A quick and general overview of the most common tube types for use in the
Herbert:
EL34/6CA7:
Aggressive, slender low end, higher total harmonic
distortion… Recommended bias setting: 30-35mA
5881/6L6:
Great tube for clean sounds, good bluesy tones, also has
strong bass and excellent clarity… Recommended bias
setting: 25-35mA
6550:
Very loud, very good dynamics, strong low end, amazingly
percussive… Recommended bias: 40-60mA
KT88/KT100:
Similar to 6550, but very punchy with great clarity and
warmth… Expensive… Recommended bias: 35-50mA
5.2.3
Life Span
Power tubes last 1 to 3 years, depending on care, volume and frequency of use of
the amplifier. If you use your amp only once a month, then the tubes will
obviously last longer. Really… We have heard tubes that are over 10 years old,
but it was not a good thing. Tubes age in a very slow manner, slow enough for the
artist to get used to the changing tone. To keep things fresh and to keep your tube
dealer in business, we recommend re-tubing, cleaning and biasing once a year if
the amp is used frequently.
Chapter Six: Functions and Switches
6.1
Programming the Herbert
It is quite easy to program your Diezel Herbert and, also, easy to explain. Pushing
the “Store” toggle switch twice must follow each change in the MIDI program.
After the first click, the selected blue LED lights will blink. Click on the switch
again and your program is in memory. Each of the 128 programs (patches,
program changes) can be changed as often as is desired.
