Layout problem. 5.1 system PREAMP DAC etc

[Alexontherocks]

Hello All! Hopefully you will be able to help me out with a problem I am facing.

I am currently building 5.1 system. All the modules are in my possession and so is the case. I just have to think of a very good layout because the number and size of the modules is just stretching the limits of the case.

Heere are some photos of the mock assembly.



THe back panel was drilled for another project so don't considers it... Here is a photo with the name and function of all the modules :



Under the preamp there is the initial rectifying board and caps. The red large 40000uf caps are actually oriented in the toher direction so that from the terminal I can feed the 2 AMP "strips" in series.

Basically a midlle bridge made of lexan will support the DC protect modules and allow for a symmetrical build.

On the left we have a toroidal (small 30/40W unit) close to the power lines. So will be the softsart module (but on the right).

Could this work? Arethe modules in the right place? Do you forsee any problems in terms of hum, hiss and buzz from power lines?

I already have tried a similar configuration in another smaller build


To keep everything simple the LCD will hang from the lexan lid.

Thanks!

[odysseybmx414]

Originally Posted by Alexontherocks

The bridges are 35A ( KBPC3510)

I did not fully understand your post... (my bad..running a slight fever )

Is there a real drawback in using the bridges' outputs in parallel? The load would be evenly spread across the 2 bridges and back to the transformers if the capcitor banks are connected in parallel would it not?

Anyways...here is a small picture..hopefully it is clear enough to show what I mean..

http://i365.photobucket.com/albums/o...008/bridge.png

Disregard last post.

You can do this (attached), and each channel will still be seperate, while not being dual mono strictly. I am still waking up this morning.

EDIT: corrected

OK, we're OT. I got your PM. Sorry.

[odysseybmx414]

Originally Posted by Alexontherocks

The red large 40000uf caps are actually oriented in the toher direction so that from the terminal I can feed the 2 AMP "strips" in series.

You don't mean that you are going to connect amplifiers in series somehow, do you?

[Nrik]

Alexontherocks
Here is what I mean

[Nrik]

...or even this

[Alexontherocks]

nono...I mean all the vcc+ and vcc- per side will be conencted to a common "rail" stemming from the final 40000uf capacitors..

I am concerned about the DAC being right on top of the transformer. Can it be an issue?

[Michael Bean]

It's not a good idea to have PCBs for audio above or below a toroidal transformer like the DAC in the picture, that area is where the strongest magnetic flux leakage radiates, it could induce hum.

Mike

[nigelwright7557]

If your really stuck you could put the transformers in another box.
Leave the smoothing caps and bridge rectifier in the amp housing.

[Alexontherocks]

I had the doubt.....I guess an external DAC is required then. Actually I was looking for a 5.1 USB decoder with some decent aesthetics. Suggestions?

I have another question.. How can I effectively have low/high input sets?

What I mean is that I would like to have 2 groups of RCA connectors. One group leads to the the preamp, and the other set leads directly to the AMP. Can this be achieved without an input selector? Is it as simple as having the leads from the preamp and from the RCA meet at the amplkifier input connector?

Sorry for the dumb questions...trying to figure this one out methodically

[Michael Bean]

If I understand your question, you could add a set of "Pre-out" and "Main-in" jacks and strap them together with short interconnects until you want to use them.

Mike