Jacken's Blog » dac

Testing the Gigaworks DAC with mods

Jacken — Sun, 11 Jul 2010 01:46:34 +0000

I’ve been modifying my Gigaworks Ebay DAC and think that the results is really showing. The second opamp is completely removed, the filter is changed to Cirrus Logics filter example from their prototype board and the first opamp is replaced with GD-Audio’s Earth HDMA. It sounds absolutely marvelous. Here’s the before and after graphs

Mods and upgrades on a Pioneer PD S-505 for better audio quality part 1

Jacken — Sat, 28 Mar 2009 20:10:15 +0000

Part two of this series is now up. Read on how to install a better clock.

So I bought this Pioneer PD S-505 for $40 to test how good audio quality I’m able to squeeze out by modifying it. But It will not be just the standard subjective judgement of improvement but also measurements. Back in 2000 you had to pay about $400 for it. It uses the stable platter which means you have to put the CD in upside down. So let’s get going.

The steps I planned is the following:

Remove the mute transistors.
Replace the output opamp
Remove headphone output
Replace the clock with a GD-Audio clock
Improve the regulated voltage feeds to the DAC and opamp
Improve the power supply
Add a separate regulated power supply for the clock and opamp

But first we need the schematic of the player, so download the Pioneer PD-S505 schematic here.

Ok, lets look at some stuff we need to do. First we have to remove the mute transistors. Less stuff in the audio path equals better sound. The transistors is just there to make the measurements look better for reviews. So they have to go.

Click for larger image

So transistors Q403, Q404, Q453 and Q454 is removed. Desolder och just clip the pins (carefully) with a wire cutter.

Next step, time to desolder the opamp which is a rather old opamp (NE5532). Desolder the opamp IC405 and solder in a socket for easy testing with different opamps. I settled on LM4562 at first.

Remove the heaphone opamp if you don’t going to use it. It’s better to buy an external headphone amplifier like V-CAN Tube Headphone Amplifier or better.

That’s about it for today. Next installment, upgrade the clock to improve jitter numbers…

On to part two on how to add a better clock to your PIONEER PD S-505

Go EMU! The drivers for EMU 0404 USB released as Open Source

Jacken — Tue, 13 Jan 2009 15:16:35 +0000

I’m more and more impressed with EMU0404. They released the EMU 0404 USB driver code for Macintosh. This is a smart move. I once called them about a problem I had with the input pots being to sensitive. The tech support guy told me they actually had to use cheaper parts to be able to use better sounding parts. My god! Honesty! You don’t get that too often when calling a company about their products.

Zhaolu 2.5 DAC

Jacken — Mon, 03 Sep 2007 22:20:30 +0000

I just bought a new Mac Mini Core Duo2 as a media player in my bedroom. I connected it an old 23″ Cinema display that I don’t use. First I was a bit annoyed that I needed to use the keyboard and mouse, but then I found Remote Buddy. What a relief! I can now do almost anything with Apples lovely simple remote. I’m going to use it for playing back my CD collection that’s been ripped to a large hardisk. Watching DiVX, DVD, MPG films on it. And watch TV with my EyeTV kit.

So the next step was getting the audio out of the mini. Well, let’s face it, the output quality from line-out isn’t something you can call great. So I’m about to order an Zhaolu DAC 2.5 and mod the crap out of it! I’m thinking of installing a ZapFilter, better clocking etc. I’m then going to use mini-spdif connector to get the digital data out from the mac to the DAC.

Now I just need to get my home built amp finished.