New Stasis front end

[2 picoDumbs]

Ok good.

This is the secret recipe.

 

[indra1]

Be careful, correct recipe for downunder is 42 degrees Celsius measured 42 um below heat source. 😀

 

[2 picoDumbs]

Thanks for that detail.

Got it.

 

[hirscwi]

Hi hirscwi, Zen Mod has added the three V+ and V- psu rail connection points to allow for a low impedance connection to the main psu cap bank. Up to you whether you use 1 point or all 3 in parallel. The 3 off LS+ connections also allow you to wire a paralleled lower impedance connection to the loud speaker + terminals, again choice is up to the builder.

There is a power supply GND connection on the RHS of the O/S pcb just under C3, this should be wired back to your PSU star point ground bus, this is only used to connect C3 to ground and does not go anywhere else on the O/S pcb. The loud speaker terminal neg connection should also be directly wired back to the star point GND bus.

Also the 2SA1294 is not a complement to the 2SC3519 although very similar. Difference being in VCEO. Complements are: 2SA1294 and 2SC3263 (230V) and 2SA1386 and 2SC3519 (160V) - but your combo should work fine, as you will be way inside SOA DC curve for both types with the Stasis design.

Hope that is all clear.

Yes, perfectly clear. Thanks for the explanation.

I assume there is a connection from `P gnd' on front end to the star groud - correct?

 

[hirscwi]

Hi hirscwi, Zen Mod has added the three V+ and V- psu rail connection points to allow for a low impedance connection to the main psu cap bank. Up to you whether you use 1 point or all 3 in parallel. The 3 off LS+ connections also allow you to wire a paralleled lower impedance connection to the loud speaker + terminals, again choice is up to the builder.

There is a power supply GND connection on the RHS of the O/S pcb just under C3, this should be wired back to your PSU star point ground bus, this is only used to connect C3 to ground and does not go anywhere else on the O/S pcb. The loud speaker terminal neg connection should also be directly wired back to the star point GND bus.

Also the 2SA1294 is not a complement to the 2SC3519 although very similar. Difference being in VCEO. Complements are: 2SA1294 and 2SC3263 (230V) and 2SA1386 and 2SC3519 (160V) - but your combo should work fine, as you will be way inside SOA DC curve for both types with the Stasis design.

Hope that is all clear.

For what it's worth, I mistyped: I have SA1386, not SA1294. Just looked at wrong notes. I have 4 each of the A1386 and C3519 so I hope I'll be able to get a decent match to the new ones. I've ordered the "non-A" version because that's what I had already.

 

[gary s]

There is a GND connection on both the new NP FE pcb and the ones that ZM has done, to be wired to the GND star point. Good to hear you have complementary output transistors as well.

 

[bknielsen]

Output BJTs, what to look for?

There are many complementary BJTs covering the needed SOA. What else makes them good candidates for this amp except maybe from constant hfe as a function of collector current?

PS: Thank you Papa and ZM for all the design work. I think I should add this project to my backlog.

 

[Mark Johnson]

The ones John Curl uses in his 400 watt per channel "Parasound JC-5" are the Sanken 2SA2223 and its complement, 2SC6145

They have nice specs, they aren't ridiculously expensive, and best of all: Mouser doesn't sell them, so they confer the bragging rights of of rarity and inconvenience.

 

[gary s]

Thanks for the reply Mark, those 2 Sanken devices you mention are also used in the monster D'Agostino amps. So there can't be much wrong with them.

The hobbyist and professional manufacturers have a better arsenal of output transistors to select from these days, compared to what Nelson would have had to pick from, back in the Threshold glory days - 35 years or so ago.

 

[bknielsen]

+1.....and me having no power BJTs in the drawer I see no reason not to use those Sankens. Thank you.

 

[gary s]

There is also an "A" version from Sanken of both, which are dearer. Both have the same specs, but I do not know what the difference is - maybe some other member around here will know. No mention of any difference in their data sheets that I can see.

 

[bknielsen]

Maximum VCE it seems

 

[gary s]

Thanks for pointing that out, totally overlooked it - the 'A' version has Vceo of 260V and the non 'A' version is 230V. I have no need for the 'A' version, 230VDC is plenty high enough rating for me.

 

[hirscwi]

Thanks gary s for the information!

 

[Blk Dynamite]

Just got these boards ordered and it had me thinking “what is a good program to design a PCB?” Just wanting to poke around w a program and learn for general knowledge

 

[gary s]

I have not tried myself, but others around here use Eagle or Kicad, but there are others I believe.

 

[Blk Dynamite]

Cool, thanks! That gives me something to start off with

 

[gary s]

Have a look at this link.

Top 10 Free PCB Design Software for 2019 - Electronics-Lab.com

 

[Mark Johnson]

What I like about KiCad is that you get unlimited number of layers and unlimited board size, for free. All of KiCad is completely free. When I was shopping for a PCB layout tool, a few years ago, all the other PCB software outfits charged money, sometimes a lot of money, for these capabilities. Maybe that has changed, it's been a while since I actively looked at other alternatives.

 

[woofertester]

What I like about KiCad is that you get unlimited number of layers and unlimited board size, for free. All of KiCad is completely free. When I was shopping for a PCB layout tool, a few years ago, all the other PCB software outfits charged money, sometimes a lot of money, for these capabilities. Maybe that has changed, it's been a while since I actively looked at other alternatives.

In my day job, a principal designer uses Kicad. Just a data point for consideration.

The fact impressed me enough to start learning Kicad. I am using Kicad for the upcoming Mini Beast with 320 JFETs.