The Zishan dsd's corner

[moshe tes]

@moshe tes
About the socket opamp:
https://www.head-fi.org/threads/the-zishan-dsds-corner.826185/page-106#post-14742758
https://www.head-fi.org/threads/the-zishan-dsds-corner.826185/page-106#post-14742933

Dang!! The eval board sheet is what I've been missing. I have scoured through the actual datasheet and although that helped a lot, I wasn't making much progress. Thanks a lot!! You are the real MVP!

 

[moshe tes]

I just noticed that the main power reserve caps for the opamps are in a series set of 3 parallel caps. Doesn't that effectively half the capacitance? I think the capacitance would come out to about 102uF.
I also noticed the same for the opamp bypass caps. The two on either side are in series. Please forgive my ignorance but could someone explain why?

 

[Merlin-PT]

k14 is writen on top of each one of the 4 diodes used in the dac board for the dc converters.
google what type of smd component is something with k14 marking and you'll find it's a schottky diode, if i remember correctly rated 1A 40V, now you can seach for a replacement.
I think I got 4 of these, probably I liked the price at the time: https://www.arrow.com/en/products/b140hwq-7/diodes-incorporated

The opamps power is +9 and -9v, each capacitor block is for each one of the power rails.
There are current demands in real time from all components and the batt power source is the same for all, so they provide a bigger power reserve bank for all opamps and 10uF near the + and - opamp supply pins so they never run out of juice.

The 10uF caps each side of the opamps are not in series.
https://www.allaboutcircuits.com/textbook/direct-current/chpt-13/series-and-parallel-capacitors/

 

[DBaldock9]

I've changed the listing order of my op-amps (in my profile "Headphone Amp Inventory"), to sort them by Voltage, and then by Price.
This helps with making selections during op-amp rolling, due to the different supply voltages in my various amps.
For instance, my Loxjie P20 has ±18VDC rails, and the iBasso PB2 has ±16VDC rails.
My other (Walnut & Zishan) DAPs / Amps are mostly ±9VDC to ±12VDC.
.
**** Op-Amps to use in most of the Headphone Amps ****
**** Sorted by Voltage, and then Price ****
** ±24VDC **
01.) OPA-2604-AP - Dual Op-Amp on DIP-8 header, ±24VDC (stock in F2) [3x, $9.02 ea]

** ±22VDC **
02.) OP-275 - Dual Op-Amp (SOIC), ±22VDC, (stock in DSD LPF) [2x]
03.) TI NE-5532-P - Dual Op-Amp, ±22VDC (stock in Z1 & V2) [2x]

** ±20VDC **
04.) PHILIPS NE-5532-N - Dual Op-Amp, ±20VDC (Vintage - mid-90s) [3x, $3.95 ea]
05.) JRC-5532-D - Dual Op-Amp, ±20VDC (stock in P20) [4x, $1.16 @ Mouser]

** ±18VDC **
06.) Sparkos SS3602 - Dual Discrete Op-Amp on DIP-8 header, ±18VDC [1x Original, $84.00][2x Newer Low Profile, $83.00 ea]
07.) OPA-627-AU - 2x Mono Op-Amps on DIP-8 header, ±18VDC [2x, $55.42 ea][4x, $61.82]
08.) BUF-634-U - 2x Mono Buffers on DIP-8 header, ±18VDC [2x, $24.22 ea]
09.) OPA-1622 - Dual Op-Amp (VSON-10) on DIP-8 header, ±18VDC [2x, $12.66 ea; 4x, $7.89 ea]
10.) OPA-189-IDR - 2x Mono Op-Amps on DIP-8 header, ±18VDC [1x, $9.95 ea]
11.) LT-1678-IS8 - Dual Op-Amp on DIP-8 header, ±18VDC [2x, $9.58 ea]
12.) OPA-2209-AID - Dual Op-Amp on DIP-8 header, ±18VDC [2x, $8.83 ea]
13.) OPA-196-IDR - 2x Mono Op-Amps on DIP-8 header, ±18VDC [1x, $8.15 ea]
14.) TLV-172-IDR - 2x Mono Op-Amps on DIP-8 header, ±18VDC [1x, $7.17 ea]
15.) AD-825-AR V3 - 2x Mono Op-Amps on DIP-8 header, ±18VDC [2x, $7.00 ea]
16.) OPA-1688-ID - Dual Op-Amp on DIP-8 header, ±18VDC [2x, $6.08 ea]
17.) OPA-2134-PA - Dual Op-Amp, ±18VDC (stock in F1) [2x, $2.30 ea]
18.) LF-353-N - Dual Op-Amp, ±18VDC (purchased in the mid-80s) [3x]

