Linn Sondek, diy Armageddon,Ekos,VdH Frog 0.65mV .The system is fully balanced and real dual mono from the AC voltage to speakers.I run biamp with two pre -xo ccs x bosoz
with 1.2r volt reg and ccs a la Salas .Power amps are 4 Millenium 150 and the speakers are
a "clone" of the Duntech Severeign but with all components Beyma professional and AMT tweeter.I run with the source in the middle of the gig, two preamp xo, one at left and one at right side , and the amps attached to the back of the speakers.
with 1.2r volt reg and ccs a la Salas .Power amps are 4 Millenium 150 and the speakers are
a "clone" of the Duntech Severeign but with all components Beyma professional and AMT tweeter.I run with the source in the middle of the gig, two preamp xo, one at left and one at right side , and the amps attached to the back of the speakers.
My preamp and xo of right channel. The left channel is specular. Each preamp consist of a Seiden pot and three board: one receive the signal from pot ,amp it
and send it to amp of mid woo, mid and hi freqs.The other receive the signal from pot, amp it and send it to the third board. This cut the hi freqs end send the signal to bass amp.
I build 12 1.2r volt regs and 12 Salas CCS(string of BJT, the same of 1.2r).
and send it to amp of mid woo, mid and hi freqs.The other receive the signal from pot, amp it and send it to the third board. This cut the hi freqs end send the signal to bass amp.
I build 12 1.2r volt regs and 12 Salas CCS(string of BJT, the same of 1.2r).
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I would share my experience about the hum of the NJFET RIAA, the only issue that I 've
encountered in this project.
First I builded one channel balanced , that is the same of a stereo unbalanced, and I heard it. The arm ground connected to star ground of circuit. The sound in stereo unbal mode was fine, but the hum was too high. When I configurated the board in mono balanced mode, the hum was greatly reduced. Then i build the other channel and heard it. I connected the arm ground to ground of both channels, the hum reduced , but the soundstage collapsed. Then I connected the arm ground to chassis, and I leave both channel grounds floating.Now the soundstage is open, the dynamic high,. but the hum
too boring. If I connect both the circuit grounds to chassis , the hum disappears, but the soundstage collapse again. I can't get the best of two worlds; or soundstage with hum, or
no air without buzz.When you get a real dual mono system and connect the grounds of both channels in only one point, the soundstage get narrower, less airy.
So I thinked: if the hum (50Hz)is a problem of low freqs and open soundstage a problem of hi freqs, I need to connect the circuit grounds to chassis ground by means a reactive component, with hi reactance at low freqs and low reactance at hi ones: a inductor.
When I made so, I've both the things : no hum and airy sound. Trying some situations,I view that the quality and the value of the coils matter.The coils are a low pass filter between the circuit grounds and chassis ground, and filtering away hi freqs garbage.
I use two 3mH Alpha Core with great results.The highs are sensibly better, and I could
hear easily all the bass lines.
encountered in this project.
First I builded one channel balanced , that is the same of a stereo unbalanced, and I heard it. The arm ground connected to star ground of circuit. The sound in stereo unbal mode was fine, but the hum was too high. When I configurated the board in mono balanced mode, the hum was greatly reduced. Then i build the other channel and heard it. I connected the arm ground to ground of both channels, the hum reduced , but the soundstage collapsed. Then I connected the arm ground to chassis, and I leave both channel grounds floating.Now the soundstage is open, the dynamic high,. but the hum
too boring. If I connect both the circuit grounds to chassis , the hum disappears, but the soundstage collapse again. I can't get the best of two worlds; or soundstage with hum, or
no air without buzz.When you get a real dual mono system and connect the grounds of both channels in only one point, the soundstage get narrower, less airy.
So I thinked: if the hum (50Hz)is a problem of low freqs and open soundstage a problem of hi freqs, I need to connect the circuit grounds to chassis ground by means a reactive component, with hi reactance at low freqs and low reactance at hi ones: a inductor.
When I made so, I've both the things : no hum and airy sound. Trying some situations,I view that the quality and the value of the coils matter.The coils are a low pass filter between the circuit grounds and chassis ground, and filtering away hi freqs garbage.
I use two 3mH Alpha Core with great results.The highs are sensibly better, and I could
hear easily all the bass lines.
Grounding with an inductor i.e gradually floating towards HF its ''creative grounding'', clever since you got the result. Don't know, did not have hum problems that I could not kick with solving ground loops etc. in the various builds, and I could not experience the sound stage differences described in the process although I got one in a balanced system but pseudo balanced out as phono source and the amp has a common PSU.
