The less spare current you run, same stability degrees can be maintained with smaller R9 value. Has also to do with how much voltage there is across M2. This is Vout and changes its parasitic capacitance figures. You basically play with the phase margin and its zero dB transition frequency slide in the several MHz area. R9 470R gate damping was a midpoint subjective consensus from local beta testing builders before SSLV1.3's release. Across powering different analog and digital diy gear in their different systems as a whole. With various spare currents & output wire connection lengths also. Your preference mileage in your application may vary.
Hi everyone!
Few months ago I found the GLED431 voltage reference by Walt Jung and i now put it in everything I can: https://refsnregs.waltjung.org/GLED...D Reference Cell _Walt's Blog 2014_092418.pdf
It measures about 1nV/root(Hz) and the voltage is 2.5V
It needs 7-8mA current in order to perform its best so I replaced 2x270R resistors in BC859C current source with 2x82R to get that desired current.
Also I added 10nF PPS capacitor across the reference.
It sounds a bit better. Has anybody modified the reference? Is there a better way to do this?
Few months ago I found the GLED431 voltage reference by Walt Jung and i now put it in everything I can: https://refsnregs.waltjung.org/GLED...D Reference Cell _Walt's Blog 2014_092418.pdf
It measures about 1nV/root(Hz) and the voltage is 2.5V
It needs 7-8mA current in order to perform its best so I replaced 2x270R resistors in BC859C current source with 2x82R to get that desired current.
Also I added 10nF PPS capacitor across the reference.
It sounds a bit better. Has anybody modified the reference? Is there a better way to do this?
Only Vref "mod" we did was to add an NTC across R5 (original schematic) to stabilize drift if for exact voltage sensitive load. Since the super noiseless GLED431 sounded just a bit better when incorporated, then it looks like our standard ref does a good job so maybe try the most simple NTC "mod" too. Use 4.7k 3650K.
Hello everyone. I was hoping to join the team . Managed to get board at last Group buy. I have soldered everything today and was happy to run and Set unfortunaetly after applying 10v from transformer the led has not glow. I checked ac supply and its ok. I checked output and I got solid 15v dc unable to Set with trimmer.
I have used trimmer 10k to Set the voltage closer to output .
Iam trying to power my reclocker usb to spdif which needs 750ma . So I calculated resistor 0.6ohm nearest value at 2W I could get fro mouser was 0.68ohm. And that is what I installed . I had nippon capacitor 10000uf SMH series and that was fitted . I have fitted VRR 75k ohm .
Can someone help me diagnose please where I have problem ?
I would love to fix it .
Thanks
I have used trimmer 10k to Set the voltage closer to output .
Iam trying to power my reclocker usb to spdif which needs 750ma . So I calculated resistor 0.6ohm nearest value at 2W I could get fro mouser was 0.68ohm. And that is what I installed . I had nippon capacitor 10000uf SMH series and that was fitted . I have fitted VRR 75k ohm .
Can someone help me diagnose please where I have problem ?
I would love to fix it .
Thanks
Hi . Yes I have done first run with 5W 10ohm resistor . That is what I calculated from instructions. Checked all transistors - no shorts . I have not wind trimmer prior to first run . Now I have swaped 0.68 ohm for 1ohm as this is next value i had . Same result . Led not lit and ouput voltage 15v dc. I have 10v ac transformer and looking for 7.5v output.
Thanks
Thanks
0.68Ω R1 with 0.58V Vbe drop across it by Q1 (conservative low side tolerance) can provide 0.85A CCS. So it was a good value for your 0.75A spec application. Allowing 100mA spare. Plan is good.
About troubleshooting: Outputting 15VDC no adj tells its just passing the rectified AC level. Something might be wrong either with Q2 and/or Q3 would be my first check.
About troubleshooting: Outputting 15VDC no adj tells its just passing the rectified AC level. Something might be wrong either with Q2 and/or Q3 would be my first check.
Thank you for help. Is it worth doing any measurements in that case ? . Bc560 is unobtainable . I have 5 spares and rest is in mini kits . Any others i can use just in case . Shell i apply lower value resistor just to be safe ? Perhaps 0.5 ohm emiter resistor type ? Also I read that R9 should be 1k ohm in higher current application . Last thing i want is turn it on and blow another BC560. Should I turn trimmer clockwise all the way in ? Is 10K trimmer ok for my case ? Rf is 0.33 ohm 1 watt if it matters . And finally should I do test run with or without load if I replace q2 and/ or q3. My transistor tester packed up last week too so I can only Pull it out and test with my meter which is not ideal . Thank you again.
Test CB,BE junctions in diode meter mode (power off Ubib first) as basic pass/fail when without a transistor tester.
You can use BC559 as BC560 replacement for up to 30Vout applications.
0.5Ω R1 would produce about 1.2A CCS. You don't want to deal with such an excess. Typical R9 is OK for normal spare mA.
Now with 15V out your 10Ω dummy load tries to pull 1.5A i.e. >>CCS setting. Use a a light dummy 27-47Ω not to over-drain.
You can use BC559 as BC560 replacement for up to 30Vout applications.
0.5Ω R1 would produce about 1.2A CCS. You don't want to deal with such an excess. Typical R9 is OK for normal spare mA.
Now with 15V out your 10Ω dummy load tries to pull 1.5A i.e. >>CCS setting. Use a a light dummy 27-47Ω not to over-drain.