Vacuum Tube - 7591, JJ Electronics
The JJ Electronic 7591 is a reliable and accurate reproduction of the classic tube. This 19 Watt pentode has been used in a variety of amplifiers including Hi-Fi amps and Ampegs. The JJ 7591 is a great replacement for any 7591 tube position.
Matched versions of this tube use Apex Matching
RoHS Compliant
Accessory Items:
| Single or Matched | Our Part Number | UPC/EAN | JJ Electronics Part Number |
|---|---|---|---|
| Apex Matched Pair | T-7591-S-JJ-MP | 609722122924 | |
| Apex Matched Quad | T-7591-S-JJ-MQ | 609722122931 | |
| Single | T-7591-S-JJ | 609722122917 | 7591S |
| Body Height | 93 mm | |
| Cathode Current (Ik) | ≤ 85 mA | |
| Filament Current (If) | 0.8 A | |
| Filament Voltage (Uf) | 6.3 V | |
| Gain (μ) | 16.8 | |
| Grid 2 dissipation (Wg2) | 3.3 W | |
| Grid Circuit Resistance (Rg), Cathode Bias | 1 MΩ | |
| Grid Circuit Resistance (Rg), Fixed Bias | 0.3 MΩ | |
| Grid Current 2 (Ig2) | 8 mA | |
| Grid Voltage 1 (Ug1) | -10 V typical | |
| Grid Voltage 2 (Ug2) | ≤ 440 V, 300 V typical | |
| Grid capacitance (cg1) | 10 pF | |
| Grid to Plate Capacitance (ca/g) | 0.25 pF | |
| Item Diameter | 33.3 mm | |
| Item Height | 79 mm | |
| Plate Capacitance (ca) | 5 pF | |
| Plate Current (Ia) | 60 mA | |
| Plate Dissipation (Wa) | ≤ 19 W | |
| Plate Voltage (Ua) | ≤ 550 V, 300 V typical | |
| Transconductance (S) | 10 mA/V |
| Packaging Dimensions | Apex Matched Pair version | T-7591-S-JJ-MP | 4.8 in. × 3.3 in. × 1.6 in. |
| Apex Matched Quad version | T-7591-S-JJ-MQ | 4.8 in. × 3.3 in. × 3.3 in. | |
| Single version | T-7591-S-JJ | 1.6 in. × 1.6 in. × 4.6 in. | |
| Weight (Packaging) | Apex Matched Pair version | T-7591-S-JJ-MP | 0.2204 lbs. |
| Apex Matched Quad version | T-7591-S-JJ-MQ | 0.4408 lbs. | |
| Single version | T-7591-S-JJ | 0.1102 lbs. |
| T-7591-S-JJ-MP - Apex Matched Pair version | Body Height | 93 mm |
| Cathode Current (Ik) | ≤ 85 mA | |
| Filament Current (If) | 0.8 A | |
| Filament Voltage (Uf) | 6.3 V | |
| Gain (μ) | 16.8 | |
| Grid 2 dissipation (Wg2) | 3.3 W | |
| Grid Circuit Resistance (Rg), Cathode Bias | 1 MΩ | |
| Grid Circuit Resistance (Rg), Fixed Bias | 0.3 MΩ | |
| Grid Current 2 (Ig2) | 8 mA | |
| Grid Voltage 1 (Ug1) | -10 V typical | |
| Grid Voltage 2 (Ug2) | ≤ 440 V, 300 V typical | |
| Grid capacitance (cg1) | 10 pF | |
| Grid to Plate Capacitance (ca/g) | 0.25 pF | |
| Item Diameter | 33.3 mm | |
| Item Height | 79 mm | |
| Plate Capacitance (ca) | 5 pF | |
| Plate Current (Ia) | 60 mA | |
| Plate Dissipation (Wa) | ≤ 19 W | |
| Plate Voltage (Ua) | ≤ 550 V, 300 V typical | |
| Transconductance (S) | 10 mA/V | |
| T-7591-S-JJ-MQ - Apex Matched Quad version | Body Height | 93 mm |
| Cathode Current (Ik) | ≤ 85 mA | |
| Filament Current (If) | 0.8 A | |
| Filament Voltage (Uf) | 6.3 V | |
| Gain (μ) | 16.8 | |
| Grid 2 dissipation (Wg2) | 3.3 W | |
| Grid Circuit Resistance (Rg), Cathode Bias | 1 MΩ | |
| Grid Circuit Resistance (Rg), Fixed Bias | 0.3 MΩ | |
| Grid Current 2 (Ig2) | 8 mA | |
| Grid Voltage 1 (Ug1) | -10 V typical | |
| Grid Voltage 2 (Ug2) | ≤ 440 V, 300 V typical | |
| Grid capacitance (cg1) | 10 pF | |
| Grid to Plate Capacitance (ca/g) | 0.25 pF | |
| Item Diameter | 33.3 mm | |
| Item Height | 79 mm | |
| Plate Capacitance (ca) | 5 pF | |
| Plate Current (Ia) | 60 mA | |
| Plate Dissipation (Wa) | ≤ 19 W | |
| Plate Voltage (Ua) | ≤ 550 V, 300 V typical | |
| Transconductance (S) | 10 mA/V | |
| T-7591-S-JJ - Single version | Body Height | 93 mm |
| Cathode Current (Ik) | ≤ 85 mA | |
| Filament Current (If) | 0.8 A | |
| Filament Voltage (Uf) | 6.3 V | |
| Gain (μ) | 16.8 | |
| Grid 2 dissipation (Wg2) | 3.3 W | |
| Grid Circuit Resistance (Rg), Cathode Bias | 1 MΩ | |
| Grid Circuit Resistance (Rg), Fixed Bias | 0.3 MΩ | |
| Grid Current 2 (Ig2) | 8 mA | |
| Grid Voltage 1 (Ug1) | -10 V typical | |
| Grid Voltage 2 (Ug2) | ≤ 440 V, 300 V typical | |
| Grid capacitance (cg1) | 10 pF | |
| Grid to Plate Capacitance (ca/g) | 0.25 pF | |
| Item Diameter | 33.3 mm | |
| Item Height | 79 mm | |
| Plate Capacitance (ca) | 5 pF | |
