Modify behringer DEQ2496?

[sendler]

Originally Posted by paulebappie

I used the Jan Didden filter from that article and it works great.

I install AK4395 or AK4396 dac chip and run with no filter to keep the output impedance low. Just a high quality coupling cap. Sounds better with no filter.

[kalmi79]

Hy!

I started to modify to my deq2496. I killed the analog power line from the original psu. The original psu just give the 3,3V and the 5V to digital circuits. Both digital power line has got new bigger caps. Replaced the original two 1000uF and the two 470 uF to four 2200 uF.

The new analog psu have two traditional transformers. One is for the +/- 15V opamp power, and one is for the DACs and ADCs analog 5V power.

Every tansformer have dedicated rectifier bridge and many big buffer elkos. The original 7805 which was on the main panel, jumped out to the heatsink around the psu with the 7815 and 7915.

The two analog devices chip, and the ADC chip has got som extra heatsink, because their temperature was high.

This is the current state!

I will rebuild the total analog and digital inputs and outputs. The original backboard put the trash, except the RTA/MIC input and the auxiliary input, because this part is cut out of it!

I'll be back soon!

[Bernie7]

Very interesting kalmi79.

Look forward to your updates as you venture into modding the DEQ2496!

[gp4Jesus]

Awesome! Soooo... How about a schematic for the less gifted. I need to replace a blown PS in one of my DEQs.

Thanks tony

[dickmc]

Hi,

Just a couple of comments upon carefully reviewing this thread.

The idea of taking the output from a DAC directly through an output capacitor is a fairly common and successful audio mod.

It was initially known in 2004 as the 'Swenson' mod and can be found at a link on Page 2 of the included Squeezebox Mods Detail.doc which is contained in the attached SBox Mod Detail Word97 doc + Audio Pass Calcs Excel97.zip file.

There was a lot of discussion of this when the Slimserver Squeezebox V2 first appeared. The general consensus was that the DAC output capacitor bypass was a reasonably useful audio quality improvement. The attached zip file reports on my experience doing that mod. That attached zip file also usefully contains an Excel spreadsheet called High Pass Filter.xls which shows that for a 50K Ohm input amplifier even a 0.47 microFarad cap should work reasonably well.

Some of the links in the above document no longer work. Thus, also attached as squeeze audio mod overall view .jpg and slim install closeup high resolution.jpg are what that particular DAC output bypass looked like.

There does not appear to be any reason why the same kind of DAC output capacitor bypass would not conceptually work equally well with the DEQ2496.

Regards,
Dick

[tower2010]

Hello:

First, say sorry for resurrect this old thread, but I need some help.
I would like to make a capacitors upgrade on the DSP board (AKM chips, etc). I have several Sanyo OSCON SEPC 470uf 16V in my drawer. Do they have too much capacitance? The actual DSP capacitors are 10uf.
Would I have some problem with the experiment?

I'm new in the DIY, so sorry if the question it's very basic.

Best Regards