Class D is just Dandy!

I don’t "blame" preamps for changes in frequency response. I say high output impedance causes frequency response changes which vary based on the load. This is an irrefutable fact based on simple serial circuit analysis. Anyone with a basic understanding of AC circuit analysis would conclude the same.

And I showed the math for why that is not so: the first half of your quote here is false, the second half being based on the first is thus also false.

                                             **Do the math**.

Its the coupling cap at the output, not the output impedance that governs the frequency response.

Example: I've seen ARC preamps with 20uf output coupling caps. If you put them on a 10K load, they will be as flat as they are on a 100K load in the audio passband. Yet the very same preamp according to ARC should not be asked to drive anything less than 30K.

Your claim to which I was objecting was that the higher output impedance of tube preamps leads to frequency response errors and the simple fact is this is not so- it depends more on the timing constant that may or may not be present at the output of the preamp in question.  I showed the math. If you wish to refute this, then show the math.

Yes I agree,Class D not Digital is Dandy.

I have reached 100 hrs on my dragon s500 and not really much change.It's a little lean and bright,nothing horrible,compared to my 600m's.I won't fully evaluate it till past 1000hrs,I have it playing in my 2nd system for now.Time will tell.

Kenny.

Erik. Keep up the good work on this thread about class D amplifiers, Designers such as Atamasphere will beat a topic into the ground to prove their point. He isn't the first, won't be the last. Again, good work on your part. I have a Class D integrated hybrid, and couldn't be happier.

Done.

E