What to expect from a Zen amp by someone who as never heard one... but don't worry, he's an engineer and some engineers don't have to listen to see if something sounds good or not, because they already know.
Yes, I found the following comment on our Youtube channel:
Quote:mosfet500
You really can't here an exceptional amp or speakers on YT, too many factors. What we do know from electronics is that, while the amp might play loud with efficient speakers, it does not have the dynamic range of amps capable of a couple of hundred watts. That's just math. The next thing is that this amp is limited to very high efficiency speakers. There are some exceptional speakers with SPLs in the mid 80's that this amp will not drive. So it is limited to specific types of music and speakers. Engineers do this all the time, they limit parameters to maximize cost saving. You don't build a two ton truck and expect it to be a good commuter car. I looked at the schematic of this amp. DC is DC regardless whether it's a rectifier tube or a silicon diode. Once it's rectified and filtered it is DC and there is no tube characteristic. A tube can turn on the plate voltage slowly but a semiconductor circuit can also turn on the filament slowly extending tube life. Why are people thinking they get something special out of tube rectifiers is beyond me. This you would have to prove in a DBT and no one I know has done it yet. The other thing I see is that you use two resistors in the cathode circuit, 2.7k and 1.5k. That equals .964 ohms, why aren't you simply using a 1 ohm resistor? I'm looking at your output transformers, they don't look special to me, what I see is triode single ended stage at two watts. While I think the EL84 is a very good tube, it is not the only one and not the only triode. So we have this amp, and I'm not doubting you, it might sound very good with certain music and speakers, but we can get class D amps well under $1k that have exceptional linearity and dynamic range. If you drive them with a tube buffer or preamp (I am an 6922 stage) then you can get a very smooth sweet sound. I'm not the only one doing this, by the way. A class D amp doesn't limit the speaker or music selection either. What I ask people to do is to put their biases aside and audition both. That's what I did. Go listen to Holst's Mars on this and class D and honestly ask yourselves which one sounds best. By the way just like digital chips have improved so has class D, now we use GaN's that are hard to beat.
I didn't post this to start trouble, but rather as a reminder of why so much audio gear sounds so similar.
Steve