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Reference DAC Module - Discrete R-2R Sign Magnitude 24 bit 384 Khz

spzzzzkt

Disabled Account
2005-05-21 4:24 am
Melbourne
oh carp... parcel is stuck in customs due to problems with documentation.

"The number of packages does not match the invoice, waybill, or label. We're working to resolve this discrepancy."

Given the order is meant to be one box, I'm baffled. a waybill without a box? or more boxes than intended?


ADD: It had been sitting with an exception all morning, but immediately after posting, the UPS site updated to say it's been released from customs.
 
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Initial listening impressions of the DAM1021-01.

Disclaimer - I have only been listening to this dac for about an hour, at the most, and not very intensively. No A/B reference testing yet.
My test setup - Squeezebox Touch USB out->Amanero I2S->DAM1021-01 onboard xlr out->Questyle CMA800R solid state headphone amp->Audeze LCD-3 (non Fazor vers.) I consider my LCD-3 rather laid back, which I like. And I’m also normally a tube fan. So now you’re warned.

No distortion whatsoever on low level solo piano music (sustained notes) like my old unipolar r2r dac had.
Very detailed, as in micro details - quite unsuspected from this type of dac.
Sound is quite harsh to my ears - dac probably needs to settle and get some more hours to burn in. Only about 24 hours at the time of listening.
Very up front sound signature, forward, in-your-face picture. Not very relaxed. (Which I quite frankly hate).
Wiiiide sound stage. Not much going on center. Very left/right orientation w. some music, at times it sounds almost as something is a little bit out of fase. Sound coming almost from behind rather than in front.
Focus on upper mid and treble. Less bass and oomph. Which is why I at first didn’t bother to try it with my electrostatic Sennheiser HE60 & Stax hybrid amp, as these stats are focused on the mid- & upper region.
A short click is heard when changing between tracks w. different sample rate and the FIFO takes a while to settle thus cutting off the beginning of the track. Sometimes the FIFO makes the music fade in lasting 1 second or so.
Apart from this the timbre of the instruments sounds right w. some air/spacing between instruments. Seperation could be much better though, like r2r dacs normally present.

Okay, so just by chance I swapped in my Senn stats and the Stax amp that has a tube output stage. (balanced input).
Accidentally I played a rock music track by Beck from Guero album (a music genre that not normally suits the Senns IMO). Lo and behold. All of the above impressions didn’t apply anymore!
Frequency spectre was much more linear w. a bass punch I’ve seldom heard from this setup. Lovely airy separation between instruments, more holographic like the r2r’s I’m used to. More laid back presentation. Quite relaxed.
In short, the whole system was playing MUSIC. Effortlessly.

Is this a synergy thing? Shifting from dynamic headphones(speakers) and solid state to stats and tubes.

Still, it’s VERY early days but this dac definitely has got potential.

Is there a default filter selected? Default oversampling & upsampling?

We're you using the same output off of the DAM 1021 in both cases? It seems like it, first you say XLR out, second time balanced out, which is the same, right? I wouldn't expect a big "synergy" difference, since both headlamps are SS. Possibly overloading in the first case? Or impedance issues? In any case, it's great that you got such a "musical" output. I've got my board in now, but still need to set up for input and power, so I'm a few weeks away at my slow pace.
 

spzzzzkt

Disabled Account
2005-05-21 4:24 am
Melbourne
"The number of packages does not match the invoice, waybill, or label. We're working to resolve this discrepancy."

I am starting to think this translates to: "The package is listed as being part of the shipment, but we have NFI where the physical box actually is. Hopefully one of our staff will find it soon". Package was meant to be delivered this morning but now says "Scheduled delivery information is not available at this time. Please check back later."

They are nicknamed OOOOOPS with very good reason. grrrrr.
 
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TNT

Member
Paid Member
2003-04-26 10:25 pm
Sweden
I have a new version of the FPGA firmware where the mute function should work much better, could somebody with the Amanero USB interface please try it ?

1) Download and unzip attached file 1021fpga_090.zip
2) Connect the dam1021 serial port to a PC serial port with a terminal program (I use HyperTerminal), set for 115200,n,8,1, no handshake.
3) Enter uManager on dam1021 by typing "+++" followed by a 1 second pause.
4) Type "download" and start sending file from the terminal program using 1K X-modem protocol.

