HI Br3098,
Basically, I agree with your last sentence. However, I think there are exceptions. For example, I have modified my ARC D250 Mk II Servo amp. It was designed in the mid 1980's. At the time, it might well have been the finest amp you could buy. J. Gordon Holt (RIP), the founder of Stereophile, thought so. I bought mine used in the early 1990's. By the year 2000, one of the things that had changed since the amp was designed was capacitor technology. The D250 had the finest Rel caps available at the time the amp was designed.
Around 2000 I decided to replace all the interstage coupling capacitors with the latest and greatest. MIT was my manufacturer and technology of choice. Unfortunately they did not manufacture caps with the necessary voltage ratings. In fact, no one did with the capacitance value I needed. Were the original Rel caps a custom design for ARC? Could be. They certainly were not in the catalogs.
After a long search I decided to request a custom design from MIT. They agreed and we struck a contract (I had to pre-pay). They were expensive which was mostly a result of the limited production run of 20 pieces. Of course, even their off the shelf standard capacitors were expensive. Mine were more so. After 6 months I had the capacitors.
The new caps definitely improved the sound of the amp. Better resolution, transparency, and speed. This amp was already excellent in these areas. I'm certain that if the amp had been redesigned the caps would have been replaced with more modern improved designs. I simply anticipated the redesign that never happened.
At this time I do not plan on replacing the 6550's with the new KT120's. However, once more is known about the KT120 performance in older amp designs, I might change my mind. The KT120's will not result in more power but might offer significantly longer tube life.
And there have been no downsides to my cap upgrade. The amp just keeps chugging along and I love it. It's truly a great amp.
Sparky
Basically, I agree with your last sentence. However, I think there are exceptions. For example, I have modified my ARC D250 Mk II Servo amp. It was designed in the mid 1980's. At the time, it might well have been the finest amp you could buy. J. Gordon Holt (RIP), the founder of Stereophile, thought so. I bought mine used in the early 1990's. By the year 2000, one of the things that had changed since the amp was designed was capacitor technology. The D250 had the finest Rel caps available at the time the amp was designed.
Around 2000 I decided to replace all the interstage coupling capacitors with the latest and greatest. MIT was my manufacturer and technology of choice. Unfortunately they did not manufacture caps with the necessary voltage ratings. In fact, no one did with the capacitance value I needed. Were the original Rel caps a custom design for ARC? Could be. They certainly were not in the catalogs.
After a long search I decided to request a custom design from MIT. They agreed and we struck a contract (I had to pre-pay). They were expensive which was mostly a result of the limited production run of 20 pieces. Of course, even their off the shelf standard capacitors were expensive. Mine were more so. After 6 months I had the capacitors.
The new caps definitely improved the sound of the amp. Better resolution, transparency, and speed. This amp was already excellent in these areas. I'm certain that if the amp had been redesigned the caps would have been replaced with more modern improved designs. I simply anticipated the redesign that never happened.
At this time I do not plan on replacing the 6550's with the new KT120's. However, once more is known about the KT120 performance in older amp designs, I might change my mind. The KT120's will not result in more power but might offer significantly longer tube life.
And there have been no downsides to my cap upgrade. The amp just keeps chugging along and I love it. It's truly a great amp.
Sparky