Hi
Powered with 110-115 Vac mains, SMPS1200A400 J3 jumper has to be closed and all voltage levels are correct then. 😉
Hi asnakeon your voltage supply request at post 1220 is answered first post this thread, data there says: Supply voltage +/-40 V to +/-63 V.
This info also appears in the doc that comes with the unit, but as recommended voltages, ie the 40V lower recommended doesn't necessarily mean minimum.
You right, just thought you haven't seen the data and didn't know you already have the goodies, good building/soldering.
Hi LC, just my feedback re FO. I tried with SPMS PSU but the problem does not go away ie noise through speakers even without preamp. My speaker cables are spiral types. I wonder whether this cause the amp to oscilate ?.
Quan
Quan
Observe the output with oscilloscope for any sign of oscillations.
Connect the speakers with plain electrical wires to check whether the noise disappear.
Thanks LC, i don't have a scope . There is no problem with plain vanila speaker cables.
Quan
OK then, First One having 0,3 uH output inductor only, so try to put extra 0,5 uH parallel with 2,2 Ohm/2 W resistor (serial output RL filter) in series with positive output wire. Normally amps having serial output inductor ranging from 0,5 - 1,5 uH. Impedance in this case should change enough (higher with freq) to prevent any unwanted effects. 😉
Thanks LC. How easy is it to remove the original inductor and resolder a higher one?.
Quan
No, no don't do that. Extra inductor should be added on inside chassis side of plus speaker's terminal, in series of plus wire which comes from the First One module. The original inductor on PCB has to be left as it is, new one will be just added in series meaning complete inductance will be sum of both inductors.
Hi Dirk
SMPS1200A400 datasheet with connection diagram you can find here.
DC sense is connected to shutdown function pins - connector J4: pin 9 (-), pin 10 (+)
Connection sch will be published here before anyone will receive DC sense, so no worries at all.
Regards L.C.
Hi Andrej,
Question for the DC sense, since I only have one SMPS1200 powering both FO amp (stereo), could I connect both DC sense board in parallel to J4: pin (9) and (10)?
Or does DC sense only meant for dual mono?
Yes, both DC sense output SW (optocoupler output) can be connected in parallel to J4: pin 9 and pin 10, so DC error from any channel will shutdown SMPS1200. 😉
My apologies to Hypex. If I hadn't been so arrogant as to skip past the Principle of Operation section, I would have noticed that the answer to my question is right there in the block diagram...doh!
🙂
That's very interesting...
Can you please share your speaker cables because I'm apprehensive now that the amp will oscillate simply due to the speaker cables used.
Are these some strange flat solid conductor spiral WHOO (snake oil) cables or what?
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Perhaps you could incorporate this into a future rev of the DC sense PCB?
Do you have a chassis available to build this amp out into a five module chassis?
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