Paradisea DAC Mod

tanchiro58 · « **Reply #40 on:** 10 May 2007, 06:09 pm »

Quote

you could try running a ground wire back the IEC jack.

jhm731,

F100 and I tried to use the AC plug ground but some experts said that we should absolutely not use that since most of EMI are concentrated there. That is why I have used the gound plane.

Gary,

I think we are all getting confused. I personally do trust my ears and had done several experiments and finally choose the secondary(5,6,7,8) to RCA connector (driving): primary(1,4) from R66 and ground in SB3 and primary(1,4) from 75Ohm: secondary(5,6,7,8) to RCA connector (driven) in the DAC. My music sounds the best.

Tan

jhm731 · « **Reply #41 on:** 10 May 2007, 10:21 pm »

Quote from: GBB on 10 May 2007, 04:46 am

Quote from: jhm731 on 9 May 2007, 09:46 pm
Mr.Paul told me the shields should face the driving or driven IC.

Just to clarify this comment, in their FAQ http://www.scientificonversion.com/faq.html, Scientific Conversions
highlights Fig 40 of their AES 2003 paper as a good reference for reducing EMI emission and susceptibility. It shows the shield side of the transformer going towards the DAC receiver chip.

So I believe you are suggesting that on the SB3 side of the system, the secondary of the transformer should be driven and the primary should go to the SPDIF output jack. And on the DAC receiver side, the primary should go to the SPDIF jack and the secondary should go to the DAC receiver as shown in the Figure.

Is that right?

Thanks,
---Gary

Gary-

That's right.

Thanks for posting the diagram.

Builder Brad · « **Reply #42 on:** 10 May 2007, 10:48 pm »

here is the transformer installed:

I scraped off some of the enamel on the pcb to create pads for the primary(pin 1,8) connections from signal to earth, cut the trace that takes the signal to the BNC digital jack and also isolated the BNC eart by cutting the very small traces that link its solder pad to the pcb ground.

there is a definate improvement in the sound of my system most noticable in the bass region.

Builder Brad · « **Reply #43 on:** 10 May 2007, 10:51 pm »

the clear material behind the transformer is off cuts of Kynar insulation

F-100 · « **Reply #44 on:** 11 May 2007, 03:04 am »

Very nice, Brad!!!

Did you also add the transformer on your source too? If so, how do you like the sound?

I installed the transformers on both my SB3 and Paradisea DAC but it sound kind of flat in my system.

I didn't like the sound at all so I removed the transformer from the DAC and only use one transformer on the SB3 and the system now sound very nice and lively.

Here is a pin-out diagram if anyone is interested.

tanchiro58 · « **Reply #45 on:** 11 May 2007, 04:15 am »

I mod my DAC first but not my SB3. It was sounding lively and spacious. Then I decided to try the mod on SB3 later on. My music sounds even better with more bottom, more black background and mid and high seems to be more revealing.

Builder Brad · « **Reply #46 on:** 11 May 2007, 08:29 am »

F-100 + Tan,

I have only upgraded the Paridisea so far. I have 2 x SB2s, one standard and one that was modded by Vinnie of Red Wine Audio. I do like the sound at the moment but will definately use the transformers very soon in the SB2s, possibly in the standard unit first and comparing it to the RWA modded one.

Brad

tanchiro58 · « **Reply #47 on:** 11 May 2007, 06:30 pm »

Quote

possibly in the standard unit first and comparing it to the RWA modded one.

Brad,

You will be amazed after modding your standard SB2 with pulse transformer. My modded sources (SB3 and DAC) are in the process of break-in right now. Every day I hear a better and better sound I have ever listened since I started in this hobby.

:DI suggest you would not want to mod on the already modded unit.

jhm731 · « **Reply #48 on:** 11 May 2007, 07:57 pm »

Quote from: tanchiro58 on 11 May 2007, 06:30 pm

Quote
possibly in the standard unit first and comparing it to the RWA modded one.

Brad,

You will be amazed after modding your standard SB2 with pulse transformer. My modded sources (SB3 and DAC) are in the process of break-in right now. Every day I hear a better and better sound I have ever listened since I started in this hobby. :DI suggest you would not want to mod on the already modded unit.

