Here is what Semi states above: Which tube equipment does not have heat related damage?
The answer: Most tube equipment doesn't have heat related damage, particularly tube preamps, which produce limited amounts of heat. You want to know what was wrong with SF designs? Ask the head guru, Chris at PCX. PCX started doing mods on the SFL2 where they actually cut out small ovals of the circuit board material itself, claiming it eliminated heat damage to parts. Now, does this sound like a well executed design? Cutting holes into circuit boards to correct this?
You can have their mods; I want no part. As far as personal experience with their products, I do. My friend's SFL2 developed noises, and SFL found numerous parts that had become noisy and/or defective. Remember their highest quality parts philosophy?
I personally compared this unit to modest preamps, like the Rogue 99, and the SFL2 sounded dry and lifeless.
I owned an Power 2 and a VT-100 at the same time. Despite any tube changes I made, the Power 2 was too distant in the midrange, lacked air and definition, and had virtually no tube-like sonics to it. Others agree with this assessment.
I spoke to a very famous tube designer who laughed at SF designs, saying these guys were copying old textbook circuits that were like sow's ears, meaning no matter what parts you put in them, you were just putting lipstick on a pig.
I don't mean to imply the Power amps were bad sounding units, but they just didn't have anything special to offer, other than beautiful looks.
I agree that the VT series circuits were run at too high voltages, pushing components to the upper ends of their limits. ARC has had their own issues, and I'm not tooting their horn. In fact, I don't own any ARC products
Yes, I don't have first hand experience with their latest LS26 or Ref 3, but when I hear source after source talking about how good they sound, these pieces definitely deserve a listen. Which is what I would recommend to Spaz.
I'll admit I haven't personally evaluated a Line 3, and it has had a following, but there has also been written enough criticisms of it being dry and analytical, which is similar to the SFL2, which many considered the most musical sounding of the SF preamps. Not an opinion I share with them.