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Tone as BIG as Texas! www.tejastubes.com (713)471-5408
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. Various Brandings such as Siemens, Audio Research, Lorenz, etc CV492 (see below)
Tejas Tubes! NOS Pre-amp Tubes!
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NOS Tungsram 12ax7 $89.99 low noise NOS Tungsram 12ax7 Balanced Sections $99.99
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Out of Stock!
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GE JG 12AX7 Long Plate tested and noise tested Price: $109.99 per tube
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Price: $39.99 Balanced Triodes Price: $49.99
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Sylvania Triple Mica Black Plate 5751 The "Holy Grail" of 5751 tubes $199.99 per tube Matched Pair Sylvania Triple Mica Black Plate 5751 $399.99 per pair Sylvania Triple Mica Grey Plate 5751 Same excellent sound quality as above only Grey plates with triple mica spacers Just $129.99 per tube Matched Pair Sylvania Triple Mica Grey Plate 5751 $259.99 per pair |
NOS Telefunken Long Plate12AX7 (Smooth Plate) Diamond Bottom screened and tested for noise and microphonics Price $224.99 each NOS Telefunken Long Plate12AX7 (Ribbed Plate) Diamond Bottom screened and tested for noise and microphonics Price $199.99 each NOS Mullard 12ax7 short plate (various brandings) screened and tested for noise and microphonics Price $174.99 NOS Heerlen (Amperex/Philips 12ax7) short plate (various brandings) screened and tested for noise and microphonics Price $174.99
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Price: $449.99 per matched pair Mullard NOS M8137 CV4004 DAC/driver grade 1960's Just $149.99 per tube (7 pcs available!)
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NOS Sylvania 12AX7 Black Plate Price: $119.99 per tube LOW STOCK WARNING!
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Sylvania 1950's 12AX7 Short Plate tested and noise tested (recommended for dumble Dumblatorand other tube buffered effects loops) Price: $99.99 per tube
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Sylvania 12AX7 Long Plate Same ultra durable construction as JAN 12AX7WA LOW STOCK WARNING! Price: $74.99 per tube
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GE NOS 12AX7 Price: $79.99 per tube (enter qty for matched pair etc)
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Philips or Sylvania NOS 12AX7WA (Philips shown above) Price: $149.99 per matched pair (please specify brand when ordering)
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NOS GE 12AX7 (branded as International) Price: $149.99 per matched pair
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Philips or Sylvania NOS 12AX7WA Singles Price: $74.99 per tube (please specify brand when ordering)
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(Various brandings, all made in pre-war Yugoslovia) (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 $79.99 per tube
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NOS RFT 12ax7 (various brands) Price: $59.99 per tube
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enter qty 2 for matched pair, 4 for matched quad etc Price: $199.99 per tube Click Link above for phono grade and balanced tubes
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