Matched Pair 
JAN 6B4G 
Sylvania 
same code = AAC/7513
Vacuum Tubes
Fat Tubular Type Bottles
Gray Plates
Halo Getters

The regular 6B4G tubes are directly heated triodes. It has been brought to my attention that these tubes are indirectly heated pentodes (or beam power tubes) wired internally for triode operation.

Tested at  117 & 120+

Passed 'Life Test'

on a calibrated B&K 747B tube tester

where the Good range is 65-120

*B&K 747B calibrated

*Dan Nelson calibrated TV-7D/U with sweep tube adapters, & digital meter with plate current test at 150V.

*Paul Hart calibrated/modified Westmore 501 (Triplett 3444)

Test results may differ between various testers for many reasons such as technical design, aging components, etc. So while test results are a good indication of quality there can be some difference between the many differently designed & maintained testers.

The following definitions are mine as I use them.
'Balanced' refers to comparing the gm test results between the lowest to the highest identical
sections of a single tube. Within 3% I consider to be 'Balanced'.

'Matched' refers to comparing the gm test results between the lowest to the highest of the identical sections of a set of tubes.
     'Matched' I consider to be within 10%. Some call similar 'Gold Matched'
     'Closely Matched'  I consider to be within about 5%. Some call similar 'Platinum Matched'
     'Tightly Matched' I consider to be within 2%.
*For Multiple item purchases click the "Add to Cart" selection for each item
*After all items have been added to your cart click on "Request Total From Seller"
*An invoice will be returned with the correct 'combined shipping' & total due

*If your purchase is not fully satisfactory please contact me .

  • International customers welcome: Please do not ask for false value on the customs form
  • For combined international shipping you need to send an email listing the items you want to buy and I will create a single listing for all the items that you can buy with the corrected shipping charge

*Tubes will be shipped in a cardboard box with packing, usually bubble wrap or sheet foam

       Packed for protection

       Packed for ease in unpacking

*Tubes will generally be cleaned

       Clean tubes will radiate heat better & operate cooler

*Pins will generally be straightened/cleaned as needed

       Cleaned pins make better electronic connection

*Most tubes are shipped in their boxes (or replacement boxes)

       I often repair a box so it will function properly

*I try to get your package in the next mail after receiving your order.