1101 Audio custom crafted headphone amps
Feb 26, 2021 at 12:38 PM Post #646 of 788

bcowen

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The oldest 6H8C i have are from 58 they really sound great, I also have some from 64,66 which are frankly not so bad but sold all the 70' for almost nothing. I also have a pair from 0880 for the fun :)
Those tubes are very stable once hot (no hum, no rfi, autobias of CTH never drop).
The one with silver paint on the left is from 58, the one on the right from 67..

8n8s.jpg
Any of the 1950's production dates sound great to me. The ribbed plate versions sound just a bit better than the smooth plates, but the difference isn't huge. I wouldn't pay a huge premium for a ribbed versus smooth plate one, but if you run across some '55 or earlier for a decent price, they're worth the grab (IMO).

1953 with the ribbed plates:
Foton 1953.jpg
 
Feb 28, 2021 at 9:19 AM Post #647 of 788

L0rdGwyn

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The oldest 6H8C i have are from 58 they really sound great, I also have some from 64,66 which are frankly not so bad but sold all the 70' for almost nothing. I also have a pair from 0880 for the fun :)
Those tubes are very stable once hot (no hum, no rfi, autobias of CTH never drop).
The one with silver paint on the left is from 58, the one on the right from 67..

8n8s.jpg

Any of the 1950's production dates sound great to me. The ribbed plate versions sound just a bit better than the smooth plates, but the difference isn't huge. I wouldn't pay a huge premium for a ribbed versus smooth plate one, but if you run across some '55 or earlier for a decent price, they're worth the grab (IMO).

1953 with the ribbed plates:
Foton 1953.jpg

It's funny you should mention these tubes. I have very few 6SN7 left after selling my collection, but needed 6SN7 to use the DarkVoice. I rummaged through some drawers and found these tubes, three of them, looks like all from 1956, two with ribbed plates, one with smooth plates. I was pretty impressed by the sound, I have to admit! And here I thought I was using junk tubes :joy:
 
Feb 28, 2021 at 9:12 PM Post #648 of 788

leftside

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Difficult decision to make today. I had an existing EL6. I also managed to find an EL6 that was sealed in original box. I was going to leave it sealed, but ended up opening it to make a nice pair with my existing EL6. I don't think I've had too many old tubes that were still sealed - and it was a tough decision deciding to open this one up and use it. It's now being used for the first time ever! Would have been in that box for about 70 years.

Interestingly, the pins still looked used - but it must simply be from age. I will clean them later with my Dremel. The cleaner pins (on the right) is a used tube - but pins were cleaned with my Dremel.

These EL6/4699 are great sounding tubes.

IMG_5889.jpg


IMG_5890.jpg
 
Mar 1, 2021 at 4:10 PM Post #649 of 788

hpamdr

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For those tube, you only need to cleanup the external border as only this part will be in contact with the socket...
This is a very nice cleaning job and much nicer like this !

Do you use some fine lapping paste or just the polishing disk ?
 
Mar 1, 2021 at 4:24 PM Post #650 of 788

leftside

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Mar 1, 2021 at 4:46 PM Post #651 of 788

bcowen

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Difficult decision to make today. I had an existing EL6. I also managed to find an EL6 that was sealed in original box. I was going to leave it sealed, but ended up opening it to make a nice pair with my existing EL6. I don't think I've had too many old tubes that were still sealed - and it was a tough decision deciding to open this one up and use it. It's now being used for the first time ever! Would have been in that box for about 70 years.

Interestingly, the pins still looked used - but it must simply be from age. I will clean them later with my Dremel. The cleaner pins (on the right) is a used tube - but pins were cleaned with my Dremel.

These EL6/4699 are great sounding tubes.

IMG_5889.jpg

IMG_5890.jpg
Nice! Do you replace the solder in those pins (one on the right, anyway)? Looks like a lot of the factory solder is conspicuous by its absence... :laughing:
 
Mar 1, 2021 at 8:56 PM Post #652 of 788

leftside

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Nice! Do you replace the solder in those pins (one on the right, anyway)? Looks like a lot of the factory solder is conspicuous by its absence... :laughing:
I haven't. But you raise a very good point. I have checked the pins and they seemed firm, but I will double check again.... I have a soldering iron, and know how to solder. Any particular type of solder you recommend for these pins?
 
Mar 1, 2021 at 9:10 PM Post #653 of 788

bcowen

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I haven't. But you raise a very good point. I have checked the pins and they seemed firm, but I will double check again.... I have a soldering iron, and know how to solder. Any particular type of solder you recommend for these pins?
Any quality solder with a rosin flux core should work fine, but preferably one that has some silver content to it. I've used Cardas for years, and @Paladin79 recommended this Kester solder which I like too. The .020" diameter works very nicely for tube pins.

https://www.amazon.com/gp/product/B004DEUYBY/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1
 
Mar 1, 2021 at 9:16 PM Post #654 of 788

leftside

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Mar 2, 2021 at 9:28 AM Post #655 of 788

hpamdr

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Any quality solder with a rosin flux core should work fine, but preferably one that has some silver content to it. I've used Cardas for years, and @Paladin79 recommended this Kester solder which I like too. The .020" diameter works very nicely for tube pins.
I'm using this cardas equivalent 3% silver professional grade from a known brand. (you should get it from farnell instead of amz)

// the kester is for sure a good product easy to work with but it contain lead.
---- Edited
@A2029 Misha () is right and I missed that re-soldering pin need to match old soldering material pre rohs.. Another advantage is that fusion temp is lower <= 180° C instead of >= 220.
 
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Mar 2, 2021 at 10:27 AM Post #656 of 788

A2029

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I'd recommend either a good rosin core 63/37 solder, or the 62/36/2 that bcowen suggested. Back in the day ROHS (lead free) requirements were not in place, so it's more likely that they were using a lead based solder (either 60/40 or 63/37). You don't want to mix a lead free solder into the lead based solder as it can give very poor joints and much higher temperature required for the solder to flow.

Also recommended putting a small bit of flux into the pin hole, as that will help the solder flow more easily and produce a better solder joint. You want an electronics rosin flux such as this: https://www.amazon.ca/SRA-Soldering-Products-Rosin-2-Ounce/dp/B008ZIV85A
 
Mar 2, 2021 at 10:59 AM Post #657 of 788

Galapac

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Is it true in a pinch you can use Vasoline as flux? I'm not that cheap and have never used it but was wondering if that was true or BS.
 
Mar 2, 2021 at 11:31 AM Post #658 of 788

A2029

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Is it true in a pinch you can use Vasoline as flux? I'm not that cheap and have never used it but was wondering if that was true or BS.
Hmm, never heard of that before. I'd not recommend it and I lean towards it being BS as oils (e.g. even oils from your skin) are seen as contaminants to a proper solder joint that can affect the joint quality.
 
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Mar 2, 2021 at 12:38 PM Post #659 of 788
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Is it true in a pinch you can use Vasoline as flux? I'm not that cheap and have never used it but was wondering if that was true or BS.

Hmm, never heard of that before. I'd not recommend it and I lean towards it being BS as oils (e.g. even oils from your skin) are seen as contaminants to a proper solder joint that can affect the joint quality.

In a pinch, I would recommend the oil left on the fryer from the morning bacon! 🤣















(I am just kidding - please do NOT do it!!!!!)
 
Mar 2, 2021 at 1:18 PM Post #660 of 788

Galapac

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..Firing up my amp takes on a new meaning...what's that bacony smell? :)
Sorry for the derailment, please back to the subject of 1101 Audio custom crafted headphone amps...
 

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