[deuginthesky]

With several months of hearing, how does it compares to Zhaolu 2.5 versions ?
I have had both CS4398 and 2 AD1852s
Still have one AD1852 which is modded with
-LM4562s
-AD08 (power board)
-new main 4300µF 35V caps + rubycon ZLH on the power board
-rubycon ZLH on analog stage (100µF)
-Muse bipolar caps removed
-1% appaired film caps (MKP2 0,15µF) instead of 0,1µF green film caps
-1% appaired PIO
-47pF 5% silver micas (as written on the board)
-470pF 1% polystyrene caps
-1000pF 2,5% FSC polystyrene caps
-clarity caps PX 6,8µF soldered on gold plated RCAs
-2mm blackson film
-resoldered fuse socket
-removed headamp
-Teflon "shielded" snubber

Would you think a Citypulse DA 7.2 will sound better ?

Have the issues (background sound and so on) been fixed from factory ?

What are the good and cheap mods to do on it ?

First aim will be to use it as dedicated DAC behind a Teac P-500 transport.

Thanks.

 

[HumanMedia]

Quote:

Originally Posted by deuginthesky /img/forum/go_quote.gif With several months of hearing, how does it compares to Zhaolu 2.5 versions ? I have had both CS4398 and 2 AD1852s Still have one AD1852 which is modded with -LM4562s -AD08 (power board) -new main 4300µF 35V caps + rubycon ZLH on the power board -rubycon ZLH on analog stage (100µF) -Muse bipolar caps removed -1% appaired film caps (MKP2 0,15µF) instead of 0,1µF green film caps -1% appaired PIO -47pF 5% silver micas (as written on the board) -470pF 1% polystyrene caps -1000pF 2,5% FSC polystyrene caps -clarity caps PX 6,8µF soldered on gold plated RCAs -2mm blackson film -resoldered fuse socket -removed headamp -Teflon "shielded" snubber Would you think a Citypulse DA 7.2 will sound better ? Have the issues (background sound and so on) been fixed from factory ? What are the good and cheap mods to do on it ? First aim will be to use it as dedicated DAC behind a Teac P-500 transport. Thanks.

As an owner of a similarly tweaked Zhaolu 1.3 (with AD 1852), if you tweak a Citypulse to the same degree it is far better. I couldnt go back to the Zhaolu, and I keep it as a fond curio.

However adding a Oritech or Zapfilter output stage to the Zhaolu would make it better than the Citypulse.

 

[HumanMedia]

Quote:

Originally Posted by paulb30 /img/forum/go_quote.gif humanmedia - I was reading your upgrades with interest - and I am looking to get a warm sounder from my citypulse 2.03e. Chatting with Wu - it seems that the same mod can be applied to this model. Being competent with a soldering iron - but not competent with the inner workings of the DAC - are the output caps easy to find? Can you give me some pointers? - I might try the same thing as you.

Its the single cap directly under each of the red plastiic boxes. ie You need to pull the red boxes out, and it is directly underneath in the middle. See my previous post with more detailed instructions. Note again that the cap you will replace it with will be far larger and need extensions to its legs and will need to be placed on top of the red boxes. While you have the red boxes out, clean and splay the legs out so the friction is greater when they are reinserted. Use a contact enhancer on the legs also.

In addition to cleaning and treating all plugs and contacts, adding ceramic fuse (contact enhanced and heatshrinked in), I also used ERS paper around the toroid, on top of the DAC chip and receiver chip, the upper case, between the red boxes and the (nw) cap on top of them, and on top of the caps. I also dampened everything I could, new footers for the case, teflon tape between all touching caps, blutac on the timing crystal etc. I even rested a sheet of acoustic rubber/foam laminate on top of the unit at all times to dampen the case.

 

[deuginthesky]

Quote:

Originally Posted by HumanMedia /img/forum/go_quote.gif As an owner of a similarly tweaked Zhaolu 1.3 (with AD 1852), if you tweak a Citypulse to the same degree it is far better. I couldnt go back to the Zhaolu and keep its as a fond curio. However adding a Oritech or Zapfilter output stage to the Zhaolu would make it better than the Citypulse.

What about stock citypulse vs a modded D2.5A or D2.5C with same kinds of mods than mine ?

Do you know if background noise issues have been solved ?

 

[HumanMedia]

Quote:

Originally Posted by deuginthesky /img/forum/go_quote.gif What about stock citypulse vs a modded D2.5A or D2.5C with same kinds of mods than mine ? Do you know if background noise issues have been solved ?

The stock Citypulse will have better bass but inferior treble.

I never had a background noise issue with mine - although I never use the variable analog outs (in fact I removed them altogether) and only use fixed analog outs.

 

[Spare Tire]

Quote:

Originally Posted by ack_0220 /img/forum/go_quote.gif Hi everyone, I am using my citypulse on my computer with Foobar and Asio4all. I've been trying out the 2xFs lately, on certain tracks it sounds better, more natural and less noise, but it makes some popping sounds sometimes, not very loud but audible. When i turn the Fs off, its ok. Was wondering if any of you guys have any idea on this. Also, what sampling rate does the 2xFs actually upsample to?

