Quietest amp you ever owned ?

Elevick I never knew the Dynaco ST-80 was that quiet; I had a ST-120 way back in the early 70s. The reason I am asking this question is that I am running a pair of modified Klipsch KLF-20s in a second system and, as Raqual has pointed out, the more efficient the speaker the more the amplifier noise comes through. Speaking of Dynaco I had a ST-70 at one time with the Sutherland front end board and it was dead quiet; on the other hand the stock amp with the 7199s was pretty noisy. Thanks everyone for your input; I've learned a great deal.

Yamaha M-80

SNR -127dB

Yamaha MX1000U
(1979 - solid state, 760wpc @ 4ohm; 960wpc @2ohm; 460wpc @8ohm) which I still use with fabulous results. I am amazed that for the power output and the cheesy original power cord that this monster does not put out ANY noise. Totally clean.
Even my CR-1020 (1978 - 90wpc @4ohm; 70wpc @ 8ohm) which is in a separate system performs in the same quiet manner.
A while ago I sold my much newer Mac and a Krell but kept the Yamahas. Do it again Yamaha ... where'd you go.

Bob,
The 80 can't be compared to anything Dynaco originally produced. I've played with 70's and even had a pair of fully restored/upgraded MKIV's. Nothing can touch this amp. Panor+25 years of technology really made a difference.
The re-release of the 70 should be quite nice also. Finally, I do believe there is a 160 out there.

Elevick I'll have to try to pick up one of those 80s.