Vacuum Tube - 7581A, Tung-Sol Reissue

Vacuum Tube - 7581A, Tung-Sol Reissue

Tung-Sol
Vacuum Tube - 7581A, Tung-Sol Reissue image 1
Customer image:<br/>"Dynaco ST70 with 7581a"
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Vacuum Tube - 7581A, Tung-Sol Reissue image 1
Customer Images:
Customer image: "Dynaco ST70 with 7581a"
Starting at: $46.60
In Stock

Rated for more power than the standard 7581 (35W plate dissipation vs 30W plate dissipation).

SKU:
T-7581A-TUNG
Item ID:
041541
Brand:
Tung-Sol
Type:
RoHS Compliant
Part Numbers
Single or MatchedOur Part NumberUPC/EAN
SingleT-7581A-TUNG841358107870
Matched PairT-7581A-TUNG-MP0084135811050
Matched QuadT-7581A-TUNG-MQ0084135811051
Body Height3.688 in.
Capacitance, grid to plate0.6 pF
Capacitance, input10 pF
Capacitance, output6.5 pF
Grid 1 Voltage-14 V
Grid Circuit Resistance (Rg), Cathode Bias0.5 MΩ
Grid Circuit Resistance (Rg), Fixed Bias0.1 MΩ
Heater Current900 mA
Heater Voltage6.3 V
Heater to cathode voltage (Uk/f)200 V
Item Diameter1.562 in.
Item Height4.25 in.
Plate Current, pentode (Ia)210 mA
Plate Current, triode (Ia)72 mA
Plate Dissipation (Wa)30 W
Plate Resistance (Ra)22.5 KΩ
Plate Voltage, pentode (Ua)≤ 500 V, 70 V typical
Plate Voltage, triode (Ua)≤ 450 V, 250 V typical
Screen Current, pentode25 mA
Screen Current, triode5 mA
Screen Dissipation5 W
Screen Voltage, pentode≤ 450 V, 300 V typical
Transconductance (S)6,000 μmhos
Packaging Information
Packaging DimensionsMatched Pair versionT-7581A-TUNG-MP4.75 in. × 3.5 in. × 1.75 in.
Matched Quad versionT-7581A-TUNG-MQ4.75 in. × 3.5 in. × 3.5 in.
Single versionT-7581A-TUNG1.5 in. × 1.5 in. × 4 in.
Weight (Packaging)Matched Pair versionT-7581A-TUNG-MP0.5644 lbs.
Matched Quad versionT-7581A-TUNG-MQ1.1288 lbs.
Single versionT-7581A-TUNG0.1411 lbs.
T-7581A-TUNG-MP - Matched Pair versionBody Height3.688 in.
Capacitance, grid to plate0.6 pF
Capacitance, input10 pF
Capacitance, output6.5 pF
Grid 1 Voltage-14 V
Grid Circuit Resistance (Rg), Cathode Bias0.5 MΩ
Grid Circuit Resistance (Rg), Fixed Bias0.1 MΩ
Heater Current900 mA
Heater Voltage6.3 V
Heater to cathode voltage (Uk/f)200 V
Item Diameter1.562 in.
Item Height4.25 in.
Plate Current, pentode (Ia)210 mA
Plate Current, triode (Ia)72 mA
Plate Dissipation (Wa)30 W
Plate Resistance (Ra)22.5 KΩ
Plate Voltage, pentode (Ua)≤ 500 V, 70 V typical
Plate Voltage, triode (Ua)≤ 450 V, 250 V typical
Screen Current, pentode25 mA
Screen Current, triode5 mA
Screen Dissipation5 W
Screen Voltage, pentode≤ 450 V, 300 V typical
Transconductance (S)6,000 μmhos
T-7581A-TUNG-MQ - Matched Quad versionBody Height3.688 in.
Capacitance, grid to plate0.6 pF
Capacitance, input10 pF
Capacitance, output6.5 pF
Grid 1 Voltage-14 V
Grid Circuit Resistance (Rg), Cathode Bias0.5 MΩ
Grid Circuit Resistance (Rg), Fixed Bias0.1 MΩ
Heater Current900 mA
Heater Voltage6.3 V
Heater to cathode voltage (Uk/f)200 V
Item Diameter1.562 in.
Item Height4.25 in.
Plate Current, pentode (Ia)210 mA
Plate Current, triode (Ia)72 mA
Plate Dissipation (Wa)30 W
Plate Resistance (Ra)22.5 KΩ
Plate Voltage, pentode (Ua)≤ 500 V, 70 V typical
Plate Voltage, triode (Ua)≤ 450 V, 250 V typical
Screen Current, pentode25 mA
Screen Current, triode5 mA
Screen Dissipation5 W
Screen Voltage, pentode≤ 450 V, 300 V typical
Transconductance (S)6,000 μmhos
T-7581A-TUNG - Single versionBody Height3.688 in.
Capacitance, grid to plate0.6 pF
Capacitance, input10 pF
Capacitance, output6.5 pF
Grid 1 Voltage-14 V
Grid Circuit Resistance (Rg), Cathode Bias0.5 MΩ
Grid Circuit Resistance (Rg), Fixed Bias0.1 MΩ
Heater Current900 mA
Heater Voltage6.3 V
Heater to cathode voltage (Uk/f)200 V
Item Diameter1.562 in.
Item Height4.25 in.
Plate Current, pentode (Ia)210 mA
Plate Current, triode (Ia)72 mA
Plate Dissipation (Wa)30 W
Plate Resistance (Ra)22.5 KΩ
Plate Voltage, pentode (Ua)≤ 500 V, 70 V typical
Plate Voltage, triode (Ua)≤ 450 V, 250 V typical
Screen Current, pentode25 mA
Screen Current, triode5 mA
Screen Dissipation5 W
Screen Voltage, pentode≤ 450 V, 300 V typical
Transconductance (S)6,000 μmhos