** ±17VDC **
19.) MUSES-8920E - Dual J-FET Op-Amp on DIP-8 header, ±17VDC [2x, $16.75 ea]
20.) MUSES-8920E - Dual J-FET Op-Amp, ±17VDC, to replace OP275 in DSD & JRC4580 in F2 [6x, $13.75 ea]
21.) LME-49720-HA - Dual Op-Amp (TO-99 round metal case), ±17VDC [2x, $9.68 ea; 4x, $11.16 ea]
22.) LME-49710-HA - Mono Op-Amp (TO-99 round metal case), ±17VDC [10x, $7.67 ea]
23.) LME-49720-NA - Dual Op-Amp, ±17VDC [2x, $2.95 ea]
24.) LM-4562-NA - Dual Op-Amp, ±17VDC (stock in Z2, Z3, & DSD) [3x]

** ±16.5VDC **
25.) Burson V6 Classic - Dual Discrete Op-amp on DIP-8 header, ±16.5VDC (used) [3x, $54.62 ea]
26.) Burson V6 Vivid - Dual Discrete Op-amp on DIP-8 header, ±16.5VDC [2x, $50.00 ea]

** ±16VDC **
27.) NJR MUSES02 - Dual Op-Amp, ±16VDC [2x, $46.25 ea]
28.) Burson V5i - Dual Hybrid Op-Amp, ±16VDC [2x, $34.50 ea]

** ±15VDC **
29.) ADA-4627-1BRZ - 2x Mono Op-Amps on DIP-8 header, ±15VDC [1x, $46.39]
30.) AD-797-BRZ - 2x Mono Op-Amps on DIP-8 header, ±15VDC [2x, $28.73 ea]
31.) HiFi Fever OP03 - Dual Discrete FET Input Op-amp on DIP-8 header, ±15VDC [2x, $25.90 ea]
32.) THS-3091-D - 2x Mono Op-Amps on DIP-8 header, ±15VDC [2x, $22.65 ea]
33.) AD-828-ARZ - Dual Op-Amp on DIP-8 header, ±15VDC [2x, $9.31 ea]

** ±13VDC **
34.) AD-8620-ARZ - Dual Op-Amp (SOIC), ±13VDC, to replace OP275 in DAC LPF [6x, $16.67 ea]

** ±12VDC **
35.) AD-8066-ARZ - Dual Op-Amp on DIP-8 header, ±12VDC [2x, $10.19 ea]
36.) AD-8397-ARZ - Dual High Current Op-Amp (SOIC), ±12VDC, to replace OP275 in DAC LPF [2x $5.85 ea; 2x on DIP-8 headers $8.88 ea]

**** The Next 5 came with the iBasso PB2 Amp ****
37.) OPA-604-AP - Mono Op-Amp, ±24VDC [4x]
38.) BUF-634-P - Mono Buffer w/Class A Bias Resistor, ±18VDC [4x]
39.) BUF-634-U - Mono Buffer SOIC-8 on DIP-8 header, ±18VDC [4x]
40.) LME-49710-NA - Mono Op-Amp, ±17VDC [4x]
41.) AD-797-AR - Mono Op-Amp / Buffer SOIC-8 on DIP-8 header, ±15VDC [4x]

 

[Setmagic]

Most wanted question is:
What is your favourite headphone out OPAmp in Zishan?

 

[moshe tes]

k14 is writen on top of each one of the 4 diodes used in the dac board for the dc converters.
google what type of smd component is something with k14 marking and you'll find it's a schottky diode, if i remember correctly rated 1A 40V, now you can seach for a replacement.
I think I got 4 of these, probably I liked the price at the time: https://www.arrow.com/en/products/b140hwq-7/diodes-incorporated

The opamps power is +9 and -9v, each capacitor block is for each one of the power rails.
There are current demands in real time from all components and the batt power source is the same for all, so they provide a bigger power reserve bank for all opamps and 10uF near the + and - opamp supply pins so they never run out of juice.

