Classe DR-2 vs Classe DR-3

Does anyone know the differences between these 2 vintage class
A running amps produced by Dave Reich?
Sorry, I have not seen this thread in some time.

To answer Nurxhunter: Forced air should not be used because it raises the bias current. The amplifier, by design, seeks to reach equalibrium between temperature and electrical operating point. If you've ever had to wait for an amplifer to "settle in" for it to sound its best, it is because of this. As it is, the bias current of these amplifiers is quite high because of genuine class A operation, forcing it to go higher will shorten the life of the output devices because they will try to run hotter even though forced air may seem to make it run cooler. It was designed to be perfect without forced air - the huge heatsinks take care of that just fine.

You may also note that these amplifiers run cooler the harder you push them (as opposed to class AB amplifiers which get hotter) - that's because some of the power that is otherwise dissipated by the heatsink at idle is now going into your load. In other words, these amps run hottest during idle.
does the dr-3 also have the brick which is supposed to be placed between the heatsinks? what exactly is is for. I bought a dr-2 without the brick as the previous owner lost it and it seems to work just fine
I have owned both the Classe DR-2 and the larger DR-3 VHC amplifiers. And Woodmann's characterization of the sound is spot on.

The DR-3 was 45 wpc pure class A, while the DR-2 was only 25. The VHC had more of everything soundwise - with plenty of bass. Using a pair as monoblocks would produce to quote one audio reviewer - "sonic steamrollers," capable of powering the most difficult loads, including the notoriously inefficient Apogee Scintilla at one ohm.

The The DR series of Classe Amplifiers (short for their designer - David Reich) does run very hot, and uses quite a bit of electricity.

So using them in a warm climate is out of the question. When I owned my Classes back in the 1990's, I would only operate them during the Winter time. Moreover, unlike a tube amplifier which can be cooled down with a fan, doing so with the DR amplifiers is ill advised, because it will only cause the amp's to work harder to maintain the operating temperature that they are designed for.

All and all, a great design. The DR-3 VHC in particular was a work of art, as anyone who's opened the bottom of its chassis can tell you. This was a large amplifier in its day, weighing in at slightly over 100 lbs. Then again, the VHC was an expensive beast, costing nearly $5,000 in 1987. You can pretty much double that price in today's market given inflation.

I purchased mine in the mid 1990's for about $1800 - a bargain at the time - in near mint condition. The only reason I sold it was that it just ran too hot to use all year round, and used a lot of electricity.

An interesting point in regard to the rarity of these amp's, particularly the DR-3 VHC.

I found mine on Audiomart. The guy I purchased it from asked if I would give him first right of refusal to buy the amp back if I decided to sell it. So when I did, I called him up and he bought the VHC back from me.

A year later, I saw it for sale on Audiomart again and snapped it up at the same price I'd paid for it earlier.

Alas, the VHC simply ran too hot and used too much electricity for daily use, so I sold it. However, if you collect vintage audio amplifiers and don't plan on using this one a regular basis, it makes for a great collectible piece of gear, and doubles as a nice pot belly stove during those cold winter months of the year.

I have a 1 ohm Scintillas and 2 DR3 VHC's. Does anyone know if they can properly drive them UNbridged, where one drives left and right Tweeters and other drives left and right midrange/bass.
...FWIW, I noticed that both of these amps have a high DC turn-on transient that will push your drivers out as far as they can go!...

Maybe you can get that fixed. Did new ones do that?