Power cycle when done, you can verify by entering uManager again, FPGA revision should then be 0.9.

Did you fix the swapped left / right channel issue? Or maybe you want to change the drawing / silk? :)

//
 
Assuming I use a DC power supply, I guess I need 2,5W for each of the symmetric supply voltages and 5W overall?

Thanks
Sven

The positive supply draw about 3 times as much current as the negative, in my test here I have around .18A / 0.06A at 10V input, total about 2.4W, the current is almost independent of input voltage.
 
SebastianL,

I could not help but think you are describing the effect of incorrect polarity.

If you have a way to invert polarity (which everyone should) I bet that recording might sound just fine.

Wish all resolving gear would include a polarity switch!

This DAC not having a balanced output makes it impossible to change polarity with a switch on the output.

Maybe your player has this function.

Maybe SOEKRIS can incorporate this into the firmware? Sure would be a boon to enjoyment of ALL recordings.

I doubt that is the problem as I have been playing the same couple of albums with a number of different gear. Also if the material is 180 degrees phase inverted I would get a sensation of nausea which I don't. (Believe me, I've tried that several times having worked as a pro audio technician).

Edit: I'm also feeding the dac board AC, and using the same signal cables I've used for years, so I hardly think I'm having a polarity issue.

A polarity function on the dac would be a good idea though.
 
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I was asked by a friend who has an XMOS OEM board which requires external master clock if that could be made to work the the DAM1201 - is there a way to send the clock to the USB to I2S board? (link to the board: OEM board - I2S over USB Audio )

One of the pin of the main DAM1201 connector is a MCLK output !

But this is not very usefull: such links needs a good coax and also the connector is important. Here the lacke of uf-L addes connectors on the DAC makes hard the connection work ! To rephrase it, you risk to have issue quality just with the plug you will add to your MCLK !

that's my understanding but at least I'm not a electronic technician ! I have a lot of hassle to make my independant wires to connect the I2S and SPIDF and avoid shorts ! Why such a connector on the DAC !

I really think a revision board will need more serious connector for the MLK output, the 50 ohms I2S like the 75 ohms SPIDF (layout for a PE or NEvawa pulse transformer... this connector really complicate things as already said there is no official standard for classing the outputs.

Is this pcb you link needs the external 5V or does it accept the voltage provided by the USB as well ! (as the DAM1201 has an isolator). Has it a 3.3 V output for the isolator chip of the DAM1201 ?
 
We're you using the same output off of the DAM 1021 in both cases? It seems like it, first you say XLR out, second time balanced out, which is the same, right? I wouldn't expect a big "synergy" difference, since both headlamps are SS. Possibly overloading in the first case? Or impedance issues? In any case, it's great that you got such a "musical" output. I've got my board in now, but still need to set up for input and power, so I'm a few weeks away at my slow pace.

Yep, using the exact same onboard balanced XLR output in both cases. The only analog output I have so far.
The Stax 006t amp is a hybrid amp w. a tube output stage. Might make a difference.
Overloading or impedance mismatch might also be a possibility. Have to check that.

... There is also onboard balanced output drivers that can drive high impedance (>= 300 ohm) headphones directly.
 
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Could someone explain to me please in the SE spidf shematic Soren provides (I linked like Soren did the links in first page to open it fastly on the other thread as well) where the 1.2 V goes ?

On THE J2 1.2V ? Is this an input 1.2 V on J2.... I don't really understand what is the J2 utility ?

So J2, 1.2V pin to J3 IN- with a 1K R between. And between IN- and a J2 GND via I putt a 0.1 5 mm pitch legs MKT ?

Am I ok ?

So a two cents question as well : no problem to feed this 1.2V if SPIDF is connected to a device without playing (but switched on) while the USB entry is playing ? The FGPA will connect only the input where it sees a clock signal ? So I don'care if the LVMS for the SPIDF and the isolation chip for the USB are both powered as far as I don't inject in the same time two playing signals. It's to know if the DAM1201 can be connected to two different sources without deconnecting the wires !
 
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