General Electric7581Aused7581A GE GENERAL ELECTRIC VINTAGE TUBE 7581 6L6GC NOS SLEEVE OF 4 **Curve Tracer Tested**SLEEVE OF 5 GENERAL ELECTRIC 7581A \ 6L6GC VINTAGE VACUUM TUBES These are 35W direct replacements for 6L6GC tubes, and one of the most rare variants in existence. Sleeves like this only come b...699.99

7581A GE GENERAL ELECTRIC VINTAGE TUBE 7581 6L6GC NOS SLEEVE OF 4 **Curve Tracer Tested** [Expired]


no longer for sale

SLEEVE OF 5 GENERAL ELECTRIC 7581A \ 6L6GC VINTAGE VACUUM TUBES
These are 35W direct replacements for 6L6GC tubes, and one of the most rare variants in existence.  Sleeves like this only come by once in a lifetime, it's difficult to even find a matched pair of these in NOS condition, let alone a matched quad + 1.

Includes one identical matched quad, and one bonus GE manufactured Westinghouse 7581.   
Includes full data set with results for plate current, plate resistance, transconductance, and voltage gain.
Corners test simulates when voltage spikes naturally occur in a circuit and track variations in plate current. 

First four identical tubes test well above nominal based on manufacturer specs.  Plate resistance, plate current, transconductance and voltage gain are all extraordinarily well matched.
The fifth tube is Westinghouse labeled, and manufactured by GE.
The bonus Westinghouse tube tests lower than the rest but is still viable and could be matched with some of your other tubes.

Tubes have also been audio tested in a 1963 blonde \ blackface Fender Tremolux, and sound great.

Tube #1 -

mA = 48.1
Rp = 1660
Gm = 4586
Mu = 7.6
Corners = Pass

Tube #2 -

mA = 49.2
Rp = 1638
Gm = 4628
Mu = 7.6
Corners = Pass

Tube #3 -

mA = 45.2
Rp = 1716
Gm = 4566
Mu = 7.8
Corners = Pass

Tube #4 -

mA = 47.8
Rp = 1640
Gm = 4680
Mu = 7.7
Corners = Pass

Tube #5 -

mA = 34.8
Rp = 2094
Gm = 3907
Mu = 8.2
Corners = Pass


Gm Nominal = 4100 \ Minimum Good = 2000 No Shorts or Leaks
Thank you for looking!

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