Want to use vintage tubes and have them last a looooong time?
We have a new option that can be installed to allow the use of vintage tubes that works perfectly with Tunable Biasing.
The upgrade costs $85.00 and is designed to allow 6L6GA's and similar vintage models to work in an environment that will be extremely easy on the tubes. This feature also reduces amp power output to 20 watts/channel when engaged. Use it with new tubes if a lower wattage is desirable. If the amp is to be used for background music, flip the switch for excellent sound and extremely low heat output.
NOTE: The NS-40 MKIII in stock form is best used with high current 6L6GC style tubes for 40+ watts/channel. It can use vintage tubes as-is, but this upgrade will allow the amp to conform better to older tube styles.
Good news: This circuit does NOT go in the audio path! Two circuits are modified and it will perfectly emulate a 5U4 tube rectifier as well.
How it works: Just flip a switch to turn the upgrade on before powering on the amp. In the off position, the circuits are reverted back to their original parameters.
