DIY D1 I/V STAGE

[merlin el mago]

I see this other schematic with reversed drain/source IRF610 position

An externally hosted image should be here but it was not working when we last tested it.

Wich one is the correct?

 

[Zen Mod]

sources are down ( to negative ) and drains are up ( to positive ) ;

I never look at symbols in schematic , mostly because I just can't remember what's source and what's drain on them ......

so - those details - mistakenly reversed symbols , reversed caps and zeners - I usually can't spot them

 

[merlin el mago]

Please check the datasheet of the dac.

measure dc at the source of t1a/b and/or the output pins of the dac. should be the same.

How is it all wired up?: cdplayer/i2s signal -> reciever/dac -> i/v?

regards

Output pins DAC & source of t1a/b both channels -0.740VDC, so it's the same in DAC like in the I/V.

Is wired: PC usb // HiFace usb receiver s/pdif output // CS8414 receiver PCM1704 DAC SE.

Thks for help.

 

[merlin el mago]

sources are down ( to negative ) and drains are up ( to positive ) ;

I never look at symbols in schematic , mostly because I just can't remember what's source and what's drain on them ......

so - those details - mistakenly reversed symbols , reversed caps and zeners - I usually can't spot them

Thks ZM, so my schematic is OK, right?

 

[merlin el mago]

Could anybody simulate the schematic to know where measure DC & the corrects values?

 

[Zen Mod]

Thks ZM, so my schematic is OK, right?

yes - schematic from http://www.diyaudio.com/forums/pass-labs/181449-diy-d1-i-v-stage-2.html#post2534689 is correct - sources pointing down

PCM1704 - if connected by datasheet - have 0 offset at output

connect D1 to it , then you must set - with P1 - that you still have 0V at PCM output/D1 input

rest is irrelevant

 

[merlin el mago]

PCM1704 Left channel 0.004V Right channel 0.006V so 0 offset but now the I/V input is in both channels -29.5VDC & the trimmer can modifie the value so is fixed -29VDC both inputs channels😕

 

[Zen Mod]

PCM1704 Left channel 0.004V Right channel 0.006V so 0 offset but now the I/V input is in both channels -29.5VDC & the trimmer can modifie the value so is fixed -29VDC both inputs channels😕

give us complete schematic of PCM stage you are using

we are looping this way - you obviously didn't understood what's written

 

[merlin el mago]

I don't have the schematic it's an Elektor Audo DAC 2000 without I/V Audio DAC 2000 (3) - ELEKTOR.com | Electronics: Microcontrollers Embedded Audio Digital Analogue Test Measurement

PCM1704 measurements are done disconnected from I/V, I/V mesurements are done without PCM1704 connected.

 

[Zen Mod]

before connecting D1 to PCM - you need to set P1 to have approx. 0V at I/V input , measuring against gnd

then you connect D1 to PCM , power up everything and do fine setting after some time ( when everything is in temp. equilibrium .

simple as that .

if something is not working - something is dead .

either PCM or D1 .

edit :

schematic with approx. voltages attached ; what is important is just red 0V value ;

all other voltages approximately , and valid only for troubleshooting purpose

 

[merlin el mago]

Thanks, I/V 0Vdc at input, now I have to check DAC because is moded with a clock at the receiver CS8414 so must check all.

 

[merlin el mago]

before connecting D1 to PCM - you need to set P1 to have approx. 0V at I/V input , measuring against gnd

then you connect D1 to PCM , power up everything and do fine setting after some time ( when everything is in temp. equilibrium .

simple as that .

if something is not working - something is dead .

either PCM or D1 .

edit :

schematic with approx. voltages attached ; what is important is just red 0V value ;

all other voltages approximately , and valid only for troubleshooting purpose

While adjust DAC I measured I/V:

Left channel
R6 // Drain T1 // C3 14.20V
R5 // Gate T1 // C2 // P1 3.45V
C5 // Source T2 // R4 10.77V
R2 // Source T1 0 V

Right channel
R6 // Drain T1 // C3 14.17V
R5 // Gate T1 // C2 // P1 3.45V
C5 // Source T2 // R4 10.74V
R2 // Source T1 0 V

Are the measurements right?

 

[Zen Mod]

obviously yes ;

I told you - all voltages are just approx , counting roughly that Ugs of mosfet is 4V

that 0V point is what is important/needs setting

 

[merlin el mago]

Thks for all help ZM the NP D1 I/V it's singing

 

[Zen Mod]

😉

 

[merlin el mago]

🙂

 

[merlin el mago]

For R6 used 1K660 but need more gain, how can do?

 

[Zen Mod]

increase it , but observe 0V level on input ;

maybe it will need re-setting

 

[merlin el mago]

I have 1K820 & 2K21 on hand so first I will try 1K820 to see what's happen with gain.

 

[merlin el mago]

After 9 days of extensive listening sessions I can conclude that sounds a lot better CS8414+DF1704+PCM1704+D1 I/V NP than BII+Legato in single end & balanced mode vs single end mode PCM1704+NP D1 I/V, details:

CS8414+DF1704+PCM1704 with Erno Borbely series regulators (one +5V (CS8414+DF1704 & two +-5V for PCM1704, NP D1 I/V LM317+LM337 for +-30V

BII+Legato with Salas regs V1.2R for BII, Salas reg V1.0 remote sense for Legato & set of 3 Trident regs for BII

I use Sony Vaio laptop like source, both share USB 2.0 HiFace with Salas 1.0 remote sense reg

N.B. Erno Borbely adviced me that PCM1704 sounds better than BII, next step I will change Legato I/V for Classic Pass Labs D1 I/V with an ESS Dac designed by Owen (opc)