The 10uF caps each side of the opamps are not in series.
https://www.allaboutcircuits.com/textbook/direct-current/chpt-13/series-and-parallel-capacitors/

So I was thinking I probably do not need to replace the MP1542 as it can easily supply 15V. Are there any drawbacks to it that you are aware of?

 

[Merlin-PT]

So I was thinking I probably do not need to replace the MP1542 as it can easily supply 15V. Are there any drawbacks to it that you are aware of?

Only what Slavalun pointed out, probably the noise he saw is from MP1542 dc converter when the voltage is increased.
I didn't noticed that, because I didn't measured and because I use a LDO after the dc converter, TPS7A3901 with low noise (21uV), high PSRR (69dB).

 

[moshe tes]

Only what Slavalun pointed out, probably the noise he saw is from MP1542 dc converter when the voltage is increased.
I didn't noticed that, because I didn't measured and because I use a LDO after the dc converter, TPS7A3901 with low noise (21uV), high PSRR (69dB).

The TPS7A3901 has an output current limit of 150mA. I would think that is too low for the opamps as I am also thinking of using an LME49600 buffer on the output and it is capable of 250mA output current.

 

[Merlin-PT]

What matters is the current consuption of all opamps used, not the output. In my case if I remember right it was around 50mA per voltage rail.
https://www.head-fi.org/threads/the-zishan-dsds-corner.826185/page-155#post-14904169
Anyway there is very few space to put LDO. It's good, but too much trouble to do. So I'm not suggesting you to do that. You can also replace the dc converter and measure the noise, but no guarantees, dc converters generate noise, you need to test the replacement. The obvious easy solution is not to increase the voltage.

 

[moshe tes]

What matters is the current consuption of all opamps used, not the output. In my case if I remember right it was around 50mA per voltage rail.
https://www.head-fi.org/threads/the-zishan-dsds-corner.826185/page-155#post-14904169
Anyway there is very few space to put LDO. It's good, but too much trouble to do. So I'm not suggesting you to do that. You can also replace the dc converter and measure the noise, but no guarantees, dc converters generate noise, you need to test the replacement. The obvious easy solution is not to increase the voltage.

Oh so does the opamp convert input voltage to output current?

 

[Merlin-PT]

You must find the opamp max current consuption in the datasheet or measure it, that is what matters for the power supply.
https://duckduckgo.com/?t=ffab&q=does+the+opamp+convert+input+voltage+to+output+current?&ia=web

 

[slavalun]

We must understand that our desires do not always work in a portable form factor. So for the LME49600 with LDO, a sufficiently powerful stabilization system is required, which will only dissipate more than 1 Watt into the shoulder. You will also need capacitors with a capacity of 600-1000 uF, which in the case of + -15V supply will be too large for installation in a player. You will also need a rather complex board in design and installation for the subtractor-filter and composite amplifier. I have such a board has 4 layers and five revisions, which took a year and a half to develop ...
To work with LDO, I raised the power supply to + 10V, -9.6V,
in order to get the stabilization system at the output
+ -7.5V.

For normal operating modes with the MP1542, you just need to install the highest quality strapping (thin film Susumu resistors, 1206 Kemet X7R ceramics) This will be more
than enough to get super high results.

 

[Merlin-PT]

@slavalun
Impressive work, all analogue part, more than half of the PCB size is your design.
I also prefer the analogue POT, would like it was released with one.

What capacitance do you recommend for the DAC and DC converters?

 

[slavalun]

@slavalun
Impressive work, all analogue part, more than half of the PCB size is your design.
I also prefer the analogue POT, would like it was released with one.

What capacitance do you recommend for the DAC and DC converters?

Yes, this is my board design and my schematic.

The capacity can be different, depending on the task and the type of capacitor.

For the + 5V DAC, I use two 330μF Kemet 6.3V polymer.

For powering Kemet, Murata 10-22 uF X7R 1206-1210 case 16-25V.

 

[Setmagic]

@slavalun it is possible to buy your design board?

My Zi DSDs D4497 have schizophrenia. Today was 3rd time he thinks is 4499. Turbo mode apires in menu and stop give me sound when music was played. Need to remove TF card and push reset button.
Can't recover to Dual4497 still 4499 in system info.