Tube Advice Request

pitdogg2

pitdogg2 wrote: »

I read that years ago. Most if not all of the links are now dead, shame as it had great pictures of tubes and their construction.
(I didn't check all the links, all the links I checked were DOA)

I agree with one statement he made GE tubes with the exception of the 5692 to my ears they are not bad tubes but they are not good tubes. For me that includes all the small signal tubes as well. Every 12-au/ax 7, 5814 and 5751 to my ears they are tizzy. There is a bit of distortion to them I find unpleasant. That being said I did find a set of GE 6sn7 tubes that were pretty darn good. The 6sn7 bridged filament tubes were like no other 6sn7. You can tell them because the filament comes out of one triode across the top and down into the second triode. This filament stays red hot the whole time the tube is in use. Now I did find some that were built the same way by RCA. They are not the same tube at all. In looks only. The difference being as you start the tube the filament glows red hot and then goes out. Unlike the GE tube that stays scorching red hot the whole time it is in use. Whenever I'd use the GE tubes people that came to my house for just mesmerized by the Red Hot wire going across the top of the tubes.
Those GE bridged filament were made in both standard bases and coin base.

https://www.ebay.com/itm/143395295529


https://www.ebay.com/itm/143543495996

Now to see them at this price 15 years later WOW have they went up!
I bought pairs of them for $20.

Fixed it.

jbreezy5

pitdogg2 wrote: »

I read that years ago. Most if not all of the links are now dead, shame as it had great pictures of tubes and their construction.
(I didn't check all the links, all the links I checked were DOA)

I agree with one statement he made GE tubes with the exception of the 5682 to my ears they are not bad tubes but they are not good tubes. For me that includes all the small signal tubes as well. Every 12-au/ax 7, 5814 and 5751 to my ears they are tizzy. There is a bit of distortion to them I find unpleasant. That being said I did find a set of GE 6sn7 tubes that were pretty darn good. The 6sn7 bridged filament tubes were like no other 6sn7. You can tell them because the filament comes out of one triode across the top and down into the second triode. This filament stays red hot the whole time the tube is in use. Now I did find some that were built the same way by RCA. They are not the same tube at all. In looks only. The difference being as you start the tube the filament glows red hot and then goes out. Unlike the GE tube that stays scorching red hot the whole time it is in use. Whenever I'd use the GE tubes people that came to my house for just mesmerized by the Red Hot wire going across the top of the tubes.
Those GE bridged filament were made in both standard bases and coin base.

https://www.ebay.com/itm/143395295529


https://www.ebay.com/itm/143543495996

Now to see them at this price 15 years later WOW have they went up!
I bought pairs of them for $20.

Insane prices on the GEs in the links you referenced.

Valves'n'More has some good videos on YouTube.com. They suggested the GEs would be best in the cathode follower positions on the Freya+ and less desirable as driver tubes. Seems to match your sentiments.

heiney9

5 Star GE 5751 3 mica black plates & very early (1953-54) GE JG-5814 ladder plates, (black or carbon) are superb. This was right around the time GE took over production for Ken Rad if IIRC.

Later 3 mica GE pinch black plates 5814's are excellent (especially the 5 Starr version).

But overall GE tubes are bright towards brittleness and are thin sounding as house characteristics.

The 5 Starr 12AT7's I've used in the past had a wonderful 3D presentation and excellent bass.

So there are a few specific gems. IIRC the 5 Star line of tubes were used in radio broadcast consoles of the day.

H9

jbreezy5

heiney9 wrote: »

5 Star GE 5751 3 mica black plates & very early (1953-54) GE JG-5814 ladder plates, (black or carbon) are superb. This was right around the time GE took over production for Ken Rad if IIRC.

Later 3 mica GE pinch black plates 5814's are excellent (especially the 5 Starr version).

But overall GE tubes are bright towards brittleness and are thin sounding as house characteristics.

The 5 Starr 12AT7's I've used in the past had a wonderful 3D presentation and excellent bass.

So there are a few specific gems. IIRC the 5 Star line of tubes were used in radio broadcast consoles of the day.

H9

Good news is I can put what I have from GE in driver position and hear how it plays out. No reason not to. Thanks for the above info!

invalid

You can also use the local base 7n7 which is identical electrically to the 6sn7 except the pins are loctal and the pinpout is different, but there are adapters available. They are pretty cheap to try.

mhardy6647

So... in the interest of completeness (I guess)... there are even more esoteric (which just an esoteric way of saying bizarre ) ways to expand the repertoire! The 6SN7 is essentially two 6J5s in one bottle. There are "adaptors" available to use
two 6J5s in the stead of one 6SN7.

see, e.g.,
https://audiokarma.org/forums/index.php?threads/the-best-6sn7-just-might-be-a-6j5-gt-6j5-g-or-a-british-made-l-63.935489/




I report, you decide.

jbreezy5

Bizarre indeed. I’m not a fan of the construction, but interesting.

mhardy6647

jbreezy5 wrote: »

Bizarre indeed. I’m not a fan of the construction, but interesting.

