Helium

Is that clear type LED 1.7Vf? It must be 1.7Vf (usually red color). Fill with solder all vias. Helps to reduce overall impedance of PCB.

Can anyone confirm please that output power is the same in case of using SE inputs? Any drawbacks?

Why are you biasing to 270mV only? With off-board heatsink, dynahi must be biased to 750mV (and even more if you like and as long as temperature is OK). With onboard heatsink, half of that (375mV) or more as long as temperature is OK.

But did anyone confirm that they are good for order (no errors ets.)?

You may want the latest PS900 (2nd one), not PS800.

Paid. Thanks!

Try Metcal PS-900. Clearer better than Hakko 888d (I have both). Hakko 888d is a great station, but sorry to say, Metcal is better. Reason I still keep Hakko is that I already invested in lots of Hakko tips, including so called 'microwave' tips which I use for soldering SOIC packages and the like (when heat transfer speed is not critical). But most of soldering is done by Metcal, including joints to heavy ground planes.

To be honest, modern BC546/556 from ON are measuring like crap. Last lots I bought (genuine of course) measured Hfe 250-280 @ 10uA base current, some hardly reaching 300. Try to get from AMB his NOS stock from Fairchild. As I remember they measured 300-330 and up consistently. If I recall correctly, BJT transistor leads from amb didn't magnetize as well. Now I feel sorry that I didn't have time to order and have them shipped from him for my CFA amp which is in progress.

No, formed leads are what fits best for this board (though looking at the PCB you might think that lead spacing is for straight leads. No, it for formed.

I'm making it. Boards are ready, paired with 2xGRLV and nice amb's deltas. Cases are not))

Did anyone run KSA5 at 30VDC? I like all my dynamic amps running at 30VDC. I'm scared a bit to fire it up. Don't want to fry anything. Balanced version was more difficult and expensive to make than I expected. P.S. I'm using OPA445 and G5V-2-H1-DC24 relays. And all other components are according to BOM and PCB silkscreen.

mwl168, Pars thank you. Pars would you mind sharing Gerber and BOM for discreet rectifier board please? I don't think that I will participate in the nearest PCB GB, but I'll try to have them made when I order PCBs for myself next time.

Pars, any chance you have more rectifiers left? I'd like to try them out on one set of GRLVs.

Interested in x1 (maybe x2, depends on final price) with Alpha FP.

Yes, it crimps both wings at the same time. First you crimp conductor (wire), then you crimp insulator with larger die that is close to holders. I was looking at Engineer PA-09/20 as well, but it doesn't have separate die for crimping insulator. Regarding width, I cannot measure it at the moment. But I always use Molex, e.g.lock header 22-11-2022 + crimp terminal connector 0008550131/0008550130 + lock housing 0009508023. Fits perfectly. I also used it with TE Connectivity connectors which are Molex analogue.

I'm using Molex 0638111000 (Digikey WM9999-ND) for Molex KK connectors. Nice tool.

What are the consequences if you just wire jumper 5R1?

Is OPA134 or LME49710 good for +/-30VDC output? Supply voltage is ±2.5V to ±18V, so I guess not. Only choice is OPA445 then. Could you elaborate more on zener please? Is 9.1V 1W 1N4739A from the BOM good for +/-30VDC output?

Kevin, still I have a question about input impedance. Maybe I don't get it right. There is a diffrence between schematic and PCB silkscreen. Schematic says R17 is 10K (=input impedance). Board silkscreen says R17 is 1K + 20K. Does it mean that actual input impedance is 21K? Or is it 1K? I'm trying to figure it out to build relay attentuator. 10K vs 21K is huge difference for proper potentiometer selection.

I may be missing something, what is GRLV plus? Edit: I mean GRLV vs GRLV plus.

Yes, but it's better to know voltage first. If it's close to 30V, I personally wouldn't use tantalum cap rated 35V. They will be at boarderline of specified voltage and tend to explode, unlike MLCC.

@Pars, What p/n you used for 47uF cap? Can you please measure voltage across it (at 30VDC power supply)? I have difficulties in finding that rated over 25V.

Well, maybe Kevin knows something I don't know) Anyway, I would use metal-oxide or metal film insted. To be specific, I'm ordering 71-CPF3-D-1. Also I remember AMB clearly discouraged against using wirewound in similar locations in his beta.

Are you using 1 Ohm wirewound type resistor? I would stay away from wirewound type in sigal path due to their high capacitance and inductance.

What's the input impedance of cfa3? And same question for krell ksa5 klone please. My guess is 10K and 50K respectively, but want to reconfirm.