Sony VFET Amplifier Part 2

Now what?

Several months ago I was getting nowhere with my V-FET build and hoping to see some progress I thought I would change the layout and some of the wiring. I had progressed to the point of installing the V-FET's when I did this. After the change in layout I tryed to proceed with the one channel without any success. At this point I noticed that I had reversed the wires going from the bridges to the power supply board. Any thoughts on what damage I may have done?
 
I looked into this pretty thoroughly and it could work fine. However, I went with linear supplies because they were simpler and cheaper.

Most SMPS' are not designed for the sort of continuous current that a class A amp requires, and the only reliable supplier I could find that produces suitable supplies were Meanwell - and the price was ultimately more that a linear PSU. Also, as Nelson says, the noise needs to be filtered very well. Many SMPSs are only specified for transient current and are not properly specified for the current requirements of a class A amp.
 
Member
Joined 2008
Paid Member
I looked into this pretty thoroughly and it could work fine. However, I went with linear supplies because they were simpler and cheaper.

Most SMPS' are not designed for the sort of continuous current that a class A amp requires, and the only reliable supplier I could find that produces suitable supplies were Meanwell - and the price was ultimately more that a linear PSU. Also, as Nelson says, the noise needs to be filtered very well. Many SMPSs are only specified for transient current and are not properly specified for the current requirements of a class A amp.

well, SMPSes are different.

1. sony ta-n9 - up to 80W in class A, using SMPS and sounds fantastic
2. sony ta-n900 - up to 200W class AB, also using SMPS (very similar to N9)
3. sony ta-n86 - up to 20W in pure class A, SMPS as well (classic)
4. sony ta-n88 - up to 180W in class D using v-fets

I have all of these and most of all I like N9. However their SMPS has shunt regulator at output. And yes, they all sound fantastic.
 
Member
Joined 2008
Paid Member
If you can filter the noise and they have enough current capacity, I think
they would be OK.

Thanks, Nelson. I am looking to use 300W rated "audio grade" soft-switching SMPS, usually found in "pro" amps. For each channel. So, at +/-30V on rails and 4ohm load it should be not drawing more than 2 amperes. I also think to use CLC filter on PSU output.