Glenn Swiderski  (             2/1/02

Using an 8 ohm load and applying 7.5 v p-p the following distortion measurements were noted.
  Frequency  % Distortion                   Frequency  % Distortion
     40                    15                          400                 1.8
     50                    10                          1k                   0.72
     60                    8                            2k                   0.59
     80                    6.4                         3k                   1.3
     100                  4.3                         6k                   2.2
     200                  2.4                         10k                 2.2

Hum noise  with 8 watts out = -59db
          with 1 watt out = -70db
SMTE was 1.3% at 8 watts

        Nick Claus  (    2/14/02
Below is a picture of the chassis he mounted his tube kit into.  A rather interesting chassis!

    Page Updated Dec. 2019

       Alan Ersen  of Sacramento, Ca.                              5/7/02
  The top is hand polished aluminum!

Read the review:
         "Audio Xpress"                         November 2002 issue

    ( Following are a few excerpts from "Audio Xpress".)

    S-5 Electronics K-12m -- "As our team of reviewers discovers, the musical quality from this low-cost tube amp may surprise you."
Reviewed by Charles Hansen........................................47

    "What can you get for $140 nowadays? If you're willing to play by the rules as defined by this integrated amplifier, the answer is quite a bit. The K-12M produces a smooth, musical sound that rarely offends. When coupled with appropriate components, it is a joy to hear. We have not heard a better-sounding amplifier in this price range."
    "The comparison between the AMP-1 and the K-12M was much closer. The AMP-1 had a deeper and stronger base response and over all good sound, but when compared with the K-12M it sounded slightly harsh, unnatural, and "hi-fi". Although the AMP-1 was significantly more expensive, we both preferred the natural sound of the K-12M."
    "The K-12M's sound coupled with its modest price tag blew me away. I've heard amplifiers I liked better with our system but none for under $800. If you'd told me before I heard the K-12M that a $140 amplifier could sound this good, I wouldn't have believed you."
Reviewed by Duncan and Nancy MacArther         

        Dan Corcoran                                                                        Jan 2003

"I have thoroughly enjoyed assembling the kit and the "finished" amp.  Thanks for a great sounding piece of equipment."
Thank you for your pictures and responses!  If you have enjoyed your kit, personal adaptations and unique mounting designs, we would love to see them.  We will make every attempt to place your amp on our site for others to enjoy and receive inspiration for their own individualized amp.  Thank you again and we hope to hear from you all! 

The K-12  (G) Tube Amp Team.

        William Rogers                                                                12/02

A Tube Amp for US Poor Folks "Hi Fi Heaven!"
"Measurement Don't Mean xxxx its the sound!"

         Martin Boehling                                                                     May 04

I just finished building your Model 12M - I JUST LOVE IT! WOW!
I am an Organist/Pipe Organ Builder. Therefore, the music I play through it contains the EXTREMES for frequencies from 16.35 hz, to beyond the range of human hearing.
I hooked the 12M up to a couple of old "OHM" speakers: 10" woofers and Piezo tweeters. Even these old 'warhorses' sound better. The Strings in the orchestral music literally jump out of the speaker cabinets. BUT - what I REALLY NOTICED was the "bell percussions" in the theater organ recordings that I've played.
Thanks again for such a lovely sounding amplifier!

From  Lenny Bove
September 06

"G" Series

From Mark Houston 2007
From David Wells 2007
From Jason Sartor Tempe Arizona  2007
From Rudi Slejkovec  Slouenia Europe  2007

The chassis is made of a base of solid mahogany with a transformer case of figured redwood, bloodwood, and manzanita root burl in the corners. Note the ventilation slot on top, in the bloodwood.I added a thermal reed switch that is in series with L1, plus a tiny fan inside the transformer housing.

Ken Rauen
All good fun putting it together, sounds really great for a 180 buck amp!
Sounds especially lush through a set of heavy 1970's Diatone DS-301 speakers

Bill O'Connor - Japan

From Ken Rauen
The chassis is made of a base of solid mahogany with a transformer case of figured redwood, bloodwood, and manzanita root burl in the corners. Note the ventilation slot on top, in the bloodwood.

From Daniel Ruhe
( This is another example of some real
wood working cratsman ship ).