Hello All,
I am about to build Balanced Mains Filter (by Ray - 6h5c) Ray's Audio Page
For those in the know, how does (if at all) component values relate to the power of the transformer.
Ray's project is built arround 500 VA transformer. Would any of the values of caps/resistros change if I want to use smaller (200 VA) or larger (2kVA) transformer.
Many thanks for any input.
Best,
Goran
I am about to build Balanced Mains Filter (by Ray - 6h5c) Ray's Audio Page
For those in the know, how does (if at all) component values relate to the power of the transformer.
Ray's project is built arround 500 VA transformer. Would any of the values of caps/resistros change if I want to use smaller (200 VA) or larger (2kVA) transformer.
Many thanks for any input.
Best,
Goran
This "Balanced filter" is dangerous as the earth connection will make an effective 2 phase output with the neutral line at half mains potential!
The neutral line will become half mains potential.
The neutral line will become half mains potential.
Dear Jon,
Thank you for your input. However, my query was related to the interaction of the components in a given circuit, design of the circuit is (at the moment) irelevant.
Best,
Goran
Thank you for your input. However, my query was related to the interaction of the components in a given circuit, design of the circuit is (at the moment) irelevant.
Best,
Goran
Well, the project as shown handles slightly more than 2A in/out. Now if you load a 500VA transformer with 500VA it will likely have dropped a little voltage, so I would derate the filter (isolator really) and only load it to about 70-80%.
Actually beside a few small caps this is more a DC blocking and isolation circuit. For it to be called a filter it should have some series inductor or at least resistance to create a filter with the capacitors.
Like a line fuse, the filter/isolation transformer must not be loaded down stream by anything higher than the rating of the fuse/isolation transformer. So if a 1kW amp is down stream, you must use a >> 1kVA isolation transformer. If a 10W preamp is down stream, a smaller 100VA isolation transformer is likely much better (smaller has less stray capacitance, loads the line less, cheaper, etc).
Btw Ray modifies his transformer by adding turns to the primary. If doing so please distribute the winding evenly over the entire toroid core. No need to unbalance a 'balanced' filter. If output voltage is higher than input, it is not a 1:1 transformer. Add some series fitler components and drop some voltage that way, which would also serve to create an actual filter.
Actually beside a few small caps this is more a DC blocking and isolation circuit. For it to be called a filter it should have some series inductor or at least resistance to create a filter with the capacitors.
Like a line fuse, the filter/isolation transformer must not be loaded down stream by anything higher than the rating of the fuse/isolation transformer. So if a 1kW amp is down stream, you must use a >> 1kVA isolation transformer. If a 10W preamp is down stream, a smaller 100VA isolation transformer is likely much better (smaller has less stray capacitance, loads the line less, cheaper, etc).
Btw Ray modifies his transformer by adding turns to the primary. If doing so please distribute the winding evenly over the entire toroid core. No need to unbalance a 'balanced' filter. If output voltage is higher than input, it is not a 1:1 transformer. Add some series fitler components and drop some voltage that way, which would also serve to create an actual filter.
My dear always faithful friend,
Many thanks for your observations but in all of my dumbness I still don't get it.
I believe the extra (swicthable) winding on the primary winding only serves to compensate for over-voltage, consequently bringing secondary voltage down by a notch.
My initial question was would transformer power rating influence values of other (resistance, capacitance etc...) components in the circuit.
I am trying to learn something here. I wish Ray would step in but I still haven't figured out how to get in touch with him. It is his design anyways, I believe...
Best,
Goran
Many thanks for your observations but in all of my dumbness I still don't get it.
I believe the extra (swicthable) winding on the primary winding only serves to compensate for over-voltage, consequently bringing secondary voltage down by a notch.
My initial question was would transformer power rating influence values of other (resistance, capacitance etc...) components in the circuit.
I am trying to learn something here. I wish Ray would step in but I still haven't figured out how to get in touch with him. It is his design anyways, I believe...
Best,
Goran
If you mean the shunting elements? They should not care. They will react to high frequency spikes, which are present or not depending on your power supply line and load. Independent of transformer size. Transformer capacitance and leakage inductance varies with transformer size, usually capacitance gets worse on bigger sizes.
The L2/C8 combo is interesting, with resonance at ca 41kHz, not sure if they are a good idea. Those values might be good to experiment with depending on your situation, if you want them at all.
The L2/C8 combo is interesting, with resonance at ca 41kHz, not sure if they are a good idea. Those values might be good to experiment with depending on your situation, if you want them at all.