{"id":171,"date":"2017-02-12T19:31:51","date_gmt":"2017-02-12T17:31:51","guid":{"rendered":"http:\/\/zadvitsky.com\/?p=171"},"modified":"2019-02-05T02:17:06","modified_gmt":"2019-02-05T00:17:06","slug":"tape-saturation-compressor","status":"publish","type":"post","link":"http:\/\/zadvitsky.com\/index.php\/studio-devices\/tape-saturation-compressor.html","title":{"rendered":"Tape saturation compressor\/limiter in a wooden box"},"content":{"rendered":"

Long time ago a friend of mine asked me if I could build something like this:<\/p>\n

\"KIT-012\"<\/a><\/p>\n

Link to the original product: https:\/\/www.diyrecordingequipment.com\/products\/15ips-colour<\/p>\n

But we ended up with this wooden 19-inch 2-channel studio box.<\/p>\n

\"X3dkKEOg-0s\"<\/a><\/p>\n

\"16343899_10206122514620146_1761307310_n\"<\/a><\/p>\n

When I first looked at the schematic I thought it was a joke.<\/p>\n

\"tapesat2a\"<\/a><\/p>\n

The diode clipping stage looked like one in a distortion pedal. What could people possibly make out of it? A\u00a0guitar overdrive pedal? Then I looked at a\u00a0video from diyrecordingequipment.com<\/span> and realized that maybe this very soft clipping effect could be useful for something. I came out with the following schematic. So let us look at the schematic more carefully.<\/p>\n

\"\"<\/a><\/p>\n

A tape saturation limiter consists of:\u00a0balanced input, a high-frequency boost, a soft diode limiter(saturation) high-frequency frequency attenuator that restores frequency balance back, and balanced output. The high-frequency boost is needed to make the effect softer. Low-frequency clipping sounds are very fuzzy.\u00a0I’ve put the electric scheme inside a 19-inch wooden box. The device has 2 channels with the op-amp based balanced input and output. It is charged from\u00a02 soviet vu-meters driven by \u041a157\u0414\u04101 chip.<\/p>\n

\"\"<\/a><\/p>\n

Here is the first version with germanium diodes made from transistors. Such diodes appeared to have a very different voltage drop and later I switched to normal germanium diodes.\u00a0\"\"\"\"<\/a>\"\"And the final version:\"\"<\/a>\"\"<\/a>\"\"<\/a>\"\"<\/a><\/p>\n

I have decided to increase the number of diodes and to put a switch that would allow you to use different numbers of them. With 3 buttons we have 3 regimes:<\/p>\n

    \n
  1. soft saturation \u00a0 \u00a0 \u00a0 \u00a0 \u00a0– with 2 silicon and 16 germanium diodes for each channel;<\/li>\n
  2. medium saturation – with 2 silicon and 12 germanium diodes;<\/li>\n
  3. hard saturation \u00a0 \u00a0 \u00a0 \u00a0– with 2 silicon and 8 germanium diodes.<\/li>\n<\/ol>\n

    Besides the clipping control buttons there is another one for switching the vu-meter from input to output and 2 more buttons that make the left channel settings to be a master channel\u00a0which controls both channels.<\/p>\n

    A power supply was made using LM317\/337 voltage regulators that provide\u00a0+15\/-15 V, low Z Hitano ESX capacitors and Schottky diodes with a film capacitor in parallel to them.<\/p>\n

    Here is the audio demo of this wooden beauty:<\/p>\n