Dacmagic1 after upgrade. Some advice please. - Page 2 - diyAudio
Go Back   Home > Forums > Source & Line > Digital Line Level

Digital Line Level DACs, Digital Crossovers, Equalizers, etc.

Please consider donating to help us continue to serve you.

Ads on/off / Custom Title / More PMs / More album space / Advanced printing & mass image saving
Reply
 
Thread Tools Search this Thread
Old 14th April 2012, 01:56 PM   #11
diyAudio Member
 
Join Date: Jan 2008
Location: Virginia
Quote:
Originally Posted by gk7 View Post
Are you speaking from experience or is this the usual China bashing ?
Experience. 6 cips that are obsolete and I did try different China-based suppliers (one said "Japan" but packager arrived from HK), all had cleand the paint labeling (polished off) and laser engraved with the "better" part name. Some had laquer applied after that, very proffesional looking if you never saw the original part. Measurements showed that was a "normal" part, still "working", but not what I paid for.

Good luck buying parts from China. US government had "surprises" in their military gear.

Last edited by SoNic_real_one; 14th April 2012 at 02:07 PM.
  Reply With Quote
Old 14th April 2012, 11:40 PM   #12
diyAudio Member
 
Join Date: Mar 2012
Location: Near Falkirk, Scotland.
After a bit more research it appeats Fake components are a pretty big issue in the industry, and not limited to EBay, or buying from China.

IHS: Counterfeit parts represent $169B annual risk-

Another interesting article on the Subject

Electronic Components Distributor - Worldwide Supplier of Electronic Parts Including Obsolete Electronic Components

An extract from the above:

"The counterfeiting problem is most prevalent in mainland China. Although we do not purchase directly from that region we continue to receive counterfeit parts on a weekly basis. Often the counterfeits supplied to us are from long time good standing suppliers who are just not trained or prepared to detect counterfeits.

So it appears that even if you buy from a reputable supplier there is still a risk that you may be unlucky enough to recieve counterfiet components.

I agree that EBay is certainly the most risky, but if you do your research properly, and read the feedback before buying it can be a very handy buying resource, and sometimes allows you to buy items that are not available elsewhere.

Im always apprehensive buying on Ebay, infact buying from a non UK supplier is always a last option, It is a nightmare when something goes wrong with the order.

Was looking to try a selection of different opamps in the dacmagic, which is why that ebay selection looked like a good option.. definately want to put the 2604's back in to see if the slight issues i am getting have been caused by the opamp change, or by using oscons instead of the electrolytics. Maybe ill just buy some from farnell, or RS if there are fakes flying about.
  Reply With Quote
Old 14th April 2012, 11:59 PM   #13
kevinkr is offline kevinkr  United States
diyAudio Moderator
 
kevinkr's Avatar
 
Join Date: Sep 2004
Location: Boston, Massachusetts
Blog Entries: 6
I haven't found Oscons to be particularly suitable as audio coupling caps although they seem to be quite effective on supply rails with a lot of HF noise.

If you got counterfeit op-amps on eBay you could have ended up with something as mundane as the 4558 dual (or worse) in place of the LM4562 you thought you were getting. I don't buy semi-conductors or electrolytic capacitors on eBay any more unless very rarely buying from a U.S. or U.K. seller, and usually go to Mouser, Digi-Key or Allied instead.
__________________
"Extraordinary claims require extraordinary evidence." - Carl Sagan
  Reply With Quote
Old 15th April 2012, 12:30 AM   #14
diyAudio Member
 
Join Date: Mar 2012
Location: Near Falkirk, Scotland.
I selected the oscons after seeing them recommended on various articles on the web, and spoke to an engineer who mods hifi, he said i should measure the voltage over all the existing caps. And any that were running under 6v will be on the digital rails, and should use oscons for these. Whether i have misunderstood what he said is a possibility, as i am very new to modding audio.

Was then told by another diyaudio member after ordering the stuff from mouser that infact the oscons may cause issues due to lower resistance than electros.

Is there any chance that using oscons where i have may have made the bottom end sound slightly wooly and not as tight as before. And a slightly harsher sound? Or is it more likely to be the opamp change?
  Reply With Quote
Old 15th April 2012, 01:38 AM   #15
diyAudio Member
 
Join Date: Jan 2008
Location: Virginia
Just add those 0.1uF and you will get rid of any oscillations induced by the low-ESR oscons.
  Reply With Quote
Old 15th April 2012, 02:00 AM   #16
diyAudio Member
 
Join Date: Mar 2012
Location: Near Falkirk, Scotland.
Quote:
Originally Posted by SoNic_real_one View Post
Just add those 0.1uF and you will get rid of any oscillations induced by the low-ESR oscons.
Thanks for clearing that up sonic. That makes sense when i think about it.

Maplin sell a few different types of film caps, would you mind having a quick look to see if any are well suited. There are mylar, polyester and polypropylene caps. They all look the same to me
  Reply With Quote
Old 15th April 2012, 02:32 AM   #17
diyAudio Member
 
Join Date: Jan 2008
Location: Virginia
Go with ceramics.
Polypropylene is the best of film caps, but might have higher inductance, are better in series with signal.

Last edited by SoNic_real_one; 15th April 2012 at 02:38 AM.
  Reply With Quote
Old 15th April 2012, 09:49 AM   #18
diyAudio Member
 
Join Date: Mar 2012
Location: Near Falkirk, Scotland.
Bloody maplin, I need to go to 2 stores to buy 4 ceramic caps. They only keep 2 in stock at each store.

As i say, maplins is no longer an electronics store. It should rebrand as toys r us.

Surely they don't take up that much space?

USELESS!
  Reply With Quote
Old 15th April 2012, 01:21 PM   #19
diyAudio Member
 
Join Date: Jan 2008
Location: Virginia
RadioShack here suffers of the same transformation. From a DIY store, now the sell mostly cell-phones, batteries and TV's.
  Reply With Quote
Old 15th April 2012, 03:20 PM   #20
diyAudio Member
 
Join Date: Mar 2012
Location: Near Falkirk, Scotland.
What a joke. Don't think ill ever go back to Maplin again.

Have just had to go to 3 stores for 4 tiny ceramic capacitors. They say the reason that they don't keep them is because they don't sell. But how can they sell items when they don't keep any in stock??? Has always been like that in maplin......crazy min stock is 1, maximum is 2.

Shortsighted accounting and streamlining by bean-counters, and managers.

Are companies at all surprised that people would rather buy off the net.

The crazy thing is that in most cases they have caused this themselves....they are actually putting themselves out of business by refusing to hold basic items in stock that take up no space. They have 2 large empt racks of drawers that should be full to the gunnels with components.

So frustrating!!!!!!!!!!!!
  Reply With Quote

Reply


Hide this!Advertise here!
Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
Crossover Upgrade: Newbie Seeks Advice Lucky13 Multi-Way 20 25th August 2011 07:50 PM
Advice/Help - Cap upgrade dieselpower Tubes / Valves 6 19th June 2007 01:23 AM
Speaker Upgrade Advice Please Friends quasi Multi-Way 2 4th May 2007 03:35 AM
2 way speaker kit upgrade advice mark0311 Multi-Way 3 9th June 2005 10:46 PM
CD upgrade advice ultrachrome Digital Source 3 6th May 2004 05:14 PM


New To Site? Need Help?

All times are GMT. The time now is 07:03 AM.


vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2014 DragonByte Technologies Ltd.
Copyright ©1999-2014 diyAudio

Content Relevant URLs by vBSEO 3.3.2