Octal Tubes
(Small Signal)

As the 6SN7 is an R.C.A. development it is only fair to start with them.  The 6SN7 is truly one of the tubes that built America.  This tube was to become THE most widely produced, popular and durable receiving tube of all time.  The difference between the types is that the GT had a 300 volt limit on the plates.  This went up to 450 in the GTA.  The GTB incorporated a high precision heater wire so as to be usable in series string TV & radio sets. 

[NOTE:  Because of the depth of the inventory, this is a very partial stock list.  Please call for current pricing and availability. Tubes are added regularly and the inventory changes so please call/email us if you have a specific need.]

Type

Manufacturer

Date

Microphonics

Quantity

$ Each

Description

 6SN7-GT

 RCA-Victor

 1940’s

 Moving-Mag.

 4

 76.00

The first regular production 6SN7 tube.

 Super-Line

 10

64.00

Graphite coating on the inside of glass

Line

4

54.00

for shielding & secondary emission

during use in TV deflection (pulse)

circuits. [R.C.A. Service News - July,

1950] Nice, full, neutral sounding tube

with great RCA dynamics. Mica snubbers on top mica.

6SN7-GT

R.C.A.

Later 40s

Moving-Coil

2

86.00

Second version tooling still no snubbers with graphite coated bulb. Classic,

Moving-Mag

12

76.00

beautiful, sound.

Super-Line

10

68.00

Line

2

62.00

6SN7-

R.C.A.

1956 +

Moving-Coil

3

46.00+

Third version tooling, still the same

GTB

Moving-Mag

14

38.00+

Its surprising that RCA

Super-Line

16

34.00+

ran such old equipment so long into

Line

10

30.00+

the 50’s, 60’s & 70’s. Fact is they

knew They had and were smart enough

not to "F*#@!" it up!

6SN7-

R.C.A.

Mid 60’s

Moving-Mag.

4

36.00+

Internals not changed

GTB

Super-Line

10

34.00+

Line

4

30.00+

6SN7-

R.C.A.

Late 60’s

Moving-Coil

4

44.00

Still a fine tube.

GTB

Moving-Mag.

18

40.00

Base has been shortened to about one

Super-Line

21

34.00

half inch tall, plate tooling still the

Line

11

28.00

same as 1940s, heater wire is now

bridged between the two halves.

pricing on these tubes is getting close

competing directly to today’s junk!!!

6SN7-

R.C.A.

1970’s

 Moving-Mag

8

38.00

For peats sake, the plate tooling is the

GTB

 1

 34.00

same as in the 1940’s! A round getter

 Line

 1

 20.00

ring now and button type base. STILL

a good, clear well balanced tube!

5692

R.C.A.

Mid 40s-

Moving-Mag.

6

Call

The classic Red base ruggedized 6SN7

Mid 50’s

Super-Line

4

Call

first developed by R.C.A. for use in

Line

6

Call

heavy artillery communications and

sighting installations where the regular

stuff was literally falling apart. These

tubes can take an incredible pounding

not that this has much to do with audio,

but the super-refined chemistry,

metallurgy, and ultra-hard vacuum sure

does!

5692

R.C.A.

60’s &

Moving-Mag

2

Call

Same great tube with a few changes, as

70’s

Super-Line

5

Call

with all of these, they basically all

Line

4

Call

measure the same but there were a few

internal production changes. They all

have that old black magic that’s for

sure! The last few years production

had gray plates.

6SN7-GT

Sylvania

1940’s

Call

Call

Call

For those of you that have been with

me for years know well, nothing beats

a Sylvania in this tube. I have set up

hundreds & hundreds of great systems 

with these over the last ten years and 

these tubes are truly loved! It has been 

great to see many of the current amp & 

preamp manufactures going back to this 

tube as one can really touch the end of 

the golden age of largely hand made 

tubes (Early 40’s).

6SN7-GT

Sylvania

1940’s

Moving-Coil

3

98.00

These early versions of the 6SN7 by

/ VT-231

Moving-Mag.

12

88.00

Sylvania simply provide more informa-

Super-Line

14

78.00

tion and air than anything else on the

Line

8

68.00

Planet! Cymbals and little tinkly things

appear for the first time on recordings

that you’ve been hearing for 25 years!

The textures of music and instruments

is laid out before you with real life

presence (presuming the system is

Capable.) It’s like the first time you

ever heard a vintage tube all over

again!

6SN7-W

Sylvania

1940’s

Moving-Coil

6

Call

The other ultimate 6SN7 and the first

Moving-mag.

9

Sold Out

ruggedized issue. I have only run into

Super-Line

19

Call

one stash of these in 31 years of serch-

Line

54

Sold Out

ing so get them while you can! These

were made at the same time as the

6SN7-GT. Beautiful to the eye as well

as the ear, with its beautiful mirror

finish getter coming half and some-

times all the way down the bulb.

All these early, super nice units have a

transparency that is addictive.

6SN7-

Sylvania

40’s -

Moving-Coil

3

Call

First coined here as the "chrome-

GT

1953

Moving Mag

8

Call

domes". There were several versions of

Super-Line

12

Call

this top gettered superlative 6SN7

Line

14

Call

using the same tooling as the W version

but without the extra support rod.  I was

 preaching the glories of ALL these good

 old Sylvania 6SN7's and 6SL7's back 

 about the same time the VTV crowd

 was just swapping in their Kenwood

 and Pioneer receivers for Dyna-70's!

