NOS 12AX7 / ECC83 / CV4004 / 7025 / B759 / M8137 / ECC803S

  • BEL 12ax7

    BEL 12ax7

    The India made BEL 12AX7 is by far the best value in 12AX7 tubes.  Made on Philips Mullard equipment and identical to a mullard 12ax7, but pumped in India, these have the exceptional tone of a Mullard and accentuated mids without the hefty price tag.  Branded BEL or other branding. $69.99 per tube

  • EI 12AX7 Pre War Yugo

    EI 12AX7 Pre War Yugo

    NOS 12ax7 CV492 Of all the 12AX7 tubes we have tested here at Tubes Unlimited, these amazing CV492 smooth plate tubes made in pre-war Yugoslovia have tested with some of the highest umos levels we have seen! These were also used as original equipment in the Audio Research SP-6/8. Here is what one of our customers have said about these powerful tubes: " These tubes kick butt! A huge upgrade for the Behringer 1953 microphone pre-amp!" Brian Puglisi If you are an audiofile or musician, you owe it to yourself to pick up a couple of these NOS tubes! Tubes Unlimited has one of the largest known supplies left in the world of these amazing tubes, so we can offer unprecedented matching and noise testing! Recommended by Dr. Z for all of his amps! Original equipment for Audio Research SP-6/8. Just $79.99 per tube (various brandings)! Balanced Triodes Just $89.99 per tube! Pre-war Yugo CV492 NOS NIB-Various brandings, all made in pre-war Yugoslovia) $79.99 per tube

  • GE 12AX7 1960s-1970's

    GE 12AX7 1960s-1970’s

    1960-1970's GE NOS 12AX7 tested and noise tested $79.99 per tube. Warm, punchy and clear and sound excellt when driveninto distortion,,,excellent for guitar amps where low noise and low microphonics are required!

  • GE 12AX7 JG 1950's Long Plate

    GE 12AX7 JG 1950’s Long Plate

    1950's GE JG 12AX7 Long Plate tested and noise tested. $109.99 per tube. These GE 12AX7 long plates are my favorite tube of choice for V1 of most guitar amps.  Excellent detail, warm and bluesy, they sound amazing at the front end of your lower gain guitar amps, and in the "clean" channel of channel switching amplifiers.

  • Sylvania 12AX7 Long Pinched Plate

    JAN Philips 12AX7WA

    1980's Philips (made on Sylvania equipment) 12AX7WA NOS Long pinched Plate $79.99 per tube. Same ultra durable construction as the Sylvania 12AX7WA. Not recommended for high gain positions.

  • Japanese 12ax7

    Japanese 12ax7

    Super high quality japanese made 12ax7 (very similar construction to the GE 12ax7). Punchy, low noise, low microphonics!  Incredible value and far better than anything being made today!

  • Mullard 12ax7

    Mullard 12ax7

    The Mullard short plate 12ax7 if highly regarded as it should be!  Vintage Mullard 12AX7 made in the 1960's and 1970's  have great accentuated midrange tone and bass, and are an overall excellent 12AX7 choice for  Hifi and guitar amps! Just $174.99

  • Mullard CV4004

    Mullard CV4004

    Mullard CV4004 12AX7 Mullard CV4004 12AX7 tubes we have tested here at Tejas Tubes, are of amazing quality and have an exceptional tone. These tubes were manufactured in England by the Mullard company. They are renown for their tone in both guitar amps and hifi stereo. Try some out in your system and expereince the best!!! This is a suitable replacement for any 12AX7 tube type. Various brands available.

  • Philips 12ax7 Bugle Boy Holland

    Philips 12ax7 Bugle Boy Holland

    The Bugle Boy Holland made Philips Amperex 12AX7 is one of the earliest Holland made 12ax7 tubes! They are incredibly lively with a warm punchy sound, excellent bass, and enhanced great upper midrange! Tested and noise tested! Just $249.99 NOS in original boxes, screened for low noise/low microphonics in our Vacuum Tube Valley tube characterizer.

  • Philips 12ax7 Holland

    Philips 12ax7 Holland

    The  Holland made Philips / Amperex 12AX7 is an amazing sounding Holland made 12ax7 tube!  Warm, punchy with excellent bass, and  great upper mids!  Slightly less expensive than the earlier Bugle Boy Holland 12AX7, the dimple getter Holland 12AX7 are Just $175.00 NOS in original boxes, screened for low noise/low microphonics in our Vacuum Tube Vally tube characterizer.

  • Raytheon 12ax7

    Raytheon 12ax7

    The JRP Raytheon tall black plate 12AX7 is an awesome choice for many guitar amps and hifi systems! Just $149.99. Most were made in the late 50's and 1960's.  Highly recommended for the following equipment:

    • Bad Cat 'Custom Shop' Cub II R 1 x 12 Combo Tube Amplifier Rogue Cronus Fender Guitar Amps Broskie Aikido PH1 Quicksilver Carver 180 amp
    • Cayin A-50T
    • THOR phono stage
    • Rogue Tempest
    • CAT JL-2 amp
    • Rogers High Fidelity EHF-100 2011
    • Aguilar DB750 bass amp

  • RCA 12ax7

    RCA 12ax7

    1960's -1970's RCA short Plate 12ax7 NOS Tube.  These are incredible sounding 12ax7 and were original equipment in older Fender guitar amplifiers.  One of teh best Rock N Roll guitar amp tubes ever made!  Screened for low noise and microphonics just $134.99

  • NOS ITT 12AX7 (2)

    RCA 12AX7 ECC83- Italy

    This 12AX7 is actually very rare as I have never seen these available elsewhere.  These were branded ITT, but made at the RCA plant in Italy (Geloso), they have excellent detail and clarity.  If you are looking for NOS 12ax7 at an exceptionally low price, then the RCA Italy 12ax7 is a no-brainer!

