Fancy building your own CD player with built in non-oversampling DA converter from a kit?

Look no further.

Based on a TEAC transport and ye olde Philips TDA1543 for the nonoversampling DAC

DAC is basically the Progression DAC (see DAC of ther Klones) reborn.

or salient details:

-top loading, close to the lit to automatically load the TOC.
- isolated digital and analog power supplies
- ATMEL AVR microcontroller, custom program/operating system
- simple, easy to understand display and controls
- standalone or use as a transport with external DAC
- small footprint, B5 size(W250 × H65 × D175mm)
- comes with a remote!

Although offered as a kit or pre-built, my suspicion is that all the real work has already been done: programming the microcontroller, now that's an area where most DIYers still fear to tread!

Not too many kit/home build CD players...

This is interesting.

A stereo amplifier.

Yes. Well, think of it as a bulked-up headphone amplifier. The design is one of those "ah, I should have thought of that" moments, but the details are quite tricky, as usual.

If the extend the basic "voltage stage + current buffer" topology of the 47 Labs 0147 headphone amplifier out to 40 wpc territory, you end up with the 0347.

The high power means than unlike the headphone amp design you have to run it out of class A, and that means closed loop operation.
While most people might be tempted to wrap the voltage feedback around the whole shebang, this basically ends you up with a big op amp. Op amps, with their massive negative feedback design, are not so happy driving high inductance/capacitance loads like speakers.

The trick 47 labs uses is to have two feedback pathways, with heavy "local" feedback around the op amp and a small secondary...

While I wait for the guys at 47 labs to get the Treasure 0247 together, I took a look around at some of the alternatives.

The Yulong D100 looks quite attractive and for about 2/3 the price of the 0247 kit you get a fully assembled unit!

review at head-fi

Or if you can do without a DAC, HLLY audio has your standard "transistor buffered op amp" implementation in a no-frills case:

HLLY RMK-5

It's listed at $240 but for sale on eBay for only $99 right now.

Of course there are dozens, but I single those two out as being particularly deserving of "honorable mentions". I'm still set on the 0247 though.

Just placed my order for this. I am customer no. 00028!

47 Labs web page

I figure I owed it to them. 47 Labs has been good to me, and the DIY community over the years, one way or another: gainclone, phonoclone, even the DAC-of-the-Klones.

Besides, several reasons:

1. I really want to finally hear 47 labs gear, instead of trying to reverse engineer it all the time!
2. It will be interesting to compare it against the sapphire amp.
3. I'm sure it will be fun to build and examine up close.
4. It's my Christmas present.
5. And hammertone. Finish a audio product in grey, or even better, green hammertone, and its as bees to honey...

Will blog the unboxing, building, and testing right here.

In 2009, Penultimate Zen aka Zen V4 was my first solid state build. I used the parts that were available, did not know much about making it work well, and did not have test instruments beyond a cheap multimeter. Also, I did not have a preamplifier to work with it or speakers sensitive enough to enjoy its 25W. As a result, the amplifier turned out not quite satisfactory and for two years has been gathering dust and my wife's complaints. I was thinking about scrapping it and reusing the enclosure for something more useful. Instead, I reworked it.

I removed one of the two power transformers (moving from dual mono to stereo configuration), replaced my original dodgy Chinese PSU filter caps with Mundorf M-Lytic HC, replaced internal low voltage wiring with thick speaker wire, reconfigured grounding (so it is finally safe!) and installed balanced inputs with input transformers. What a change in sound! With my Exposure CD player, B1 clone preamp and Heresy III speakers, the amp...

DAC Symphony

Dramatically reduced the level of digital noise.
Reduced impact of interconnect.
Special power supplies provide a very clean and smooth power.
2 types of digital filters - linearphase and minimum phase.
2 S/PDIF and/or AES/EBU inputs.
Input impedance of 75 ohms or 110 ohms.
Input data word lenght from 16 to 24bit.
Sampling frequency from 32 to 192 kHz.
Automatically switches and displays the sampling frequency.
Stereo analog outputs true-balanced (XLR) or unbalanced (RCA).
Output impedance 600 ohms.
Output voltage 1.7 V rms.
Frequency range 15-45000Hz (-3dB).
Dynamic range > 120dB.
Distortion <0.001%.
Out-of-band noise (50kHz-100MHz) <-90dB.
Power supply AC 220V/50Hz or DC 12V.
Very small size and weight.


...

Back by popular demand, I have decided to go ahead and prepare full kit version of the VSPS300, Phonoclone 3, and Sapphire projects.

10 kits of each project will be available - contact me to reserve.

Phonoclone Kit : $125 (10 availble) Set of two boards and components to populate.
VSPS 300 Kit : $117 (10 available) Set of two boards and components to populate.
Sapphire Kit : $113 (10 available) Set of two boards and components to populate.

Kits will be shipping shortly after the New Year.

Current status: necessary parts shipped from Mouser, should be able to assemble kits this weekend. Also have to prepare the documentation.

RJM Audio Kits

I always ground my pot to the star ground on my other projects.. seems that for some reason this shuts down the left channel on my sapphire..

went through the whole diagnostic to narrow it down to the pot.. (or so i thought) and replaced it with a new one.. i got it working.. then i grounded it and it didn't work again..

on a hunch i removed the ground wire.. and VIOLA.. sweet sound from both cans!

-joe

Hard wired the left output to the right side (running mono R on both headphones)

testing the sound of the amp.. it's truly amazing.. nothing i have compares to it..

need to get it to the store to put it on demo.. no time to work on fixing this one.. worked til 2am last night and woke up at 4:30am.. too tired

i will probably end up building another set of boards and swap it out and debug later..

-joe

The sapphire amp is done. I ended up building an external power supply, not enough room in the hammond to put everything.

I had overheated Q3 on one of the boards and the DC output was at 8vdc! luckily I always check offset before I plug headphones in.

Ended up replacing it and it works fine..

I had originally wired the chassis for dual mono output into a Y harness back to stereo.. then my friend suggested that i wire it directly for stereo.. no sense in spending time on the harness..

upon rewiring, the left channel refuse to work.. i didn't even touch it..

i must be jinxed

-joe