Head-Fi.org › Forums › Misc.-Category Forums › DIY (Do-It-Yourself) Discussions › The Millett Starving Student Tube Thread.
New Posts  All Forums:Forum Nav:

The Millett Starving Student Tube Thread.

post #1 of 33
Thread Starter 
Hey, I purchased quite a few tubes to get the right ratings for my 3 channel build and found that there are many different styles of the 19J6 tube.

My experience is heavily with the RCA tubes and then a few Sylvania tubes.


#1


BRAND: RCA
STYLE: Flash Spot (Clear Top) with Horizontal Square Getter
DISTINGUISHING MARKS: RCA with the C almost looking like an E, White Text


#2


BRAND: RCA
STYLE: Silver Spot (Clear Top) with Horizontal Square Getter
DISTINGUISHING MARKS: White Text

#3

BRAND: RCA
STYLE: Flash Spot with Vertical "D" Getter
DISTINGUISHING MARKS: White Text, Grey "19J6"


#4

BRAND: RCA
STYLE: Silver Cap with Horizontal "D" Getter
DISTINGUISHING MARKS: White Text, Grey "19J6", RCA company Symbol Stamped.

#5

BRAND: RCA
STYLE: Flash Cap with Horizontal Halo Getter
DISTINGUISHING MARKS: Red Text, Perfectly Even Silver Cap Line, RCA company Symbol Stamped


#6

BRAND: Sylvania
STYLE: Flash Spot (Clear Top) with Horizontal Square Getter
DISTINGUISHING MARKS: Yellow Text, "Made in USA" stamped, Sylvania company Logo, White "19J6", One model had "C A" Stamped on the side with Yellow Text (Brighter on the top than the bottom which is the opposite of all the other 19J6 here)


#7

BRAND: Sylvania
STYLE: Flash Spot with Vertical "D" Getter
DISTINGUISHING MARKS: Green Text, Grey "19J6", Sylvania Company Logo



AGE (Oldest to Newest)

RCA:

#3 - #4 - #1 - #2 - #5

Sylvania:
#7 - #6 (don't know which of the two is the oldest)


Personal Favorites:

#6 - Most Detail / Soundstage, but the treble can be shrill at times - by far the best in the group and very revealing
#1-#3 - Very good Overall Balance with Good Clairty (makes even bad recordings sound OK) Lowest Noise of any Tubes, very consistent quality from tube to tube


Please Post if you have experience with these tubes or you have found another type of the 19J6. ( I think that GE, NU, Raytheon, and Westinghouse brands, but haven't found any to buy)
post #2 of 33
Germania, could you post schematic of your 3 channel amp's ground channel, how can you make it unity gain ?
Zigis.
post #3 of 33
does this really need a separate thread?
post #4 of 33
Thread Starter 
Zigis, YGPM.

Mox, I didn't want to congest the SSMH thread and this might end up being a resource for people since there isn't a whole lot of info on this tube.
post #5 of 33
What you are calling the filament is not the filament .... that is the getter. Getter position is universally referred to as top, side or bottom; not horizontal or vertical.

Secondly, tubes were often rebranded. So, you actually show three to four distinct tubes; not seven. For example, tube #3 and tube #7 are the same tube. Given my collection of 40 19j6s I would say that tube #3 is an actual RCA and the Sylvania #7 is a rebranded RCA. That particular tube construction is usually referred to as a side D getter.

The top getter tubes would typically be referred to as .... a halo (round) top getter and the other construction would likely be called a square top getter. The top D getter tube would be callled .... a top D getter. Sorry if that seems both redundant and evident. Moreover, it is hard to see the fine details of the various tubes constructions with most of the tube pics so I could be missing some differences.

The green Sylvania box is from older production and definitely precedes the yellow Sylvania boxes. The side getter tubes seem to be RCAs and are older than the halo top getter RCA .... which I believe is still an RCA. But, the halo top getter seems to be a RCA from later production runs. The square top getter is likely a Sylvania but I dont know for sure. The top D getter tube is a mystery. Of all the 19j6s I have looked through I never came across one D top getter. By far, the side D getter RCAs are the most common of the 40 tubes I have .... with a few top halo getters and one pair of square top getter tubes rounding out my stash.

The printing means very little other than the older RCA used the white and the later production RCAs used the red/ orange color printing and are newer. GE did not appear to make 19j6s from my, so far, limited research. I have some Westinghouse 19j6s that are clearly side D getter RCAs. But, I also have some Westinghouse with top halo getters. Thus, I would suspect the Westinghouse are rebrands and Westinghouse didnt actually make 19j6s and bought them from the major producer (RCA) to rebrand .

NA refers to what .... a rebrander? Whatever that brand .... NA would not have made the tube.

