SSLV1.1 builds & fairy tales

[stajo]

Topview solderings of fets

Bottom view and caps

Is there a critical length of the leg of R101 to Q101?

 

[Salas]

Just bit off board for air circulation.

 

[stajo]

Great. Maybe there will be a smoke test tonight then. Just gathering some courage at the local

 

[stajo]

Well, after first not understanding why I had 5 volts out, unable to adjust it I understood after some investigating that I had grabbed a BC560C (PNP) and not a BC550C (NPN) for the positive board. I have now made some surgery and replaced it. But with a 3K9 and 1 K trim I only come down to 17,7 volts so it seems like the K117 there is mighty strong. I guess I have to go down some steps in resistor value. Any steps I can take to smartly calculate what the values should be before I start guessing?

 

[stajo]

Of course I started guessing and put a 10K over the 3K9, making it a 2K8. I can now trim between 14,06 to 17,36 volts with 1 K trim (or 980 something). The measured value for 15 volts is 3K07. I have 200 and 500 ohms trimmers in my box and 2K7 and 3K metal film standard cheap resistors. It would be preferable for ppm and drift with a smallish trim and low ppm resistor. Would I be to daring to order some low ppm 3K resistors and put 200 ohm trim in?

Measured K117:
Q102 3,63
Q103 4,22
Q105 4,87

 

[stajo]

I wonder what those resistors could be? Measures straight with DER EE

 

[Salas]

But with a 3K9 and 1 K trim I only come down to 17,7 volts so it seems like the K117 there is mighty strong. I guess I have to go down some steps in resistor value. Any steps I can take to smartly calculate what the values should be before I start guessing?

Simply by Vdrop on the 3k9 and Ohm's law I=V/R you know what mA run in the Vref by the Jfet. From there you remove as much I*R value as much voltage created you wanted to get rid off.

 

[stajo]

Thanks! My latest plan is not to order odd values low ppm and instead parallell standard metal film. Usually makes it more stable and I can find the values I like. 5K1 and 6K8 in this case makes a 2K9 that will match a 200 ohm trim

 

[Salas]

Sounds like a good plan.

 

[Salas]

I wonder what those resistors could be? Measures straight with DER EE
View attachment 1306743

Hmm some European made type I would guess. Looking not as old ABBA but maybe as old as A-ha

 

[stajo]

Haha, probably something like that. Found them next to some CMF60 so I wondered if I might have got them at the same time but judging from the oxide, probably not.

I was six by the time of Waterloo and A-ha is Norwegian, not over my doorstep

 

[Salas]

I know. But beyond humor they maybe are Dale even.

 

[Salas]

A-ha is Norwegian, not over my doorstep

Ace of Base were from your part of lands I think?

 

[stajo]

Gothenburg. Close to my childhoods

 

[stajo]

They were maybe not my cup of tea though, when I got to age I went often to Club Errols in GBG and saw bands like Primal Scream, Skinny Puppy, Radiohead, The Leather Nun etc

 

[Salas]

Only referred to them as well known time-stamps. There was an interesting alternative scene there at the time.

 

[stajo]

Yes. They were part of what is refered to as ”The Swedish Pop Wonder” I beleave. Well known markers of history.

https://sweden.se/culture/arts-design/the-swedish-music-miracle

Neg reg coming up in a bit!

 

[stajo]

Eh. Had forgotten R201

New balls please

 

[stajo]

This one came up on first kick and without smoke. They are both a little lean on current, the positive took 203. Rethink R101/201 I think.

I used 2K7 + 1 K this time, can trim between 13,73 to 17.00. 15 v happens at 3,059 ohm since I used similar values on k170 between boards.

 

[Salas]

15V/3k056 means 4.9mA in situ. 2SK117GR comes in 2.6-6.5mA range for 10V test idss. You put BL or top dog GR?