DIY Custom Amplifier and DAC- Project H
Feb 21, 2013 at 4:01 PM Thread Starter Post #1 of 95

bowei006

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Hello everyone, I have come to share info on a recently completed DIY project. We decided to post info and make it known after we have finished it. This is because some payment was involved and that it was a unit for our friends.
 
Special Thanks to MiceBlue for fixing up our formatting!

So how did it start? Project H was initially intended as a unit for a member called Haiburi. However his age and his circumstances in how he can use money is restricted. So the project fell apart for a for a time.
Some members then realized that this unit could be used for many people instead.

And so we started off on building a DIY unit that would be able to achieve performance while maintaining costs.

Borisu engineered custom boards, circuit design, and building the units. Mechy used 3DCAD to make models for our case that were then sent to a contractor. I did the public relations and handling of features, info, looking for parts, Q and A, and general organizing of it.








Examples of CAD drawings:

















 
 
 
 

PCBs:

 
 
 
 







^ Objective 2 PCBs


^ custom controller PCBs


^ custom controller PCBs



 
 
 
 

Fully-assembled unit:

 
 
 
 








 
 

 
 
 

With that said, our project has been completed. Borisu is under taking even more fun projects. And who knows, we may do other stuff in the future!

Thanks for checking out the DIY unit guys
smily_headphones1.gif


Tell me what you think.


*Note* This is only available to Official Anime Thread Members and all slots are taken. Regulars, sorry about this. Lurkers, sorry this is not a commercial product.

Summary of Project H:
Inside Project-H is a FULL Objective 2 amplifier. It features a Burr Brown 2134 op amp, and DUAL NJM4556 recommended high output buffer performance amps to drive even those planar magnetics. The DAC is the Cirrus Logic recommended flagship the CS4398 used in many receivers and media streamers alike. All the switches and signals are sent to a main Project-H control board. This control board not only controls all the interface controls themselves but also combines and separates the units. X state will have both the DAC and the O2 working together as one. Signal into DAC, then into O2 and then out headphone out. Y state will have the DAC input through USB or coax and output only through its specific DAC fixed out RCA ports and the amp, the O2 will input through another RCA input and out the headphones. It will utilize 1/4" headphone out. The case as of right now seems to be black semi-gloss weighing in at 3.5lbs with a front 6mm solid aluminum bezel.



 

Why Project H?:
  1. Options: It not only features some of the most coveted non snake oil parts around such as a full Objective 2 and CS4398 DAC but also has a central command board to relay switch signals and combine and separate the units. This is done with a fully customized design from the engineer of the project, Borisu. There are two RCA pairs on the back. One for fixed DAC out, and one for amplifier line in.
  2. Feel: With such a decision on getting these black gloss cases, one can get the look and feel of a much more expensive unit at such a low price. The case features a 6 mm front bezel made of solid aluminium.
    The case comes in at 26 cm x 15 cm x 7 cm.
  3. Cost: An O2 would cost $170-$200($150 base+$15 adapter and $15 shipping) after shipping and wall adapter from most companies. And those utilize batteries. Batteries do have their pro's as this can make it much more room accesible around the house but also leads to lower power it can input from a DAC and a lower voltage swing for power. We did not strive for just an O2. We strived for more, we strived to make a Objective Desktop Amplifier using the O2. This is not the portable O2 anymore, this is a full desktop vartiant. Fully featured dual amp and DAC switching units are rare if non existent for most around. The DAC has been highly recommended by Kiteki for being more natural and is also used in the Marantz CD6003 player,($500 USD) Decware ZDAC 1($875 USD),and also the Esoteric X-05 SACD player ($5000 USD, that is the right zero's). At less than $200, these units and sound will be available to the clients
  4. State Switch: One Switch on the front. Flip the Switch up and State X, flip it down and State Y

    State Y: Default State. In this state, both the amp and the DAC are being used as one. So basically like a combo unit. You leave your headphone plugged into the headphone jack on the unit. What is happening inside is that all signals the unit is receiving from the computer is being sent from the DAC directly to the internal O2 amp and out headphone out.

    State X: Say you just got a new amplifier and or DAC to try out. Lets say just an amplifier in this case. You flip the switch up to change to state X. What happens now is that both units are not working together anymore. The DAC will take signals from USB or Coaxil but instead of sending them to the O2 through the control board, it will directly output the signal to its RCA fixed line out port. The O2 also will now ONLY take a input signal from the backs RCA port. It will no longer receive a signal from the DAC and will only receive an analog signal from the back's RCA and output through the units front headphone out. This allows you to use a separate DAC with the O2 and a separate amp with the CS4398.
 

