| annex666 |
I'm in the process of making an integrated dual mono amp with circuit boards care of ESP.
As the design of the beast in question entails there to be 3 toroidal transformers inside the same box as the pre-amp and power amps I want to employ internal shielding as well as earthing the case.
I've already decided to shield the pre-amp in it's own aluminium box inside the main case as this is probably the most prone to interference. I'll also be using a "zero volt line" - as described on the ESP website.
One final thing I was wondering about was sheilding the toroids?
Would it be benificial for me to source individual boxes for them for inside the main case or could I wrap foil around them or would this break the continuity of the lux lines?
Any help would be appreciated, also ideas how to reduce any kind of interference.
:confused: |
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| MRehorst |
Be careful about how you box the toroids. Most toroids mount with a bolt through the center and a large metal washer on top. If you put the thing in a box, and the box and the bolt connect to a conductive chassis, you are making a very low resistance, shorted, 1-turn secondary and it will blow fuses (assuming you use them- you are going to aren't you?) or destroy the transformer.
Make sure there is no way the bolt can come into electrical contact with the shield box.
MR |
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| Elso Kwak |
Hi Annex666,
Better use two chamber or split bobbin transformers in the preamp. I have researched this in my DAC and preamp and the latter type of transformers gave better sound. Not a day and night difference but worth the effort. To mininise hum pickup I placed the trannie for the preamp in a separate box. In the DAC hum is not a issue. The twochamber transformers have much <I><B>lower interwinding capacitance</B></I> making transfer of hash and garbage from the mains to the circuit more difficult;) |
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