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Vacuum Tubes
- 12AT7 / ECC81 / 6201 / CV4024
- 12AU7 / ECC82 / CV4003 / 5814
- 12AX7 / ECC83 / CV4004 / 5751
- 6DJ8 / 6922 / 7308 / PCC88
- EL34 / 6CA7 / KT77
- 6550 / KT88 Types
- 6L6GC / KT66 / 5881
- 6V6GT Types
- 6SL7 / 5691 / CV1985 / 6n9 / 6h9
- 6SN7 / 5692 / VT-231 / 6h8 / 6n8
- 6BQ5 / EL84 / 7189
- 5AR4 / 5U4G / & Other Rectifiers
- 300B / 845 / & Other Triodes
- Misc. Power Tubes
- Misc. Audio Tubes
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Product Description
G.E. 5751 - in military boxes. Excellent tube, especially when we select the quietest ones for you. Best choice for Conrad Johnson, as you maintain extension without brightness. Don't be fooled by the low price. Our testing, and the fact that they have a spiral-would filament for the lowest hum, make this a great tube.
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.
Platinum grade - The best of the best. Lowest noise and microphony with the tightest triode balance we have available. This is typically 10% or tighter, but may be higher depending on available stock.
Gold grade - Low noise and microphonics with a triode balance typically between 15% and 20%, but may be higher depending on available stock.
Driver grade - Lowest noise but not the lowest in microphony. Triode balance will be similar to Gold grade.
This grade is only suitable for use in the driver stage of an amplifier, or the output/buffer stage of a DAC or CD Player.
If you have a preamp or phonostage, you need at least Gold grade.
Click here for a more in depth discussion on how we grade tubes.
Price includes matching in any quantity you need at no extra charge.
Product Reviews
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A hidden gem
Posted by Scott Springer
I would have to say this is best hidden secret in the in the 12AX7/5751 tubes today. I have have tried some of the best NOS out there. But I keep coming back to this GE 5751. Quiet and great soundstage. Not to bright and not to dull. I'm not noticing any less gain in the Cary SLI-30. The GE. 5751 is just quieter to me.
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Fantastic bargain
Posted by Robert H. Levi
The underpriced GE 5751 is a winner in the Magnum Dynalab MD108 FM Tuner making it competative with the Sequerra Reference and Marantz 10B. Now outperforms any Mac MR71 or 78 with this GE tube. The Sovtec tubes supplied by MD are aweful and should be used only in emergencies. The 12AX7 varient is too etched in the MD by the way. I tried everything NOS and came away with the GE 5751 as best in blind testing with a top audiophile panel.
CRYOGENICALLY TREATED VACUUM TUBES. DONE TO UPSCALE AUDIO STANDARDS!
Most of you already know that Upscale Audio is the premier destination for expertise and availability of vacuum tubes for high-end audio equipment. So when we offer servies and options, you can be guaranteed that it represents a significant investment of research and capital, and that the end result will greatly enhance your listening experience.
Upscale has contracted with the foremost company involved in this technology, 300 Below, to treat our most popular tubes. Other tubes will be added as time allows, but it is a time consuming proccess. Our intention is to have most stocks Cryogenically treated before we even test them.
Of course, your first question is – and should be – why? In a nutshell, reducing an object’s temperature to -300ºF re-arranges its molecular structure, creating greater uniformity that results in longer life and better performance than when the product was initially designed.With vacuum tubes, this process has a profound impact on a tube’s ability to endure thermal shock. Therefore, tubes can last longer and their sound can been enhanced in ways that are simply exquisite.
After thoughtful and thorough research, Upscale Audio chose 300 Below because of their extensive experience in working with musical instruments as well as auto racing, metal tooling, and high-end sporting goods from rifle barrels to golf clubs. Expect nothing but the best from Upscale Audio.
Our charge for Cryogenically treating tubes is a fraction of what others charge, though we use the premier company. Count on Upscale to do the best job and not price gouge . Also available is cryogenic treatment for cables, along with our well-known Nordost Vidar cable treatment system. Call for details. Pricing is listed on each tube and cable page.
Warranty Information
Vacuum tubes are warranted for 90 days against defects, except in cases of abuse, and replaced with like-item only.
- Tubes being sent in for warranty must have a return authorization number from Upscale Audio. This RA number must be written on the outside of the box. Please also include a note in the box that has your name and telephone number, and please explain the issues with the tube. If this information is missing it will delay the shipment of your replacement tube.
- Vacuum tubes being sent to Upscale Audio for warranty replacement must be shipped in a box with appropriate packaging to keep them from being damaged. Vacuum tubes returned to Upscale Audio using inadequate packing will have a voided warranty and will be refused at the customer's expense.
Exceptions to our warranty policy are as follows:
- Upscale Audio reserves the right to refuse warranty at our disgretion based on the equipment being re-tubed. You will be notified of any change prior to your order being processed.
- Using a tube in an application in which it was not meant to be used. If your amp calls for a 6550, and you decide you want to plug in a 6V6GT, Upscale Audio is not liable if the tube fails, and will not honor any warranty in such a situation.
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 tube returns for refund:
Vacuum tubes are electronic parts and are not refundable under any circumstances.
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