I have read that the load or amp impedance needs to be at least 10x that of the source. I have Nuforce P9 pre input 10K ohms and output 100 ohms with Nuforce 9V3Ses amps input 22K. I have a relatively cheap Sony CD player that use the optical out to a mini max EE DAC. in the tube output Bill from Morningside Audio said the out put impedance of the DAC is 7.5K (depending on vol control settings) and SS out is 200 ohms. My question is given the tube output of the EE DAC should I look to invest in one of the impedance "matching" or buffer for a lack of better words boxes that are sold. My current set up sound fine to me?????????