That's a very diplomatic way to look at it!

jbreezy5

mhardy6647 wrote: »

jbreezy5 wrote: »

Bizarre indeed. I’m not a fan of the construction, but interesting.

That's a very diplomatic way to look at it!

Thank you, sir. 🙂

jbreezy5

Got a quad of Sylvania 6SN7s recently and they tested as two pairs of nicely matched tubes on my Dyna-Jet 707!

jbreezy5

That lot of 24 I received didn’t have many tubes that matched in terms of measurements, construction, or brands.

Got my work cut out for me.

Haven’t come across many Tung-Sol 6SN7s, but I’m eager to hear this one:

heiney9

I have the 6SL7 version and it sounds great. This one should as well.

I've said it many times, Tung Sol tubes (especially early tubes) are some of the most underrated tubes around.

H9

pitdogg2

That TS made in the 6th week of 1959.
Great tubes!

jbreezy5

The Tung-sol Gm1/Gm2 measured 76/76. Makes me think harder about whether a Lyr is in my future?! 🤔

pitdogg2

Lyr ?

jbreezy5

mhardy6647 wrote: »

That they did!
Nowadays, buyers (and sellers) are pretty savvy -- but even now (well... maybe...) one may find a "diamond in the rough" with off-brand tubes; particularly tubes branded with radio/TV/organ manufacturers' names (e.g., Maggotbox Magnavox, Emerson, Admiral, Conn, etc.).
The other interesting opportunity comes from second-tier "brands" like International Servicemaster. Such tubes were generally bargain-priced commodity tubes sold to the service trade -- but those boxes might contain anything. Always worth a look.


A totally random eBAY/internet photo of an International Servicemaster-branded 12AU7.

Now -- since I am both very lazy and, shall we say, recollectionally challenged , I am not sure these resources have been mentioned... but here are a couple of handy tools for "tube explorers". I apologize if this is old news to the OP!

EIA manufacturer codes:
There are many, many on-line resources devoted to these (since it was a list that's ebbed and flowed over many decades). Here're a couple of fairly useful ones:

https://tubemaze.info/eia-codes-to-id-tubes/
https://www.ecianow.org/assets/docs/EIAStandards/1.7.4_EIAcodes1961.pdf
https://el34world.com/Forum/index.php?topic=27470.0

Pretty much everything you'd want to know about the 6SN7 may be found starting on page 3 of https://worldradiohistory.com/Archive-All-Audio/Archive-Vacuum-Tube-Valley/Vacuum-Tube-Valley-Issue-11.pdf

VTV was a heck of a resource. WRH gets big points for managing to secure (apparently) the rights to host the whole run of VTV online in the form of searchable PDFs.
Ludwell Sibley (of Tube Lore fame) put together an index of VTV that may be handy (I just used it to find the 6SN7 issue!). I am not sure of the original source, and it is copyrighted, but I am taking the liberty to attach a PDF version here.

Thomas Mayer's "tube of the month" entry on the 6SN7 and its kin may be found at:
http://vinylsavor.blogspot.com/2014/02/tube-of-month-6sn7.html

Hope that some of this is helpful!

So I did get a pretty well-matched pair of “diamond in the rough” organ tubes.

These are Baldwin (Sylvania 6SN7GTBs). They have chrome tops, however, the chrome on these cover less surface area than the ones posted earlier. 3-hole, black T-plates. The chrome is basically covering the very top of the tube, but doesn't extend much below the getter. Not sure if that’s of any significance.

Codes on both tubes are: 39, 12, 26

Faustin

In my humble opinion, tubes pulled from organs can be great finds. Unfortunately they have gotten as pricey as tubes that are not labeled for organ manufacturers. Sigh.

heiney9

Organ tubes are tested to be among the lowest noise tubes, so yes they can be consistently better than regular stock of the same tube. Organ tubes are hand picked (in a sense) for lowest noise possible.

H9

jbreezy5

pitdogg2 wrote: »

Lyr ?

https://www.schiit.com/products/lyr

Keiko

My CD3 tube buffer and CV181 Black Bottle Treasure Tubes still going strong.

Keiko

On a side observation: Prices on tubes, like everything else have gone way up in just a few short years. I'm glad I got my stash when I did, Sadly, my Telefunken 12AT7s have decided to start hissing and don't have that good sound that they used to. I bought this pair used and even so they cost me in the ballpark of 40.00USD. They've now doubled in price at best for a used pair and much, much more for NOS premiums.

Keiko

jbreezy5 wrote: »

pitdogg2 wrote: »

Lyr ?

https://www.schiit.com/products/lyr

Randy, aka The Cheap Audio Man reviewed this product about a month ago. Schiit does have an impressive lineup of gear. Made right here in the USA.

https://www.youtube.com/watch?v=lY1nRTx9Qks