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Cynosure
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Joined: Dec 11, 2010 Posts: 966 Location: Toronto, Ontario - Canada
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Posted: Fri Jul 07, 2017 5:17 pm Post subject:
Stereo to Mono |
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1. When mixing a stereo signal into mono should the amplification be 0.5 since the two signals have the potential to be twice as loud once mixed?
2. What power supply voltages should I use for a line level signal? I am thinking of using a TL072. _________________ JacobWatters.com |
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blue hell
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Joined: Apr 03, 2004 Posts: 24079 Location: The Netherlands, Enschede
Audio files: 278
G2 patch files: 320
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Posted: Fri Jul 07, 2017 5:46 pm Post subject:
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1 - yes and no and no .. to avoid clipping at all cost (for fully correlated signals - or split mono) use 0.5 ... however when the signals are uncorrelated (noise) you'd want to use 0.707 to keep the perceived volume level the same .. however when the signals are anti-correlated (like a left / right ping pong) you'd want 1 even. For music its somewhere in between usually ...
0.707 is the square root of 0.5 .. as to why .. it's all about throwing dice and counting .. erm statistics.
Ideally add a volume control
Ideally add a cross fader too
2 - a couple of volts of headroom, or maybe 3, should give decent performance .. as line levels are around a volt and a pibolar bower subbly is ideal .. +5 and -5V .. that would leave some headroom too. _________________ Jan
also .. could someone please turn down the thermostat a bit.
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Cynosure
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Joined: Dec 11, 2010 Posts: 966 Location: Toronto, Ontario - Canada
Audio files: 82
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Posted: Fri Jul 07, 2017 6:38 pm Post subject:
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Thanks Jan! That should be easy to do. I will aim for 0.7 and use a trimpot to set it manually. _________________ JacobWatters.com |
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PHOBoS
Joined: Jan 14, 2010 Posts: 5591 Location: Moon Base
Audio files: 705
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blue hell
Site Admin
Joined: Apr 03, 2004 Posts: 24079 Location: The Netherlands, Enschede
Audio files: 278
G2 patch files: 320
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Posted: Sat Jul 08, 2017 3:54 am Post subject:
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Is easy to do PHOBos, just before order exchange p&b keys
what i forgot about the 5V ... that is a practical minimum of course .. the maximum is in the datasheet .. and then just pick what suits you. _________________ Jan
also .. could someone please turn down the thermostat a bit.
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Cynosure
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Joined: Dec 11, 2010 Posts: 966 Location: Toronto, Ontario - Canada
Audio files: 82
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blue hell
Site Admin
Joined: Apr 03, 2004 Posts: 24079 Location: The Netherlands, Enschede
Audio files: 278
G2 patch files: 320
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Posted: Sun Jul 09, 2017 5:11 am Post subject:
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TL should be stable without the lil caps.
... But I would not do the volume control pot in the feedback ... at the very least connect the wiper to one of the sides .. as otherwise when the wiper has bad contact things will get LOUD.
... But also .. you will need wires from the opamp to the pot and you may introduce unwanted signals this way being picked up by the wires .. or introduce inductance when the wires are longish. Better to do do the 'traditional thing' .. with a pot after the first opamp .. when you do not want to allow the signal to go to zero add a resistor between the pot and the ground. _________________ Jan
also .. could someone please turn down the thermostat a bit.
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PHOBoS
Joined: Jan 14, 2010 Posts: 5591 Location: Moon Base
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Cynosure
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Joined: Dec 11, 2010 Posts: 966 Location: Toronto, Ontario - Canada
Audio files: 82
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PHOBoS
Joined: Jan 14, 2010 Posts: 5591 Location: Moon Base
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Cynosure
Site Admin
Joined: Dec 11, 2010 Posts: 966 Location: Toronto, Ontario - Canada
Audio files: 82
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Posted: Wed Aug 16, 2017 9:40 pm Post subject:
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Luckily, the radio/reveiver section worked fine.
I had to change some of the speakers. It has on old electrostatic tweeter that still works.
I had to do some work on the turntable, which was kind of a new and interesting project because it is all mechinal and I am used to electronics.
I also updated the ungrounded plug to a grounded version.
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RCA jack hang out the back - sloppy but simple. |
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_________________ JacobWatters.com |
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