pcm63pk in piggy back mode.

Status
Not open for further replies.
Jump to Latest
#47
What do you think about stacking a DAC like akm with diff. voltage out?
Click to expand...

There is an effect in making DELTA SIGMA DAC parallel.
The voltage output can be easily summing up by the resistance.

if 4 paralling up voltage output DA chips
load-resistance in 1/4 of the specified value
To protect, it makes a low-resistance (47ohms to 100ohms)series in each DAC chips.
summing point is a load-resistance
a loss by the resistance but the effect which depends in parallel exceeds.


it's my latest project, 4paralled CS4340 with resistance summing up
and 4paralled CS4331 test head
 

Attachments

  • cs4340.jpg
    cs4340.jpg
    51.7 KB · Views: 778
#48
fumihiko

So you you think the stacking of the single ended cs chips will work?
I don't see a pdf on there website for the 4330.

Here is what I am trying to stack:
3 images, from the akm4383pdf

first one:
 

Attachments

  • specakm.jpg
    specakm.jpg
    90.4 KB · Views: 632
#53
My experiences

OK, tried the mod (using Rudi's method of using an adaptor)and have had it running for a couple of days now.
Initial impressions are of:

More detail, especially very low level stuff like the sound of a singer's dry lips parting at the start of her singing or the sound of other band members preparing to play (the double bass being moved etc) or a myriad other little details. Basically, this info was below the systems noise floor before. So maybe there is some truth in the square-root of 2 enhancement...

More layering-It has become easier to follow different layers-seperated yet integrated with the whole.

More depth and staging.

The big issue here is that the volume virtually doubles and one has to try to adjust for that in order to perofrm meaningful A-B comparisons.

Not sure about using 3-maybe someone else can post their experiences with more DAC's?

FWIW,
Ryan
 
#55
Jusy had a look at data sheets. PCM56 is 16 pin for a start. Ryan is kindly having a look at it with a view to providing some suggestions. I would welcome input from anyone else who would care to have a look. Strangely enough, PCM56 does not seem at all difficult to find. Does anyone think it will make much difference if the standard grade part is used? (PCM56P)
 
#56
Pcm 63 piggyback mod problem

Hi

I`ve modded a pcm63k by disabling pins 1,3,4,9,10,23,24,25 and adding oscon 10V 4.7uf caps betweeen pins 1>28, 3>7, 4>7, 23>7 and 24>7 (7 is ground). w/ the modded chips installed, my dac frequency lock light glows, but there is no click from the Siemens relay and the mute fails to disengage.
also...
w/o the oscon caps installed, the chip piggybacked straight onto my existing pcm63 produced sound, but there was considerable dc offset, the woofers moved in and out w/the volume control (muusic not playing) and produced a muffled sound

Any suggestions much appreciated.

Bill
 
#57
What make is the unit? If you have an opamp based i/v stage disabling pins 9 and 10 isn't a good idea, if you are not certain the internal feedback resistor is not in use. Also check pin5. If it is not connected or grounded it changes the idle point of the dac and that may cause a DC offset further down the line.
 
#58
Thanks for the quick response - the dac is a Polyfusion 800. I`ll check pins 5,9 & 10 - i suspected it might be the latter 2 as the schematic for the chip shows them directly leading to the output stage (BB2604`s, in my case). Will post back w/results.

Bill
 
Status
Not open for further replies.
Top Bottom