I bought this China clone "Marantz-7-M7-Tube-Buffer-Audio-Preamplifier-Pre-AMP-Board-KIT" I thought that it was just simple. I just don't want to throw it away, but what does 220v mean input meant in this? Does it go straight to the utility power? or is there a 220v in and 220 out transformer?????(Is this question stupid?)

This question is also about sound quality too? so please give me some advice how to power this properly.

Picture came from Ebay or Alibaba

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    \$\begingroup\$ Chances are that you need 6.3 VAC (for the 6Z4), 12.6 VAC (for the 12AU7 and 12AX7), and 220 VAC (for the plate voltages.) Though it's possible that the plate voltage must be DC. I can't tell from just the picture. \$\endgroup\$ – jonk Apr 19 at 8:46
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    \$\begingroup\$ Don't suppose it came with instructions or a data sheet, did it? Looks like it needs three supplies and as there's a very good chance of touching the input/output connections you'd need a transformer for isolation. \$\endgroup\$ – Finbarr Apr 19 at 8:48
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    \$\begingroup\$ Not a bridge rectifier, the 200-260v AC is rectified by the pair of 6Z4s schematic here \$\endgroup\$ – Michael Harvey Apr 19 at 11:07
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    \$\begingroup\$ This is not a project for a beginner. \$\endgroup\$ – Michael Harvey Apr 19 at 11:21
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    \$\begingroup\$ Markieboy, the type of transformer I am talking about, for vacuum tube equipment, that provides HT for the tubes, and also 6.3 for the heaters, is very common. They are marketed for people who build their own equipment. This UK company ships worldwide. You need to know the HT and heater current you require. Link here Secondaries of around 200-250v plus standard 6.3v heater are fairly normal, it's the 12v that's odd. Maybe a separate small one? Or a transformer with 2 x 6.3v outputs, put them in series? Or center-tapped 12.6v. \$\endgroup\$ – Michael Harvey Apr 19 at 17:37

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