Which 12ax7/5751 tube won the right to be called the best and the worst?

Updated August 5th, 2020

Based on user ratings in the last 8 years, here is the list of winners and losers. The system is based on 5 stars. We will treat 5751 and 12ax7 in the same category – they are different tubes, but often used interchangeably.

Old Stock 12ax7

Winners

1. Sylvania 5751 Gold Brand Gray Plates Triple Mica (4.8)
2. RCA 12ax7 Carbon Black Plates (4.6)
3. Raytheon 5751 Black Plates Triple Mica (4.6)
4. Mullard 12ax7 Short Plates (4.5)
5. RCA 5751 Black Plates Triple Mica (4.5)

No surprises here, all of them are highly desirable tubes.

Losers

1. GE 12ax7 Gray plates (3.0)
2. GE 5751 Gray Plates (3.0)
3. Ei 12ax7 Long Gray Plates (3.14)

I was a bit surprised by Ei 12ax7 low rating, but due to their tendency to become very microphonic, it makes sense.

New Production 12ax7

Winners

1. Electro-Harmonix 7025/12ax7 tube (4.33)
2. Electro-Harmonix Gold 12ax7 Russia (4.14)
3. TJ Full Music 12ax7/ECC83 Box Plates Gold Pins (3.67)
4. Mullard 12ax7/CV4004 Short Plates Russia (3.67)
5. JJ ECC83S (3.56)

Great job by Electro-Harmonix 7025 tube, it leads the list with a good margin.

Losers

1. ShuGuang 12AX7 (2.5)
2. Electro-Harmonix 12ax7 (3.0)
3. Psvane 12ax7-T Mark II (3.37)

Yeah, ShuGuang 12ax7 is by far the worst of the worst – too bad that a lot of manufacturers choose to ship their equipment with this tube.

DISCLAIMER: This is not a definitive list of all best and worst 12ax7. It’s purely based on over 5,000 ratings submitted by the users of this site.