If you decide to try it, that part will benefit from a .01 ceramic across the -/+ power pins 4, and 8, along with a 10uf electrolytic.
The dac I had just like that one sounded good with an opa2604, not available anymore I believe, but a good fet input op amp like the ad744 would probably be my choice, on a dual adapter, all things considered.
Sounds like the heatsink might be a good idea, coffee is usually hotter than 120 deg F, which is a what I like to see transistors limited to. Do you have a thermometer by chance?
I use a cheap non-contact device to check stuff.
12.4v is typical for an unloaded 12v transformer.
Any scrap or used places nearby to find a larger 9v transformer?
The dac I had just like that one sounded good with an opa2604, not available anymore I believe, but a good fet input op amp like the ad744 would probably be my choice, on a dual adapter, all things considered.
Sounds like the heatsink might be a good idea, coffee is usually hotter than 120 deg F, which is a what I like to see transistors limited to. Do you have a thermometer by chance?
I use a cheap non-contact device to check stuff.
12.4v is typical for an unloaded 12v transformer.
Any scrap or used places nearby to find a larger 9v transformer?
One of the regulator gets really hot, enough to induce pain when touching. I misplaced the heatsinks and I'll see if I can get one from my company store. I'll try again with the heatsink on.
AD744 ?
I'll be paying my local electronics shop a visit today to see if they have any opamps in stock.
I do have a thermometer(contact type) but it's for measuring body temperature. As for non contact type, can I use the forehead temperature thermometer available for cheap on Amazon ?
Would it work ?
Ok, I'll see if I can source a ceramic cap.
AD744 ?
I'll be paying my local electronics shop a visit today to see if they have any opamps in stock.
I do have a thermometer(contact type) but it's for measuring body temperature. As for non contact type, can I use the forehead temperature thermometer available for cheap on Amazon ?
Would it work ?
I recall that 138F is the pain temperature, so that’s a bit high for long term use, as far as I have concluded, maybe someone else has more info on that particular regulator.
A chunk of aluminum would work probably if you cannot find a proper heat sink.
A chunk of aluminum would work probably if you cannot find a proper heat sink.
Yeah, I think so.
The regulator in question is 7805TC by the way.
Yeah, I thought that too. I'll first see if I can score a copper block first (copper is better than aluminium, right ?). If I can't get any, I'll get an aluminium block.
The regulator in question is 7805TC by the way.
Yeah, I thought that too. I'll first see if I can score a copper block first (copper is better than aluminium, right ?). If I can't get any, I'll get an aluminium block.
I'll be buying the 9V, 1A transformer as well as the heatsink today. Hope that these would stop the heating issue of the voltage regulator.
I got the 9v 1amp trafo hooked up. Load voltage is 8.9v which is pretty good. Also got the heatsink.
Then I said what the heck, lemme try the lme49720na ! Wow, this thing is loud ! The bass kicks harder and the treble is more prominent. But the treble can be a bit....grainy ? Huge change in sound signature for the better (for my taste). Sorry @Phase, I haven't tried your suggestion of adding ceramic as well as a electrolytic cap on the power pins of the opamp.
But I took a good look at the circuit and found that a 1000uF (16v) electrolytic cap was connected to the pin 4 and an another 1000uF (16v) cap connected to the pin 8. Is it ok ?
EDIT:
The brand name of the cap is showing as KZJ.
By the way, I have a 8 pin chip labeled "JR21ACE3 LF 356N". Is it an opamp and any idea on how good is it ? Seems like the LF356N is a single channel opamp.
So, any opamp recommendations other than the AD746 ?
I got the 9v 1amp trafo hooked up. Load voltage is 8.9v which is pretty good. Also got the heatsink.
Then I said what the heck, lemme try the lme49720na ! Wow, this thing is loud ! The bass kicks harder and the treble is more prominent. But the treble can be a bit....grainy ? Huge change in sound signature for the better (for my taste). Sorry @Phase, I haven't tried your suggestion of adding ceramic as well as a electrolytic cap on the power pins of the opamp.
But I took a good look at the circuit and found that a 1000uF (16v) electrolytic cap was connected to the pin 4 and an another 1000uF (16v) cap connected to the pin 8. Is it ok ?
EDIT:
The brand name of the cap is showing as KZJ.
By the way, I have a 8 pin chip labeled "JR21ACE3 LF 356N". Is it an opamp and any idea on how good is it ? Seems like the LF356N is a single channel opamp.
So, any opamp recommendations other than the AD746 ?
I tried eBay and the dual AD744 along with the mono dip adapter is costly. So, I'm gonna get the AD746 and OPA 1612 !
Not from ebay I hope. Opamps are often fakes there, not really the parts that the part number printed on them says.
@Markw4
Ouch ! I just bought a LT1361 from eBay just for checking. Only paid 2 bucks 😛 Shall I cancel it ?
Haven't bought the AD746 yet though. I wish the shipping charges were not that huge for mouser (US to India).
Ouch ! I just bought a LT1361 from eBay just for checking. Only paid 2 bucks 😛 Shall I cancel it ?
Haven't bought the AD746 yet though. I wish the shipping charges were not that huge for mouser (US to India).
LT1361CN8 @Mouser India: ₹461.78 or $6.55 // Duty, customs fees and taxes are collected at time of delivery (meaning that there will be an added cost) Quite a difference between an official and trusted distributor and an eBay reseller... It's your money after all.
Yeah, its not cheap !
But, I'm OK with the LME49720 though. First I need to add the caps as Phase recommended to the opamp pin (is 25V capacitors enough?).
