|
Propeller Head Plaza Technical and scientific discussion of amps, cables and other topics. |
|
|
|
Propeller Head Plaza Technical and scientific discussion of amps, cables and other topics. |
|
In Reply to: Re: I ran some simulations (long, and images) posted by real_jj on April 24, 2006 at 12:57:28:
I know it's perhaps asking too much, but you could also model different sizes of filter and input bypass caps.
The cap I used are set to the standard 3,000uF/Arms. Increasing their value will (1) lower the frequency at which intermodulation components are at some level (say 10dB) under the mains 3rd harmonic. With the value I used, it is around 180Hz. But you won't so far, a cap 4 times large lowers it to 150Hz for example, so...
Note: Obviously, the situation would be very different with a L-shaped filter with an inductance in the 50mH/Arms. The mains current harmonic structure is then very different, much less peaky, so much more even harmonics, and about 5 to 10 times less odd harmonics than with the simple storage cap scheme . But then, the audio influence on the mains current is quite completely negelectable. The initial question of this thread was about this topic, and not about power supplies structures, so I stop here. Furthermore, the one I prefer are switching power supplies with Cuk structure, and a PFC with ZVS softswitching in fronty of it. A lot of advantages, only one drawback, needs time and resource to design properly. But then...
As for input bypass, I won't simulate them because the model is inadequate (because non realistic) above say 200KHz (I neglected inductances, interwiring capacitance in Xformer etc, which I didn't care in the audio band). Below that frequency, they are unlikely to change anything, since their impedance is way too large at the frequency of interest (remember that the mains source comes from a standard LISN with impedance around50 ohms above 1MHz).
Simulation for EMI/RFI is a completely different matter (done with other software like Ansoft's Maxwell, that I use)
This post is made possible by the generous support of people like you and our sponsors:
Follow Ups
- won't change the main figure - Jacques 13:58:46 04/24/06 (1)
- I think so... - real_jj 20:37:15 04/24/06 (0)
Top of Page ]
[ Contact Us ]
[ Support/Wish List ]
[ Copyright © 2025, Audio Asylum, all rights reserved ]
