Dacmagic1 after upgrade. Some advice please. - 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 13th April 2012, 01:08 AM   #1
diyAudio Member
 
Join Date: Mar 2012
Location: Near Falkirk, Scotland.
Default Dacmagic1 after upgrade. Some advice please.

I recently upgraded a dacmagic1, replacing the below items. I was wondering if someone would be able to take a look at what i have replaced so far.

Im new to modifying audio, and would really appreciate some feedback as to where i may have gone wrong, and, or, where i may improve on what i have done to date.

The 2 opa2604ap opamps were replaced with lm4562na into 8 pin gold plated sockets.

All caps were replaced with same values. As follows:

14x 100uf 10v Vishay OS-CON organic polymer capacitors for to replace the existing electrolytics

10x 3300 uf 25v Panasonic FC to replace the existing smoothing electrolytics.

4 x nichichon FG to replace the existing 47uf 16v on the opamps

6 x nichicon KW 2200uf 16v caps

10 x nichicon KT caps 10uf 35v

I have heard a difference after the mods, But before i go any further i would like to make sure there are no problems with what i have done to date. I do feel it sounds a bit harsh at times, and the bottom end sounds a bit wooly. I wonder if i have introduced an issue somewhere with the oscons, or opamp change, or elsewhere.

I was considering buying a scope, but don't have much experience using one, not sure if it would be a waste of time and money at this stage.

Could post some pics of the mods done if it would help

Thanks
  Reply With Quote
Old 13th April 2012, 01:33 AM   #2
diyAudio Member
 
Join Date: Jan 2008
Location: Virginia
Try some extra 0.1uF decoupling on each OpAmps power rails. Pin 4 to GND and pin 8 to GND.
  Reply With Quote
Old 13th April 2012, 11:09 PM   #3
diyAudio Member
 
Join Date: Mar 2012
Location: Near Falkirk, Scotland.
Quote:
Originally Posted by SoNic_real_one View Post
Try some extra 0.1uF decoupling on each OpAmps power rails. Pin 4 to GND and pin 8 to GND.
Thanks sonic, very helpful.

What type of decoupling caps would you recommend?

Was also thinking of trying some other opamps, first to see if maybe it is just the lm4562's i don't like. possibly even retrying the original opa2604's as they actually sounded sweeter. With a much larger stereo image, much tighter bottom end as well. Maybe try a few others as well while I'm at it.

If i did the decoupling mod to the opamp dip sockets, is this intended for the lm4562 only ?

Or will it be suitable for any opamp i happen to try that is a suitable replacement?

Also, are there any other areas where it may be prudent to add decoupling caps?

Thanks again.
  Reply With Quote
Old 13th April 2012, 11:57 PM   #4
diyAudio Member
 
Join Date: Jan 2008
Location: Virginia
The 0.1uF is a good addition for any OpAmps, but the faster they are, the more they need those capacitors:
http://www.analog.com/static/importe...als/MT-101.pdf
See page 5,6 of above. Film is best for audio. Ceramics are good too (at least some of them).

Last edited by SoNic_real_one; 14th April 2012 at 12:00 AM.
  Reply With Quote
Old 14th April 2012, 10:57 AM   #5
diyAudio Member
 
Join Date: Mar 2012
Location: Near Falkirk, Scotland.
Quote:
Originally Posted by SoNic_real_one View Post
The 0.1uF is a good addition for any OpAmps, but the faster they are, the more they need those capacitors:
http://www.analog.com/static/importe...als/MT-101.pdf
See page 5,6 of above. Film is best for audio. Ceramics are good too (at least some of them).
Found this selection of opamps on ebay for Ģ20, there are some monos, which will not really be much good to me. But looks quite a wide range.

http://www.ebay.co.uk/itm/Audio-OPAM...ht_11646wt_982


Do you think this is a pretty good selection of alternative opamps for the dacmagic, or would i be better buying in pairs?

Could someone suggest a list of decent alternatives to the lm4562 and opa2604?

Thanks

Last edited by Reference1042; 14th April 2012 at 11:00 AM.
  Reply With Quote
Old 14th April 2012, 01:39 PM   #6
diyAudio Member
 
Join Date: Jan 2008
Location: Virginia
Don't buy from eBay, especially from China - you will get fakes and then complain that the "recomended OpAmps suck". The fakes have laser engraving now, look "authentic", but I think you don't want a "jelly-bean" OpAmp labeled as LM4562.
Buy from a distribuitor. I think Farnell is in your area?
I did try OPA2604 and wasn't impressed. Only sligtly better than 5532, good if you really need j-fets. LM4562 is equal to LME49720 (renamed to match the naming scheme). National now is owned by TI.
If you are in SMD work, you can try also AD8599. I did like it.

Last edited by SoNic_real_one; 14th April 2012 at 01:49 PM.
  Reply With Quote
Old 14th April 2012, 01:51 PM   #7
Gopher is offline Gopher  United Kingdom
diyAudio Member
 
Join Date: Nov 2005
Location: UK
I don't understand why these people in China go to so much trouble making fake op-amps. Most large quantity orders will always be placed through authorised distributors. E-Bay sales can't be that big.

Also, why do people take the risk of buying off E-Bay when going to the distributors will often only cost a few dollars more for the genuine article. Are they stupid or just hooked on E-Bay???

Last edited by Gopher; 14th April 2012 at 01:56 PM.
  Reply With Quote
Old 14th April 2012, 01:52 PM   #8
gk7 is offline gk7
diyAudio Member
 
Join Date: Oct 2007
Location: Vienna, Austria
I havenīt seen the schematic of the Dacmagic, but if it had FET opamps (OPA2604) originally, itīs probably not a good idea to replace them with bipolars (no matter how "good" they are).
  Reply With Quote
Old 14th April 2012, 01:54 PM   #9
gk7 is offline gk7
diyAudio Member
 
Join Date: Oct 2007
Location: Vienna, Austria
Quote:
Originally Posted by SoNic_real_one View Post
Don't buy from eBay, especially from China - you will get fakes and then complain that the "recomended OpAmps suck". The fakes have laser engraving now, look "authentic", but I think you don't want a "jelly-bean" OpAmp labeled as LM4562.
...
Are you speaking from experience or is this the usual China bashing ?
  Reply With Quote
Old 14th April 2012, 01:55 PM   #10
diyAudio Member
 
Join Date: Jan 2008
Location: Virginia
Well, usually the DAC's don't require j-fet's, they are sometimes used in older devices for other reasons - speed.
Sure, only schematic can elucidate that for sure.
  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 10:03 AM.


vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2014 DragonByte Technologies Ltd.
Copyright Đ1999-2014 diyAudio

Content Relevant URLs by vBSEO 3.3.2