Mk III? This status must be due to some rebuilding by ARC since this amp's discontinued production in the mid 80s. To my knowledge, the D70, D115 and D250 only got a Mk II status with the D250 then getting a "Servo" update. The D250 had many reported reliability issues but I do not think this plagued the 70 or 115 models.
As for these three amps, it was the end of all tube designs that only returned with the VT150 mono blocks 10 years later; these were phenomenol! The D series were excellent but lacked the refinements at the frequency extremes compared to designs of today. But I much prefered these models to the Classic series that followed them in the late 80s and early 90s. The Classic series were just too analytical sounding and lacked the magic of the all tubed D amps and the SP-10.
One problem with ARC amps, even the later models like the VT amps was that resistors will often be destroyed when tubes fail. I went through this hassle a few times with the VT130 amp.
For $1000 or so on the used market, I think you will not find much better sound than this but perhaps the headaches and maintenance of this old design might not be worth it in the long run. If you want an ARC amp, I see the VT130 up for sale from time to time in the $1500-1700 price range and this is an outstanding value....always was a sleeper in the ARC line. But it only has balanced inputs so this may be a limiting factor to you.
John
As for these three amps, it was the end of all tube designs that only returned with the VT150 mono blocks 10 years later; these were phenomenol! The D series were excellent but lacked the refinements at the frequency extremes compared to designs of today. But I much prefered these models to the Classic series that followed them in the late 80s and early 90s. The Classic series were just too analytical sounding and lacked the magic of the all tubed D amps and the SP-10.
One problem with ARC amps, even the later models like the VT amps was that resistors will often be destroyed when tubes fail. I went through this hassle a few times with the VT130 amp.
For $1000 or so on the used market, I think you will not find much better sound than this but perhaps the headaches and maintenance of this old design might not be worth it in the long run. If you want an ARC amp, I see the VT130 up for sale from time to time in the $1500-1700 price range and this is an outstanding value....always was a sleeper in the ARC line. But it only has balanced inputs so this may be a limiting factor to you.
John