BA-3 Amplifier illustrated build guide

Trying to find a cure for the "audio nervosa" illness I ran across this post, which made me laugh audio nervosa

have a good one everybody :wave:


You could insert a dial to everything. It should basically give you haptic and visual feedback (like, dim a led) but not touch the circuits. It could me made so that some sort of equilibrium between them could be achieved (much like biasing ba-3 pre). If you feel AN, touch one of them.
 
I´m afraid you lost me there with the dials in my head :hypno2: 😀
 

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F5 v1 and BA-3 Fe have no parallel output devices, so no matching required besides the JFETs.

The more output devices and the lower the source resistors the better the match needs to be so output current is equally shared.

That being said the 100 pieces from the same batch that I measured were really close. My chances would have been 5% or so to get a really bad match and hence start blowing devices.

But as Papa says it is easy to do and if it makes the amp safer and better why not do it. One can always sell, gift or keep left overs as spares for a lifetime supply. :cheers:
 
I'm really struggling to understand how to build the rectifiers and filters in the diyA Universal PSU design. My inclination is to build the First Watt Power Supply on the Universal PCB and use monolithic rectifiers. As far as I can tell, this shouldn't be a problem, right?
 
Yep should be easy peasy. Screw rectifier to heatsink (often case). Connect transformer secondary to rectifier (marked with a sine symbol or so). Connect + (usually marked + or pin little different or edge chamfered) and - from rectifier to capacitor PCB. Take care to solder the capacitors minus pole to the minus side (white bar on the pcb cap symbol).
 

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If using that PCB, IMO, you should EITHER get hold of soft recovery diodes - ie not in the BOM, which can be expensive, or use - as you suggest, monolithic bridges.

If using monolithic bridges, you need to snap off/break apart the diode section from the PCB. No biggie. In a cold room, just snap it off. Than road is clear for using monolithic bridges.

So:

1: Transformer
2: 2 x bridges (standard Vishay 35A is fine)
3: Universal PSU PCB but without the diode (front) section.

Remember, solder when possible, omit snapons/blades if you dare. Euroblocks are also not the best solution, but very very practical.

If I were you? I would ask Zen Mod if he has some spare PSU PCBs for you, in exchanfe for mighty amount of greenies.

Regards,
Andy
 
They are especially cool in that they are not so universal, rather optimized for FW and such amps (bipolar). The ground plane tracing is especially cool. Pictured myself the perfect way, then I saw my thoughts in that PCB, but of course better than what I had imagined :cheers:

A worthy addition the store, IMHO.

Regards,
Andy