Tube handling


We deliver our amplifiers with output tubes that we have put through their paces:

The tube types we selected were tested for durability in painstaking long-term tests. Due to the selection, the protective circuits used and the soft-start electronics, the power tubes we insert have a service life of up to five years or more.

The tubes used are precision selected by us. This means that we measure all tubes and put the tubes with the same values ​​together into sets. The values ​​determined are recorded in the test report for each amplifier, as well as the selection codes attached to the socket of the tubes. This means that in the event of a tube failure, a single tube can be replaced without any loss of sound quality. The replacement tube then has exactly the same value as the other tubes.


Please note that replacing tubes may only be carried out by a technician!

Of course, it is attractive to change the sound of a system by using a different type of tube. “Tube rolling” is almost part of our hobby. There are always old tubes appearing on the market that are “hyped”, which are said to have legendary sound and/or performance characteristics, as well as new tubes, such as the available KT 120 or KT 150 performance tubes. Not all of these tubes are suitable for all of our amplifiers.

See compatibility lists: unfortunately we cannot list all tubes with the same socket in the lists. We only focused on the most common ones.

* The V 70 Class A has an auto bias. When changing tubes, matched tubes must be used for Class A.

For example, if you would like to insert a KT 150 tube into a V 40 (SE) - which we expressly do not recommend -:

Your V 40 (SE) with KT 150 would not have more power because the same power supply is still used in the amplifier

Your V 40 (SE) would get way too hot, which could be dangerous for you and would dramatically shorten the lifespan of the tubes and the device

The sound depending on the type of tube depends on your personal taste in music, but above all on the speakers and the entire system. For example, an XY tube used in combination with low-impedance loudspeakers provides an audible sound gain, while the same XY tube on a high-impedance loudspeaker sounds too artificial and too technical, or vice versa.

The BIAS setting

Adjusting the bias causes all power tubes to run at the same current, which in turn has an impact on the sound and durability of the tubes

With Octave devices, the bias can be conveniently adjusted externally by the listener itself

With the integrated amplifiers you can adjust the bias in the window on the front, with the power amplifiers (except the Jubilee power amplifiers) directly next to each power tube.

The two most common mistakes when setting the bias:

Not waiting long enough for the device and tubes to heat up
! When the amplifier is still cold, the bias is not stable. During warm-up it may change.

The bias controls are turned too hard
! The bias control is managed by potentiometers. In both directions they have an end position. Don’t use too much power when reaching the end of rotation. Otherwise they can break or you can over-tighten them.


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