You can find the answer to the pops in the thread about the 2.03e. I had similar experience.

 

[paulb30]

Quote:

Originally Posted by HumanMedia /img/forum/go_quote.gif Its the single cap directly under each of the red plastiic boxes. ie You need to pull the red boxes out, and it is directly underneath in the middle. See my previous post with more detailed instructions. Note again that the cap you will replace it with will be far larger and need extensions to its legs and will need to be placed on top of the red boxes. While you have the red boxes out, clean and splay the legs out so the friction is greater when they are reinserted. Use a contact enhancer on the legs also. In addition to cleaning and treating all plugs and contacts, adding ceramic fuse (contact enhanced and heatshrinked in), I also used ERS paper around the toroid, on top of the DAC chip and receiver chip, the upper case, between the red boxes and the (nw) cap on top of them, and on top of the caps. I also dampened everything I could, new footers for the case, teflon tape between all touching caps, blutac on the timing crystal etc. I even rested a sheet of acoustic rubber/foam laminate on top of the unit at all times to dampen the case.

Cheers...
I will let you know how I get on. Wu suggested trying some Mundorf Silver/Oil mcaps as replacements for the stock ones - "It sound more smooth and slim but very detail."

The electolytic 100uf replacement changes the timing making the bass longer and hence warmer (I suppose) - I might try this first (as its cheaper).

On your other mods; interestingly I opened my old Sony CDP X559ES the other day to fix the optical out. The chassis is solid copper (weighs a ton), and their is a copper shield between the power /CD tray side, and the DAC side. Also inside the lid there is a large strip of dampening material, almost bitumen like.
Only thing it didn't have was any mains earthing

..not cool.

 

[eaoyama]

Hello!!..

I started my mods in the DAC, i'm just waiting some components to come, till now i just bypass all tantalum capacitors with styroflex caps, changed the fuse ( this really works ), now the sound is more warm, more bigger, changed the 100nF in the bridge of digital supply to 10nF with a RC filter, after 100hs of burn in, the sound is better and less harsh. I'm planning now change the regulators like 7805s and the 7812 and 7912 to another power supply, another thing i was thinking is to change the choke of 6.8uH on audio output with a air core. One question, looking in the bottom of the red box, i can see a IC, is this a opamp? If yes, i think this isn't a totally discrete output...

 

[pompon]

Quote:

Originally Posted by Magsy /img/forum/go_quote.gif I've run it for 48 hours solid playing music and I still don't like the way it sounds. I prefer my modded 0404 by quite a lot, this shouldn't be. High's are harsh and it just never evelops me and sucks me in, it .

Let it burn ... even 200 hrs is not enough. Think 500hrs+.

 

[parrymike]

I'm quite keen on getting one of these from Eddie but I'm put off by the possibility of import duty and tax etc.

Has anybody in the UK bought stuff from Eddie? Could you let me know how you got on with customs?

Cheers,
Mike

 

[jmudrick]

Given the 7.2's sensitivity to power supply issues, am wondering whether anyone has tried running the unit off the grid?? Since all my other components will be battery powered, it would be nice to be able to do that with the Citypulse as well. (I pick mine up in January when I'm back in the States).

Also, I see that Discovery Hi-fi in Bangkok mods the units. I can't read Thai so Ï'm wondering if anyone is familiar with the mods they do. It would be easy for me to bring the unit to them on my way back home.

http://www.discoveryhifi.com/citypulse_upgrade.html

Thanks.

Jeff
Phnom Penh

 

[he46570]

If anyone's interested, I have a DA2.03e for sale in New York. I'm downsizing my office system, hence the sale.

 

[regal]

You know it should be possible to to remove the caps in the signal path between the DAC and the discrete opamps by trimming the voltage to the DAC-out potential.

http://www.candeias.com/file/CC80-Datasheet.pdf


This should also allow removal of the coupling caps.

Could make a drastic sound improvement.

 

[LawnGnome]

I bought this DAC. And have been very disappointed. It measures very badly, has has weird peeks in its output.

Also, the build quality of my unit is very poor, components improperly placed, and many many dry solder joints.

Also, just to note, if you buy the upgrade TXCO clock, you will LOSE the oversampling feature.

Because the frequency of that clock is thirty something mhz. And the only sampling frequency that the DAC will work with with that reference clock speed is 44.1khz.

So forget anything above that, like SACD. When I turned on oversampling with a higher sample rate, I got loud cracking and popping. And I measured the noise floor to shoot up to -30dba.

You can figure out more when you read the TI white papers for the DAC chip.

 

[pompon]

Quote:

Originally Posted by LawnGnome /img/forum/go_quote.gif Also, just to note, if you buy the upgrade TXCO clock, you will LOSE the oversampling feature. .

I have the 7.2x version 1 .. not the version 2 and I have TXCO.

My oversampling work fine. Give me a bit smoothing highs. I prefer without oversampling (FX).