| Plate Current (Ia) | 60 mA | |
| Plate Dissipation (Wa) | ≤ 19 W | |
| Plate Voltage (Ua) | ≤ 550 V, 300 V typical | |
| Transconductance (S) | 10 mA/V |
 Specification Sheet | All Models |
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Specifications, Files, and Documents
Questions and Answers
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2 answers
I saw the review about the vintage ampeg but I just wanted to be certain..this tube is rated 19W but my amp is only 15W. Would the 19 want to pull too hard on the system or is 4W not gonna make a difference. I know some systems can't handle that much difference but those we low voltage, sensitive electronics
Asked by ergonomical69 on March 3rd, 2018.
March 7th, 2018
Staff Member
This tubes is 19 watts.
The output power rating of a given amp hinges largely on the amp's power supply voltage. Designers are careful to choose voltages for the output circuit that won't push the tubes past their (max) power ratings. The 7591 is nominally listed at a max sustained capacity of 19WRMS, and your amp limits the output supply (plate) voltage so that the tube can safely operate below that maximum, at just 15 watts. In brief, your tube lasts a lot longer, and run a little cooler. And don't worry, this in no way reduces an amp's ability to sing its little heart out. As a general rule, this
practice has been an industry-wide standard for a long time, for almost every popular amp, including those used by celebrated players.
1 answers
The datasheet on your website for the JJ 7591S has a couple of errors. It identifies Pin 5 as Grid 1. Pin 5 should be Cathode and Grid 3. Also, it identifies Pin 8 as "K" for cathode. Pin 8 should be Grid 2. The internal wiring on the specsheet is drawn correctly but the identification labels are wrong.
Asked by Anonymous on June 26th, 2019.
The JJ Specification drawing is wrong but the tube is made correctly and functions properly. I have compared the Westinghouse and Sylvania spec sheets for the 7591 tubes and they agree. Pinnouts as follows: 1 -no pin on tube, 2=Heater, 3=Plate, 4=Grid 2, 5=Cathode & Grid 3, 6=Grid 1, 7=Heater, 8= another Grid 2.
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Out of 2 matched quads, (8 tubes), I have 2 that RED PLATE in a working Fisher unit. I put Tung-sols in and it works fine. I also notice that the "JJ's run very hot compared to the others.
I will never by "JJ" anything again. BAD, BAD tubes
Appears as ordered.
Out standing quality, price, and delivery!!! Brought new life to my 1961 Pilot 654MA!!!
Meh. Westinghouse, Tung Sol, or other USA 7591As will last 5-20x longer than JJs, and the A suffix simply sound better and last longer. I just put Westinghouse 7591As in a pair of Mc30s (Mc Intosh) monoblocks, and they were worth the $250 over the JJs. I consider the JJs to be one of the better 7591s but lately I have had some real problems with JJ not properly annealing their glass. I have never had any RCA, Westinghouse, GE or Tung Sol's bottle crack from the heat. Tung Sol as in Tung Sol made in USA not Mike Mathews' New Sensor reissue stuff from Russia. So far I haven't had too many problems with New Sensor tubes cracking from heat & cooling. That is mostly a JJ problem, and it's getting really old too.
I have used the JJ 7591 tubes in numerous customer amps over the past few years with good results. They sound good, and have bias levels similar to the originals, the supply of which continue to diminish.
I love having AES within a 30 minute drive. I can actually order something simple, like tubes, in the morning and pick it up that same day during their 90 minute window of opportunity. Their prices are great, they have what I need for most of my vintage tube stereo needs. Life is good
Scott 7591a works very well in my Scott 299c and LK-72 .
Tubes worked great in my 50 year old Ampeg amplifier. The people at Antique Electronic Supply, especially the person I spoke with (I think his name was Justin), were more than helpful in understanding what I needed, and getting me the difficult to find replacement tubes. Great product and great service.