NATIONAL NU-57 Nos Union Vacuum Tube Hickok 139

( Brand: National ), ( Model: NU-57 ), ( Type: Vacuum Tube ), ( Country/region Of Manufacture: United States )

Review NATIONAL Nos Testing Union Engraved Vacuum Tube Hickok Tested 139

The Nu-57 NOS (New Old Stock) National Union vacuum tube, specifically model 139, is a historical artifact and a testament to the golden age of vacuum tube technology. This tube is a 12AX7 equivalent, known for its high-quality sound and reliability.

The Nu-57 NOS National Union 139 is a triode vacuum tube, which means it uses a single control grid to control the flow of electrons between the cathode and anode. This design enables the tube to amplify or rectify electrical signals, making it a crucial component in various audio applications such as guitar amplifiers, hi-fi audio systems, and even vintage radio sets.

The Nu-57 NOS National Union 139 is manufactured using the original specifications and techniques of the 1950s and 1960s. This means that each tube is hand-selected, tested, and packed with the utmost care, ensuring that it meets the high standards of vintage tubes. The glass envelope is made of high-quality borosilicate glass, which is known for its durability and resistance to thermal shock.

The Nu-57 NOS National Union 139 is a direct replacement for 12AX7 tubes and can be used in various applications where a high-quality, vintage-sounding tube is required. Its robust construction, combined with its high-quality materials, makes it a reliable and long-lasting component in any audio system.

In summary, the Nu-57 NOS National Union 139 is not just a vacuum tube; it's a piece of audio history. Its vintage sound, high-quality construction, and reliability make it a must-have for any audio enthusiast, whether they're building a vintage guitar amp or restoring a classic hi-fi system.

1. High Quality: This tube is a new old stock (NOS) item, which means it's a vintage tube that has been in storage for a long time and never used. NOS tubes are often considered to be of higher quality than modern tubes due to their superior craftsmanship and materials.

2. Authentic Sound: Vacuum tubes like the Nu-57 can provide a warmer, more natural sound compared to solid-state electronics. This can be particularly appealing to audiophiles who value sound quality and authenticity.

3. Durability: Vacuum tubes can last a long time if they are properly maintained and used in the right equipment. This can make them a cost-effective option in the long run, especially if you plan to use the tube for a long time.

4. Collectibility: Vacuum tubes, especially vintage ones, can be collectible items. If you enjoy collecting, the Nu-57 may be of interest to you.

1. Limited Availability: NOS tubes can be hard to find, especially for less common models like the Nu-57. This can make them more expensive than modern tubes.

2. Requires Maintenance: Vacuum tubes require more maintenance than solid-state electronics. This can include regular cleaning and replacement of parts, which can be time-consuming and expensive.

3. Limited Compatibility: Not all equipment is compatible with vacuum tubes. Before purchasing, make sure that the Nu-57 is compatible with your equipment.

4. Limited Power Efficiency: Vacuum tubes are not as power-efficient as solid-state electronics. This can result in higher energy bills, especially if you use the tube frequently.

The Nu-57 NOS National Union Vacuum Tube Hickok 139 is a high-quality tube that can provide a warmer, more natural sound compared to modern electronics. However, it also comes with some drawbacks, such as limited availability, maintenance requirements, limited compatibility, and lower power efficiency. Ultimately, whether or not to purchase the Nu-57 depends on your personal preferences, budget, and equipment compatibility. If you value sound quality and are willing to put in the maintenance required, the Nu-57 may be a good choice for you. However, if you prioritize convenience and energy efficiency, you may want to consider a modern tube instead.

Details:

In regards to the case cover then this grading means or sleeve is badly torn, scuffed, cracked and falling apart. I am not a huge retail outlet. I may have the same tube but from differing years matched up in test results, which means they cosmetically or internally look a little different.

This means that I have tested something not to its full extent am human. Light and medium scratching. Very good plus - used, some light scratching to either the case or CD record.

