First impressions, etc.

[Adrian]

Just completed the build of my new Stereomour II.
What a great sounding amp.  I'm comparing it to my S.E.X. 3.0 I was using in a near field desktop configuration with computer source input through an AMB Labs Gamma-2 DAC, using Decware Trapezium speakers.
The sound is clean and well balanced.  The bass is more extended with a smooth and tight mid-bass.  The mid-range is to die for!  The upper frequencies are also extended and not overly bright.  I am listening to Lee Ritenour's "Rit's House" and his guitar through his Mesa Boogie amp is captivating; The drums, cymbals, and bass sound just right. I'm only an hour in and this is an amp I may put into my larger system to (temporarily?) replace my Paramounts.

Technically, the voltage checks were all good.  I did notice however, that the voltages on terminals 10 and 11 initially read 300-400 mvdc compared to 0vdc .  Because these connections are from the center tap of the volume pot, I ran the volume to minimum and remeasured and got 0vdc.  The instructions did not say to put the volume to minimum in order to get the 0vdc in the manual.

Thanks, BH for this great sounding 2A3 amp!

[Paul Birkeland]

0.3-0.4V is pretty close to 0V and isn't anything to be too worried about in an amp like the Stereomour.

[Adrian]

Thanks, PB.  I wasn't really concerned because of how close it was to 0vdc AND because it is performing so well!

[Adrian]

The speakers I am using are not highly efficient (about 89dB), I adjusted the hum balance by ear.  My voltmeter does not read AC voltages to the single mv level. I definitely heard some hum and could adjust it to no audible hum.
I installed the DC Filament upgrade and could not hear any hum regardless of hum pot setting. I set the pots at about mid range anyway.
The DC Filament upgrade did indeed reduce to inaudible hum!  I do not have high efficiency speakers to compare this mod to and probably will not have high efficiency horn speakers.
Anyway, this upgrade did just what it advertised.

[Adrian]

I couldn't wait and installed the shunt regulator upgrade.
After about 10 hours runtime I "thought" I heard what I'll call a smoothness to the amp throughout the frequency range, especially the higher frequencies. I was thinking I needed more time to recognize any change.
My wife was sitting at my desk yesterday and commented that the amp sounded even better than a couple of days ago.  She was unaware of any changes I may have made.  It seems she independently verified my thoughts.
If I'm not careful, she's going to want this on her desk to replace the recently added S.E.X. 3.0 I set up for her.