Nuforce STA200

NuForce uses a hybrid approach, very similar to Carver's idea, and << cough >> borrowed by Yamaha in the EEEngine design. Not sure if Yamaha ever licensed it or waited for patents to expire.

The voltage + and - rails are Class D, and they swing up and down. In between the rails is a Class A or A/B (not sure) linear amplifier.

It's quite clever. By keeping the voltage rails from deviating too much from each other, the power dissipation in between is always limited to a few watts compared to a linear power amp of the same output.

For instance, a 120 W amplifier might have +- 50 V rails. The amp between has to dissipate a lot of heat as a result of the 100V difference. But if the voltage between the two rails is kept small, say 30V, then the heat and size of the amplifier can be made much smaller, with much less wasted power.

Best,

E

@erik_squires My understanding about the STA 200, is, it is a conventional AB design, taken from a circuit developed by Goldmund, also used in the Job 225. But yes, Nuforce ( Nuprime ) does use designs in other models in which you speak of.

@mrdecibel

Then I stand corrected. :)

Erik

Ordered a pair of Goldenjacks 10 db attenuators. Will see if it reduces the hum, without affecting the sonics ( doubtful ). If this does not work, might need to go back to passive ( never liked ), change to a lower gain preamp, or a different amp ( although I do like the STA 200 ). I gave up on tubes a while ago.

Just do what i did. I have a tube pre amp and the high gain causes the hiss to become louder thAn normal. I have zu 101 db speakers. Order the Schiit $49 passive preamp and place between pre and nuforce. Adjust the schiit volume to an accepttable level where hum is not heard at sitting position. Very transparent and better than attenuators. I tried attenuators and the sound was slightly smeared. No noticable sound quality reduction with the Schiit.