[boinger]

How precisely do i check my tree i disconnect it from the inputs only or everything ?

I did do the intial check before wiring up all my readings seemed ok i let it warm up for 10 minutes and all my Dc offsets were 0.0 - 0.1 mv

i assumed the .1mv is ok ?

Edit: im double checking it again after letting it warm up some

also when im measuering from input L / R to output L / R what exactly should i be looking for ?

 

[ShinyFalcon]

You can disconnect just the signal input and signal output on the Tree assuming you didn't hardwire/solder them. We only need the Tree working to make sure it works as intended. Your DC offset is fine.

We're checking to make sure that the resistance across the respective channel follows the volume. For example, when the volume is at 0%, the resistance across left.input & left.output / right.input & right.output should be a very high number. On any volume, the resistance of the left channel should be similar to resistance on the right channel.

If the volume is at 0, we expect very high resistance (for example, 50K ohms or infinity). If the volume is half way, we should see for example 30K ohms. If we maximize the volume, we should see low ohm. The higher the resistance, the lower the volume, and vice versa.

 

[boinger]

ok did that check im getting 1.821 k ohms regardless of volume setting im assuming the amp had to be on ?

on one board the reading is 1.821k ohm regardless of volume

second board its 1.821kohms at lowest

than 700~ ohms at full

you think my ribbon cable could be the culprit ? the top cable doesnt look like it sfully through but i cant seem to get it through

 

[ShinyFalcon]

If the power to the I2C shares power with the β22, yes turn it on.

I attached a picture hoping it makes measurements clearer. Clicky.

Did you build the Tree yourself? Maybe some pictures may help.

 

[boinger]

I did build the tree myself and yes thats what im measuring the readings are the same as the top...

im taking some pictures now will have em up soon

 

[boinger]

here is what im talkin about

_DSC6432.jpg photo - boinger photos at pbase.com

the board of which the ribbon cable is on top in that picture is the one that wont budge on the resistance stays at 1.82kohms

on both + and - rail

the board with the ribbon on the bottom changes from 1.82kohms to 700 ohms

 

[ShinyFalcon]

I would give the boards another look and see if you bridged anything or missed a joint, or maybe swapped orientation of a chip. Your ribbon seems to have the red stripe on the left, and according to TPA's site it should be on the right side.

In the meantime if you have software volume control you can tie your signal wires together (ground can go through Tree) and see if your β２２ is making some music. I think -60dB is okay; be careful, it can get VERY loud.

 

[boinger]

im redoing my sanity checks and if i have the molex plugged into the board (input) i am getting a different reading as compared to when it is unplugged? any reasons for this...

and when its plugged in on the opposing ground pad when im using it to measure dc offset the lowest i can get it is about 30 mv

but when i unplug the input it can get down to 0 mv

you think my source can be adding some voltage to the system my source is a buffalo 32 btw

 

[MrMajestic2]

Quote:

Originally Posted by boinger /img/forum/go_quote.gif you think my ribbon cable could be the culprit ? the top cable doesnt look like it sfully through but i cant seem to get it through

It looks like you dont have the cover on the connector which will push the cable down. You seem to be trying to put two ribbon cables on top of each other, it will only take one.

 

[boinger]

i had actually read somewhere that it can take 2 and thats how you were supposed to do the balanced jtree... but they broke =x so i just forced teh cable down on it it is working now i pushed a little harder and i am measuring dif resistances in both boards

now im just struggling with my dc offset issue

 

[johnwmclean]

Quote:

Originally Posted by boinger /img/forum/go_quote.gif im redoing my sanity checks and if i have the molex plugged into the board (input) i am getting a different reading as compared to when it is unplugged? any reasons for this... and when its plugged in on the opposing ground pad when im using it to measure dc offset the lowest i can get it is about 30 mv but when i unplug the input it can get down to 0 mv you think my source can be adding some voltage to the system my source is a buffalo 32 btw

Your source will add voltage, even more when music is playing, although 4Vp-p (balanced) is idle for the Sabre32.

 

[boinger]

i think i have narrowed down my bad sound quality problems i think it may be my cable from the dac to the b22... is it possible for you to make a cable so bad that it is all garbled... bass sounds like its ripping n generally teh sound is like gurggling.

 

[johnwmclean]

Quote:

Originally Posted by boinger /img/forum/go_quote.gif i think i have narrowed down my bad sound quality problems i think it may be my cable from the dac to the b22... is it possible for you to make a cable so bad that it is all garbled... bass sounds like its ripping n generally teh sound is like gurggling.

Check the continuity from the pins.

 

[boinger]

well if the continuity wasnt the same wouldnt it not play ?

i can hear music just not very well ... or do you think i may have the + - reversed ? will that even work ?

i did check the resistance and got .2 ohms for every pin

 

[johnwmclean]

Set your DMM to continuity beeper, make sure there is a beep between wires on either end of the cable. Ground to ground and signal to signal etc, if there is a gross error you’ll hear “no beep”. Check continuity between the opposing wires there should be “no beep” again if there is, the cable is probably faulty.
If this checks out maybe have a look at your Sabre32 outputs and make sure everything is ok there.