Finally, I have Tung Sol branded 19j6s which are clearly side D getter RCAs. I have International Service Master 19j6ds that are either side D getter or halo top getter RCAs. I have Delco 19j6s that are side D getter RCAs. The single pair of top square getter 19j6s I have are in Standard (a rebrander) boxes. So, it appears any type of 19j6 can end up in any companies box. But, the pattern here indicates RCA was the major producer of 19j6s. For those needing 19j6s, if I were ordering 19j6s, I would ask for construction matched pairs and not worry about the designated brand.
post #6 of 33
Thread Starter 
WOW!

Thanks for the clarification!
My camera has the worst macro focus and is therefore terrible at these kind of pics.

Can you explain the C.A. marking? That tube "burns" brighter on the top than the bottom, which is the opposite of all of the ones I have seen.
It is the one on the far left.


I actually have a couple of the top D getter RCA's and they tend to be the darkest sounding of the varieties.

NA = National Union, but I meant to put NU.

I will make the changes per your clarification.
post #7 of 33
This is a great idea and a fun way to keep track of the differences between SSMH tubes. Like the Millett Hybrid/MAX/MiniMAX, these tubes appear to have been manufactured by a few manufacturers and re-branded by many.

Just a few pointers in making this thread more useful.
  • Better pics - sorry, but we can't see any detail in the tube pics you've included. Boxes are fine, but often they have little connection to the tubes that may be inside them.
  • The "filament" you refer to is the getter. The getter is a square, rectangular, or circular loop that's used to ionize the surrounding air and promote a chemical reaction with the getter "flash" which is the silver reflective splotch on the glass. This splotch actually reacts chemically with any gases that may have infiltrated into the glass, aided by the ionization provied by the getter.
  • It would be great to keep the terminology consistent with what I've seen in many tube journals and online discussions:
  • contiguous, circular ring - that's a "Ring Getter." If it's on top, it's often referred to as a "Halo Getter," for obvious reasons.
  • A semicircular or partical circle, connected with a rod that spans the open ends - a "Horseshoe Getter."
  • Then there's a "Square Getter, " or a
  • "Rectangular Getter," depending on how specific you want to get.

Also, a true tell-tale on mfr:
  • A gray-black etched, "squished" octagon with the tube designation inside (ala "19J6") is manufactured by RCA, period - regardless of what's painted on the tube.
  • A tube designation etched in white, with a series of dots, is GE, period - regardless of what's painted on the tube.

Note that you will find GE tubes with RCA painted on them and RCA tubes with GE painted on them.

Most likely, anything that doesn't fit that description is probably Sylvania, perhaps Tung-Sol, but admittedly, I don't have as good a feel for these tubes as with the Millett's.

So, great idea - maybe just some pointers to keep it going.


EDIT: I see sacd-lover beat me to it!
post #8 of 33
Quote:
GE did not appear to make 19j6s from my, so far, limited research.
Actually GE was selling these too. I had a set of GE 19j6s.
post #9 of 33
Quote:
Originally Posted by rds View Post
Actually GE was selling these too. I had a set of GE 19j6s.

You may have had a GE box but you dont know that the tube was actually made by GE. That is what is so difficult to piece together about tubes that were sold by various rebranders and that had manufacturers buying from one another. You almost always need to have several different tubes to baseline the construction and hopefully you find tubes with actual date codes or identification to help you figure out who made what tube.
post #10 of 33
Quote:
Originally Posted by -=Germania=- View Post
WOW!

Thanks for the clarification!
My camera has the worst macro focus and is therefore terrible at these kind of pics.

Can you explain the C.A. marking? That tube "burns" brighter on the top than the bottom, which is the opposite of all of the ones I have seen.
It is the one on the far left.


I actually have a couple of the top D getter RCA's and they tend to be the darkest sounding of the varieties.

NA = National Union, but I meant to put NU.

I will make the changes per your clarification.


First, the CA marking can mean anything .... so I cant explain that. Why the tube burns brighter probably has nothing to do with the CA marking. Tubes had production variations like any other product and some identical tubes will have slightly more filament exposed .... thus emitting more light. That is my guess. The other possibility is the tube could be from a different manufacturer. Look carefully at the construction .... if the construction is the same I say production variation. If you see structural differences the reason is you have a different tube.

NU went out of busines around 1950. I highly doubt this tube was even invented before NUs demise. There is very, very little information on this tube so I have found nothing available to research who registered/ invented the tube.

Out of curiosity, I went down and looked at every 19j6 I own. I found some interesting variations. Most were side D/ horseshoe getters in Tung Sol, International Service Master or Delco boxes (good call tomb .... horseshoe and D are often used interchangeably). But, some had the getter sitting directly on the top mica while others had a post that elevated the getter above the mica, and consequently, slightly higher up the side of the tube. Since the D getter is facing down you will possibly have people refer to the getter as a U getter. But, the getter is not open like a U and is in fact a D getter .... but one that faces downward.

