Prosyl - tomberry.free.fr

Hifi


Contents :

The curiosity

In 1998, I began to be interested in home theater. Meanwhile, the different equipment's acquisitions were tending me to hifi, because in my opinion, these two domains are complementary and will be together one day with tha arrivals of lossless audio codec.
But watching the hifi amp price, I have been decouraged in comparison with the price of home theater amp. There was a good reason : the conception quality and the internal composants. Then, I began to compare prices of the different hifi brands.

The researches

After several researches and posts on forums, I have been oriented to a Yamaha hifi amp. I was ready to buy an ax596 In Germany, for its price, its power and its processor function (which can bypass the preamp section of the amp and then permit to the input signal to get directly into the amplificator section, avoiding to be manipulated by the preamp section).
But my fear was to find the same problem than my Yamaha home theater amp (specially hifi quality).

One day, I was reading a topic about a small amp, the Sonic Impact T-Amp (from a hybrid class : class T = fidelity of the AB class and efficacity of D class) which people were wondering if it was a toy or a true amp. Indeed, when we read the test of this small amp able to be on batteries, we can wonder how it's possible. To get an opinion, I have read those tests, and after some hesitations, I got it.

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First contacts

When I receive this amp, it was frightening, so light : with the eight batteries, it was the batteries which makes all the weight !

My first impression with the T-Amp on batteries, linked with the headset output on my Yamaha amp, was good : there was poor highs and poor bass but good mids, it was musical and own a potential. The mids are fine, and the details were better than my Yamaha amp.

After connected on a stabilized alimentation (13,8V), it was a great improvement. No more lack of bass or highs. But, bass are cut and on the Michael Mardis website, the measurements prove it. On highs, it's sometimes good sometimes strange depending on musics. But they are more precise than when the amp is on batteries. In any case, no agressivity, music is comfortable. With it, no analyse, I am listening ^^.

Precision : the sound level with my speakers (90 of sensivity) in 11m² is very sufficient, the small T-Amp is at 9 o'clock max. Maybe the impefections are because the alimentation is at 13.8V, not 12V.

In conclusion, I would say that the quality/price is very high, with this amp, we have a musical amp, for some dollars. Surprising !

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First change : the Super T-Amp

Some times after, Sonic Impact has released the same amp, but with audiophile modifications, to make it less like a toy. I have bought it and I have make a comparison. First of all, my impressions on the Super T-Amp.

It is smaller that I have thought, but it's solid. Volume pot is good. With the amp, we have a RCA gold plated stereo cable, speaker cable (not tested), and an alimentation (with cable). I have connected the amp on my stabilized alimentation 3A, 13.8V.
I was used to my Yamaha and when I launched the musics, I was impressed : no more lack of bass. The mids are very good, no strange highs.

Another point, the soundstage is impressive as well as dynamic. Micro-informations are here ! Some tracks that I know were different !
As soon as we pull the pot up, the sound is clear, precise. I have not tested with the alimentation furnished yet.
The negative side, the blue LED on the front side is too powerful for me lol !

In home theater : I have connected the Super T-Amp on my Yamaha fronts pre-out (I have used the gold plated RCA furnished with, because with a simple RCA, I had noise), for testing. With Dolby Digital or DTS dvds, or with a DSP (Dolby Prologic II or other), it makes a big difference. It\s simple, all the good points above are here too. Wide soundstage, with movies, it's top.
The fact that this amp can give a hifi sound helps with restitution of strong mids on movies. And the dynamic is very good too, DSP's are transformed.

February 2015, operating system update from Ubuntu to... Archlinux ! Fed up having old software packages and needed to compile each time I want a new version of package. By the way, Rhythmbox is replaced by Audacious.


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Today's configuration

Today :

AMP5 from 41Hz.com

Progress of the assembly of the AMP5 : caption

Stages of the assembly of the AMP5
StagesStatusCommentaryProblemsSolutions
Capacitors OK
Resistors OK 100 and 101 jump R150-R153 Values OK
Diodes OK
Input capacitors OK Heat needed
Electrolytic capacitors OK
Axial choke OK
Two pot OK
LED OK
Voltage regulator OK
Rectifier OK
Pin (J8 and J10) OK
Solder terminals OK AC1/AC2/PGND : heat needed
Test +5V OK Fuse 2.5A ok. 10V instead of 5V. OK with DC +4.95V
Relay OK
Output filter capacitors OK Four capacitors
Toroids OK One not very tight Unsoldered and done it again
Tripath chip + 2 capacitors OK Heat needed
LED/MUTE test OK
Relay test OK LED OFF and clic !
Speakers Offset OK Out1/Ret1 = 0.004V, Out2/Ret2 = 0.005V
Sound test OK Music !
Case OK
Volume pot In progress Diameter a little too small
Final test OK On 2010/05/15 : Music OK, excellent sound quality, feedbacks's coming soon L/R inversion|medium hiss on the right output, very small on the left (as expected) Inductor replacement (too weak value)

Caption
Normal
Secondary stage
Critical stage

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AMP5 photos

Here are some pictures for now :

Resistors's colors

Resistors's colors
NameColors
R150yellow - purple - black - gold
R151green - blue - black - black
R152red - red - black - black
R153brown - black - black - black
R155red - red - black - orange
R201-
R202-
R203-
R204-
R30brown - black - black - brown
R31gray - red - black - brown
R311brown - black - black - brown
R32red - red - black - red
R33brown - black - black - brown
R34brown - black - black - brown
R35brown - black - black - brown
R36brown - red - black - brown
R37gray - red - black - brown
R371brown - black - black - brown
R38brown - red - black - brown
R39brown - red - black - brown
R40brown - red - black - brown
R41gray - red - black - brown
R411brown - black - black - brown
R42gray - red - black - brown
R43orange - white - black - red
R44orange - white - black - red
R45red - red - black - orange
R451red - purple - black - red
R46red - red - black - orange
R461red - purple - black - red
R47red - purple - black - black
R48red - purple - black - black
R49green - blue - black - brown
R50brown - black - black - brown
R51red - red - black - red
R52gray - red - black - brown
R521brown - black - black - brown
R53green - blue - black - brown
R54-
R55-
R56green - blue - gold - gold
R57green - blue - gold - gold
R60red - red - black - black
R70red - red - black - brown
R80brown - black - black - red
R81brown - black - black - red

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AMP10 from 41Hz.com

Finished. Incoming details...


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