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4-ch gain stage - BOOST your 2x4 output voltage! 6 years 10 months ago #16996

  • CharlieLaub
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Ah you finally have your miniDSP 2x4 speakers up and running - they sound GREAT! You crank up the volume only to hear DISTORTION! Ahhh what is that? It's possible that you have discovered one shortcoming of the 2x4 and other miniDSP crossover products - in order to get the volume up you have to raise the signal level enough to cause clipping inside the DSP, in the digital domain. To play it loud, YOU NEED MORE GAIN!

A related problem can occur when you use a lot of boost in one or more stages of the crossover - the peak of the boosted signal can also exceed the maximum digital signal level. This is easily done if there is boost EQ, or a Linkwitz Transform equalizer in use.

In order to prevent digital clipping you have to back off the volume, but then the average level has to be much lower and quieter. YOU NEED MORE GAIN!

After experiencing this problem with a couple of my projects I decided to design a PCB to implement a four channel gain stage as an add-on to the 2x4 or any other single ended miniDSP output (this is not for balanced circuits). This is now available. More info can be found at:
www.diyaudio.com/forums/minidsp/237510-4...-11.html#post4152521

Any questions, feel free to contact me.

This will make your great miniDSP product even better and provide the analog headroom that you are missing.

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Last edit: by CharlieLaub.

4-ch gain stage - BOOST your 2x4 output voltage! 5 years 8 months ago #23230

  • SM10VB
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Please make the boards available again.

I play music with very low noise floor passages followed by full forte (huge dynamics), and I can't get my amp (Outlaw 750) to sing like it use to when I didn't use a miniDSP 2x4.

I've tried with and without preamp (Outlaw 975); with the miniDSP 2x4 jumpers in both positions (0.9 vs 2.0), and every combination.
Same results below:

0.9 = distortion, but dynamic headroom
2.0 = no distortion, but no dynamics

Perhaps a software-based DSP on Raspberry PI is in my future . . .

:( neil

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Last edit: by SM10VB.

4-ch gain stage - BOOST your 2x4 output voltage! 5 years 8 months ago #23365

  • CharlieLaub
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For those who would like to increase the voltage output of your miniDSP, or any other audio gear, I have released the design files and a bill of materials for a redesigned 4-channel gain stage board with onboard power supply. This can be configured in an A or B version, the latter without the power supply section. For an 8-channel version, use one version A board and one version B board together, supplying power to the B board via the DC power connector.

For more details, please see this thread at DIY audio:
www.diyaudio.com/forums/analog-line-leve...y-4.html#post4600044

This project is offered to the DIY community and is not intended for commercial use.

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