6SN7-

Sylvania

1953

Moving-Mag.

4

52.00

The A version of this tube is a complete

GTA

Super-Line

12

46.00

re-engineering that consist of three

Line

16

40.00

main points, (1) Replacement of the

flat press Stem with button type base

on all models. (2) Repositioning of the

plates to an "oblique angle" [Sylvania

Tech report Nov. 1954] to lower

microphonics and increase mechanical

rigidity (3) Enlarged wing size on

plates about one third to allow higher 

dissipation and adjusted some 

clearances to allow raising maximum  

plate voltage from 300 to  450 volts.  

Same matchless, transparent, 

beautifully textured & delineated  

Sylvania sound. I might mention that the 

tubes I am talking about are the first  

versions ONLY! For example the next  

tube I am going to describe, the Syl. 

6SN7-GTB has about 28 different 

versions by Sylvania alone and were  

still being made in the 1980’s. What I am 

talking about is the first edition and the 

first few years of manufacturing. 

6SN7-

Sylvania

1954 +

Moving-Coil

8

58.00

Same tube as above but with tighter

GTB

Moving-Mag

18

50.00

tolerances on heater wire to control

(Type 1)

Super-Line

22

44.00

heater current for use in series wired

Line

23

40.00

sets. (Does not apply much in Hi-Fi

use) Unfortunately this tube started a

gradual 30 year slide downward both

visually and sonically, but just stick

with O’l Andy and I will get you the

best tube and the best sound no matter

how little or how much you spend!

6SN7-

Sylvania

1960’s

Moving-Coil

12

54.00

Still a very fine tube. On of the best

GTB

(early)

Moving-Mag.

18

46.00

bargains in the world of tubes!

Super-Line

0

40.00

Line

3

36.00

6SN7-

Sylvania

1960’s

Moving-coil

4

46.00

Same machinery still going strong, and

GTB

(late)

Moving-Mag.

16

40.00

running a bit faster. A few changes

Super-Line

8

36.00

here and there.

Line

0

32.00

6SN7-

Sylvania

1970’s

Moving-coil

2

30.00

Same machinery still chugging along!

GTB

 Moving-Mag.

 4

& under

But Oops… a button base now. Still a

 Super-Line

 2

great tube! Cripes, the micas look like

 Line

 2

there are punched from the same die as

they were using in the 1940’s... I Love

It!

6SN7-

Sylvania

Late 40’s

Moving Coil

22

50’s

Ruggedized GT.  Same tooling as W 

WGT

50’s

Moving-Mag.

18

40’s

model and still possessing that Old 

Super-Line

14

40’s

Black Magic.

6SN7-

Sylvania

50’s

Moving-Coil

4

WGT

Moving-mag.

16

40’s

has the magic!

Super-Line

10

40’s

 12SN7-GT

 & GTA + B

 I have a

Call for details

 (616) 454-3467

Type

Manufacturer

Date

Microphonics

Quantity

$ Each

Description

6SL7

R.C.A.

40’s

Moving-Mag.

3

54.00

R.C.A. original version with carbonized

Super-Line

12

46.00

bulb.

Line

8

40.00

6SL7-

R.C.A.

50-55

Call

Call

30’s+ &

Second version, basic tooling stayed

GT

 40's+

the same all through the 40’s 50’s &

60’s!

6SL7-

R.C.A.

55-70’s

Call

Call

20’s+

Yes unlike today, in the good old day’s

GT

30’s+

companies such as R.C.A. knew a good

&

thing when they saw it and didn’t

GTB

screw it up. In the case of the 6SL7 the

tooling stayed virtually the same from

the 40’s until the end in the mid 70’s!

6SL7/

Sylvania

1945

Moving-Coil

8

58.00

Beautiful WW-2 stock from the 40’s

VT-229

Moving-Mag

28

48.00

with the same magically transparent

Super-Line

85

38.00

sound as the early 6SN7’s. (see 1940’s

Line

74

28.00

Sylvania 6SN7).

6SL7

Sylvania

Mid 40’s

Moving-Mag.

2

42.00

Rare and Beautiful early "Chrome -

Mid 50’s

Super-Line

2

32.00

Dome" Units. Pretty to both the ear and

eye.

6SL7-

Sylvania

Mid 50’s

Moving-Coil

5

36.00+

A good thing keeps going, though the

GTB

Mid 60’s

Moving-Mag.

5

32.00+

getters are not quite as shiny as the

Super-line

8

28.00+

years go on.

Line

9

24.00+

6188

Sylvania

Mid-Late

Not yet tested

12

20’s-30’s

A 6SL7 selected for balanced half's.

70’s

(Later stuff)

6SL7-

Sylvania

1950’s

Moving-Mag.

6

30’s-40’s

Short Plate units, not quite as good as

WGT

Super-Line

4

30’s40’s

the others but not far behind either.

Line

6

"

W represents ruggedized construction.

6SL7-

Sylvania

1955 -

Moving-Coil

2

30’s+

Still super tubes at super prices.

WGTA

60’s

Moving-Mag.

6

20’s+

Super-Line

4

20’s+

5691

R.C.A.

1940’s -

Moving-Coil

2

86.00

See 5692 for sonic and technical details

50’s

Moving-Mag.

16

68.00

"Special Red"

Super-Line

30

62.00

Line

26

56.00

5691

R.C.A.

60’s-

Call

Call

Call

See 5692.

70’s

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