If it does not say matched then please do consider them to be such. Fair - the CD. Record plays, sometimes skips. They will normally want to see the item and packing.

In regards to the case or cover, then cover is just holding itself together. Vacuum tube testing I do not sell just passable tubes. It is up to you make a judgment call and decide if worth the risk of buying. The numbers letters in parentheses are equivalents put to help people find correct tube.

Cover is in good condition but has normal wear and tear.

When using the word matched it means in test results rather than cosmetic looks. Cd record still plays ok. If not fully tested, then items are to the full extent and may have something wrong that I discovered.

Rectifiers and diode tubes do not have trans conductance values. May be very light scratching but not noticeable or the case cover scuffed a little excellent ware to both CD record. I try to resolve any issue both our best interests.

I also sometimes use a hickok 752 for testing if state any values they are guide only. It is just my opinion and I would rather paint a bleaker picture of something than saying better.

May be good or above. This offer is for a. If it does not say base, stand, table in either the main body of or title. Via messaging.

By buying on this item you agree to these stipulations and follow the instructions of post office, or carrier.

Cd still plays well.

So to recap. Sorry for you having to read this but would be surprised how many people think the items come with my table or a part of anatomy that I have accidentally caught on camera. If you're unhappy with an item.

Please realize when buying antique, vintage or used equipment that they cannot be in an absolute mint perfect condition, might need some service, now later. Like new - used but no obvious signs of use.

Or if this is in grading regard to the case cover then there may be cracks torn has rips along its edges scuffed quite badly. I take lots of pictures so you can see cosmetics.

Very good - used light scratching to both the case and CD record. I am quite harsh on what is good and bad.

Then I have not test it. I make mistakes once in a while. Low and weak tubes are unceremoniously thrown in the nearest trash can, unless they collectors items.

In these cases it is best buying on as if was broken. It is impossible to describe every scratch, scuff or mark. Medium to heavy scratching.

All tubes have passed the gas and short tests. Then they are not included in the sale. So this shows what I get, and you get may be slightly different.

In photographs we occasionally use props to display items the best light possible. If I say untested. Cd record does not play.

Whilst I endeavor to put tubes together from the same year and look same, this is not always case. So take a good look.

All tubes purchased have loads of life left in them.

I use a tv7 u military spec tester which is calibrated. We check and describe the as much of functionality can. Light scratching to the case cover.

I have 4 of these machines and all display a slightly differing value if test the same tube, as two testers are never. I do not publish test results in the listing as what get, and someone else might get can be different.

Please have a look at the pictures for cosmetic condition. Most have one. Use the zoom function and have a good look.

This is a process, and it takes time. Fully working. New - unopened brand new, sealed. That is what they are there for.

Or have only gone so far to test it. If fully tested then that is what they are.

I also pack well. Slightly heavier than above.

part #: nu57 prices

• $5.00-$111.19

specifications tubesocketvintagego:

• brand: National
• model: Nu-57
• type: Vacuum Tube
• country/region of manufacture: United States

Ratings:

1. VERY NICE TUBE THANKS! 11-06-17
2. Tube arrived as described and right on time. Thank you! A 11-03-17
3. Well packaged, great condition, AA 11-04-17
4. Item arrived as described prompt shipping no problems 11-06-17
5. as represented, well packed. 11-05-17

Returns tubesocketvintagego:

• time: 14 Days
• policy: returns accepted
• paid by: Buyer
• type: Money Back

Payments tubesocketvintagego:

• PayPal

Offer tubesocketvintagego:

• Sold: 0
• best offer: true
• bids: 0
• Started: November 7, 2017, 2:54 pm
• quantity: 1

Seller tubesocketvintagego:

• city: Kingman, Arizona
• zipcode: 86401

General tubesocketvintagego:

• consumer electronics > vintage electronics > vintage audio video parts accessories consumer electronics > vintage tubestubes sockets audio
• in stock: Yes

Shipping tubesocketvintagego:

• type: Calculated
• handling: 2 days
• cost: $3.96

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