The simplistic Salas low voltage shunt regulator

[merlin el mago]

V1.2R

A couple of V1.2R feeding the balanced phono RIAA

 

[klewis]

A couple of V1.2R feeding the balanced phono RIAA

Sweet!

 

[merlin el mago]

Thank you klewis, your work is very neat & looks professional I never will arrive to this quality.

 

[klewis]

Thank you klewis, your work is very neat & looks professional I never will arrive to this quality.

I guess that's my architectural training showing through.

 

[Salas]

A couple of V1.2R feeding the balanced phono RIAA

Nice combo. Looks good together.

 

[smpkje]

I will try to make a 12R positive 21Vin/12V out, also 12R minus -21Vin/-12Vout.
Can I use BF245A for Q8(2N5457) and 2SK170 for Q3(2N5459)?

 

[Salas]

For Q8 you can use BF245A, for Q3 you can't use 2SK170. But you can try BF245B if you can find instead of 5459.

 

[smpkje]

Thanks. What do you think about WIMA MKS4 4.7uF/63V for C1,C3?

 

[Salas]

If you can bypass them with 0.01uF MKP they will do better.

 

[smpkje]

I have on hand WIMA FKP2 10nF/100V. Are they ok?

 

[Salas]

Yes they will help.

 

[smpkje]

Thanks. I’ll try the same solution on V1.00 / C1 and let you know.

 

[klewis]

Hi Salas,

I've been able to get the V1.2R up and running with heat sinks and about 60vout on both channels. As I was setting it up, I was running it for brief periods without the heat sinks for ease of setup, changing out the voltage setting resistors. So, I never ran it for periods longer than 10 or 15 seconds. Now with the heat-sinks on I have run it for longer periods and it's doing the Vout climbing voltage thing again. The fix you suggested for the V1.2 stopped the Vout climb, but, apparently isn't doing the trick here.

Any thoughts? I hope you enjoy challenges...

Regards,

Ken

 

[Salas]

V1.2R has another error amp's base resistor than V1.2. Much larger. Its all about the tempco of the Jfet and the Bjt to find some balance. Try one Led in series with the ref resistor at its root over the fet. Sometimes it counteracts a bit.

 

[klewis]

V1.2R has another error amp's base resistor than V1.2. Much larger. Its all about the tempco of the Jfet and the Bjt to find some balance. Try one Led in series with the ref resistor at its root over the fet. Sometimes it counteracts a bit.

Like this?

 

[Salas]

Yep, and looking the other way in the positive. Will contribute a couple of Volt also but you can trim those out from the resistor if it will be helping the drift.

 

[klewis]

Well, that did the trick. Vout move around ever so slightly then seems to settle in.

 

[Salas]

Cool.

 

[TheShaman]

Is the BC550CG a direct replacement to BC550C ?
Comparing specs on Mouser yields no obvious differences.
See attached pic (left BC550C, right BC550CG).

 

[quanghao]

Is the BC550CG a direct replacement to BC550C ?
Comparing specs on Mouser yields no obvious differences.
See attached pic (left BC550C, right BC550CG).

it is one!