Found these in an alley - RCA and Sylvania 6BQ5/EL84's

michaeljhsda2

I was delivering furniture with a friend earlier today and he spotted these laying there bare **** naked on the ground in an alley. 3 RCA's and 1 Sylvania. All 4 tubes test strong. The RCA on the far left has a 30 degree slanted disk getter. The other 2 RCA's have disk getters but aren't slanted as much.
I noticed that there is a delta mark on the bottom of the RCA's and in between the pins there is a "61" (tube on the far left) "12" (2nd from left) "3" (3rd left). The Sylvania is on the far right but I couldn't find any other markings on the tube.

Any help figuring out the dates would be greatly appreciated. Where are you Brock? :biggrin:

RuSsMaN

Got a BB gun? Wow, tubes in an alley? How does that happen?

Date codes will be on the side if they haven't been rubbed off. From the logos, they are mid 60's.

michaeljhsda2

RuSsMaN wrote: »

Got a BB gun? Wow, tubes in an alley? How does that happen?

Date codes will be on the side if they haven't been rubbed off. From the logos, they are mid 60's.

LOL. If I would have found these 40 years ago when I was kid I'm sure I would have smashed them right on the spot just to hear them pop! The story is strange but true...karma is all I can figure. I was giving away some furniture to a friend and my buddy says "hey look what's next to your foot...tubes." They were just laying on the concrete next to a utility pole. My guess is that someone pulled them out of a console and either forgot them or didn't want them.

Would the date codes be the "CD" "CY" "DD" that is seen on the side in photo 1?

RuSsMaN

I'll dig out my RCA book here in a few.

michaeljhsda2

Tubes date to 1965 perhaps? ...got the info from here. http://mysite.verizon.net/tubetronic/PDF_FILES/RCA%20DATE%20CODES.pdf

michaeljhsda2

The "etched" octagon indicating the tube type had breaks indicating the year and month of manufacture. A break in the corner gave the year; in the straight part, the month.
Interesting way to put dates on tubes. My guestimate of 1965 was based not on that but on the 2 letters on the tubes. I'm sure that I'm way off...

heiney9

CD = Sep 1968

CY = Jun 1970

DD = Nov 1970

on the 3 RCA's

heiney9

I don't know much abut EL84's since I don't have anything that uses them. It would be odd that a true RCA would have a solid disc getter. In small signal tubes those are a European thing.

Hard to tell if these are re-branded Euro tubes or if RCA actually manufactured them. Again, not really up on the different characteristics of EL84's as much as I am on the EL34, 6V6 and various small signal tubes.

H9

michaeljhsda2

heiney9 wrote: »

CD = Sep 1968

CY = Jun 1970

DD = Nov 1970

on the 3 RCA's

Cool. Thanks!

I'm thinking rebranded RCA's because there is a triangle on the bottom which could be from the Philips, Copenhagen factory....at least according to the Brent Jesse website.

george daniel

be sure to straighten those pins on one tube in particular--nice score--you must be living right.

heiney9

michaeljhsda2 wrote: »

Cool. Thanks!

I'm thinking rebranded RCA's because there is a triangle on the bottom which could be from the Philips, Copenhagen factory....at least according to the Brent Jesse website.

Usually that's not how they do it, most Euro tubes are acid etched in the side glass. But again, I don't have a lot of research under my belt about EL84's so who knows. The solid disc getter for that late of a tube would be a tell tail sign they *could* be of Euro origin. If you poke around on the web for a few days doing research you might come up with solid confirmation.

Also I wouldn't use those tubes until they are tested. Sounds fishy to me to leave perfectly good tubes just lying there.

H9

michaeljhsda2

george daniel wrote: »

you must be living right.

...that's not Beyond the realm of possibility, Captain Thanks. It was Instant Karma I tell ya'...alright enough of the puns. Seriously though, I was just helping out a friend in need and there they were on the ground. Should I buy a pin straightener or just use a pair of pliers on them?

BTW, Captain Beyond had some really good musicians in that band didn't they? Starglow Energy and Evil Men are some good tracks. I would like to hear them on vinyl at some point, just need to get my turntable up and running.

michaeljhsda2

heiney9 wrote: »

I wouldn't use those tubes until they are tested. Sounds fishy to me to leave perfectly good tubes just lying there.

H9

I tested them on my Eico 667 and all 4 test strong.
There were a couple more tubes laying there but that were smashed. There is another small tube labelled Motorola that wasn't smashed but I can't read all of the writing on it so I can't test it.

michaeljhsda2

My research so far has led me to believe the EL84's were made in Copenhagen, Denmark by Philips (triangle on the bottom of the tube between the pins) before 1954, because after 1954 Philips started putting the factory and date codes on the side of the tube towards the bottom. My hunch is that the tubes were bought by RCA who affixed their labels on them in 1968 and 1970. I emailed Brent Jesse recording studio about the tubes so perhaps he can shed more light on their origins.

heiney9

I doubt very much those are pre 1954 tubes. RCA nor Philips would hold on to tubes for that period of time before releasing them. It wasn't common practice for Philips tubes to have symbols embossed in the glass between the PINS. Telefunkens all had the diamond in the bottom or it's not a true TFK, but a relabeled tube.

Hopefully BJ can shed some light on the subject. Pre 1954 tubes of common use in audio today are extremely hard to come by. The EL84 came into existence in 1954. In your photo's I see the plates are smooth, not ribbed. They maybe late models. Not even sure RCA made EL84's..........are you sure the triangle isn;t a diamond? TFK's had smooth plates.

