T-7591A-TUNG-MP - Matched Pair version | Amplification Factor | 16.8 |
Body Height | 2.75 in. |
Capacitance, grid to plate | 0.25 pF |
Capacitance, input | 10 pF |
Capacitance, output | 5.0 pF |
Cathode Current (Ik) | 85 mA |
Grid 1 Voltage | -10 V |
Grid Circuit Resistance (Rg), Cathode Bias | 1.0 MΩ |
Grid Circuit Resistance (Rg), Fixed Bias | 0.3 MΩ |
Harmonic Distortion | 13 % |
Heater Cathode Voltage, Negative | 200 V |
Heater Cathode Voltage, Positive | 100 V |
Heater Current | 0.8 A |
Heater Voltage | 6.3 V |
Item Diameter | 1.28125 in. |
Item Height | 3.3125 in. |
Load Resistance | 3 kΩ |
Plate Current, max signal (Ia) | 75 mA |
Plate Current, zero signal (Ia) | 60 mA |
Plate Dissipation (Wa) | 19 W |
Plate Resistance (Ra) | 29 kΩ |
Plate Voltage (Ua) | ≤ 550 V, 300 V typical |
Power Output | 11 W |
Screen Current, max signal | 15 mA |
Screen Current, zero signal | 8 mA |
Screen Dissipation | 3.3 W |
Screen Voltage | ≤ 440 V, 300 V typical |
Transconductance (S) | 10,200 μmhos |
T-7591A-TUNG-MQ - Matched Quad version | Amplification Factor | 16.8 |
Body Height | 2.75 in. |
Capacitance, grid to plate | 0.25 pF |
Capacitance, input | 10 pF |
Capacitance, output | 5.0 pF |
Cathode Current (Ik) | 85 mA |
Grid 1 Voltage | -10 V |
Grid Circuit Resistance (Rg), Cathode Bias | 1.0 MΩ |
Grid Circuit Resistance (Rg), Fixed Bias | 0.3 MΩ |
Harmonic Distortion | 13 % |
Heater Cathode Voltage, Negative | 200 V |
Heater Cathode Voltage, Positive | 100 V |
Heater Current | 0.8 A |
Heater Voltage | 6.3 V |
Item Diameter | 1.28125 in. |
Item Height | 3.3125 in. |
Load Resistance | 3 kΩ |
Plate Current, max signal (Ia) | 75 mA |
Plate Current, zero signal (Ia) | 60 mA |
Plate Dissipation (Wa) | 19 W |
Plate Resistance (Ra) | 29 kΩ |
Plate Voltage (Ua) | ≤ 550 V, 300 V typical |
Power Output | 11 W |
Screen Current, max signal | 15 mA |
Screen Current, zero signal | 8 mA |
Screen Dissipation | 3.3 W |
Screen Voltage | ≤ 440 V, 300 V typical |
Transconductance (S) | 10,200 μmhos |
T-7591A-TUNG - Single version | Amplification Factor | 16.8 |
Body Height | 2.75 in. |
Capacitance, grid to plate | 0.25 pF |
Capacitance, input | 10 pF |
Capacitance, output | 5.0 pF |
Cathode Current (Ik) | 85 mA |
Grid 1 Voltage | -10 V |
Grid Circuit Resistance (Rg), Cathode Bias | 1.0 MΩ |
Grid Circuit Resistance (Rg), Fixed Bias | 0.3 MΩ |
Harmonic Distortion | 13 % |
Heater Cathode Voltage, Negative | 200 V |
Heater Cathode Voltage, Positive | 100 V |
Heater Current | 0.8 A |
Heater Voltage | 6.3 V |
Item Diameter | 1.28125 in. |
Item Height | 3.3125 in. |
Load Resistance | 3 kΩ |
Plate Current, max signal (Ia) | 75 mA |
Plate Current, zero signal (Ia) | 60 mA |
Plate Dissipation (Wa) | 19 W |
Plate Resistance (Ra) | 29 kΩ |
Plate Voltage (Ua) | ≤ 550 V, 300 V typical |
Power Output | 11 W |
Screen Current, max signal | 15 mA |
Screen Current, zero signal | 8 mA |
Screen Dissipation | 3.3 W |
Screen Voltage | ≤ 440 V, 300 V typical |
Transconductance (S) | 10,200 μmhos |
Product Reviews
So far so good after about 20 hours! The truth is, old worn out NOS tubes don't compare to a fresh set of properly matched new production tubes! Used in a Fisher X-101b, these tubes have plenty of bottom end, clear mids and clean highs. Perfect for making the old fisher good as new!
The Tung-Sol 7591A tube is as close to the original tube as I've found. It far outperforms all other current-production 7591's, sounding just as good as the original.
They sound great in my Fisher 500C. The JJ's I had before had a little more bass response, But they were unreliable. I am pleased with these.
Did not work for me
If you are looking for a NOS sounding (as well as size-wise) 7591, then stop here. Your search is over. The EHs are much cheaper, but they sound dry by comparison. And I could not stand the sound of the EHs inside of my MC225. It just lost all of its "magic".
These tubes have gorgeous mids and highs, and sound nearly identical to the original Westinghouse tubes, and are well worth the price difference IMO.
I own a 1964 Fisher Control (Integrated) Tube Amplifier. Previously, I would re-tube with NOS 7591 or NOS 7591A Power Tubes. And I was very happy with these tubes sonic. The 7591 family have been called low power KT-88s.