SSLV 1.3 negative voltage adjustment
Hi, Salas,
I've just assembled and tested SSLV 1.3 for DCG3 (works excellent) with 2x18V transformer. The positive reg. works fine with 500mA CC and I can adjust 17V output but negative with 300mA CC can be adjusted to only -13.5V and it doesn't go lower (less is possible to adjust). What could be wrong?
P.S.: And many thanks for all your projects and help to all of us DIYers!!!
Hi, Salas,
I've just assembled and tested SSLV 1.3 for DCG3 (works excellent) with 2x18V transformer. The positive reg. works fine with 500mA CC and I can adjust 17V output but negative with 300mA CC can be adjusted to only -13.5V and it doesn't go lower (less is possible to adjust). What could be wrong?
P.S.: And many thanks for all your projects and help to all of us DIYers!!!
What test load you use? The real preamp? If so, with how much bias load demand for each reg section? By not lower you mean it does not go down to -17V?
Q2 could be broken is one suspicion. Measure its Vbe as it works. Normal is about 0.62V in this circuit. We will see about other semis if it's not that.
Q2 could be broken is one suspicion. Measure its Vbe as it works. Normal is about 0.62V in this circuit. We will see about other semis if it's not that.
Hi all!
Wanted to assamble UltraBib 1.3, but some parts are absolute or have a large lead time on mouser. Could someone suggested where to buy this parts or on which parts it could be changed:
1) 844-IRF530PBF MOSFET 100V N-CH HEXFET
2) 647-UES1H330MPM Nichicon, Aluminium Electrolytic Capacitors - 50volts 33uF
3) PF5102 (512-J113) JFET N-Channel Switch
4) 647-UKZ1H102MHM Nichicon, Aluminium Electrolytic Capacitors - 50volts 1000uF
Wanted to assamble UltraBib 1.3, but some parts are absolute or have a large lead time on mouser. Could someone suggested where to buy this parts or on which parts it could be changed:
1) 844-IRF530PBF MOSFET 100V N-CH HEXFET
2) 647-UES1H330MPM Nichicon, Aluminium Electrolytic Capacitors - 50volts 33uF
3) PF5102 (512-J113) JFET N-Channel Switch
4) 647-UKZ1H102MHM Nichicon, Aluminium Electrolytic Capacitors - 50volts 1000uF
ok, is it right replacement:
1) 844-IRF530PBF replace 942-IRF530NPBF
2) 647-UES1H330MPM (50volts, 33uF) replace 555-RFS35V330MH3#5 (Elna SILMIC II, 35V)
4) 647-UKZ1H102MHM (50volts 1000uF) replace 667-EEU-FR1H102 (Panasonic)
?
3) 512-J113 is absent on mouser, may be buy on ebay?
1. Maker Infineon OK
2. Silmic II (RFS) does not mention 100kHz ESR in datasheet. From some other values I measured, the RFS line also has LOW ESR characteristic although not advertised as such. Should be OK for C3 but no clear info. Can't absolutely guarantee.
3. In general J113 isn't an expensive NOS JFET to be mainly offered counterfeit but don't buy Jfets from ebay unless there is a seller you have bought good semiconductors before. Mouser will have thousands in the summer again. Did you also look in other big stockists?
4. UKZ for C2 is a great choice.
2. Silmic II (RFS) does not mention 100kHz ESR in datasheet. From some other values I measured, the RFS line also has LOW ESR characteristic although not advertised as such. Should be OK for C3 but no clear info. Can't absolutely guarantee.
3. In general J113 isn't an expensive NOS JFET to be mainly offered counterfeit but don't buy Jfets from ebay unless there is a seller you have bought good semiconductors before. Mouser will have thousands in the summer again. Did you also look in other big stockists?
4. UKZ for C2 is a great choice.
I saw on tanδ characteristic, it seems similar to ESR 100KHz. But may be I am wrong.
647-UES1H330MPM also doesn't have in datasheet ESR 100KHz parameter
https://www.mouser.de/datasheet/2/293/e_ues-1669896.pdf
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I use 50 ohms resistor load for positive reg. (500mA CC) and 100 ohm for negative reg. (300mA CC - R1 is 2 ohm).
Yes, negative reg. can be adjusted be from -5V to -13.5V only. VR1 is 10k and -13.5 is approximately its middle position.
I've already changed Q2, Q3 and J2. Vbe of Q2 is 0.69V. Voltage on M1 pins are app. 23V, 17V and 13.5V.
For C2 ESR we don't care in this application. For C3 we care. Dissipation factor and ESR are associated and proportional figures but not the same thing.