Hello--I have an isolation transformer that I obtained surplus years ago. At the time, I put a nice outlet on it and a couple caps for filtering. And back in the 1995-2000 period I had it as part of my (different from my current) system and did not notice any problems. Just last week I dusted it off and inserted it between my computer and the wall, sharing the same duplex wall outlet as my PS Audio Power Plant Premier. The Premier handles all the rest of my system: Tact 2.2 Mini Preamp, Tact S2150 Amp, Martin Logan Speakers. Turned on the system and the sound was completely distorted, with no upper frequencies at all! I shut it all down, removed the transformer, tried again and all was back to normal.
Here is a pic of the inside of the case.
You can see the unit is potted so it is impossible to see exactly where the wires are going. But, you can see how I have the transformer wired. The AC coming in connects to the two black wires going to the primary. The AC ground goes to the case. Coming out of the transformer are three pairs of yellow and black wires. I assume this means the transformer has three isolated secondaries. I connected two of the yellows and two of the blacks together and sent them to a large can oil cap with an AC-rated bypass cap and then up to the outlet. I connected the other yellow/black pair to the other side of the outlet. Also coming up from the transformer you can see three white wires. I assume these are going to three faraday shields. I connected them back to the case and the incoming AC house ground. You can also see I placed big ferrites on the ground and the AC going to the transformer's outlet.
Can anyone tell me what happened when I plugged it in and is there something wrong with how I have wired this? Curious because it showed up with my current system but did not arise with my old system.
Here is a pic of the inside of the case.
You can see the unit is potted so it is impossible to see exactly where the wires are going. But, you can see how I have the transformer wired. The AC coming in connects to the two black wires going to the primary. The AC ground goes to the case. Coming out of the transformer are three pairs of yellow and black wires. I assume this means the transformer has three isolated secondaries. I connected two of the yellows and two of the blacks together and sent them to a large can oil cap with an AC-rated bypass cap and then up to the outlet. I connected the other yellow/black pair to the other side of the outlet. Also coming up from the transformer you can see three white wires. I assume these are going to three faraday shields. I connected them back to the case and the incoming AC house ground. You can also see I placed big ferrites on the ground and the AC going to the transformer's outlet.
Can anyone tell me what happened when I plugged it in and is there something wrong with how I have wired this? Curious because it showed up with my current system but did not arise with my old system.
Bone--Probably cause I didn't know what I was doing?! The intent was to filter digital noise coming in from that side of the outlet. I believe my intent was to use one side for digital and the other side of the outlet for amp, preamp, etc.
The value on the big oil can is 5mfd and it is bypassed by two .047mfd oil caps. They are simply going across, or connecting, the positive and neutral wires coming up from the transformer secondary and to the transformer's outlet (where I would plug in the equipment).
The value on the big oil can is 5mfd and it is bypassed by two .047mfd oil caps. They are simply going across, or connecting, the positive and neutral wires coming up from the transformer secondary and to the transformer's outlet (where I would plug in the equipment).
GloBug--Yeah, I am suspect about tying those 2 outputs together too. I think I will undo that by just taping off the extra pair of output wires and then pull the capacitors out of there too. Will try hooking it up again after those changes and see what happens. I am just concerned I have the grounding screwed up.
Thanks Whizgeek. Yes, I only had my computer hooked into the iso transformer, and that of course has an SMPS. It seemed like the iso transformer might have been affecting the amp/preamp which was plugged in (via a PS Audio Premier) to the other side of the same wall outlet. The preamp has a SMPS. I have taken out the filtering and separated the three outputs of the transformer to three separate outlets and it seems OK now. When I took the transformer apart I could also see that it was rated for only 350va per output, so another problem was the computer (which is rated for 6.5 amps) was placing too high a draw on the transformer.
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