Then, I'll checkout the power supply part of the DAC board.
But, I'm OK with the LME49720 though. First I need to add the caps as Phase recommended to the opamp pin (is 25V capacitors enough?).
Then, I'll checkout the power supply part of the DAC board.
I have purchased what had been advertised as a dual opa627 from ebay for $6, is really a dual ad744, and has been sounding great for years in the servo on my dac board.
I should have mentioned that in my earlier post, haven’t tried to purchase an ad744 otherwise.
Nothing wrong with the opa1612 from what I have read either, another good one is the ad827.
I should have mentioned that in my earlier post, haven’t tried to purchase an ad744 otherwise.
Nothing wrong with the opa1612 from what I have read either, another good one is the ad827.
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There is no telling what you will get from ebay these days. Probably depends most if you are looking to buy something expensive where a lot of money could be made with a fake, or maybe even if you want to buy something for less than it costs to buy it in China and ship it here. In that case what do you expect them to do? Opamps are more likely to be a problem than some other things because they mostly have standard pinouts. Very desirable and hard to find transistors get faked too. Some things are unique enough they probably can't be totally fake, but they might be factory reject parts that don't meet specs. You can measure what you buy if you really want to know, or just buy from reputable dealers you don't have to worry about. Or, you can take your chances, which I would not do. I don't want worry about parts quality affecting what I am trying to do, since I have enough to deal with already.
No claim is made to that effect. Might have been news for eljoantonyn, though. Dunno.
Beyond that, it seems kind of hard to find much in the way of exciting news in the <$30 dac market.
Say, any chance you would have some new news for us on that? 🙂
Beyond that, it seems kind of hard to find much in the way of exciting news in the <$30 dac market.
Say, any chance you would have some new news for us on that? 🙂
Nope, sorry, nothing new to report, but that fake opa627/ad744 was easy to live with for the couple years I had it in my dac.
I had a good feeling it wasn’t legitimate, but had some good reviews, and when it was revealed what they really were, it wasn’t a surprise. I still use one of them in the servo, but gave the other one away to my dad to use in his setup. It was easy to forward bias slightly for a cleaner sound.
I had a good feeling it wasn’t legitimate, but had some good reviews, and when it was revealed what they really were, it wasn’t a surprise. I still use one of them in the servo, but gave the other one away to my dad to use in his setup. It was easy to forward bias slightly for a cleaner sound.
support for fake components...?!
Quite an unfortunate turn of words sending the wrong message to those with low budgets for DIY spenditure on their quest for reaching the Holy Grail of Sound... This is tantamount to supporting the manufacturers and peddlars of fake components IMHO...
Quite an unfortunate turn of words sending the wrong message to those with low budgets for DIY spenditure on their quest for reaching the Holy Grail of Sound... This is tantamount to supporting the manufacturers and peddlars of fake components IMHO...
Thanks for the comments guys I'll post a reply when I get back home.
But, here is the thing. My partner is away for like 2 weeks and I have to improve the SQ in that time or I'll be forced to get the Schiit Modi 3. Currently the dac sounds worse than my iPad.
So, where should I start ?
Power supply ?
But, here is the thing. My partner is away for like 2 weeks and I have to improve the SQ in that time or I'll be forced to get the Schiit Modi 3. Currently the dac sounds worse than my iPad.
So, where should I start ?
Power supply ?
Maybe some line conditioning, a .1uf X polypropylene capacitor across the incoming ac power. That's pretty easy to accomplish and has always helped, especially in line level devices.
A snubber across the diode bridge is another example of low hanging fruit.
I have my own experience to call from regarding the quality of the various suppliers of components. Unfortunately for us hobby consumers, the very best of the runs tend to go out the oems. Even parts available to us low volume consumers from the popular distributors are not going to be the best always. With that, much of the surplus that goes onto the market through various outlets will be often better than what can be available through preferred channels. You are free to buy from whomever you wish, it is a free market. If the abundance of different vendors on an auction site is overwhelming, and you don't have the ability to discern between the different parts and vendors, then maybe another source would be better for you.
A snubber across the diode bridge is another example of low hanging fruit.
I have my own experience to call from regarding the quality of the various suppliers of components. Unfortunately for us hobby consumers, the very best of the runs tend to go out the oems. Even parts available to us low volume consumers from the popular distributors are not going to be the best always. With that, much of the surplus that goes onto the market through various outlets will be often better than what can be available through preferred channels. You are free to buy from whomever you wish, it is a free market. If the abundance of different vendors on an auction site is overwhelming, and you don't have the ability to discern between the different parts and vendors, then maybe another source would be better for you.
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@phase
I have a 1.5uF polyester cap. Can I use it ? If I can't, should I go for the "audiophile grade" 3% polypropylene cap or just a "normal" 5 or 10% cap ?
The other thing you mentioned; its an interesting information for me and it makes sense. I don't understand why people with good ratings on eBay sell counterfeits ! If I do get a counterfeit, I'll surely give a negative feedback and get the refund.
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OPA1688 DIP Version Ultra High Quality Audio Operational Amplifier - DIYINHK
I have a 1.5uF polyester cap. Can I use it ? If I can't, should I go for the "audiophile grade" 3% polypropylene cap or just a "normal" 5 or 10% cap ?
The other thing you mentioned; its an interesting information for me and it makes sense. I don't understand why people with good ratings on eBay sell counterfeits ! If I do get a counterfeit, I'll surely give a negative feedback and get the refund.
------------------------
How reputed is this site ?
OPA1688 DIP Version Ultra High Quality Audio Operational Amplifier - DIYINHK