faxurda said:Ok Need help!!
I finished mu VSPS base on this board (http://skycoral.com/?p=49).
I used the double schottky diodes rectifier.
RIAA resistor is carbone, all other is metal.
RIAA cap are 1nf Panasonic poly
My output cap is Clary Cap SA.
Opamp: Try op2134 and lm4562 (both sound good)
All the solder joint look perfect, I tested all the resistors, the value is OK
I got issue with my first version of my rectifier.. I miss connected the transfo and burn couple diodesand at this time my opamp was not in the circuit.. So I redo my rectifier ...
But now my Right channel play couple db lower that my left.. And I can't figure where is my problem...
I don't know but i'm sure Ahaja could help you.
have you measure the supply voltage after the rectifiers and in opamp V+ and V- legs?
Can you post some pics?
my vsps experiments:
http://ignatiusprojects.blogspot.com/
Drawings of these projects:
http://ahaja.fotosik.pl/albumy/580167.html
I just wired power supply connected to preamps, set the voltages.
Later I make a sound tests
Regards Krzysztof
http://ahaja.fotosik.pl/albumy/580167.html
I just wired power supply connected to preamps, set the voltages.
Later I make a sound tests
Regards Krzysztof
Newbie question: I am building the VSPS doing point to point soldering on a generic pcb. It is my first project so it is not going quite to plan and I am wondering how can I test my opamp (OPA2134) to see if I have fried it or not? I don't have much besides a multimeter. Any help is appreciated!
Newbie question
I am testing the PSU for the VSPS phono-pre built following the diagrams in the RJM webpage (I hope). I am using a trafo 80VA with
12VAC dual secondaries. At the diodes out I measure 11.2VDC between V+ an COM and -11.2VAC between V- and COM. Is this right? I did expect 17VDC.
Thank you for your help
Renato
I am testing the PSU for the VSPS phono-pre built following the diagrams in the RJM webpage (I hope). I am using a trafo 80VA with
12VAC dual secondaries. At the diodes out I measure 11.2VDC between V+ an COM and -11.2VAC between V- and COM. Is this right? I did expect 17VDC.
Thank you for your help
Renato
Hi,
forgive this newbie boring you again!
My question is now how can I check the VSPS pcb for beginners (taken by skycoral.com) before connecting it to the amp.
I connected the pcb to the psu alone: no smoke, no smell, but the light bulb tester is lighting. Does it mean that there is a short in the pcb?
Thank you
Renato
forgive this newbie boring you again!
My question is now how can I check the VSPS pcb for beginners (taken by skycoral.com) before connecting it to the amp.
I connected the pcb to the psu alone: no smoke, no smell, but the light bulb tester is lighting. Does it mean that there is a short in the pcb?
Thank you
Renato
The great thing about a PCB is the possibility for error is much reduced compared to a perf-board project. If you've go it hooked up and nothing exploded, there's a pretty good chance it's working fine.
I'd check the voltages at the input and output (should be near zero) and at the op amp power pins (+/- 12 V or whatever it should be). If those are OK then hook the VSPS up to your system and give it a listen.
I'd check the voltages at the input and output (should be near zero) and at the op amp power pins (+/- 12 V or whatever it should be). If those are OK then hook the VSPS up to your system and give it a listen.
is the bulb socket wired correctly?northernsky said:
Check the voltage at the transformer input. If the bulb is correctly wired and lit then the voltage must be lower than full mains voltage.
If the bulb is bright expect <10% of mains voltage, If the bulb is glowing expect 90 to 95% of full mains voltage.
I don't understand how it's possible to develop such a huge potential drop on the AC line ... think about this for a second ... the kind of current required to do that to a properly connected AC grid should have blown every fuse in the neighborhood, as well as reducing the VSPS to molten slag in milliseconds.
Or the simple problem: the power cord or the AC socket that the circuit is plugged into has a very loose connection.
The issue is anyway upstream from the IEC connector I think.
Or the simple problem: the power cord or the AC socket that the circuit is plugged into has a very loose connection.
The issue is anyway upstream from the IEC connector I think.
He has sensibly fitted a low wattage light bulb in the mains feed to the potentially faulty equipment.rjm said:
A 40W 110/120Vac bulb has a hot resistance of ~330r.
It's cold resistance will be around 100r. This cold resistance can be measured with a resistance meter.
A 40W 230Vac bulb is ~1k3
The cold resistance ~ 400r.
Now look at his result.
He shows 84Vac at the transformer. This indicates ~ 146Vac dropped across the lit bulb. The bulb will not be at full running temperature, but a bright glow. I'll guess the warm resistance is ~ 1000r. You can work out the approximate current flowing into the transformer: ~140mA.
The power input ~12W. Take off losses through the transformer and rectifiers and you may find that the circuit is presented with just 6W maximum to attempt to operate.
That is the effectiveness of the light bulb. It prevents even fuses blowing as well as all the circuit board components.