DX7 backgrond noise

DETOX · Joined: May 22, 2008 Posts: 143 Location: Germany

yo !

i finally got into programming my dx7 and even getting some nice results. the only thing i don't like about it (except the interface...) is a relatively loud background hiss. is this a common problem or does my unit just need to be cleaned somehow? how can i eliminate the problem?

thanks for your advice !

nobody · Joined: Mar 09, 2008 Posts: 1687 Location: Not here

I would love a DX7. I don't know anything about this problem, but I'm curious how it turns out.

xjscott · Joined: Apr 25, 2007 Posts: 232 Location: Appalachia

It's normal for them to be pretty noisy. They have a 12 bit output from a BA9221 DAC, which couldn't do better than 12x6 = 72dB S/N. Then they run that output through a voltage divider and tap those into all the inputs of a TC4066 quad bilateral switch and have a 4 bit control of it, which seems to be some sort of hack to get additional range out of the DAC or something, but would also add noise from all the switching.

v-un-v · Posted: Wed Jan 20, 2010 3:51 am Post subject:

Hiss is good! Since the advent of 24bit signals and the like, I have found my ears tiring faster than signals of old. I guess it's because I'm past the thirty-something sweet-spot? Shocked

nobody · Joined: Mar 09, 2008 Posts: 1687 Location: Not here

Speaking of the DX7, I watched "Monsters Vs. Aliens" last night. As far as animated kiddie flicks go, this was pretty funny even for adults. The POTUS went up the stairs to the robot drone to communicate with it via a DX7 and played "Axel F". Since that was the instrument actually used to play that synth pad, I was cracking up.

DETOX · Joined: May 22, 2008 Posts: 143 Location: Germany

xjscott · Joined: Apr 25, 2007 Posts: 232 Location: Appalachia

Assuming the best it might bring you from 60dB SNR to 60.5, or some such miniscule improvement. You're never going to have a clean signal with the 12 bit DAC.

Your best bet is to buy a DX7II, which can read the patches and has 16 bit converters. Otherwise accept it as is.

Of course I've not heard the noise on yours in particular, it's possible that you've got something wrong with it beyond the normal. Back in the day, when vinyl records ruled, those 12 bit converters weren't so bad and were better than the 8 bit converters on the Ensoniq Mirage sampler.