Fully real balanced DAC?

[elviukai]

Hi I would like to ask few questions? Thay can be pretty silly so don’t shoot me at once

I have dac. it has both balanced and unbalanced outputs.manufacturer claims that it is -PUSH PULL FOR EACH CHANNEL AND FULLY BALANCED DIGITAL OPERATION. It has 4x burr brown pcm 63p-k . physically it is 2 dac players inside. When I disconnect second plate with 2x pcm 63 everything works fine except line output is less stronger. and the bass is event better(with 4x pcm it is too boomy and even dominant) I LOOKED IN HOW THEY CONECTS- 1 MAIN BOARD (WITH RECEIVER AND DIGITAL FILTER AND OTHER STUFF) connects to RCA left right, ground and also to balanced + and ground.
The other board(pcm63p-k and all analoge stage stuff . I think This board also can work as separate dac if I feed them and add receiver and digital filter) outputs goes to balanced - and balanced gnd.



I am about to redesign my dac to pass labs Dac 1. so question is WHAT IS REAL BALANCED OUTPUT? HOW IT WORKS? And of course what should I do to convert my dac to pass labs d1,which is balanced design. II have heard that there are true balanced designs and untrue. Somehow I think that this is the way pcm63 conect. And my dac seems have different conection than pass labs. thee are lot of operationa amplifiers - 16 pieces per whole dac. I have heard somehow balanced output can me make with opa /Or I am wrong?
Will wait any advice.. I am about to mach dac to balanced aleph x which itself are balanced design and gives lower discortion when feeded in balanced mode. also 4x pcm would be benefit because I run dac directly to amp via pasive attenuator

 

[phn]

This should answer most of your questions Balanced Line Technology

 

[elviukai]

thanks, I read all page (and will try once more time)and what I am understanding that I do not understand- I cant read schematic and compare www example to my dac..

 

[phn]

Just ask again if needed. Somebody else will have to answer, though.

 

[giulio]

I am about to redesign my dac to pass labs Dac 1. so question is WHAT IS REAL BALANCED OUTPUT? HOW IT WORKS? And of course what should I do to convert my dac to pass labs d1,which is balanced design. II have heard that there are true balanced designs and untrue. Somehow I think that this is the way pcm63 conect. And my dac seems have different conection than pass labs. thee are lot of operationa amplifiers - 16 pieces per whole dac. I have heard somehow balanced output can me make with opa /Or I am wrong?

thanks, I read all page (and will try once more time)and what I am understanding that I do not understand- I cant read schematic and compare www example to my dac..

Tough to redesign anything if you do not know where you start from and cannot read where you want to get....

 

[rfbrw]

Tough to redesign anything if you do not know where you start from and cannot read where you want to get....

As if that ever stopped an audiophile.

 

[elviukai]

Tough to redesign anything if you do not know where you start from and cannot read where you want to get....

I can read pass labs dac 1 shematic, I can read audionote dac 3 siganuture schematic, amps schematic. but I CANT read parasound dac shematic. it is so complex that I copletely lost myself. there are for example 6 pin of pcm 63k I output. this is analog current signal. but it goes to firs OPA, to second ,then returns and then to third, fourth again returns and I completely lost signal. also I am wonder how audio data output from resyver(or digital filter) has only one pin but have 2 chanels. I quess its digital. but current output of pcm also is one pin. ?? how to knew when pcm63 is just paraleled and when push pull ?

As if that ever stopped an audiophile.

exactly



unknowlwdge in electronic audiophiles (like I do) want soliutons not desisons. when they do not get desison from prefesionals they stops. for a moment. and then try to build. and always here will be smoked fets( in this case pair or four pcm63p-k)

I have pass labs dac pcb and layout of output stage , I can build. but how many I need to build for balanced mode 2 or 4? and biggest question is how to conect? also I studying diferent designs with pcm63. all of them has diferent values of caps which pins goes to dac. what of theese caps are most important?
thanks for helping

 

[rfbrw]

Hi I would like to ask few questions? Thay can be pretty silly so don’t shoot me at once

I have dac. it has both balanced and unbalanced outputs.manufacturer claims that it is -PUSH PULL FOR EACH CHANNEL AND FULLY BALANCED DIGITAL OPERATION. It has 4x burr brown pcm 63p-k . physically it is 2 dac players inside. When I disconnect second plate with 2x pcm 63 everything works fine except line output is less stronger. and the bass is event better(with 4x pcm it is too boomy and even dominant) I LOOKED IN HOW THEY CONECTS- 1 MAIN BOARD (WITH RECEIVER AND DIGITAL FILTER AND OTHER STUFF) connects to RCA left right, ground and also to balanced + and ground.
The other board(pcm63p-k and all analoge stage stuff . I think This board also can work as separate dac if I feed them and add receiver and digital filter) outputs goes to balanced - and balanced gnd.



