After all, you're listening to the power supply.

I heard or read the statement above not too long ago and basically dismissed it as just curious, but life has a way of being serendipitous, ironic, cosmic and displays odd forms of synchronicity. To wit…

I have reached high-satisfaction with my DAC, amp, cables and speakers, but was still unsure of the land between source and amp in a system that had eliminated phono.  Did anything really need to be pre-amplified? Didn’t you just need a really good attenuator? This has been argued ad nauseam on these forums, so I offer my experience as a rather innocent ear-witness. I suppose my starting belief was that linestages tailored the sound, tube linestages mellowed it out, and $10k linestages were a chuckle.

Since my DAC and Amp are balanced, my starting point was balanced DAC to balanced tube Amp using DAC volume control. Everything I tried between them was also fully balanced. I first purchased a used ARC tube linestage that had been all the rage not too long ago. Not only was it too big for the cabinet, but it just seemed to add clutter, and I found I preferred the transparency of DAC to Amp. Next, I tried a very good passive with top-shelf resistor ladders. This was exceedingly clear on well-recorded acoustic, but seemed a little wooden on more dynamic sources. I found myself using rationality to keep it, which was the reason I returned it. I still had my initial investment in the ARC in the checking account, so I might as well continue my trials for another round or two. I was going to try an Aesthetix Calypso, but it was too big for the shelf.  Then I saw a used ModWright 36.5. I learned it had good reviews and it fit, so I bought it.

Here’s where it gets weird. I asked the seller why they were selling, and they said they were upgrading to the same linestage but with a very fancy external tube power supply. They also said they hadn’t noticed much change in swapping signal path tubes, but if I put in a vintage NOS Mullard GZ34 in the power supply, it would take it to the next level. I called Andy at Vintage Tube Services who had one he recommended.

I found the 36.5 to be an improvement over other options, but as I waited for the Mullard to arrive, I grew uneasy with the high frequencies through the ribbon tweets, and a sense that I was needing to play it loud to be satisfying. But even loud, I kept squirming in my chair and growing discontent. I had also had lunch at a friend’s house where she played a jazz album through her Sony receiver to Pioneer HPM-40 speakers which sounded wonderful. I was going into audiophile nervosa.

The Mullard arrived, and to put all cards on the table, I also reduced the output of the DAC 20 db to get more range in the volume control knob, which changed the DAC’s balanced output impedance from 60 to 135. When I turned the ModWright 36.5 on, there was silence. I spent a whole day swapping tubes and fuses, thinking “Great, now I have repair the linestage because of this blankety-blank Mullard and then resell it.” Finally I saw the HT toggle that had muted the output. So I put the NOS Mullard GZ34 back in for a final trial.

The entire system changed. It relaxed and yet had more energy, which seemed to push the soundstage out in 3D. Voices hung in space. It was spooky how many lyrics I had missed that were now just naturally there in the air. Voices were nuanced, etc, etc. The sound was what I had been chasing for years and I’m enraptured by what I hear on every track. It’s amazingly right.

I’m a believer. I do not sense a processed or tailored sound, but rather an illuminated, energized presentation with inner life that is engaging and in the room.  I’m also aware that tubes allowed me to hunt for the magic in a way that solid state or passive would not. They are what they are, but tube equipment can evolve, become, and transcend. To come full circle to the post title, this was one very old tube placed in the power supply that made the sound gel and delivered me to audio heaven. I was listening to a transformed power supply. Praise be. We all tend to like what we have, but kudo’s to ModWright on an extraordinary instrument. Highly recommended for power supply listening.

And yes, I know "Heard NOS Mullard in Power Supply" could be replaced with "Saw UFO" if I was an eyewitness.

I completely understand and can relate.Tubes seem to make everything come spookily alive.It's great when you stumble upon just the right combination of components and just the right tube and it all comes together.Enjoy!
Interesting writeup. So the bottom line was the better rectifier tube transformed the sound, all else being equal? 
+1electroslacker, replacing the stock rectifier tube in my Allnic H3000 phono stage with a Mullard GZ34 made one of the biggest upgrades I have experienced.  More clarity, inner detail, just more of everything.  
kalali,  yes, with the caveat that I had also attenuated the signal coming in to the linestage, so one could argue I had been over-driving it before, but pops reply gives support that it was the Mullard GZ34 rectifier tube.  I had strapped the DAC to full output on the recommendation of the passive linestage vendor, then went back to -20db when I inserted the Mullard.  I honestly could have spent a lot of money on other components chasing what that tube/ 36.5 provided.
My first mod was swapping a power supply to ultra-fast hexfred diodes. For a grand total of $8, and a little work attaching their heat sinks and getting them to fit, it is still to this day the biggest bang for the buck ever.

Probably a big reason my Melody I880 sounds so good is the D100 power supply tube. I don't know. Without being able to compare, how could I? Based on everything I have been able to compare though its a safe bet.

I would rate attending to the quality of power supply of any given component, to be as important or more important than the signal path. For example, if I only had a limited small amount of silver monocrystal wire to rewire a tube amp, I would use it on the ac input and power tubes, not the signal path.
Of course you're right. An amplifier is nothing but a modulated power supply. de KQ2E

You can also try the JJ Tesla GZ-34 tube.  Maybe not the Mullard but for the price worth a try.  I use it in all my designs.

Does it continue to sound much better, no matter the time of day? I agree that the power supply is so very important. On some days my system was unlistenable. My system was recently saved by the addition of a PS Audio P20 power regenerater. The incoming distortion is anywhere between 4 and 7%. The output is  now an impressive .1%. I have everything plugged into it except for the subs. The sound is so much smoother, more open and more detailed. No other component upgrade, save for my speakers, has made such an improvement.
@earthtones. Thanks for the tip.  I've only listened in the evening, but it has sounded consistently right each time.  I have a modest Furman conditioner fronting the DAC and linestage, but it would be interesting to try something like the PS Audio unit.

In the past, I've often listened with a "what could be improved?" ear, but for now the sound keeps surprising me at a pace that produces that deep satisfaction and love of music that silences my critique.