I’ve been moving some amplifiers around today, listening to some that have been idle for a while and doing a little side-by-side comparison. And I’ve been reminded of a very important fact about amplifier performance.
The simple truth is that a well designed amplifier will sound good and a poorly designed one won’t. There are no magical parts, no mystic capacitors, no special transformers, and no special topologies which will mitigate this simple fact. This fact seems to get lost sometimes in the search for special components or just the “right” topology.
I was reminded of this today when I swapped out the amp I was using for my office with the 6EM7 Vertical Amplifier. For those not familiar with this amp, it is a 2W per channel SET topology taking advantage of a particular dual dissimilar triode intended as a vertical deflection oscillator and driver amplifier in televisions.
On paper, the amp is nothing special. It has reasonable specification numbers and low but ample power if using moderate to high sensitivity speakers; especially in a smaller space. But what you don’t see in the numbers is the quality of the sound it produces. I designed this amp almost 10 years ago (2014) and finished assembly in early March 2015. When I plugged this amplifier into my system today I was immediately taken aback by the rich quality of the sound it produced. It has a full register with no falloffs at either end. It is fast and detailed. And it possesses that fantastic SET sound that you only know once you’ve heard it.
So I went back to the original design and looked at my development notes. I found that the operating points were very carefully chosen with attention to dynamic performance and the capabilities of each stage; driver and power. I remembered the prototyping I did to determine what seemed to work and what didn’t. And I realized that this deceptively simple design was almost a year in the making.
Usually details like this are completely hidden when just looking at a schematic. The schematic is just the output of a process which can be either long, careful, and detailed or slipshod and haphazard. And it may not be apparent from the schematic which it was. This design process was a long and careful one to make sure that I got the best performance possible out of this little tube. And it shows in the sound of the amplifier.
So this is just a reminder for builders looking for that “next” amplifier or trying to figure out “what went wrong”. The best sound comes from a good design process and good quality (but not boutique) components. Better components may make a good design sound a little better, but they cannot fix a design which was not good to begin with.
As always, questions and comments are welcome.