Dedication
Over time, we found that many of the 7591 power tubes that are available as either current production or NOS (new old stock) are prone to microphonic rattles. We find that as many as 50 percent of the current production tubes begin to exhibit an unpleasant microphonic rattle after only a few hours of use. The NOS tubes we have tried are even worse. This has caused complaints from recording engineers and players alike.
We have now revised the circuitry for the 20th Century Limited model to accept the more noise-free 6L6GC type power tube. The 6L6GC is an industry-standard design that is readily available in quantity from a number of suppliers.
The second enhancement to the 20th Century Limited model is a slight revision in the tone signature. We now have scientific research that shows that the cabinet for our 20th Century Limited is adding its own coloration to the tone that you hear. Even though the electronic signature of the amp was where it should have been, the final result was a bit off. Based on this, the circuit was revised just a bit to achieve the final result we were after.
Beginning February 2007, all 20th Century Limited amplifiers will be shipped with these circuit revisions and will be identified accordingly.
ATTENTION: PRESENT OWNERS OF A VERO 20TH CENTURY LIMITED!
We can modify your 20th Century Limited to operate with the 6L6GC power tubes as well as make the tone circuit revision. You may contact us and we will provide details what this entails and how to proceed.
Thank you for your confidence in us.