I'm not in the camp that avoids "switchers" at all cost in audio projects, with good filtering they can work well.
But, I do like to keep options open and keep the PSU boards separate. If one chooses to use the V2 PSU make the In/Out connections a simple wire jumper between boards as you did for your prototype in the above picture.
What about using a voltage doubler for the driver, then you don't need two tappings on the transformer. so feed the output section voltage through voltage doubler into the driver section. Should be easy enough and a cheap solution to get two voltages.
Biggest downside is that the DC-DC converters are expensive. About $10 each and you need 4. However, probably cheaper than the transformers or SMPS for a separate supply.
Hi Nico,
I considered that. But I'd been looking for a design to try the DC-DC converter approach after seeing it in Winfield's thread. It was new to me there, though as you pointed out not a new idea. Either approach could probably work. And by keeping it separate an alternative circuit could be developed.
I considered that. But I'd been looking for a design to try the DC-DC converter approach after seeing it in Winfield's thread. It was new to me there, though as you pointed out not a new idea. Either approach could probably work. And by keeping it separate an alternative circuit could be developed.
Trying to remember... I think I explored the double when developing the V2 PSU. I think the challenge I ran into was supply regulation. I seem to recall it being far more sensitive to mains and transformer regulation issues.
The neat thing about the DC-DC converters I spec'd is they accept an input range of 18V to 36V. With the recommended ±24V to ±30V main rails, even with regulation issues the main rails still fall within the range of the converter's input. No separate handling is needed to drive their input voltage. And the aggressive RC filter should filter out any noise they introduce.
The biggest challenge with these is managing inrush current at power on to not exceed the current limits of the converters. The V2 PSU as spec'd does this. One reason why the converters might seem oversized for the nominal current they supply.
The neat thing about the DC-DC converters I spec'd is they accept an input range of 18V to 36V. With the recommended ±24V to ±30V main rails, even with regulation issues the main rails still fall within the range of the converter's input. No separate handling is needed to drive their input voltage. And the aggressive RC filter should filter out any noise they introduce.
The biggest challenge with these is managing inrush current at power on to not exceed the current limits of the converters. The V2 PSU as spec'd does this. One reason why the converters might seem oversized for the nominal current they supply.
Here's the TLDR summary of PSRR from the guide 🙂. This shows the impact of no filters and the impact of the V2 PSU along with a typical RC filter on the main PSU. In this SIM 0.1R & 10,000uF.
You can also see my exploration of improving the V2 PSU by changing the RC to a RCRC with the same overall resistance and capacitance.
You can also see my exploration of improving the V2 PSU by changing the RC to a RCRC with the same overall resistance and capacitance.
What advantage would this have in your opinion over the DC-DC converters? Is it lowered cost in parts? Or an alternative to those than want to avoid switching converters? Or maybe both.
My amp uses this method. The supply ripple is not important as the driver voltage is twice what is needed, so even with 20V ripple it is a non issue really, the driver current is 10 mA only. It is cheaper than another winding on the Xformer.
Not trying to be critical. Hope it didn't come across that way. Always something new to learn. It would be nice if the V2 PSU cost could be lowered. The JFETs and MOSFETs already begin to add up.
No its fine my friend, as I say I am watching the development, it is always interesting to see how engineers tackles things from different angles.
Those Lat Mosfets are becoming scarce like chicken teeth.
Those Lat Mosfets are becoming scarce like chicken teeth.
Fingers crossed that Exicon states in business! As far as I’m aware they’re the only ones still making them.
What are the 12V DC-DC Converters?
U81 and U82.
I cant see what they are called.
It is not in the BOM
U81 and U82.
I cant see what they are called.
It is not in the BOM
Yes. U81 and U82. The BOM Excel file has two tabs. The second tab has the V2 PSU parts. The build guide has a longer discussion with more part options identified.
Brain, I would just let you know that by using the 10P does not have the body i
diode but the 20P and 20N has, do either add one or use the bigger bother
Do You Follw ans get out of jail free
diode but the 20P and 20N has, do either add one or use the bigger bother
Do You Follw ans get out of jail free
I thought both Exicon devices have integral protection diodes. The boards have a provision for an external diode (D96 & D97). I choose to populate these as a "belt & braces" approach to safety. There's no harm in using them if you're not sure.
Maybe some else can chime in? The Exicon databases aren't explicit about it (that I can see).
Maybe some else can chime in? The Exicon databases aren't explicit about it (that I can see).