SMD DD-1 Gain Setting

[JoshuaKNelson]

I know how to use a DD-1 from the tutorials, but have a question about it. Does it matter what ohm load your going to be running at after the gain is set? I know when you use a multimeter to set your target output voltage to whatever it is going to be, you have to take the square root of watts times ohms and that gives you your power target. So will the maximum clean signal remain the same across all loads. .5 ohm, 1 ohm, etc? Assuming your amplifier is stable at those loads. Thanks for the help.

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[CarAudio.com - Hal AI Bots]

I know how to use a DD-1 from the tutorials, but have a question about it. Does it matter what ohm load your going to be running at after the gain is set? I know when you use a multimeter to set your target output voltage to whatever it is going to be, you have to take the square root of watts times ohms and that gives you your power target. So will the maximum clean signal remain the same across all loads. .5 ohm, 1 ohm, etc? Assuming your amplifier is stable at those loads. Thanks for the help.

Great question, Joshua! When using the DD-1 (or similar tools) to set your gain, it's essential to consider the impedance (ohm load) of your speakers because it affects the output voltage and how you are applying power from your amplifier.

1. Understanding Ohm Loads: The maximum voltage output from an amplifier is based on the load impedance. Ohm's law states that V = √(P × R), meaning that for a given power (P), if you change the resistance (R) by altering the speaker impedance, the target voltage (V) changes.

2. Setting Gain with Target Load: If your amplifier is stable and can handle different loads (like 0.5 ohm, 1 ohm, etc.), when you set your gain using the DD-1, you should do so at the impedance that will be the actual operational load in your setup. For example, if you will be running a 1-ohm load, you should perform the gain setting at that impedance.

3. Maximum Clean Signal: The maximum clean signal does not remain the same across all loads. With lower impedance loads, the amplifier can output more current, thus being able to produce a higher wattage. Hence, when you're using the DD-1, if you set it for a 1-ohm load versus a 0.5-ohm load, the clean signal level you can achieve will differ. The gain settings at different loads will not yield the same voltage output.

4. Stability Concerns: Always ensure your amplifier is rated for the load you're working with, as pushing it beyond its limits can lead to clipping or damage.

In summary, yes, it does matter what ohm load you're running at after the gain is set, as it significantly influences the voltage output and overall performance of the system. You should adjust your settings relative to the impedance you plan to use for optimal sound quality.

Feel free to ask more questions or if anyone else has experience with similar setups, jump in with your thoughts!

 

[Deiimos]

Granted I do not have a DD-1, the manual does not seem to mention anything about impedance, but yes, I presume it just lets you set the amp at maximum un-clipped signal, doesn’t matter what ohm load you run afterwards.

The SMD forum came up after a quick search and someone there said it did not matter about ohm load, it sets the amp like I mentioned above to its maximum un-clipped output the amp can provide.

If you are aiming for a lower power out of the amp than its maximum, then you still need to use a multimeter to set it at a maximum target voltage.

Say you have a clean 5000 watt RMS amp at 2 ohm, and you are running a 800 watt subwoofer at 2 ohm, if you set it with the DD1 you will have 5000 watts out of the amp at maximum volume. If you want the amp to do about 800 at 2 ohm instead of 5000 watts, you would need to use the multimeter to set the output voltage of the amp, with a proper test tone, to about 40 VAC.

If just wanting maximum output from the amp, just use the DD1.

 

[Doxquzme Premium Member]

AS noted, it does not matter what impedance you run that amp at in the end, as long as you're not running it below the wired load recommended.

The two specifications, load and unclipped signal, are mutually exclusive.