Filled out and well organized build. Those extra boards are used as rectifications + pre-regulators I believe. How is hum with big trafo inside?
One K369 per channel I see. That helps not picking up noise so easily also. Is it the high MC or MM sensitivity version, for which cart, played any music?
One K369 per channel I see. That helps not picking up noise so easily also. Is it the high MC or MM sensitivity version, for which cart, played any music?
Thanks.
@merlin: The TT is a Project Carbon with Ortofon 2M Blue.
@Salas: The extra boards are actually bad, they are suppose to be shunt regulators, but they get too hot. They are honestly only use as rectifier and a bit of regulation as they are tuned:
SR50 Variable Shunt Regulator 5-50V (8A) Kit_Power Supply Kit_Analog Metric - DIY Audio Kit
The hum is really acceptable (at low volume, it is almost not audible), but I would like to improve a little bit this point, maybe shielding the trafo and/or improving signal cables.
The card is an Ortofon 2M blue, MM, the gain is set to 42DB.
It has already played a lot of music, it was before integrated in a proto case.
This was the first time I was listening vinyl with a well done RIAA preamp.
I had before two relatively cheap RIAA preamp. No comparaison possible. The simplistic njfet riaa is far far better.
I is really bluffing and I can really enjoy my vinyls.
I am really happy with it.
@merlin: The TT is a Project Carbon with Ortofon 2M Blue.
@Salas: The extra boards are actually bad, they are suppose to be shunt regulators, but they get too hot. They are honestly only use as rectifier and a bit of regulation as they are tuned:
SR50 Variable Shunt Regulator 5-50V (8A) Kit_Power Supply Kit_Analog Metric - DIY Audio Kit
The hum is really acceptable (at low volume, it is almost not audible), but I would like to improve a little bit this point, maybe shielding the trafo and/or improving signal cables.
The card is an Ortofon 2M blue, MM, the gain is set to 42DB.
It has already played a lot of music, it was before integrated in a proto case.
This was the first time I was listening vinyl with a well done RIAA preamp.
I had before two relatively cheap RIAA preamp. No comparaison possible. The simplistic njfet riaa is far far better.
I is really bluffing and I can really enjoy my vinyls.
I am really happy with it.
Low esr is the opposite of resistance in the capacitor.
A circuit that is suscpetible to ringing needs RESISTANCE to absorb the energy in the initial pulse and subsequent ringing.
Miss out the resistance and the oscillation remains either undamped, or lightly damped.
A normal esr electrolytic smoothing capacitor has enough resistance to not ring on it's own.
Adding another capacitor and some cable/wire/leadout/trace inductance creates a 2pole circuit that is susceptible to oscillation.
Getting the damping resistor wrong is the BIGGEST mistake one can make. Adding a low esr capacitor is exactly that same mistake.
One needs to add a high esr capacitor where it is needed. And this is not usually on the remote located PSU, but at the amplifier circuit.
The PSU may not ring when hit with disturbing pulses. It would not need a damping resistor.
A PSU that does ring when hit with disturbing pulses must have a damping resistor added.
Quasimodo is a tool to let you measure the optimum resistor value for a ringing system.
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Yes its alright. You usually end up with 33-34V regulated on the FSP rail so there is 10V space.
Very good. The Tx periphery and the AC voltage cables are the hum field emitting components. The improvement measures you mentioned will be good moves. You may also turn the transformer so the secondary cables exit point looks to the left side.
R4 top near C1, R14 either leg, or C3 leg edge of board side, the same voltage. C3 leg easier to reach or grab a crocodile clip on.
Hi Merlin, are you measuring raw PSU Vout at the FSP board DCin terminals? What is the drop across R1x?
There is definitely something wrong there. If Q3x is pulling 3-4mA through R3x, and R3x is 9K1, then it should have a voltage drop of 27-36V, unless I am dropping a decimal place somewhere. If D1x is dropping 1.74V, that leaves 4.11V across R3x + VR2x. Even if VR2x is shorted, that means current through R3x is 4.11/9100=0.00045A = 0.45mA. Where is the current? 