Symphony Amplifier

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#61
This amplifier produces the raw rich energy of metal well, you can hear the performer breath into the mike. However as you have seen from the video my listening setup is reasonably flat 30Hz-20kHz and pure direct. The decay is within 500ms. The amplifier is not busy, thus doesn't add much as a result it exposes some of the blandness and simplicity of some hip hop tracks, this may be both a good and a bad thing.
 
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#62
Earthing and shielding of audio amplifiers change the amplifier behavior so that an amplifier that would have scored a 10 outside the chassis now scores a 12. The shootout between the worlds best amplifiers is probably a championship between layout, shielding and grounding. Its recommended to listen to your tube amp with the tube faraday cage on. Plexiglass cases for amplifiers are not recommended.

Am currently sampling metal and indie on symphony, its just unbelievable, crazy amp. And this is with aluminums
 
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#64
Gave the speakers a good whooping in pure direct mode pc DAC until they sang hallelujah with these two albums, no fatigue, no nothing, sheer madness
(don't try to do this with this amp or any other amplifier until you've addressed grounding and shielding)
https://singwithmi.bandcamp.com/album/our-roots-run-deep
https://singwithmi.bandcamp.com/album/three-little-words
Hear a 2n5551 sing its linear heart out. Class AB is probably eternal, which row in that eternity symphony occupies? time will tell
+/-55VDC,16400UF*2, 4ohm, cant do 2 ohm cause single pair on prototype
 
#65
Its also good for movies. The Locanthi T circuit displaced quasi complementary stages, but were still addicted to them from the crown dc300, many stk subwoofer ics, lm3886, one thing to note is that it also suffers from crossover distortion probably more than the Locanthi T circuit. Our ears are more sensitive to things we assume they aren't , as such it might be a while before they accept high power class D amplifiers, or that may never happen.
 
#67
The mechanics of hearing are similar to the mechanics of running, jogging or walking, the ear is has a wave guide for very high frequency sounds for purpose of localization , a microphone, an amplifier and converter before the signals are finally interpreted by the brain. All this chain is subject to distortion and errors at various levels, in different brains even the same signals can evoke a slightly different result. The ear is not the only organ the brain uses to 'hear', we also have the skin and body cavities. Back to the ear, we dont hear sound directly through the ear, the sound has to be replayed back inside the ear something akin to normalization before encoding. Going back to the walking, jogging running example, we will equate sound pressure level to weight and frequency to running speed, whats important here are the joints and knees. At very high spl levels the ear distorts and suffers damage just like an over weight running attempting to break the 200m record, they will destroy their knees and joints. At very low spl levels akin to very light weight , a light weight runner can run very fast meaning they can hear higher frequencies. Age also is a variable as we age our knees and joints stop being supple the same happens to our ears we cannot resolve very high frequencies just like an old person cannot run very fast they may also may not be able to hear very well. Health and hearing are related. This analogy to hearing is important because sealed subwoofers and ported subwoofers are processed very differently when it come to what the brain hears. The brain will interpret a ported subwoofer to be louder and lower than a sealed subwoofer for the same spl and frequency that the spl meter records. That means that before a sealed subwoofer reaches the same level of perceived loudness as a ported subwoofer its spl is way too unsafe for the ear structures. Thus also in shoot out between ported and slotted subwoofers, the spl meter is wrong and here the ear wins on whose louder since the brain has to do the processing. Making ported subwoofers better for parties and movies while sealed subwoofers for critical listening so can babies hear 200kHz (chuckle)
 
#68
Heres one scope , find the rest of scopes in first post 8ohm load
DS0023.PNG
 
#71
Output stages are quite interesting the choice of using a lower ft and lower gain bjt as output comes into play, will it be more stable? Output stages are a world onto themselves and one has to consider local vs global feedback, ef stages are simpler but working with quasi stages brings out the nuances of output stages
 
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#72
Are these the most stable combos for output stages, where we move from high ft to low ft and from high hfe to low hfe, now to to keep that phase at -6db zobel no load 180 degrees, but with the MJL we have to loose those base stoppers for the pre drivers, the dilemma we face with high gain or high transconductance is stability even a sneeze can set off oscillation, this high gain also comes with higher distortion as seen with Darlington's or mosfets, would 5200 and 1943 and other high gain high ft types be better suited for simpler 2 stage outputs? Output stages are a world onto themselves and now this output stage is starting to look more like a Bryston distant cousin output stage although that one has some voltage gain
MJE340 MJE350
MJE15032 MJE15033
MJL21194 MJL21193
 
#76
I have shared the economy BOM and economy PCB in the first post, this should put the project within the reach of many but not all, what's needed is soldering skills alternatively for a small fee usually the price of a subway sandwich, the board house can solder parts for you
 
#80
Thanks for speaking your mind pued, self discovery and world exploration is a journey, enjoy. We are faced by choices every day, time is limited yet there is such a large search space, it is okay for you not to create it. The "explored" portion of life might realistically be far below 1% of the total possibilities available to us—whether in knowledge, sensory experiences, or meaningful encounters
 
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