Distorted
Dude! I usually turn the soldering iron on before I start prying with it.
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I wonder if the chip got fried or had a leg come loose or get bridged on your first attempt. Occasionally I get that type of low, distorted output after I replace a dac chip during an upgrade if one of the legs isn't soldered well or If I get into too much of a rush and over heat the chip. What transformer are you using? Maybe it's wrong for the job.
You can try caps instead. I like running direct out through caps the best anyway. Just use the + output through a cap to the output connector. 4-5uf of the Dayton foil caps. Any value, any cap from .47 to 200uf will work for a test.
.data said:Well I just tried that and the resistor broke into pieces while I was attempting to remove it, and that left me with just the ends of the traces, no pads just the ends of the traces
Dude! I usually turn the soldering iron on before I start prying with it.
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.data said:Oh well, doesn't work, very low gain and distorted.
Me = 0
Failed Mods = 2
Back to listening through the DVD player
Had to try
I wonder if the chip got fried or had a leg come loose or get bridged on your first attempt. Occasionally I get that type of low, distorted output after I replace a dac chip during an upgrade if one of the legs isn't soldered well or If I get into too much of a rush and over heat the chip. What transformer are you using? Maybe it's wrong for the job.
You can try caps instead. I like running direct out through caps the best anyway. Just use the + output through a cap to the output connector. 4-5uf of the Dayton foil caps. Any value, any cap from .47 to 200uf will work for a test.
Well, I give in, connected two of the wires and on attempting the third some solder flowed bridging all four of the legs for the outputs
I have tried to clean it up with braid without success.
I should have just changed the opamps as I originally was going to do, now I have to save for a new DAC, have now scraped 2 SRC 2496's trying to do a direct out mod.
In future I'm leaving the surface mounted stuff alone.
I have tried to clean it up with braid without success.
I should have just changed the opamps as I originally was going to do, now I have to save for a new DAC, have now scraped 2 SRC 2496's trying to do a direct out mod.
In future I'm leaving the surface mounted stuff alone.
Take it in for a dac swap to AK4396
Take it to a repair shop and have them replace the damaged AK4393 with a 4396 and also have them fit the wires to the resistor traces and then use a capacitor out. You will have wanted the 4396 anyway so the labor costs aren't wasted as you will also be getting the repair that you now need.
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I have tried a custom board with LT1360 opamps and it wasn't nearly as good as the direct out mod. The 5532 amps that are in the SRC to begin with are actually pretty good. The circuit is the thing that is not great with it's complexity and electrolytic coupling caps. Changing all of the opamps will be a lot of work for little gain.
Take it to a repair shop and have them replace the damaged AK4393 with a 4396 and also have them fit the wires to the resistor traces and then use a capacitor out. You will have wanted the 4396 anyway so the labor costs aren't wasted as you will also be getting the repair that you now need.
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I have tried a custom board with LT1360 opamps and it wasn't nearly as good as the direct out mod. The 5532 amps that are in the SRC to begin with are actually pretty good. The circuit is the thing that is not great with it's complexity and electrolytic coupling caps. Changing all of the opamps will be a lot of work for little gain.
The SRC uses JRC4580 opamps, not much chop.
That solder flow is under the edge of the DAC chip also, so not much I can do
But that is a very good idea you have regarding getting it repaired, though there is not much as in traces left going to where that resistor was, so I'll need him to connect to the DAC legs.
I'll make some calls tomorrow and see if I can find someone to do the job at a reasonable cost.
Thanks for the idea Scott, I was ready to bin it
That solder flow is under the edge of the DAC chip also, so not much I can do
But that is a very good idea you have regarding getting it repaired, though there is not much as in traces left going to where that resistor was, so I'll need him to connect to the DAC legs.
I'll make some calls tomorrow and see if I can find someone to do the job at a reasonable cost.
Thanks for the idea Scott, I was ready to bin it
DEQ2496
Should come to about $120.00 for the work. It still works digital in and digital out right? Use it for upsampling to a DEQ2496 which has a ribbon cable from which to grab the signals from the dac chip. Same world beating sound with the direct out mod as the modified SRC would have had, plus then you will also have digital EQ which once you try it, you will never want to do without it.
.data said:Quotes to replace the DAC chip and attach 4 wires are ridiculous.
In the bin it goes!
Staying away from surface mounted stuff from now on
Now to find something that will rival a modded SRC...
Should come to about $120.00 for the work. It still works digital in and digital out right? Use it for upsampling to a DEQ2496 which has a ribbon cable from which to grab the signals from the dac chip. Same world beating sound with the direct out mod as the modified SRC would have had, plus then you will also have digital EQ which once you try it, you will never want to do without it.
