Stereomour II setup

[brightcity]

Here is a photo of my Stereomour II setup. Stereomour II has all Bottlehead upgrades and JJ caps along with a bunch of mills wirewound. The source is a Cal Audio Labs CL-5 through a "The Fix". The cd player is to be replaced by an Audio Note Kit DAC 2.1.

[kgoss]

Looks great. I'm sure you will enjoy listening to all your music again with the Stereomour in the chain.  It is an amazingly good amplifier and the fact that you built it yourself will make the music that much sweeter.

Enjoy!

[brightcity]

Yes, I am a single ended convert. The amp is simply put a great project and listening experience.

[brightcity]

I have attached 0.056uF Russian nos silver mica caps to the eight JJ caps along with one for each DC filament rail. All attached with 3M VHB tape.

The silver mica caps noticeably lower the noise floor and increase dynamics by extending the effective operating frequency range of the electrolytic and reduce internal vibration of the electrolytic.

Not the neatest build but it all stays secure.

[Paul Birkeland]

The silver mica caps noticeably lower the noise floor and increase dynamics by extending the effective operating frequency range of the electrolytic and reduce internal vibration of the electrolytic.

Were you able to measure a reduction of the noise floor?

I ask because the noise in the filament supply is 120Hz.  The 80,000uF of capacitance per channel has an AC impedance of 0.016 ohms at 120Hz (pretty close to a dead short!).  A 0.056uF cap has about 24,000 ohms of AC impedance at 120Hz.  The impedance at 120Hz will drop by about 0.001 ohm when you add those bypass caps. 

(Still, it's not surprising that it sounds different)

[brightcity]

The difference was noticeable but not as much as clamping the HV caps on my Audio Note Kit DAC 2.1.

They made such a difference in the DAC that I put them everywhere including the filament on the Stereomour. The differences were less spectacular yet significantly noticeable, more transparency between sounds.

The power line does include higher order frequencies as noise. I really don't like the noise from switchmode power supplies which is pretty much everything these days. Silver mica should work better for these noises.

How should I go about measuring noise floor?

[Paul Birkeland]

The power line does include higher order frequencies as noise. I really don't like the noise from switchmode power supplies which is pretty much everything these days. Silver mica should work better for these noises.

This is something that really becomes quite an issue when you have toroidal power transformers.  Those things have such ridiculous high frequency bandwidth that all the grunge goes right through them.  The EI type power transformers that we use do not have that issue thankfully. 

How should I go about measuring noise floor?

An oscilloscope is a good place to start.  There are some programs that you can run on a computer with a dedicated sound card that can produce some good measurements for not a ton of money too.

[brightcity]

New setup photos w/ DAC and Fostex Tweeters, PSVANE 2a3 and Pearl Cryo 12AT7

The PSVANE's are burning in and are smoother and faster than the Sovtek. They arnt too fast but the Sovtek had alittle more bite (dwell on peaks) to help with recognizing sounds. Gonna burn it more.

If you have led or fluorescent lightbulbs, these make lighting much nicer and are cheap: https://www.1000bulbs.com/category/squirrel-cage-filament-edison-bulbs/

[brightcity]

Added empty perfume bottles under the rubber feet on the Stereomour. The decay of the inherent tube resonance has become less jarring and yet more prolonged. The initial oscillation is significantly lower though. Music sounds like night and day difference with a characteristic that is hard to describe. Clearer definition between notes without damping decaying notes.

bottles obtained here: http://theperfumedcourt.com/search.aspx?keyword=empty+bell+jar

One bottle filled with ash from fireplace and located on corner near IEC power plug.

[brightcity]

Moved the whole rig and am waiting for solen s3 and s3q teflon caps to burn in.

[JWeldon]

Are those the Madisound BK-20 speakers? I'm thinking of building a similar system.  How do you like them?