 
 

Projected unit cost FOR U.S/CANADIAN people:
  1. $130-$140 for unit itself
  2. ~$15 wall wart
  3. ~$30 shipping

Cost breakdown:
  1. ~$85 Main components and accessories:
    * Front panel switches and buttonsand RCA on back
    * Objective 2 Amplifier PCB and components (includes some custom components as well such as 1/4" headphone out and BB op amp and wiring to DAC)
    * Cirrus Logic CS4398 Flagship DAC
    * Custom b1o designed Project-H controller PCB(to control all aspects of the case it uses a micro processor which handles power management, switches, State Switching tech and more)
    * Volume Pot
  2. $30-$35 case (just an estimate right now)
  3. $15 per person *gift* to Borisu (imagine how long it took to solder all the boards, design the dam custom board, fit them into the cases, glue them and finally package and ship ten 5lb units.
  4. $15 wall wart
  5. $30 shipping

Total cost for the unit itself: $135

Total is around $170-$180 completely DONE, shipped with power supply to your house.

This is within expectations. Sub $200 unit.


 

Amplifier overview:
  1. Objective 2 Amplifier
  2. Gain Op Amp: Burr Brown(TI) OPA 2134
  3. Output Buffer: 2X JRC NJM 4556 gain amps
  4. Input: RCA
  5. Output: 1/4"
  1. Output Impedance: <2 Ohms
  2. Freq Responce: +/- 0.1 dB from 20 hz to 20 Khz
  3. Distortion: 0.01%(-80 dB)
  4. Phase responce: +/- 2 degrees phase error from 100 hz to 10KHz
  5. Input limit: 2.8 V on AC power at 2.5X gain
 
 

 
 
 

DAC overview:
  1. Cirrus Logic CS4398 DAC
  2. Fixed Line out: 2V RMS
  3. Inputs: USB (48KHz/16 bit max) and Coaxil (96KHz/24bit max)
  4. Output: Directly to Amplifier/ Fixed line out
  1. 96KHz/24bit Maximum rate supported on our board.
  2. 120dB Dynamic Range
  3. -107 dB THD+N
  4. Low-Clock Jitter Sensitivity


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%24%28KGrHqIOKjgE3ru1u9PDBOD,pZBmQg~~_3.JPG
 
 

 
 
 

Custom controller overview:
 
  1. Microprocessor: AT89C2051, 12MHz clock, 5V supply.
  2. Delay:Buttons need to be held down for at least 100ms to prevent spamming.
  3. Power on mute:500ms (to prevent the transient on "click" noise that may damage IEM's if user forgets)
  4. Power off mute stage: When the unit is turned off, the control board makes it so that output mutes before power is cut to prevent same damage
Code:
Code:
 init: mov TCON,#0 mov TMOD,#00000001b mov A,#0 mov R5,#0 mov R6,#0 mov P1,#0 mov P3,#0FFH power: jb P3.3,power lcall t100 jb P3.3,power power_0: jnb P3.3,power_0 setb P1.5 mov P1.4,C RRC A mov P1.3,C lcall t100 lcall t100 lcall t100 lcall t100 lcall t100 setb P1.2 button: jnb P3.3,poff jnb P3.4,io jnb P3.5,gain sjmp button poff: lcall t100 jb P3.3,button poff_0: jnb P3.3,poff_0 clr P1.2 mov C,P1.3 RLC A mov C,P1.4 lcall t100 mov P1,#0 sjmp power io: lcall t100 jb P3.4,button io_0: jnb P3.4,io_0 clr P1.2 lcall t100 cpl P1.4 lcall t100 setb P1.2 sjmp button gain: lcall t100 jb P3.5,button gain_0: jnb P3.5,gain_0 cpl P1.3 sjmp button t100: mov R7,#2 t100_0: clr TF0 clr TR0 mov TH0,#03CH mov TL0,#0AFH setb TR0 t100_1: jnb TF0,t100_1 clr TR0 djnz R7, t100_0 ret end






 

Clients:
  1. [b]bowei006[/b]
  2. [b]kalbee[/b]
  3. [b]jgray91[/b]
  4. [b]28980[/b]
  5. [b]Manveru[/b]
  6. [b]EveTan[/b]
  7. [b]graphidz[/b]
  8. [b]mechgamer123[/b]
  9. [b]deadlylover[/b]
  10. [b]b1o2r3i4s5[/b]



*Note* This is only available to Official Anime Thread Members and all slots are taken. Regulars, sorry about this. Lurkers, sorry this is not a commercial product.





