Sylvania Gold Brand 5751 - Super rare 1960's vintage grey plates with gold pins. These have the thicker 2-mica spacers instead of the triple micas of the late 50's and early 60's vintages, but are still highly regarded as one of the best 5751 tubes ever produced. As expected, they all test very low noise and microphonics, and with a triode balance at Platinum Grade standards. NOS in original Gold Brand boxes.
A note on the 5751:
Sometimes a 5751 can be used in lieu of a 12AX7. Some folks (guitar guys typically) that have gear that come equipped with 12AX7's will sub a 5751. They do this specifically because it colors the sound and changes the way their amp performs, as they look for ways to "distort." This is a matter of taste as the 5751 is a lower gain tube than the 12AX7. If someone tells you to use a 5751 because they like it, make sure it's the same piece of gear. A lower gain tube can, depending on the circuit, operate perfectly. However, in some extreme cases, the lower gain can cause high distortion and in some cases not even work properly.
5751 tubes do not have a "sound" that is particular to that tube, any more than 12AX7's have a "sound". It depends on who made the 5751 and when, the operating condition of the tube, and the circuit it's going into. Any other assumptions or statements about the merits of that tube are silly.
Logo may vary from picture above. Price includes matching in any quantity you need at no extra charge.
Vacuum tubes are warranted for 90 days against defects, except in cases of abuse, and replaced with like-item only.
Exceptions to our warranty policy are as follows:
Upscale Audio is not liable for any damage or injury caused by the improper use of its tubes or the use of an incorrect/incompatible tube type. If you are unsure of what tube or tubes your equipment uses, consult the manufacturer before making a purchase. Using an incompatible tube type may cause severe damage to your equipment and will void your tube's warranty.
Vacuum tubes are electronic parts and are not refundable under any circumstances.