Next, I found a few of the halo top getter types and these were all in RCA boxes with red/ orange print. Moving on, I discovered I had 7 of the top D getter types and these were in a variety of boxes .... but mostly Delco boxes.

Finally, I found a few oddballs. I had one pair of dual getter 19j6s. These had both a top D/ horseshoe getter and a side D getter .... very cool looking. Lastly, I found one side square getter 19j6. The square was fairly large and sat right on the top mica. I cant even begin to guess who made these two versions. These three tubes were in International Service Master boxes .... a rebrander.
post #11 of 33
Quote:
You may have had a GE box but you dont know that the tube was actually made by GE. That is what is so difficult to piece together about tubes that were sold by various rebranders and that had manufacturers buying from one another. You almost always need to have several different tubes to baseline the construction and hopefully you find tubes with actual date codes or identification to help you figure out who made what tube.
I'm just saying it was sold by GE (ie had their name printed on the tube). I'm not claiming anything about rebranding.
post #12 of 33
Thread Starter 
I suspect that the Top Square Getter Sylvania and RCA tubes are from different manufacturers because the sound is very different between the two.
The Treble is rolled off in the RCA and much more prominent in the Sylvania. These have the biggest difference

The Side Horseshoe Getter Sylvania and RCA sound similar, but it seems that they too have more treble in the Sylvania. Maybe different production time that Sylvania did a rebrand?

The Halo RCA is probably the newest tube as the packaging was distinctly different from the other tubes. There was no warranty info, plasticated cardboard box, and missing the warranty as on the other boxes. Plus the box and the tube look like I bought them yesterday, much better printing on the tube.

You gotta tell us how the double getter sounds!
post #13 of 33
Quote:
Originally Posted by rds View Post
I'm just saying it was sold by GE (ie had their name printed on the tube). I'm not claiming anything about rebranding.
But, that is what is so frustrating about rebranding. Any seller can put any brand on any tube whether they actually made the tube or not. As an example, Baldwin manufactured Organs and sold Baldwin tubes for their Organs. But, Baldwin never manufactured the first tube.

The tube sold by GE could have been a GE tube. But, you usually find that the actual manufacturer will sell far more of a given tube type than all the rebranders combined. So, if you see a large number of a tube type like the 19j6 in original RCA boxes, the same tube construction in various rebranders boxes and the same tube construction in another manufacturers box .... you can probably safely assume RCA was the main manufacturer. Conversely, if you rarely see a GE branded 19j6 and you dont see any of the rebranders tubes having GEs distintive identification I would bet that GE didnt make the tube. I have seen mainly RCA, some Tung Sol, a few Sylvania. Plus, lots of rebranders like Delco, International Service Master, Standard etc ... that are clearly the same construction as the RCAs.

Tooling costs for tubes were expensive and time consuming. Buying tubes from another manufacturer was often more profitable than making your own if the tube was not a large seller. However, you could still be right and the tubes you had may be GEs. After all these years the sample size could be completely off. My point was unless you can sample and compare the tubes you cant depend on the brand on the box insuring that the actual tube was made by the seller.
post #14 of 33
Quote:
Originally Posted by -=Germania=- View Post
I suspect that the Top Square Getter Sylvania and RCA tubes are from different manufacturers because the sound is very different between the two.
The Treble is rolled off in the RCA and much more prominent in the Sylvania. These have the biggest difference

The Side Horseshoe Getter Sylvania and RCA sound similar, but it seems that they too have more treble in the Sylvania. Maybe different production time that Sylvania did a rebrand?

The Halo RCA is probably the newest tube as the packaging was distinctly different from the other tubes. There was no warranty info, plasticated cardboard box, and missing the warranty as on the other boxes. Plus the box and the tube look like I bought them yesterday, much better printing on the tube.

You gotta tell us how the double getter sounds!
Look closely at RCA tube #1 and #2. I think there might be two getters. The deposits seem to be more on the side vs the top. Look through the tube opposite the burn mark and see if there is a second D getter.

Look closely at the side D getter tubes and see if the getter is sitting right on the mica or if there is a small post the D getter is connected to.
post #15 of 33
Thread Starter 
Nope - both clearly are single square types.

Upon further inspection....
The side horseshoe getter Sylvania have plates that are black and the RCA has plates that are more like a dark grey.
Both are directly on the Mica.

I did find one variance between the CA and the Non-CA marked Sylvania tubes. The one that is not as bright has an extra 1mm x 0.5mm piece of metal coming from the side of the "filament" (the glowing center piece), in the center, at the top. It is far too tiny to take pics of and barely noticible. The CA tube has a slightly shorter overall "filament" than the Non-CA. Otherwise identical.
New Posts  All Forums:Forum Nav:
  Return Home
Head-Fi.org › Forums › Misc.-Category Forums › DIY (Do-It-Yourself) Discussions › The Millett Starving Student Tube Thread.