Tan-

Why shouldn't Brad mod his RWA SB2, does it already have a SC947-02 in it?

tanchiro58 · « **Reply #49 on:** 11 May 2007, 08:09 pm »

Quote

Why shouldn't Brad mod his RWA SB2, does it already have a SC947-02 in it?

jhm731,

I do not know that RWA digital mod with SC947-02. I only saw RWA mod on analog part with BG caps form one of my friend and guess caps were applied on digital part too. What I mean is any sources which have too many mods would not sound good. I have experienced this before. Sorry for misunderstanding.

Tan

Builder Brad · « **Reply #50 on:** 12 May 2007, 07:43 am »

Probably the best way forward regarding the Squeezebox would be to add a transformer to the unmodded SB and compare it to the RWA one in the first instance. If the SB with the transformer compares favourably with the RWA unit I will probably then look to perform more tweaks on this unit, based around the digital sections - cutting the pcb in half will even be an option, with this in mind does anyone know where I can download a complete Squeezebox2 schematic?

Brad

Builder Brad · « **Reply #51 on:** 17 May 2007, 08:52 pm »

OK, here is my SB2 pcb before I start - just so I can remember where everything goes, once I start working on it!

I have added the transformer to the digital outputs with pins 6 and 7 both tied to the SB2 ground. I have removed both inductors L5 and L2, L2 connected the digital output earth to the pcb earth, so this is now completerly issolated from the pcb.

with this one mod and the standard switching PS I am no way near the performance of the other modded SB2.

next option will be to use the 5v linear PS

jhm731 · « **Reply #52 on:** 17 May 2007, 10:04 pm »

Brad- very nice work, but i suggest you install a cap between the shields and ground like you did in your
DAC. There's a lot of noise on the SB2's ground plane.

Builder Brad · « **Reply #53 on:** 18 May 2007, 05:07 am »

I used a .01 uf ceramic on the DAC - should I use the same, or something else, I have some silver mica caps and quite a few polystrene caps spare.

tanchiro58 · « **Reply #54 on:** 18 May 2007, 06:13 am »

Brad,

If you have a NOS Vitamin Q PIO 0.1uF/200V it would be the best prevention of noise in SB3. I hear more spacious and detailed sound.

Tan

jhm731 · « **Reply #55 on:** 18 May 2007, 04:49 pm »

Quote from: Builder Brad on 18 May 2007, 05:07 am

I used a .01 uf ceramic on the DAC - should I use the same, or something else, I have some silver mica caps and quite a few polystrene caps spare.

Anything in that value range should work, or you could try .1uf/.01uf combo.

Builder Brad · « **Reply #56 on:** 18 May 2007, 07:07 pm »

cheers guys,

I fitted a panasonic 0.015uf polypropylene cap tonight and have improved the sound considerbly, not up the the other SB2 yet - but I have not tried the linear PS yet.....

Brad

tanchiro58 · « **Reply #57 on:** 18 May 2007, 11:38 pm »

Quote

but I have not tried the linear PS yet.....

Brad,

You will be amazed with the linear PS hook up to your pulse transformer modded SB2. I bet the combination will beat the other modded SB2 easily. Do you use any PS for your RWA modded SB2 besides the stock one?

Tan

Builder Brad · « **Reply #58 on:** 19 May 2007, 06:21 am »

Hi Tan,

The RWA Squeezebox has been on a bit of a journey when it comes to power supplies. The unit originally was given the works by Vinnie with the full battery mod - the actual battery 12v power supply included a 5v regulator and the Squeezebox used both 12 and 5v. Whenever I charged the battery and used acheap 12v Dc plug in wall supply I noticed that there was very little difference between this and the battery supply, in fact this sometimes sounded better to me, so I evetually did away with the battery and built a modded version of the JSR04 with +12v +5v outputs, rather that the normal equal + and - rails. The unit with the JSR04 sounded considerbly better than when I used the battery supply, although all of this relates to the analogue outputs.

http://sjostromaudio.com/_unsql/forsale/index.html

I think it will be quite a challenge to improve on the current sound, although I will be pleased if I can as you can imagine.

Brad

tanchiro58 · « **Reply #59 on:** 9 Jul 2007, 09:00 pm »

To be continued....

Brad,

I have to agree with you instead of using battery for NOS DAC why don't we just go directly to AC power or JSR04 like you did. I had an Ack Dack which is also using battery and I do not like much.