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Old 22nd August 2005, 07:35 PM   #1
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Default Attenuation

Presently I am running my amp around .775VRMS the amp is rated 1.4VRMS in = 100WRMS out.
It is possibly a little underdriven but it sounds pretty good (better than any active studio monitors I've tried). Any more input voltage and It would be uncomfortably loud in nearfield position.
I am considering an ART DIO in place of Delta1010 D/A possibly get a bit more detail and free up a stereo bus.
The DIO has an output of about 6Volts. The ART tech says that I can use resistors in series. It is my understanding that resistors cause compression thus reducing dynamics. I need to drop from 6V to around 1V.
Any suggestions?
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Old 22nd August 2005, 07:51 PM   #2
AndrewT is online now AndrewT  Scotland
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Hi,
are you using analogue volume control or digital volume control?
I don't know your equipment.
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Old 22nd August 2005, 08:32 PM   #3
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Default Re: Attenuation

Quote:
Originally posted by argonrepublic
Presently I am running my amp around .775VRMS the amp is rated 1.4VRMS in = 100WRMS out.
It is possibly a little underdriven but it sounds pretty good (better than any active studio monitors I've tried). Any more input voltage and It would be uncomfortably loud in nearfield position.
I am considering an ART DIO in place of Delta1010 D/A possibly get a bit more detail and free up a stereo bus.
The DIO has an output of about 6Volts. The ART tech says that I can use resistors in series. It is my understanding that resistors cause compression thus reducing dynamics. I need to drop from 6V to around 1V.
Any suggestions?
Don't worry, resistors do not cause any compression (unless you try to force a kW through a 1/4 w resistor ).

Possibly the only thing you need to do is to turn down your volume control, but that depends a bit on your configuration. If you have a gain or buffer stage ahead of the vol control, that stage *could* be overdriven. If you go directly in on the vol control, that will not be a problem.

Anyway, you can always use a resistive divider 6:1 or something (the exact ratio is very uncritical). Like a resistor of 10k in series with the DAC output into your equipment, and a resistor of 1.5k from the equipment input to ground.

Jan Didden
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Old 23rd August 2005, 12:21 AM   #4
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Default attenuation

I have no volume control except in software which I seldom use. I may look into a vishay dale attenuator but for now it works great. If it seems too loud it's because of a problem in the mix or I am tired (time to shutdown). It has been a long journey getting the champagne sound on a ginger ale budget and the idea of using an attenuater makes me nervous. My room, amp, speakers and sub are almost perfectly linear in my chair at 85dB
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Old 23rd August 2005, 12:24 AM   #5
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Default attenuation

By digital volume control, do you mean something that will attenuate spdif digital stream?
That sounds like a great concept.
I would like that option but it is unfamilliar to me
Thanks
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Old 23rd August 2005, 07:22 AM   #6
AndrewT is online now AndrewT  Scotland
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Hi,
it sounds like you already have a digital volume control. But it is defaulting to an acceptable volume. Check that it never overloads the digital stages and run it as high as you can without overloading
Q. other than listening for distortion, is there any way to check that digital overload is not happening?
Now add an attenuator to the output of your source but at the end of the cable next to the amps. This keeps the cables into the amp short to preserve the treble.
As Janneman said you need a line resistor AND a resistor to ground.
10k for line is OK, a selection for ground connection or a 2k0 pot to give variable attenuation. Repeat this for each channel.
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