Vacuum Tube - ECC803 / 12AX7, JJ Electronics, Long Plate
Pictured: Regular
Pictured: Gold
Pictured: Regular
Pictured: Gold
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Starting at: $21.95
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The JJ Electronic ECC803 is a high performance, long plate version of the ECC83 / 12AX7. Like all JJ preamp tubes, these are built into a rugged package using the spiral filament and robust plate structure resulting in low microphonics and high reliability. The long plate version of this tube differs from the standard version with its stronger and fuller sound which offers a wider and more balanced frequency response. This tube ranges from deep rich lows to pristine highs covering a spectrum of harmonically dynamic mids along the way. This tube is an excellent choice for any guitar amp and perfect for studio and Hi-Fi equipment as well. This tube will work in any 12AX7 or ECC83 position.
RoHS Compliant
Accessory Items:
| Pin Type | Our Part Number | UPC/EAN | JJ Electronics Part Number |
|---|---|---|---|
| Gold | T-ECC803-GLD-JJ | 609722123556 | ECC803S - GOLD |
| Regular | T-ECC803-S-JJ | 609722126533 | ECC803S |
| Body Height | 51.2 mm | |
| Cathode Current (Ik) | ≤ 9 mA | |
| Filament Current (If) | 300 / 150 mA | |
| Filament Voltage (Uf) | 6.3 / 12.6 V | |
| Gain (μ) | 100 | |
| Grid Circuit Resistance (Rg) | 2,2 MΩ | |
| Grid capacitance (cg1) | 1.6 pF | |
| Grid to Plate Capacitance (ca/g) | 1.7 pF | |
| Heater to cathode voltage (Uk/f) | ≤ 100 V | |
| Internal Resistance (Ri) | 62.5 kΩ | |
| Item Diameter | 22.2 mm | |
| Item Height | 57.6 mm | |
| Plate Capacitance (ca) | 0.46 pF | |
| Plate Current (Ia) | 1.2 mA | |
| Plate Dissipation (Wa) | ≤ 1.2 W | |
| Plate Voltage (Ua) | ≤ 300 V, 250 V typical | |
| Transconductance (S) | 1.6 mA/V |
| Packaging Dimensions | 1 in. × 1 in. × 2.5 in. | |
| Weight (Packaging) | 0.029 lbs. |
| T-ECC803-S-JJ - Regular version | Body Height | 51.2 mm |
| Cathode Current (Ik) | ≤ 9 mA | |
| Filament Current (If) | 300 / 150 mA | |
| Filament Voltage (Uf) | 6.3 / 12.6 V | |
| Gain (μ) | 100 | |
| Grid Circuit Resistance (Rg) | 2,2 MΩ | |
| Grid capacitance (cg1) | 1.6 pF | |
| Grid to Plate Capacitance (ca/g) | 1.7 pF | |
| Heater to cathode voltage (Uk/f) | ≤ 100 V | |
| Internal Resistance (Ri) | 62.5 kΩ | |
| Item Diameter | 22.2 mm | |
| Item Height | 57.6 mm | |
| Plate Capacitance (ca) | 0.46 pF | |
| Plate Current (Ia) | 1.2 mA | |
| Plate Dissipation (Wa) | ≤ 1.2 W | |
| Plate Voltage (Ua) | ≤ 300 V, 250 V typical | |
| Transconductance (S) | 1.6 mA/V | |
| T-ECC803-GLD-JJ - Gold version | Body Height | 51.2 mm |
| Cathode Current (Ik) | ≤ 9 mA | |
| Filament Current (If) | 300 / 150 mA | |
| Filament Voltage (Uf) | 6.3 / 12.6 V | |
| Gain (μ) | 100 | |
| Grid Circuit Resistance (Rg) | 2,2 MΩ | |
| Grid capacitance (cg1) | 1.6 pF | |
| Grid to Plate Capacitance (ca/g) | 1.7 pF | |
| Heater to cathode voltage (Uk/f) | ≤ 100 V | |
| Internal Resistance (Ri) | 62.5 kΩ | |
| Item Diameter | 22.2 mm | |
| Item Height | 57.6 mm | |
| Plate Capacitance (ca) | 0.46 pF | |
| Plate Current (Ia) | 1.2 mA | |
| Plate Dissipation (Wa) | ≤ 1.2 W | |
| Plate Voltage (Ua) | ≤ 300 V, 250 V typical | |
| Transconductance (S) | 1.6 mA/V |
 Specification Sheet | All Models |
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Specifications, Files, and Documents
Questions and Answers
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1 answers
With the voltage gain rating being Lows:5 Mids:7 and Highs:7 could this preamp tube possibly take some lows out of my overly bassy amp?
