When I put my scope probe on the 2 screws of the Cap.(Vishay/BC10.000uF/63V) on the cap. board it shows the cap. has an awsome LF/HF suppression. Even the BHC T-Network caps. are worse.Lars Clausen said:Hi BertYes BCC's should be much better (series 101 or the older 154 are very good).I agreee completely about the screw terminal types, however you have to terminate them properly, and not let the screw sit in series with the current. The screw might have several times higher ESR than the capacitor. And steel in the signal path ....never good!
Well if you compare a stereo amplifier with a Dual Mono amplifier, then i can never disagree with you. Usually Dual mono is the best sounding option.
If you want to build the smaller option with normal stereo sound, then it's also possible, and you can get good sound also if you follow the cookbook, and use the original (or better) capacitors.
my supply line's ground wires have 4mm multistrand copper wire, + and- are 2.5mm of the same. Absolutely sufficient believe me, especially on such short lenghts. Have to use these tubings to get them in the plug holes. The 4 mm 1 does not fit but is soldered on the 2 ground pins through a U like copper wire in the connector.soongsc said:
Thinking of taking the connectors off and make a small AMP connector board with pins soldered on the NCD's PCB holes.
How come unit clips asymmetrically?f=1khz, 8 ohm resistive load.20V/div.
Also does not reach full line voltage level. Both channels the same result.
PS waveshape distortion is from generator.
idle current amp.=130mA on mains.
full power 2channels 1.2A till distortion.
Also does not reach full line voltage level. Both channels the same result.
PS waveshape distortion is from generator.
An externally hosted image should be here but it was not working when we last tested it.
idle current amp.=130mA on mains.
full power 2channels 1.2A till distortion.
in comparison to UCD400AD:
same power supply! Both channels driven.
full power(till distortion viasble)=1.5 amps on mains. But higher output, don't forget.20V/div.
An externally hosted image should be here but it was not working when we last tested it.
same power supply! Both channels driven.
full power(till distortion viasble)=1.5 amps on mains. But higher output, don't forget.20V/div.
Probably the input amp. clipping. It runs at -/+5V. Remember the tripath has the same setup, clip the input before the power amp.t. said:
That looks odd
Last time I seen a measurement like that was with a classA/B amp and one of the longtailed pair transistors was faulty, I've no idea what would cause that measurement with a classD amp
-V is the same as +V.
Lars, sorry, my faultLars Clausen said:
Because I had to switch from 0-1V RMS to 1-10V RMS to get full output the DC content of the generator had to be adjusted.
When I did that it was ok, will make another photo now.
On the UCD I get the output to clip with a level less than 1V RMS.
The NCD needs more. This shouldn't be? 45db should be enough to get full output under 1V RMS?
I'm sorry to tell you Bert, this measurement you have made does not show clipping of the input stage, or any other property of the NCD module.
I am starting to believe there is something wrong with other parts of your amplifier.
When i come into the office tomorrow (it's now saturday night) i will make a photo of how the clipping should look like on a NCD module with correct power supply and signal. And i will post it here by tomorrow.
All the best from ..
Lars
I am starting to believe there is something wrong with other parts of your amplifier.
When i come into the office tomorrow (it's now saturday night) i will make a photo of how the clipping should look like on a NCD module with correct power supply and signal. And i will post it here by tomorrow.
All the best from ..
Lars
NCD clipping after generator adj.
just before clipping
Now this looks better
An externally hosted image should be here but it was not working when we last tested it.
just before clipping
An externally hosted image should be here but it was not working when we last tested it.
Now this looks better
did some scope measurements:
full load=100V output@15khz/both channels
ripple on caps=100mv
ripple on screws of caps=20mv(steel/zinc)
ripple at 15hz=6V(10.000uF/63V) at full load
when using a centre tap. toroid=the same ripple(so whats the difference?)
speaker output terminals=6V@500khz ripple, no spikes.
inside there are spikes on the power rails@0.5-2mhz.
this is in sheer contrast to connecting an UCD400 on the same supply which has no spikes at all on the power lines. Just some tiny noise.
Connectors at the NCD pcb have some 20mv drop at 15khz.
full load=100V output@15khz/both channels
ripple on caps=100mv
ripple on screws of caps=20mv(steel/zinc)
ripple at 15hz=6V(10.000uF/63V) at full load
when using a centre tap. toroid=the same ripple(so whats the difference?)
speaker output terminals=6V@500khz ripple, no spikes.
inside there are spikes on the power rails@0.5-2mhz.
this is in sheer contrast to connecting an UCD400 on the same supply which has no spikes at all on the power lines. Just some tiny noise.
Connectors at the NCD pcb have some 20mv drop at 15khz.
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