned above used either. I also don't recall people exploring a variety of 9 pin single triodes and single pentodes. I too wonder what is possible. Much of this is beyond my ken. It's a learning experience and when I'm wrong, I would like to learn about it. If it is all possible, there are hundreds, perhaps 1,000, different tubes that one could deploy. I once read that if one only uses one section of a double it eventually poisons the other. There might be a way to unpoison it. I don't know. I also suppose using one dissimilar double as a driver would result in different sounding channels. I have seen equipment that uses dissimilar doubles, some of it expensive such as some Leben amps. Many doubles have double heaters but some only one which seems unsuitable. If the power supply is external can one use single heater doubles? It would be good to learn the history of creating doubles. If they have predecessor singles, it might simplify tinkering and rolling singles would provide an inkling about how the double would sound. I'd be surprised if rolling what above is possible resulted in eeking out signficantly better audio performance than the "13,000 and counting process of elimination posts here to identify best sounding tubes." An electrical engineering friend old enough to have studied tubes in college told me the mkIII has some fixed parameters that would undoubtedly result in different sound from different tubes. Have the 13,000 posts explored the gamut of possible sound? For now, I'd enjoy learning more and upping my tinkering game and find that I enjoy listening to tubes even if they are not going to the top of the list of best tubes. And finally, I believe there are some 7 pin triodes that would require adapters that have not been tried. If much of this is possible, the cost and time for all of it could be impossible and one has to think about when it is time to be satisficed or to save money and time for more expensive better equipment. Perhaps part of the latter could include trying to roll tubes in a Little Dot that have some odds of being suited for better equipment also. It seems possible to me that the advent of equipment like Little Dots I-IV rescued some 7 pin mini tubes from being "dumpster tubes" and that they might not often be in upgraded equipment. I don't believe in throwing tubes away, but I think it happened sometimes in the past including tubes that decades later became expensive.

 

[Cognomen]

Since we are on the subject, did anyone try to use triode-pentodes, like ECF82? I mean strapping the pentode and using it like a double triode? Is this possible or just wishful thinking?

 

[mordy]

I am not sure if you can turn a pentode into a dual triode but based on what I have seen and used myself, you will need two pentodes to be strapped into two triodes.
There are tubes that incorporate two functions within one envelope such as a triode-hexode. With such a tube it is possible to wire it so that you end up with a triode and then the hexode strapped as a triode as well = dual triode.
The problem is that since these tubes are two different tubes in one envelope each side may not be matching the other side when used as triodes.
On the other hand, using either the triode or the hexode strapped as a triode (using a pair of tubes) may yield very good results. Another advantage of this is that you may get very good sound for very little money since many of these tubes aren’t commonly used. However, you have to add in the cost of making special adapters.

 

[barbazz]

I am not sure if you can turn a pentode into a dual triode

I'm pretty sure you can't. I was referring to triode-pentodes, one triode and one pentode in the same envelope as the triode-hexodes you mentioned.

The problem is that since these tubes are two different tubes in one envelope each side may not be matching the other side when used as triodes.

Very good point. The idea of using just the triode or a strapped pentode/hexode makes more sense, although I'm not sure how these tubes react if you "defuse" one of the parts. Taking as an example the ECF82 I mentioned, we would only need to use pins 1, 8, and 9, and we would isolate the triode.

The problem would be, of course, the adapters. I need to get into DIYing those things...