Asked by Anonymous on January 12th, 2016.
January 13th, 2016
Staff MemberTop Contributor
experimenting with preamp tubes is always a good idea if you dislike certain characteristics of your sound. Going with a tube lacking in lows would definitely help the situation.
1 answers
Can I use these as a replacement for tubes in a Hammond S6 organ?
Asked by Anonymous on March 30th, 2017.
March 30th, 2017
Staff Member
Yes, if the S6 calls for 12AX7's these will be compatible.
1 answers
Other than the cool gold pins, is there a real difference between the regular and gold versions? Spec sheet shows them as identical. Does JJ do any special selection for tighter tolerances in the gold version?
Asked by tigerdognew on July 13th, 2020.
July 13th, 2020
Staff Member
There is no difference between the two other than the pins. JJ does not use tighter tolerances on the gold pins than the standards.
1 answers
Good for audio stereo amps not just guitar amps?
Asked by Anonymous on April 25th, 2021.
April 26th, 2021
Staff Member
Both the manufacturer and other customers have reported these work quite well in HiFi applications, but these reports are subjective and your experience may vary.
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Product Reviews
these are nice sounding tubes
Wow, regular shipping and possibly the USPS was way quicker than the order checkout listed. Packaging was appropriate and the boxes and tubes arrived in pristine condition. The sparkle has returned to my 64 year old tube amp (last rolled in 2005).
The JJ 12AX7 long plate has a strong muscular tone! Beautiful and robust! Highly recommend
Bought this for an early 70s Fender Champ along with a new JJ 5Y3 and 6V6. Certainly breathed new life into this little beauty.
Used this for a phase inverter slot, sounds great, so far so good.
Ordered this as a back up for the JJ in my Monoprice 5watt tuber. Monoprice has JJ's in both pre-amp and power (6V6) slots already, and the amp sounds fantastic as is. That said, I am doing a parallel speaker setup with a Randall 8" speaker cab, and OMG! We're talking "Baby-Marshall", that can be heard down the block when dimed. So far, so good with the JJ's.
I bought these for an old Supro class A amplifier I own to use as an experiment. These things break up at the earliest hint of power. If you're looking for any clean headroom at all, these aren't the tubes for you. If you want vintage grit at any volume level, these are the real deal. I expected the lack of clean as it's what I was looking for with this amp. I got exactly what I hoped for. The flavor of the grit changes the more you drive them. Good stuff.
I have an unusual stereo preamp from the 1970s that uses 4x 12AX7s in the phono section and two in the line side. Long-plate JJ gold-pins are just the ticket for this bit of kit.
For years, I ran a set of (apparently rebranded) Chinese 12AX7WAs that were "meh" at best. I replaced them with JJ short-plate 12AX7s and didn't like the result at all; to my ears they were not suited for this role; they'd be great in a guitar amp. I put two of the old tubes in the line stage, and replaced the phono stage with Mullards, which sounded nice until one failed prematurely. Guessing maybe the longer-plate design of the Russian Mullards were helping, I sprung for four JJ gold-pin long-plate 12AX7s. The noise floor (measured using Audacity and a high-res PC sound card) is lower than the Mullards and the sound is just as liquid, to my ears. So now, JJs in the phono, Mullards in the line. I'm happy!
Great sound, great price
When I first put this in my build, it came out very microphonic but after ten minutes it started to sound very good, nice tone! Rich and thick.