Page created March 10, 2018

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New Vacuum Tubes

Replacement tubes from Wright Audio are selected to perform best in Wright Audio products.  Unlike tubes supplied by musical instrument suppliers, the replacements listed here have been tested and selected for high fidelity use under the operating parameters specifically required by our amplifiers.   The appropriate tubes are selected and matched for current, transconductance (gm) and lowest noise. 

When to Replace Tubes

Normally, vacuum tubes slowly deplete themselves over their lifetime.  When their power dissipation dips much below their original specification, the output power and sound quality declines.  The sound will begin to lose its definition, color and overall dynamic drive.  For the large power output tubes in Wright Audio's single-ended integrated and power amplifiers, these qualities can occur at about the 1500 hour mark and at about 2500 hours in our push-pull amplifiers.  It is very important to replace the tubes at these points.  You may think after 3  or 4 years of moderate use that the amplifier sounds fine, but the degradation is so subtle and over such a long period of time, that only new tube substitution will remind you of the full sonic capabiilties of the equipment.

Besides the sound quality degradation, it is especially important that you replace power tubes at this time to avoid a possible catastrophic failure which may lead to an expensive amplifier repair.  Never run tubes past the expected lifetime waiting years until one fails altogether in order to replace it.  However, Wright Audio amplifiers are built to endure some abuse through over-design with parts operating at a fraction of their capability as well as fuse protection.

Smaller tubes should be replaced at about the 2500 hour mark.  Besides the degradation in sound quality, small tubes can cause noise in the form of static, hum or hiss. 

You should always keep a full set of replacement tubes on hand to make a substitution in case a problem develops.

Never substitute a tube with a number different from what was originally installed on your amplifier, or noted on the top, back or bottom of the equipment.  Contact Wright Audio if you have a question regarding substitution of a tube number.

How To Change Tubes

Grasp the expired large power and rectifier tubes by the base, not the glass.  Pull straight out.  Do not rock the tubes back and forth in an effort to extract them.  You may break off the guide post which will remain in the socket and be difficult to remove without opening the amplifier.  Likewise, pull the smaller tubes straight out.

Wash your hands before inserting the new tubes.  It is inevitable that your hands will contact the glass and some say the oils deposited may cause damage to the glass in the long term. Vacuum tube bulb temperatures for the power tubes can reach around 200 to 250 degrees celsius or about 400 to almost 500 degrees Fahrenheit.  One thing is for sure.  If your hands are not clean, whatever has been deposited will cause the tubes to smell for awhile once they heat up!

To insert the new power and rectifier tubes, visually inspect the tube's bottom post to orient the 'key' with the notch in the socket.  This is important because due to manufacturing tolerances of both the tube and the socket, it is sometimes still possible to insert the tube with an incorrect orientation which will damage the tube and possibly the amplifier once it is turned on.

Grasping the base, press the tube straight down into the socket.  Do not rock it excessively since again, the tube's center post can break. 

On the smaller tubes, a gap exists in the pins which serve for alignment in their appropriate sockets.

Set the Tube Bias

Most Wright Audio amplifiers do not require the user to make this electrical adjustment as it is done automatically.  For those amplifiers with a bias adjustment, consult the manual with the amplifier for the procedure and setting.

New Tube Warranty

New tubes have a 90 day warranty from receipt.


After selecting tubes, scroll down to bottom of page to add shipping to the shopping cart.

  Power Output Tubes 
(Order 2 Matched Pairs for a Matched Quad).


JJ  KT77

These are the least expensive, excellent-sounding output tubes recommended for our single-ended and push-pull amplifiers.  Bold, clear tone, open highs with excellent dynamics.  We prefer the smoother-sounding JJ KT77 over the JJ E34L which came with earlier amplifiers.

Matched Pair

Tung-Sol EL34B


The Tung Sol EL34B's are smooth, musical and refined-sounding with slightly richer harmonics than the JJ's.  Extremely pleasant, natural and well-balanced.

Matched Pair

Mullard EL34


The Mullard EL34's are very smooth and retrieve a recording's ambience and spatial depths well, while providing rich harmonics.  Not recommended (yet) for our single-ended amplifiers, only for our "push-pull" models.

Matched Pair

Genelex KT77

The "Audiophile's Tube".

Matched Pair

Mullard EL84

Best tube for the Mini Amplifier.

Matched Pair

Preamplifier and Driver Tubes 


JJ ECC83 / 12AX7
Special frame grid construction provides a very clear sound. 
Sections matched within 20 percent required for integrated amplifiers


Sections matched within 5 percent required for phono and line preamplifiers.


Tung-Sol 12AX7

Very musical tube with great detail.
Sections matched within 20 percent required for integrated amplifiers.


Sections matched within 5 percent required for phono and line preamplifiers.


Mullard ECC83 / 12AX7

Extremely rich, musical sound, but has less detail than the tubes above.
Closely matched sections.


Genalex ECC83 / 12AX7

GENALEX ECC83 / 12AX7 / B759

Best all around ECC83 / 12AX7 type.  Rich, colorful sound with great detail.


EH 6922


Evenly-balanced, musical tube with great detail.
Selected for closely matched sections.


Sovtek 6N1P


Beautiful-sounding tube with a vivid, illuminated midrange.
Closely matched sections.


Electro Harmonix 12AT7


Large plates with closely matched sections.



Sovtek 5AR4

Sovtek 5AR4

JJ GZ34 / 5AR4

JJ GZ34 / 5AR4
Recommended for use only with the Mini Amplifier

Add $8.95 Shipping for any number of tubes.


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