I am about to redesign my dac to pass labs Dac 1. so question is WHAT IS REAL BALANCED OUTPUT? HOW IT WORKS? And of course what should I do to convert my dac to pass labs d1,which is balanced design. II have heard that there are true balanced designs and untrue. Somehow I think that this is the way pcm63 conect. And my dac seems have different conection than pass labs. thee are lot of operationa amplifiers - 16 pieces per whole dac. I have heard somehow balanced output can me make with opa /Or I am wrong?
Will wait any advice.. I am about to mach dac to balanced aleph x which itself are balanced design and gives lower discortion when feeded in balanced mode. also 4x pcm would be benefit because I run dac directly to amp via pasive attenuator

If it is anything like the 1600 then it is fully balanced from the dacs onward i.e. 4 completely separate audio paths hence the need for so many parts. In order to add the D1 output stage you will have to disconnect the I/V op-amps connected to the 4 dacs and ideally power down the rest of the output stage. You will also need the D1 schematic .

 

[elviukai]

yes it is like 1600(1600 has hdcd) I have schematic, I have pcb layout. how many I need 2 or 4 d1 output stages.? in dac are 2 analog transformers 6w each with 21.5 secondary voltage. they vired way that wil provide +27 or so and -27v or so and zero potential. but after signal goes throught second caps and fets,transistors or I think it is active regulators or ??) to the dac are provided folowing voltages in analogue section- +18v gnd -18v and also again. +18v gnd -18v . for digital section 2x11v trafo that after theese regualtors provide +5v gnd and -5v. question how can I rise analog voltage without changing trafos and remooving those fine nichicon gol suply caps and all nine active regulators? is in regulator itself programamble to provide stable fixed voltage- in this case 18V and 5V respectively? in theory from 21.5V secondaries I can get about 26-30v. maybe there are some other voltage regulators. pass labs analog stage working at 30V as I understand. new bigger trafo will not fit there, I need then make outboard suply. and how pass d1 is critical to voltage? lets say not 30V but 18V? knowingexpierence from amps I thing output voltage would be less.

 

[elviukai]

here are picture of parasound and pass labs. diference is huge..
sometimes I wonder why manufacturer put so quality parts make so complicated circuit and makes analog stage as compicated as it can be made. for comparing my tiny akai cd 69( 2x pcm63p-j and simple AD OP 27 opa and 4 black gate f sound more close to listener then this expensive dac. problem in parts I think? the more opas, feedback in analog stage the better numbers you get on ossiloscope the less live sound it will be?

 

[elviukai]

and here is Wayne and Nelson design? pretty amazing..

 

[rfbrw]

Thje Parasound is fully balanced like the Passlabs D1. From the dacs onward, there are 4 separate audio paths. The PCM63 is a single channel device, so there are 4 of them.
It only looks complicated. I/V stage, then buffer, two opamps configured as what seems to be a FDNR filter and another buffer driving a complementary source follower. Repeat this three more times and there will seem to be a lot of opamps.
Between the PCM63 datasheet, the Parasoumd schematic and the D1 schematic there is more than enough information to install the D1 output stage. You do not even need the Parasound schematic.

 

[elviukai]

thanks rfbrw for helping. I am not expert but discrete pass labs dac1 is the same balanced with the same 4 signals but why it is so simple comparing to OPA parasound? I expected big quality from parasound (when looked inside) and listening I fell the same. but I just simply took back one day my old cdp(2x pcm63p-j) which is 5 times simpler(I did few mods- AD OPA, BG caps,also redesigned PS of this dac., changed plastic RCA, internal silver wiring to RCA) and compare again A/B. my system is easy to hear diferences on source,cables etc. and I did not like what I heard- my old cdp was better in terms on trasparency and clearlines and has some lighteness in muisc, music was light not heavy. the bad sides of this cdp- pretty sintetic digital sound. parasound sound very analogue, more like my Turnables -warm, also with tremendous bass(too much even) but it lacks trasparency , soundstage is too deep and lesss wide. and some other things.
friends saying that the best soliutions is to use transformer like sowter,lundahl.

but I will try mosfet IV stage. question number xx-

how pcm 63 recognize signal. I will build 2 IV stages(I think its double) and one conect to 2 pcm 63. and other to others 2 pcm63.one pair will have + - and GND ant other the same. I simply will get double outputs? perfect for biamping two amps directly how I need to conect?

 

[elviukai]

well sometimes its just better start from originals. I was lucky to get 1.5MB quality photo of inside comercial DAC1. what a beauty.. Wayne and Nelson are super

so what I see from inside dac-

there are only 2 stages as I thought. 1 stage per pcm 63 pair.
all 8 irfp on the output are without heatsinks

also I noticed simple stereo attenuator(ELMA) it is even series attenuator, not shunt to ground! how they very interesting control volume..