Dear All,
The Fukushima resistors 1 ohm are available here in Japan. I could run a GB for them, and if the shipment of the other resistors did not go out yet, I offer to pack them is sets of 10 (or how many one built needs), label and send packages to the distributors.
BTW, welcome to the XEN website.
D.
The Fukushima resistors 1 ohm are available here in Japan. I could run a GB for them, and if the shipment of the other resistors did not go out yet, I offer to pack them is sets of 10 (or how many one built needs), label and send packages to the distributors.
BTW, welcome to the XEN website.
D.
> Could you offer the Xen symbol engraving on the F5X front panels?
We tried.
It requires a milling cutter of 0.8mm diameter (which we can get), and a high speed milling spindle of min. 40,000 rpm, which we do not have.
And if we make a mistake and ruin a panel, we suffer (another) 3-digit Euro loss.
On top of that, it is still NP's basic circuit and not our own.
Give us 6 months so that we can get some practice first before we get 99.9% yield.
Only then, and even then only limited to our own circuit designs ......
Patrick
We tried.
It requires a milling cutter of 0.8mm diameter (which we can get), and a high speed milling spindle of min. 40,000 rpm, which we do not have.
And if we make a mistake and ruin a panel, we suffer (another) 3-digit Euro loss.
On top of that, it is still NP's basic circuit and not our own.
Give us 6 months so that we can get some practice first before we get 99.9% yield.
Only then, and even then only limited to our own circuit designs ......
Patrick
the site looks good Patrick, one comment, i dont have any real trouble due to sitting on a 20Mbit connection, but given there is a slight pause on the loading of pictures i gather either the server its on is a little slow, or the images could be more efficiently compressed, because as the name suggests its a simply laid out site and it should be more instant. other than that (and thats really not a big thing at all) i really like it.
Is the 'sisters' speaker design named as such because of its likeness in appearance to the 'three sisters' rock formations in the Blue Mountains?
Is the 'sisters' speaker design named as such because of its likeness in appearance to the 'three sisters' rock formations in the Blue Mountains?
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A regulator uses an active device together with some form of passive RC filtering to reduce the incoming ripple voltage. A CRC, on the other hand, just uses one stage of passive filtering. A link has been posted at the F5X thread for the basic theory of this passive RC filter. E.g., as mentioned at the F5X thread, a CRC as I proposed have a ripple attenuation of about 19x. i.e. if the incoming ripple voltage is 1V, I shall get 52mV after CRC.
A regulator can do much better. The one the team is testing has two stage RC with a corner frequency of 0.16Hz, and hence an attenuation of 390000. This sets the gate voltage of the MOSFET follower. The output impedance of the follower is about 1/Yfs, or less than 0.1R, compared to 0R67 in the CRC. The PSRR of the regulator depends on the Vds dependence of the MOSFET, and it is something we need to test. But at low frequencies, it has, in theory at least, a much better performance than CRC.
But all active devices has capacitances, and therefore at some frequencies (usually 10's of kHz) they can no longer respond quick enough and becomes inductive. Where as a passive RC filter will continue to attenuate at high frequencies, until it passes beyond the capacitor's resonance frequency. You can find this frequency in some datasheets (but not all). The larger the cap, the lower it is. Hence the need to parallel the large electrolytics with smaller value film caps.
Some people argue that an active regulator has its own sonic signature, and is not as "pure" as passive. It is a subjective view. In any case, the power supply requirement is not as stringend for power amplifiers, especially for well designed balanced Class A amplifiers with a good PSRR and constant current draw. So there might be less difference sonically between the two than measurements or theory.
Passive devices are in most cases more reliable, and a CRC is much simpler to implement. As fitzfish mentioned, it is one of the items on his test list.
There are some other practical reasons why I recommend you to start with CRC. Mark Lai is working hard on tests, and I shall let you know more when they become conclusive.
Patrick
A regulator can do much better. The one the team is testing has two stage RC with a corner frequency of 0.16Hz, and hence an attenuation of 390000. This sets the gate voltage of the MOSFET follower. The output impedance of the follower is about 1/Yfs, or less than 0.1R, compared to 0R67 in the CRC. The PSRR of the regulator depends on the Vds dependence of the MOSFET, and it is something we need to test. But at low frequencies, it has, in theory at least, a much better performance than CRC.
But all active devices has capacitances, and therefore at some frequencies (usually 10's of kHz) they can no longer respond quick enough and becomes inductive. Where as a passive RC filter will continue to attenuate at high frequencies, until it passes beyond the capacitor's resonance frequency. You can find this frequency in some datasheets (but not all). The larger the cap, the lower it is. Hence the need to parallel the large electrolytics with smaller value film caps.
Some people argue that an active regulator has its own sonic signature, and is not as "pure" as passive. It is a subjective view. In any case, the power supply requirement is not as stringend for power amplifiers, especially for well designed balanced Class A amplifiers with a good PSRR and constant current draw. So there might be less difference sonically between the two than measurements or theory.
Passive devices are in most cases more reliable, and a CRC is much simpler to implement. As fitzfish mentioned, it is one of the items on his test list.
There are some other practical reasons why I recommend you to start with CRC. Mark Lai is working hard on tests, and I shall let you know more when they become conclusive.
Patrick
Last edited:
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