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
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
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.
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/imported-files/tutorials/MT-101.pdf
See page 5,6 of above. Film is best for audio. Ceramics are good too (at least some of them).
http://www.analog.com/static/imported-files/tutorials/MT-101.pdf
See page 5,6 of above. Film is best for audio. Ceramics are good too (at least some of them).
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Found this selection of opamps on ebay for £20, 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-OPA...upplies_ET&hash=item256f5ffa32#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
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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.
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.
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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???
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???
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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.
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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.
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.
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.
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.
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?
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?
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
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!!!!!!!!!!!!
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!!!!!!!!!!!!
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