Novation Supernova II – DAC Replacement
Having owned a Novation Supernova II for some years I was slightly alarmed to hear of a fault that arises from time to time with the keyboard and rack versions. It concerns noise & crackles coming from the the Headphone & Main Outputs.
Read more information about the fault here:
I had recently thought of selling it as it gets little use these days. If I was to sell it on then I wouldn’t want this fault appearing shortly after the new owner takes possession of it. Things would get kinda awkward.
So, the easiest way to clear this up is to replace the could-be-faulty-in-the-future IC for a new one to ensure the unit performs as it should – for the new owner or myself.. still undecided to sell or not!
The IC in question is U45 on the main PCB – a Cirris 4391KZ 24Bit DAC.
Of course with the Supernova II being out of production for many years the IC itself is a little hard to come by. There’s always the eBay option with most of these are coming from China. Experience has taught me that ICs from the Far East can be hit-or-miss. There are a lot of counterfiet ICs going around and I have been burnt before with a dodgy batch of SRAMs.
Now the Cirris 4391KZ is long obsolete and reliable vendors do not stock it anymore. But there is a newer version – the 4391AKZZ. Happily the new “AKZZ” version behaves like the old version the “KZ”. The extra “A” denotes a newer version, and the extra “K” means it is ROHS compliant.
A quick Google brought me to DigiKey where this IC can be bought for around £7. They sell these in singles so you are not forced to buy 10 or so.
The device can be seen on DigiKey’s site here:
All that is left to do now is whip off the old one and place the new one. Time for a bit of PCB rework!
Inside the Supernova II
The photo below shows the Supernova II main PCB with no less than 9 DSPs. To put this processing power into perspective compare this to the K-Station with its single DSP, and the KS4/5 Series with their 2 DSPs.
Prepare the Patient!
To remove the old DAC I will be using a Hot Air Rework station. Basically this unit blows super-heated air on to the componment and surrounding board and melts the solder that holds the component to the PCB. When the solder melts the component can be lifted off with a pair of tweesers.
The surrounding components have been generously coated with Kapton tape to shield them from the heat. This tape behaves much like ordinary sticky tape but can withstand much higher temperatures. One point to note about Kapton tape is that it is not a good insulator – it will let the heat pass through so it is best to layer it on with air pockets between each layer.
With the new DAC in place the Kapton tape was removed and the unit was re-assembled.
The audio did not sound any different than before as the old DAC did not exhibit any signs of the crackling fault. It may seem a fruitless task to change out the DAC but for the small cost of £7 and about 30 minutes work time it should keep the Supernova II ticking along for a few years yet.
I tend to get attached to the things I have worked on so I guess I’ll hang on the the SN2 for a while yet.. unless I get an offer I cannot refuse 😉