Class D amp with Tube Preamp Combo?

Hi Larry, do you happen to remember if the JRDG device in question was a stereo or mono amp? and if mono pair. . . whaht physical size/weight?
G

Hi Guidocorona,

It was a massive, single chassis stereo amp. I think the model number was 302, but, I am not sure. The owner used it to power Kharma speakers, but sold it in favor of a Hovland amp after buying a pair of Sonus Faber Anniversarios. We got to play with it prior to it being shipped to a buyer in the far east.

Hi Larry, yes the device was very likely a 302. I have heard it a couple of times, driven by an aRC Ref 3 in both occasions. 302 was JRDG 1st gen switching amp with internal PFC. . . not bad for a first attempt, but I also observed some of the problems you found: only very moderate macro and micro dynamics, and a treble that was not too extended. These problems are solved completely by its successor--the current 312 model. Conversely, a clearly anomalous/strange sound in the treble region was probably caused by insufficient breakin or warm up. Switching amps seem to be total bears and may require well over 1000 hrs of playtime to break in. . . or at least the JRDG 312 and NuForce V9SE definitely do. The symptom seemed to me of a treble that sounds almost harmonically disjointed from the rest of the audible spectrum, and disconcertingly displeasing to boot. . . but the issue goes away completely with proper break in and warm up. . . it's just an unusual temporary artifact of these devices.

Guido and I tend to agree, but I must report that my Continuum 500 seemed fully burned-in by 200-hours. Jeff is constantly improving, so maybe his latest capacitors or something else changed the burn-in characteristic.

Others I trust report 500+ hours for 501s and 201s, so I don't think that Guido is "hearing things" that don't exist. Instead, I think that the landscape is changing very quickly and Rowland evidently hit on several ways to advance his pre and power amps very recently.

Dave

Hi Dave, the different and hotter running PFC circuit in the new Continuum 500 integrated may account for shorter break in time than on 300 series stereos, as well as JRDG monos without PFC like 201 and 501. In general, I prefer to be conservative when it comes to break in times. . . too many folks give up on a device prematurely because of their impatience with break in. G.