[C37]

Quote:

Originally Posted by Gautama /img/forum/go_quote.gif Whats the reasoning behind that? Seems like a Patrick82 mod...

Who's Patrick?

Caps are microphonic and I've noticed that they vibrate quite a bit ( in my room) ... there could be better ways to do this, but i decided to try it out first with a simple and avaible means ( and retrofittable) I had at my disposal. It' won't be long before i put the 2.5 in a new case.

 

[Gautama]

That makes sense.

Patrick is...in a word...abstract.

 

[C37]

Quote:

Originally Posted by Gautama /img/forum/go_quote.gif That makes sense. Patrick is...in a word...abstract.

Actually i just happened to wonder since i've seen this kind of damping of caps ( my dact ct 101 has heat wrap shrinking around them) if it would make any difference. Just by touching with my fingers the zap caps PSU while music was playing made an slight but clearly audible one.So i decided to try this, thinking if I don't like it, it's easy to reverse. It's staying full stop.
- This might not apply if you are using headphones though....

 

[TURBO]

I just modified my Zhoulou D3. Very simple ones, but they made the world of a difference.

- I re-soldered all solder points

- Replaced all rca jacks with high quality ones and re-soldered the rca jacks using my own wires. Je, je. I just created another monster.

- I glued the optical connector to the board, so stays stable on the board. This is a very weak connector, so now is solid rock.

- Cleaned all boards components and connectors with a high grade cleaner .

I do have a GS1 amp. These two together, have the most clinical sound gear in the whole world. Je, je. Very, very detailed sound. I never heard anything alike.

I hear details that I never heard before with a extreme decay and emphasis. I am a very happy camper. I don't think I will need to open this baby again.

Right now is burning in and I am adjusting to this new gamut of frequencies. Nice.....

 

[Ori]

Quote:

Originally Posted by C37 /img/forum/go_quote.gif Caps are microphonic and I've noticed that they vibrate quite a bit ( in my room) ... there could be better ways to do this, but i decided to try it out first with a simple and avaible means ( and retrofittable) I had at my disposal.

Large electrolytics would benefit from vibration absorbing materials. "Blu Tak" is widely used by audiophiles but you can use any "museum wax", a clay-like material from your local craft store.
If you want a complete mod for your electrolytic cap, then first strip the plastic cover with an exacto knife, the re-solder it so it is tight on the PCB and only then put a strip of damping material on the top. For long caps you may need to dampen the middle as well.
And don't think that non-electrolytics are immune to micophonics.

 

[C37]

Quote:

Originally Posted by Ori /img/forum/go_quote.gif Large electrolytics would benefit from vibration absorbing materials. "Blu Tak" is widely used by audiophiles but you can use any "museum wax", a clay-like material from your local craft store. If you want a complete mod for your electrolytic cap, then first strip the plastic cover with an exacto knife, the re-solder it so it is tight on the PCB and only then put a strip of damping material on the top. For long caps you may need to dampen the middle as well. And don't think that non-electrolytics are immune to micophonics.

Thanks for the tip, Ori, i think i remeber Peter Daniel and others from DIYaudio doing this...
What disturbs me is that the Rcore transformer buzzes and vibrates quite too much in the 2.5!!
In a series a mods for the Philips 723 player that were published in the "Nouvelle revue du son" they decoupled mecanically the tranny and made back a ground connection through a 3mH ferrite self . Can someone enlightment me why the latter? What does that do? would this be desirable?
The pic comes from http://www.petoindominique.fr/php/cd723.php where there are scans of the article I'm mentioning.(French only, c' est la vie mes amis!)The red arrow shows the self with some blu-tack on it, hence the weird aspect.

 

[Ori]

Quote:

Originally Posted by C37 /img/forum/go_quote.gif What disturbs me is that the Rcore transformer buzzes and vibrates quite too much in the 2.5!!

Check that the mounting hardware is not loose. You can always "fix" that mechanical issue with a hammer...
If not, then I'd worry first about the quality of the AC line. I always use a hefty toroidal power line filter to isolate digital noise at the digital source components, and it helps with other 'garbage' as well.
The last resort would be a new toroidal tranny, or better yet - two of them...

 

[C37]

Quote:

Originally Posted by Ori /img/forum/go_quote.gif Check that the mounting hardware is not loose. You can always "fix" that mechanical issue with a hammer...

I've noticed the black core of the transfo is loose.It plays 3-5 mm horizontally and then some 2-3 mm vertically. Centering it and levelling it deads it completely. time to take out my hammer...

 

[C37]

Still would like to know what that 3 to 4 mH self does on the grounding path in my previous post... could not find any info on that...

 

[fierce_freak]

I'm posting here since most of the zapfilter gurus seem to hang here. I recently put a Zapfilter into an Opus (twistedpearaudio.com) DAC and have a slight hum problem. I'm running two opus dac boards in dual differential mode. The output from the zapfilter goes to a set of XLR's as well as RCA's.

I'm getting the hum through the RCA's. If I disconnect the - signals between the DAC and the zapfilter, the hum completely vanishes. Can anyone think of an idea for this?

 

[SonicDawg]

Quote:

Originally Posted by fierce_freak /img/forum/go_quote.gif I'm posting here since most of the zapfilter gurus seem to hang here. I recently put a Zapfilter into an Opus (twistedpearaudio.com) DAC and have a slight hum problem. I'm running two opus dac boards in dual differential mode. The output from the zapfilter goes to a set of XLR's as well as RCA's. I'm getting the hum through the RCA's. If I disconnect the - signals between the DAC and the zapfilter, the hum completely vanishes. Can anyone think of an idea for this?

If you search within this thread you should find some info about the humming problem. Usually it is due to incorrect resistor value used by LC Audio for US appliances.

 

[fierce_freak]

Yeah, I saw those posts. I have the correct valued resistors, though

 

[fierce_freak]

-edit- scratch that

There must be a ground loop between the two, but I'm not sure where it's coming from.

 

[looser101]

Quote:

Originally Posted by fierce_freak /img/forum/go_quote.gif -edit- scratch that There must be a ground loop between the two, but I'm not sure where it's coming from.

Are the XLR's and RCA's insulated from the case? Pretty obvious but just wanted to make sure. Are you using metallic standoffs? Board might be grounding to the case through them. I don't remember if the any of the mounting pads are part of the ground circuit.

Renato

 

[keyid]

I got an used Zaholu 2.5c with 2604 opamps, I did the caps bypass and I could not stand the sibilance in the highs. Tried burning it in hoping it would go away but still the same, what was weird is that my silver plated coaxial made it worst, the cccc's and ssss's was unbearable all the highs are too electronic sounding.
When I used an optical it tamed the highs alittle more organic sounding.

Question I have is would 2107 or LM4562 tame the highs even more. I do really like sound with the bypass but I need a more natural high

This is with almost any cd with women's voices singing, I cant listen to eva cassidy anymore... My amp is a Pimeta with 627/637.