starcat

Me preparing the wiring and waiting for some Xicon 300R and finally solder the C3675 as well (still need to test). Started with the amp board as well...

Planning on using for the GRLV the OPA134PA, if it is ok. Also, which LT1021 exactly have you been using, any p/n by the hand? This one is with 0.05% tolerance.

Exactly, thread wasn't 4-40 UNC nor M3 and anything else do not fit through the insulator. Will use a longer screw, didn't thought about that, thanks. I was thinking about milling out a small portion of the two inside fins to fit in the nut.

The tread on the Aavid 581202B02500G failed completely on me. Absolutely impossible to tighten the bolt properly and there is also no space for a nut from behind. Or are you guys using different sinks for TO-220?

Some progress here and waiting on the KSc2752 transistors... Will be ordering the transformer, thinking about 2x 336@360mA secondaries for the BH Mini PSU in order to get out 400V for the CFAe boards. This is what @jose has chosen. @congo5 however used 300@340mA and ended up with 399VDC using the same BH Mini PSU. Any thoughts after running those for a while?

Very nice, Kerry! Let's have a group buy to test jointly 🙂

That's a huge tilt for these speakers...

Guys, where can I get some more information on the implementation of the SS/ZF switching board? Appreciated all the great work you are putting in.

Anyone has a BOM handy for the protect3? Appreciated, thanks!

What are the two small boards in front of the case left and right used for?

I read somewhere a comment especially on this from Kevin saying both grounds must be connected. Can't remember which amp thread this was. Are you using a separated PSU chassis?

That KOA is 4.7K, LoL. Will get the Vishay VR37000004704FR500. Thanks for the heads up!

Thanks very much. The Vishay VR37000004704FR500 looks like being 200ppm vs the KOA MF1/2CC4701F 50ppm, if that really matters on the output.

I see, thanks. I guess I haven't checked the boards yet, just ordered the BOM (and will miss some parts then) 👍

What are you guys using for the 5M resistor on the Bias output to the Stax jack? Xicon 273 series doesn't have anything above 2.2M and KOA has only 4.7M in the MF1/2 series with 0.5w 50ppm and 700V?

Sure, here is the Mouser BOM for the CFP2/CFA2, order two times for the CFP3/CFA3. Here the BOM for the GRLV 30V for it as well. Some of the transistors are currently on back order, if you know of a viable replacement would be great. I've also made the latest CFP3/CFA3 version 2oz boards, so if you need some let me know. This would be the ready made transformer for the CFA2 as well. This above is for the non-stat version. For the static CFP3/CFA3 I have it as well together with the BH Mini PSU v1.4. @Pars

Thanks, Kerry - good point. I've used for the PSU EKWB EK-TIM Ectotherm I had on pile from high-performance water cooled graphics cards and ordered some more Arctic MX-4 for the amp itself. Both are stated to be free of metal particle and non-conductive.

Ordered 2oz differential boards (for the BH Mini v4 PSU as well), all the parts from Mouser and the black chassis above... so the CFA3e is on the build list as well.

I've got the BC556ABU for the PSU as this is what they had at Mouser, but understand the BC556C has a much higher hFE. Is the C version really needed (as it is used here only for the timer circuit)? Found some BC556C at TME and could swap it out of course.

Ordered as well 2oz boards from the cfp3rssfixedsssw-CADCAM.zip gerbers and will be building one later on.

I have bought from Mouser some IXYS IXCP10M90S for my T2 just some weeks ago, hope they aren't lemons as the whole PSU is full of them (13x I think).

Looking good. Thermal grease applied evenly on both sides of isolation pad (to transistor and bracket). Tightened with 0.82 Nm. M3 stainless steel mounting hardware used with disc spring washers underneath.

Thanks, Joamat. I have missed that Aavid note. Didn't start tightening the transistors yet, so that's right on the moment. Nm in Ncm should be divided by 100, meter by centimeters. So 100 Ncm is 1 Nm and 82 Ncm is 0.82 Nm. Looks like the 10PPSG can withstand more pressure than stated. Btw, the Wiha is very nice too 🙂

Hi Craig, thanks. The rectangular bush is Aavid 7721-10PPSG (Mouser p/n 532-7721-10PPSG). It protrudes into the TO-220 package as well insulating the steel bolt from the hole inside. PS: Round for the downside (if used at all), same PPS material would be the Aavid 7721-3PPSG.

Fallacy - the bolt might be short to the bracket, but not the transistor! All good. No, I didn't tap the holes, feel like using a screw was easier and followed the ONsemi note. I can use a disc spring washer with the nut below as well.