Can a Amp be "timeless" and compete with todays amps?

VTL  250 mono blocks ,  I own for 20years , heavy yes , upkeep can be a pain , but can always be fixed , by a descent tech. I purchased them used for 3000  Used ,New today out of reach , I guess when I bias them , I appreciate them even more.

Transient response never goes out of style

My primary amp is a pair of Altec 1569A theater amps. WARNING-Using these unmodified in the home is dangerous as the 700 volt operating current puts out not insignificant amounts of radiation. My amps were gutted but for the case and transformers. They run at about 425 volts and the transformers are always barely warm to the touch. Six tubes replace the four and the two input tubes are 6GU7s with NOS RCA 6SN7s cathode follower. No one uses my 6BG6 output tubes. The amps are fully voltage regulated including the bias (very stable). It has four levels of adjustable feedback starting about 6db which I prefer. The internals have oil filled caps and there are 2 huge 3X7 electrolytic storage caps on top. They kill my EAR 890 amp. My second system has the best Dynaco 70 ever with tremendous bass control and dynamics. Again, moded to the central tap on the transformers with voltage regulated design including the tube bias and superior large electrolytic storage caps. Mr. Record says it’s the only good Dynaco 70.

I do not understand the "negative feedback" posts without describing what type of negative feedback. There is global negative feedback (my EAR 890 has none) and internal negative feedback which should be employed or else risk distortion. I think current VAC amps have 7 db of negative feedback and internal feedback. Another friend has a personally repaired RM9 ultralinear amp that sounds very nice. It’s in the design that counts, not the "modern" and "new parts design" that makes a great amp. True, my amps are radically different than most. Audio Research makes crude/primative versions of voltage regulated amps today which is inferior in the design in my amps sophisticated voltage regulation.

Please correct me if you think amps should have both zero global and zero internal negative feedback.

@fleschler 

Please correct me if you think amps should have both zero global and zero internal negative feedback

As wth nearly all things concerning audio it just depends. NFB will decrease the amplifier output impedance and increase damping factor.  For some speakers this will be beneficial.  There are speakers designed with the intention of being driven by  zero or very low NFB amplifiers. It will definitely depend on specific amp-speaker characteristics and appropriate matching compatibility. 

BTW I bet you modified amplifiers sound fantastic!

Charles 

There are certainly areas where significant improvements have been made over time. Anything in the digital realm, streaming, music storage etc.

Way back when I purchased (on sale) a Krell KST100 amplifier. It anchored many changes (upgrades attempted and upgrades achieved) upstream. After twenty plus years, some issues became apparent and I was faced with the dilemma of purchasing a new amp or servicing my Krell.

Looking at the market place, reading reviews and posts on websites (this one mainly) I called Krell. Had a brief discussion with a tech there who went over the ins and outs of bringing my KST to spec and resolving any problems they found.

The current marketplace for amplifiers that would deliver the the same or better attributes of the Krell would require quite a bit of money. At least what I paid for the Krell and quite a bit more than the cost of “refurbishing” it.

Luckily, especially given the original packaging was long gone, Krell is located less than an hour’s drive from me. I drove the amp up to Connecticut, the tech met me outside with a wheeled cart! The amp weighs around 45 pounds with sharp heat dissipation fins.

For around $1500 and a few weeks I had a like “new” 100 watt (measures 130) clean across the spectrum, the amp handles just about any speakers well, superb bass control (good slam factor).

The service at Krell is superb. The techs are enthusiastic helpful and a pleasure to deal with. I got good reasonable advice. 

I think the main advances in power amplifiers these days are size related with class D. Integration with pre amps and/or all sort of one box combinations. Was the Krell the last word in amplification? No. Even when new Krell made “bigger better” amps. The KST was actually their “dip” into the more “affordable” domaine…we are talking some $2750 back twenty five years ago! In today’s money?

In the end, considering price, the real question is personal. I am not sure moving over makes much sense. Moving up yes. So if you have a piece of gear you are happy with change for change’s sake doesn’t make sense to me especially in Audio.

The most important factor in a good audio system are the synergies among amplifier, speakers and room.

Finally. 
We audiophiles tend to get buried in the technology weeds. The key numbers/measurements for amplifiers are those that indicate how they will drive your speakers.(power, current, impedance etc etc etc).

The technology or design philosophy that achieves those numbers is at best secondary at worst a red herring. And really what counts is how it all sounds to you.