  • RCA 7025

    RCA 7025

    Tight bottom end along with the sparkle, RCA 7025 are extremely dynamic sounding,,, these are some of the best input tubes for guitar amps available! NOS Short Grey plates in military boxes.

    7025=12ax7 special quality-low noise

  • RCA 7058

    RCA 7058

    7058=12ax7 with 11V-13.5V filament

  • RFT 12AX7

    RFT 12AX7

    RFT 12AX7 No matter how these are branded (Amperex, Positron, National, Siemens,the list goes on and on) RFT 12AX7 tubes are of amazing quality and have an exceptional tone. These tubes were manufactured in East Germnay by the RFT company. They are renown for their tone in high gain guitar amps like the Diesel "Herbert" , Carmen Ghia, Dr Z Maz Jr. and Marshall's, these absolutely smoke!. We can now offer unprecedented matching as we got in a supply of over 100 pcs! Now just $59.99 per tube!

  • Siemens E83CC 12AX7 LN

    Siemens E83CC 12AX7 LN

    Siemens Rohre E83CC Low Noise version, laboratory screened to be within 3dB theoretical noise limit of the 12AX7. These are the tube of choice for the most picky set of ears!  Highly recommended for reording studios and audiophiles who demand a low noise floor!    We have three different grades (versions) of the Siemens E833CC.  Please see the descriptions or contact to determine which is most suited to your particular application!

  • Siemens E83CC 12AX7 SLN

    Siemens E83CC 12AX7 SLN

    Siemens Rohre E83CC Super Low Noise version laboratory tested so these are higly select,,, within 1dB of theoretical noise limit for the 12ax7.  These are the quietest of the quiet. Extremely neutral and open soundstage!  For super critical low noise applications such as recording, microphones, and phono stages.

  • Siemens E83CC 12AX7 Std

    Siemens E83CC 12AX7 Std

    " Joshua, love the Siemens E83CC tubes. Put them up against ribbed Telefunkens and Mullards M8137s and they came in on top! I'd like to purchase another matched and balanced pair to have as a backup. Thanks!" Carlos Lopez Wellington FL   Siemens Rohre E83CC Made in Munich West Germany in 1977-1979, these are an excellent choice for audio hifi or guitar amps. Extremely low microphonics and huge wide open sound stage make these an excellent choice for the most finicky audiophile or guitar player. Known for their clear, transparent quality, the Siemens E83CC have unparalled detail, resolution, and a sweeet high end! All pieces are thoroughly noise tested and screened for microphonics, and then additionally tested for gas, shorts, leakage, and transconductance on our computerized and calibrated Hickok 118B.  If you are an audiofile or musician, you owe it to yourself to pick up a couple of these NOS tubes! Tubes Unlimited has one of the largest known supplies left in the world of these amazing tubes, so we can offer unprecedented matching and noise testing! Considered to be THE "reference" 12ax7 by Audio Research Corporation.   For lab screened low noise versions of this tube click here. For lab screened Super low noise version (quietest of the quiet!) of this tube click here

  • Sylvania 12ax7 1950's Long Black Plate

    Sylvania 12ax7 1950’s Long Black Plate

    1950's Sylvania NOS 12AX7 Black Plate $124.99 per tube. These 17mm black plate 12ax7 are rumored to be Briam May's favorite and have excellent clarity and sound beautiful when overdriven in a guitar amplfier, especially recommended for the Vox AC30 and other clean amplifiers where you want a balance of warmth and sparkle!


12AX7 Vacuum Tube Reference Information

ECC83: This European nomenclature for 12AX7.

ECC803/ECC803S/E83CC: This "premium" version of European made 12AX7. The "S" on the ECC803S indicates "select" and are usually gold pin. These are usually found on Telefunken and Siemens branded tubes and a very rare Radiotron ecc803S version from the Philips factory in Australia.

12ax7: Original version of the 12ax7. Early production was manufactured in the USA by Tung Sol, RCA, Sylvania, GE etc. The earliest 12ax7 have larger 17mm 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 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 made by Sylvania and NEC in Japan. Great for audio applications that uses a 12AX7.

12DT7, 12DM7, 12DF7: Special quality low noise/low microphonic versions of the 12AX7. Usually branded as Westinghouse or Raytheon.

7025: Hifi low noise version of the 12AX7 with all other specifications being the same as 12AX7. Tubes marked with both 12AX7 and 7025 are usually low noise as well.

5751: Military version/drop in replacement for the 12AX7, but is actually different. The 5751 has identical plate resistance to the 12AX7, but the gain is 70 compared to 100 for the 12AX7. Early production 5751 have extra thick mica spacers (often three know as triple mica) and extra support rods to minimize microphonic response. Many 5751 also have matched triode units.

7729: CBS made industrial version of the 12AX7 with gold pins for special applications requiring reliability and low noise/low microphonics.

6681: The mobile version of a 12AX7. Usually these are the same as a regular 12ax7 which have been tested and screened to perform well in circuits with large variations in filament voltage.

7058: Same as a 12AX7 but 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.