How about as analog in, digital out? I use my SRC2496 as an outboard ADC for recording. I run optical to an Audigy 2 ZS sound card with a Toslink receiver I added, or a ADSTech "Instant Music" USB sound box for recording in the field.
I suspect you could recover some of your cost by selling the units as-is to people with similar applications.
I suspect you could recover some of your cost by selling the units as-is to people with similar applications.
Analog PSU and Transformer hum
I did some basic mods (PSU caps, diodes, digital decoupling...) and found that the worst part of the SRC is the cheap transformer. It vibrates and hums noticeably with the upper case lid acting as a resonator. So I thought let's replace the thing but unfortunately I don't understand the circuit: The analog PSU (+-26V and after Reg +-15V) is fed via two diodes only (between the two blue Philips caps) and the transformer does not seem to have a center tap. There are only two secondaries one with 22V (analog?) and 12V (digital?). I just don't get it how they can create a symmetric 26V out of one 22V secondary with just two diodes.
The digital supply looks like I have expected, 12V secondary full wave bridge with four diodes.
So is there a schematic out there helping me to understand the PSU? A new transformer with new rectifier and reservoir caps is probably the best solution, there is enough space.
Joe
I did some basic mods (PSU caps, diodes, digital decoupling...) and found that the worst part of the SRC is the cheap transformer. It vibrates and hums noticeably with the upper case lid acting as a resonator. So I thought let's replace the thing but unfortunately I don't understand the circuit: The analog PSU (+-26V and after Reg +-15V) is fed via two diodes only (between the two blue Philips caps) and the transformer does not seem to have a center tap. There are only two secondaries one with 22V (analog?) and 12V (digital?). I just don't get it how they can create a symmetric 26V out of one 22V secondary with just two diodes.
The digital supply looks like I have expected, 12V secondary full wave bridge with four diodes.
So is there a schematic out there helping me to understand the PSU? A new transformer with new rectifier and reservoir caps is probably the best solution, there is enough space.
Joe
Attachments
Well, I ended up finding someone to replace the DAC chip with the newer ak4396, and it had distorted signal out of the first channel and a fainter signal from the second output from the DAC.
He tried again with another new chip just in case too much heat was applied on the first attempt, but got the same result again
Has anyone at all successfully installed a AK4396 into a SRC2496?
Sure I have seen it used in the DEQ, but I'm wondering if it even works in SCR
So after 2 x SRC's and 3 x AK4396 chips, still no DAC to use, grrrrr!
He tried again with another new chip just in case too much heat was applied on the first attempt, but got the same result again
Has anyone at all successfully installed a AK4396 into a SRC2496?
Sure I have seen it used in the DEQ, but I'm wondering if it even works in SCR
So after 2 x SRC's and 3 x AK4396 chips, still no DAC to use, grrrrr!
data said:Well, I ended up finding someone to replace the DAC chip with the newer ak4396, and it had distorted signal out of the first channel and a fainter signal from the second output from the DAC.
He tried again with another new chip just in case too much heat was applied on the first attempt, but got the same result again
Has anyone at all successfully installed a AK4396 into a SRC2496?
Sure I have seen it used in the DEQ, but I'm wondering if it even works in SCR
So after 2 x SRC's and 3 x AK4396 chips, still no DAC to use, grrrrr!
I tried to put the ak4396 on my deq2496 and failed too. I give up and try my luck on the very simple tda1543 and tapped the I2S signal and it worked.
So maybe the src also uses I2S to the ak4393, if so, you can do the same trick. Yes, it sounds better then the ak4393 with direct out.http://www.diyaudio.com/forums/showthread.php?s=&threadid=142084&highlight=
Cheers for those suggestions, but I'm liking the sound of the AK4396 chip, albeit at a lower gain being from the chip.
Once I replace the cheap poly's with some nice caps, it will be even sweeter
I had to leave the two negative outs from the chip bridged, and not connected elsewhere, this seemed the only way to get a non distorted result. Anyone know a better way?
Once I replace the cheap poly's with some nice caps, it will be even sweeter
I had to leave the two negative outs from the chip bridged, and not connected elsewhere, this seemed the only way to get a non distorted result. Anyone know a better way?
Better way
The better way would be for the chip to be fully functional as normal but they are very fussy to replace. I have done 70 chips or so and probably average 90% without the problems. The other 10% end up with similar issues to what you have described.
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With the wear and tear already on your board, you might want to quit while you are ahead if you don't need the balanced output.
The better way would be for the chip to be fully functional as normal but they are very fussy to replace. I have done 70 chips or so and probably average 90% without the problems. The other 10% end up with similar issues to what you have described.
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With the wear and tear already on your board, you might want to quit while you are ahead if you don't need the balanced output.
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