H9

heiney9

Also be aware that Tesla (Czech) made smooth plate copies of TFK's since they bought TFK's tube making equipment.

See link;

Your tube looks like the one on the left

http://www.tubemonger.com/Tesla_NOT_JJ_Telam_EL84_SET_of_3_USED_1960s_70_p/896.htm

michaeljhsda2

heiney9 wrote: »

are you sure the triangle isn;t a diamond?

Check out the 3rd and 4th photos from the top at the beginning of this thread. It clearly shows a triangle IMO.

heiney9

http://www.tubemongerlib.com/gallery2/v/EL84/RCA+EL84+6BQ5+Oval+Plate+Flat+Disc+Getter+1+-+USA.jpg.html

Here you go they are USA made EL84's, both GE and RCA made these tubes. All Euro tubes by Philips have a completely different plate structure. They are HEX shaped and are almost always stapled or welded. It appears from my research only RCA and GE had the smooth round style plates, they seem to be the only ones with a solid disc getter as well.

I'll continue researching but the the TUBE MONGER LIBRARY so far has shown all Euro tubes to be completely different as far internal structure goes.

H9

heiney9

Alot of the Euro tubes have cooling fins/wings as well, these don't. I am 100% your 6BQ5 are USA-RCA made tubes from the associated dates I listed.

H9

michaeljhsda2

heiney9 wrote: »

Alot of the Euro tubes have cooling fins/wings as well, these don't. I am 100% your 6BQ5 are USA-RCA made tubes from the associated dates I listed.

H9

Thanks for the info so far.

What do you think that triangle and the numbers on the bottom of the tubes represents?

I wish we could see a view of the bottom of those tubes from the Tube Monger Library to see if they have any marks on them.

heiney9

It has nothing to do with helping describe it's origin.

Tube indentification rules

1) check for a standard, common known date codes.
2) check for internal structure.

I have found identifying internal build structure an even more precise method of figuring out what you have. I have a pair of NOS in box Siemens EL34's. They look nothing like any Siemens EL34 produced (including common RFT/East German runs) so it had to be a lesser known relabled tube. Through painstaking research of all sorts of EL34 photo's and descriptions I finally found these were the last "good" production run of Tesla EL34's run before JJ took over.

Had I not been able to scrounge around for all sorts of photo's of internal structure's I never would have figured it out.

Now the photo's of the unlabled tube you posted is very difficult if you don't even know it's designation. One would actually probably need the physical tube in front of them and a HUGE visual knowledge of all the differences in small signal tubes.

If I had to guess it's a 12** series of tube.

H9

michaeljhsda2

H9,
Have you ever heard of this method of determining the RCA date of manufacture as described in the Bro. Patrick Dowd-AWA-RCA Harrison archive? It reads in part: The "etched" octagon has breaks in the octagon indicating the year and month of manufacture. A break in the corner gave the year; in the straight part, the month."

Here's the link
http://mysite.verizon.net/tubetronic/PDF_FILES/RCA%20DATE%20CODES.pdf

heiney9

michaeljhsda2 wrote: »

H9,
Have you ever heard of this method of determining the RCA date of manufacture as described in the Bro. Patrick Dowd-AWA-RCA Harrison archive? It reads in part: The "etched" octagon has breaks in the octagon indicating the year and month of manufacture. A break in the corner gave the year; in the straight part, the month."

Here's the link
http://mysite.verizon.net/tubetronic/PDF_FILES/RCA%20DATE%20CODES.pdf

Can't say that I have, but remember back in the day the dates were merely used as an inventory tool both as to stock rotation and in some cases origin for rebranded and privately branded tubes. No one back then cared if the tube was from Holland or Germany, or what year sounded the best, etc. They wanted a working tube for whatever appliance, radio or device they were using.

After they were starting to be used for serious Hi-Fi, we enthusiasts started documenting and noting subtle tonal qualities about different kinds of tubes as well as longevity, etc.

Get what I'm trying to say.......so that's why date documentation and the codes have had to be painstakingly organized today, because back then it seems they all had their own way of tracking inventory and it there was never a central organized log until much later on.

People did research way after the fact like what you see complied in the link you gave me to help us today and identify the better tubes.

H9

michaeljhsda2

Today I went back to the alley where i found the tubes to see if I could find any more scattered about. All I found were a few remnants of what was probably a console stereo.

michaeljhsda2

Response from Brent Jessee:

"You have RCA made "smoke glass" tubes from the early 1960s. This can be seen from the small solid disc getter at the top (the Philips solid disc getter is much larger) the solid plates and the very slight swirl of smoky tone to the inside of the glass. Also the bottom indentation is slightly beveled, the glass slightly grainy on the bottom, and the mold marks are RCA. Philips marks are either on the side of the glass or on the bottom in black ink. These are excellent tubes, but are 1960s RCA made.

Regards,

Brent Jessee"

heiney9

So I was right :biggrin:.

The date codes show 1970 on a couple. From what I've read briefly about them they are a solid EL84 tube, probably typical RCA signature sound, smoooooooth as Marvin Gaye!

Enjoy your totally FREE find

H9

michaeljhsda2

heiney9 wrote: »

So I was right :biggrin:.

The date codes show 1970 on a couple. From what I've read briefly about them they are a solid EL84 tube, probably typical RCA signature sound, smoooooooth as Marvin Gaye!

Enjoy your totally FREE find

H9

Thanks H9, you.....are.....da......man!!!. :cool: I'm going to roll these into a Channel Master EL84 based integrated amp along with some 1958 Siemens & Halske ECC83 longplates. The tubes are worth more than the amp about 10x over.