12AX7 - 12AX7A - 12AX7WA - ECC83 - ECC803S - E83CC - CV4004 -
CV492 - 6681 - 6057 - M8137 - 5751
Descriptions of 12ax7 Vacuum tube types and variants:
ECC83: This European nomenclature for 12AX7 vacuum tube.
ECC803/ECC803S/E83CC: This "premium" version of European made 12AX7 vacuum tube.
The "S" on the ECC803S indicates "select" and are usually gold pin. These are usually found on
Telefunken brand tubes and a very rare Radiotron ecc803S vacuum tube from the Philips factory in Australia. 12ax7:
Original version of the 12ax7 vacuum tube. Early production was manufactured in the USA by Tung Sol, RCA,
Sylvania, GE etc. The earliest 12ax7 vacuum tubes have larger plates. The 12ax7 version without an "A" suffix is to be used
only in parallel filament circuits, so do not use these in a “series” circuit. This is an unusual problem to run into as they are
normally found in TV sets. The best way to tell if your circuit is a series circuit is by examining all of the vacuum tubes and
looking at the voltages (voltages other than 6 and 12 volts). If all tubes in your circuit start with 6 or 12
(except for 5 Volt rectifiers) , then it is a parallel.
12ax7a:
Can be used in series or parallel circuits. Many manufacturers marked 12AX7's as 12ax7 without the “A” suffix
well into the 60's and 70's, but these are most often 12AX7A's marked as 12AX7.
12AD7: Non-microphonic/low hum version of the 12AX7 vacuum tube made by Sylvania. Great for audio applications that
uses the 12AX7 vacuum tube.
12DT7, 12DM7, 12DF7: Special quality low noise/low microphonic versions of the 12AX7 vacuum tube. Usually branded as
Westinghouse or Raytheon.
7025: Hifi low noise version of the 12AX7 vacuum tube with all other specifications being the same as 12AX7.
Tubes marked with both 12AX7 and 7025 are usually low noise vacuum tubes as well.
5751: Military version/drop in replacement for the 12AX7 vacuum tube, but is actually different. The 5751 vacuum
tube has identical plate resistance to the 12AX7, but the gain is 70 compared to 100 for the 12AX7 vacuum tube.
Early production 5751 vacuum tubes have extra thick mica spacers (often three know as triple mica) and extra support
rods to minimize microphonic response. Many 5751 vacuum tubes also have matched triode units.
7729: CBS made industrial vacuum tube with gold pins for special applications requiring reliability and low noise/low
microphonics.
6681:
The mobile version of 12AX7 vacuum tube. Usually these are the same as a regular 12ax7 vacuum tube which have
been tested and screened to perform well in circuits with large variations in filament voltage.
7058: Same as a 12AX7 vacuum tube with a 13.5 volt non-tapped filament. Can be used in circuits which do not utilize the
6.3V filament tap. Performance is same as regular 12ax7 vacuum tube.
Suggestions on our best sounding IN STOCK 12ax7 vacuum tubes to buy now :
- Mullard CV4004: Very LOW noise, immaculate detail, wonderful warmth and articulation
- Philips Heerlen Holland 12ax7 (labeled as Philips, Amperex, GE, etc):
- Incredible liveliness and 3
- dimensional sound, beautiful
- vocal quality mids!!
- Siemens E83CC Munich : Special quality design, transparent, with amazing clarity, detail, resolution,
- and high end extension!
- All made in Munich Germany 1977-1979
- Tungsram CV492: Perfect for guitar amps ( this is my personal favorite!)
- Very very open with amazing top end and balanced all the way through!
- Sounds beautiful when pushed. Recommended for Train wreck amplifiers. Back In Stock!!!
- GE JG 12ax7: Excellent value, warm nice detail and an articulation which is unmatched for the money!
- Telefunken smooth or ribbed plate 12AX7: Incredibly high resolution tubes!
- Known for their detailed clarity and extension in the high end range!
- PRE-War Yugo made 12ax7- "I love the Ei 12AX7 tubes of old, they were hands down the best sounding pre-amp tubes.”
- Dr. Z Owner/Creator Z Amplification. Branded as Siemens CV492 (see below)
Tejas Tubes!
Lowest Prices for
NOS Pre-amp Tubes!
Special Note to our International Customers:
Please note that we use Express Mail International via USPS
for online tracking and confirmation of delivery which requires
more postage than the auto-calculated amount, So please click
on the button below to add the $25.00 USD extra to your shopping cart
to cover the additional shipping costs for your order!
12AX7 ECC83 5751 CV4004:
|
 |
|
|
|
 |
|
|
Tungsram CV492/12AX7
Compare elsewhere at $90.00!!!!
Low Stock Warning!!!
Just $69.99!
|
|
Brimar CV4004
Compare elsewhere at $85.00!!!
Low Stock Warning!!!
Out of Stock!
|
|
GE JG 12AX7 Long Plate
tested and noise tested
Price: $79.99 per tube
|
|
|

GE JAN 5751
Compare elsewhere at $38.00!!!
Price: $21.99
Balanced Triodes
Price: $31.99
|
|

Sylvania Triple Mica Black Plate 5751
The "Holy Grail" of 5751 tubes
$174.99 per tube
Matched Pair Sylvania Triple Mica Black Plate 5751
$349.99 per pair
Sylvania Triple Mica Grey Plate 5751
Same excellent sound quality as above only
Grey plates with triple mica spacers
Just $79.99 per tube
Matched Pair Sylvania Triple Mica Grey Plate 5751
$159.99 per pair
|
|

NOS Telefunken 12AX7
(Smooth or Ribbed) Diamond Bottom,
Blackburn Mullard, or
Heerlen Philips Holland (all have different branding)
Please specify which brand when ordering!
Price $149.99 each
|
|
|

NOS Mullard CV4004 12AX7
Price: $349.99 per matched pair
|
|

NOS Sylvania 12AX7 Black Plate
Price: $89.99 per tube
LOW STOCK WARNING!
|
|

Sylvania 12AX7 Short Plate
lightly used, tested and noise tested
Price: $49.99 per tube
|
|
|

Sylvania 12AX7 Long Plate
lightly used, tested and noise tested
Same ultra durable construction as JAN 12AX7WA
LOW STOCK WARNING!
Price: $39.99 per tube
|
|

GE NOS 12AX7
Compare elsewhere at $65.00 per tube!!!
Price: $99.99 per matched pair
|
|

Philips, GE, or Sylvania NOS 12AX7WA
(Philips shown above)
Compare elsewhere at over $60.00 per tube!
Price: $99.99 per matched pair
(please specify brand when ordering)
|
|
|
 |
|
 |
|
|
|
|
NOS GE 12AX7 (branded as International)
Price: $99.99 per matched pair
|
|
Philips, GE, or Sylvania
NOS 12AX7WA Singles
Price: $49.99 per tube
(please specify brand when ordering)
|
|
Siemens CV492 NOS NIB
(now back in stock!)
Awesome sounding 12ax7 from pre-war Yugo!
“I love the Ei 12AX7 tubes of old, they
were hands down the best sounding
pre-amp tubes.” Dr. Z
Owner/Creator Z Amplification.
Just $69.99 per tube
|
|
|
NOS RFT 12ax7 (various brands)
Price: $45.00 per tube
|
|

NOS NIB Siemens E833CC
enter qty 2 for matched pair,
4 for matched quad etc
Price: $129.99 per tube
Click Link above for phono grade and balanced tubes
|
|
|
|
|
|