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Specifications, Files, and Documents

PDF: Specification Sheet Specification Sheet3.94 MB
Questions? Contact us at [email protected], or give us a call at 480-820-5411

Product Reviews

5.00 out of 5 based on 2 reviews
Reverb Rey - March 24th, 2023
5 out of 5

I had a 1950's Fisher AZ-80 monoblock hifi amp that originally used EL37's, which of course are no longer available. Wanted to use KT-66's but most of them are too fat a bottle to fit under the tube cage. Also, the cathode bias circuit was running the KT-66's at 28 watts plate dissipation (on a 25W tube) which could not easily be rectified without mods. These 7581A's fit nicely in the chassis under the tube cage, and are rated at 35W dissipation. They biased at 28 watts idle so no issues there, and sounded great.

Dan L - October 3rd, 2022
5 out of 5

Not sure why you leave a tube review when you should be reviewing the post office for damaging your shipment...

I'll leave a tube review. These are wonderful tubes. I've used a pair in an Ampeg B15 bass amp clone and also rotate a quad of them in a Dynaco ST70 HiFi amp. In the bass amp, they offer exceptional bass tone with clean articulate highs and solid mids. They will break up when pushed hard, but do offer a bit more clean headroom then their 6L6GC cousins. I would say they are a 6L6GC that can take a bit more heat. In the HiFi amp they offer a different flavored tone structure then the EL34 / KT77 the amp is built around. In that amp the mids are very slightly pulled back (compared to an EL34, you'd never noticed if you hadn't listen to the amp with EL34). The bottom is tight and much harder hitting than an EL34. Highs are clean not harsh. I use these for hard rock, they hold up very well in that "wall of sound" type of music, but don't suffer with lighter stuff. I could be happy leaving them installed all the time to be honest. Add to that, they have a great blue glow when the lights are down. I have a few vintage 6L6GCs that do it too, but I've not had many new issue tube glow. Purely visual, but in an open chassis like the Dynaco, it's very cool...