There is about a billion capacitors in those preamps! Okay not quite, but close enough in audio terms. I had one, it was a decent pre but newer pre's easily best it for the money.
I put it directly against a new Marsh 2000B no phono however, and it just killed the classe. To be fair the Marsh has 160.00 audiocap thetas already in it and only 4 of them in the whole design. So at about 1400 retail far better with an outboard phono than the older classe' I had.
Also pit against a PS audio GCP200 which was far more user friendly with features, better build, and sound was completely transparent with better bass along with lower distortion making it a tad smoother than the old Classe' in the end.
Again to be fair this unit has virtually Zero parts as it uses the PS audio gain cell units which are basically direct line active with a volume control. Very hard to find used, and it is the best PS audio ever built however and not cheap.
I also had several Tube pres, one that really beat it with good tube phono stage inside was an Audio Mirror, but it looks like your more interested in staying solid state.
So I had a DR-6 with the rarer full metal remote control, and was going into the upgrade path realizing changing out all the critical caps, diodes etc... Would rail up the costs well into the several hundreds done on your own if you can fit new hi line caps, and can solder, and then into the thousands to send it out for any significant upgrades.
I can agree to the above, this is one of the classics that truely is not worth the cost in the amount of complexity and parts in the design, by the way you could just do the power supply box alone and gain some, putting in the fast diodes, but again its very little to what those old classe's had going on in total.
Any of the newer designs have about 60% less parts, and are of excellent quality, this way you just need to upgrade a few caps, or diodes, volume pot etc... and get a solid upgrade for the money.
I think most people really try to hold onto these as they do have a rather good phono stage which can compare to some stand alone units, but you can do much better in that area as well if your really looking to spend the money.
All that being said it is VERY difficult to beat, and all the ones I metioned are pure CLASS A topology with true balanced circuitry as the old classe' has...
With those few Niche' pieces I mentioned, against some of the standard Levinson, Mcintosh, even Pass stuff you would pay a lot more sometimes for no more performance than the old Classe' from my experience after testing them out.
Also I always ran these in BALANCED with true balanced amplifiers, so single ended could be a little different story, full balanced had more powerful gain and of course cleaner signal.
And just so you know I saw a guy had a DR-5 for sale on this site for a couple of months with all the cap upgrades etc... Costs on the upgrades do to the amount of parts was like 3000! He had it up for sale at about 5000, finally came down to about 3800 just trying to re-cover the cost of the mod's, I don't think it ever sold.