Tube kits

General tube information

Classic range

Nagra PL-P,  PL-L, VPS, JAZZ and Classic PREAMP rely on ECC 81 and ECC 83 tubes to deliver striking performance.

Nagra uses different tube brands depending on the application. ECC 81 and 83 are Electro Harmonix Gold Pin. These premium tubes have a large plate, they provide a superior dissipation over the originals designs. The gold pins avoid any risk or corrosion and contact issues over time.

General tube selection process

Each and every tube installed by Nagra goes through a very complex selection process. It begins with a 48 hour burn-in, followed by individual measurements. The resulting selected tubes – less than 50%, are then rated to become either line stage tubes phono stage tubes. Depending on the batch, usually less than 1% become a phono stage tubes!

845 and 300B tube selection

Nagra has built special electronic devices to burn-in the 845 and the 300B tubes. They go through a 24 hour burn-in of  8 hours a day for 3 consecutive days. This eliminates any defective tubes or ones with major problems that will not survive this initial alignment stage.

Each tube is individually warmed-up and measured on a computerized bench-test. They must fit a specific performance window which is narrower than the general tube specifications. As a result less than 50% of the tubes are selected.

The tubes are then matched in pairs before being tested on a reference amplifier, giving an overall test period of 48 hours in total, prior to official Nagra certification.

Tube ageing, when to replace them?

The ECC 81 and ECC 83 minimum tube life is 5000 hours. Actually, most tubes operate consistently for more than 10 000 hours.

Thus, the useful life of the tubes is somewhat unpredictable. Rather than replacing the tubes arbitrarily after 5000 hours, we suggest that you identify the signs of ageing:

• The distortion gently increases to an audible level;
• Presence of clicks (dry and short noises, like that of breaking dead wood);
• Presence of pops, short noises in the low frequencies;
• Presence of hiss, higher background noise.

As soon as one of these signs appears, please contact your Nagra dealer to order a replacement tube kit corresponding to your equipment.

Can I use other tubes than the one supplied by Nagra

As a rule, we do not recommend using tubes from other sources. We often run tests with other tubes and we won’t recommend them due to various technical and reliability issues. Beware, that using tubes other than those supplied by Nagra will void the warranty of your unit.

For amplifiers, should I change one tube, a pair, a quad?

It is recommended to change tubes as a pair or preferably a quad as tube age will change the sound slightly so changing them by quad will ensure a consistent left / right performance.

However, in some situations of early failure, your Nagra dealer in contact with our Service Department, can provide a single replacement tube as close as possible to the one you want to change.

Different Nagra tube kits available

Tube warranty period

All tubes and tube kits supplied by Nagra have a limited warranty of 6 months.