 

The Project was completed. It was completed well within parameters of cost being only $150 for the entire unit and any fees associated. Shipping and then wall wart and accessories put it at just about $200 for most members.

This project was started officially mid October with initial batch orders of CS flagships (non experimental).
It's almost exact to the day of 4 non mathematical months that the units shipped. October 14 2012 marked the day of massive studying of DAC units and later the ordering. February 14 2013(HK) the first generation of units left the door.
  1. During the inception of the project in September, we worked as a team to come up with plans and solutions and compromises to an idea.
  2. In October, we realized that the idea was doable and in Mid October, the project officially started with the ordering of major PCBs.
  3. In December, 3D CAD for the unit case was designed, PCBs were assembled, units were tested.
  4. In January, the cases shipped and finalization work began.
  5. And this month, the units in final shipped. In full glory to the parts of the world.

The sun was once said to never set on the British Empire. I can say that the sun will not set on the Project series units. From the ices of Russia to the heats of Malaysia, and from Australia tunneling up to America. The Project series will be in a land where the sun doesnt set.

Ladies and Gentlemen, it has been an honor to do some coordinating in this project. And thank you Borisu and Mechy for your work and to everyone for making this project a reality




 

Project-H is licensed under a Creative Commons Attribution-NonCommercial 3.0 Unported License (CC BY-NC 3.0).

 
Feb 21, 2013 at 4:20 PM Post #2 of 95

MrViolin

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:D the original 10
 
Feb 21, 2013 at 4:42 PM Post #4 of 95

MrViolin

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Quote:
Manveru was the only one who dropped. And you took his spot.

~are you okay today panda? All the periods make it seem like you're a bit bothered. 
 
Feb 21, 2013 at 4:53 PM Post #6 of 95

MrViolin

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Quote:
It took me a few seconds to get the joke.

It wasn't meant to be a joke -_- I'm serious. 

Well, guys who look at the thread, hope you all will be satisfied!
 
Feb 21, 2013 at 9:02 PM Post #7 of 95

miceblue

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Wow, looks nice! I'm curious to know how the OPA2134 sounds and measures compared to the "stock" NJM2068 op-amp for the O2. I'm also curious as to how the DAC section sounds compared to something like the ODAC.
Looks pretty promising for a sub $200 desktop DAC/amp.
 
Nice job!
smily_headphones1.gif

 
Feb 21, 2013 at 9:04 PM Post #8 of 95

bowei006

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Quote:
Wow, looks nice! I'm curious to know how the OPA2134 sounds and measures compared to the "stock" NJM2068 op-amp for the O2. I'm also curious as to how the DAC section sounds compared to something like the ODAC.
Looks pretty promising for a sub $200 desktop DAC/amp.
 
Nice job!
smily_headphones1.gif

Thanks.
 
I would need to get my hands on an O2 with that op amp. Changing op amps often from the PCB leads to bent pins and etc.
 
The CS4398 works extremely well. It does its job beautifully. The Wolfson accentuates the vocals more than the CS, but the CS sounds a bit more natural and smooth as it doesn't have that slight accentuation.
 
Feb 21, 2013 at 9:24 PM Post #9 of 95

mechgamer123

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I'm pretty sure there's a small bit of distortion in the bass of that CS DAC...

Other than that, this thing is awesome!!!
 
Feb 21, 2013 at 10:03 PM Post #10 of 95

bowei006

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I'm pretty sure there's a small bit of distortion in the bass of that CS DAC...


Other than that, this thing is awesome!!!
I didnt detect anything there. And my testing of the bass with actual bass phones concluded that the Q701 was indeed just having trouble
 
Feb 21, 2013 at 10:08 PM Post #11 of 95

DingoSmuggler

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Quote:
I'm pretty sure there's a small bit of distortion in the bass of that CS DAC...

Other than that, this thing is awesome!!!

That distortion plot is of a 1kHz test signal, so the harmonic distortion products are at 2k, 3k , etc.
Anything in the bass region is noise, not distortion.
 

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