Hello! I'm still here! Today I replaced the opamps !!
woow what a hard job!
it was my first time! I was good ... I also replaced the "potato" chip.
Well, I'd say I've done it all, I just miss the most important thing, the clock and its power.
In summary, is the best solution to use FLEA? ..with the clock, instead of on the FLEA pcb, mounted on the cambridge board?
And where should you get the power supply of the FLEA board?
Thanks
full c cup images
woow what a hard job!
it was my first time! I was good ... I also replaced the "potato" chip.
Well, I'd say I've done it all, I just miss the most important thing, the clock and its power.
In summary, is the best solution to use FLEA? ..with the clock, instead of on the FLEA pcb, mounted on the cambridge board?
And where should you get the power supply of the FLEA board?
Thanks
full c cup images
Hi Taso. Good work sir. I was soldering some small OPA1656 onto adaptors and got them wrong way round so I know how hard desoldering SOIC is. Well done.
I had read that the clock on the DM isn't a bad one but I'm sure it could be improved with a separate psu like a flea. Havent tried that myself.
Did your tank cap over the clock rail there make a difference? I suppose small increments.
I had read that the clock on the DM isn't a bad one but I'm sure it could be improved with a separate psu like a flea. Havent tried that myself.
Did your tank cap over the clock rail there make a difference? I suppose small increments.
The two tantalum caps (you see in the picture) I put them when I changed all the capacitors on the board and at the same time I removed the output caps, so I can't tell you how much only they made.
When I did this upgrade the difference was so great. like removing a curtain in front of the sound. probably mainly due to the output caps bypassed with a wire.
Now I buy the flea card. But I have to understand well he should take the power of the flea. I guess I'll get power straight in from the power connector.
I will put a mini pcb with diodes and leveling caps that will power the flea.
i also have to decide which oscillator to use.
I don't know if it's better in tentlabs or the crystal.
I will inform!
When I did this upgrade the difference was so great. like removing a curtain in front of the sound. probably mainly due to the output caps bypassed with a wire.
Now I buy the flea card. But I have to understand well he should take the power of the flea. I guess I'll get power straight in from the power connector.
I will put a mini pcb with diodes and leveling caps that will power the flea.
i also have to decide which oscillator to use.
I don't know if it's better in tentlabs or the crystal.
I will inform!
Hello again Taso. I hope you are well and all the DIYA community.
Taso did you ever add a new clock to your dacmagic?I have just read through this thread again and now my knowledge is greater I understand things more.
I believe that due to the dacmagic having virtual grounds that adding your own separate psu can short the system.
I have the confidence now to add atleast a flea psu to the clock or maybe even an entire new clock.
I was interested if you did any of this?
I had mine in pieces again and I changed some caps around the dac ICs for Muse ES and solid polymer on the digital pins . Also added some of these 'os cons' to the digital receiver psu.
Sounding very good i have to say
Taso did you ever add a new clock to your dacmagic?I have just read through this thread again and now my knowledge is greater I understand things more.
I believe that due to the dacmagic having virtual grounds that adding your own separate psu can short the system.
I have the confidence now to add atleast a flea psu to the clock or maybe even an entire new clock.
I was interested if you did any of this?
I had mine in pieces again and I changed some caps around the dac ICs for Muse ES and solid polymer on the digital pins . Also added some of these 'os cons' to the digital receiver psu.
Sounding very good i have to say
Hi All
I've just embarked on recapping my DacMagic.
I previously purchased Panasonic FC for power supply only to open up and find some are simply too large diameter and the others too tall. I installed the 1000ufs and left the lid off I also installed muse dc blocking caps.
The sound was extremely detailed, maybe a little too bright.
In the meantime I managed to destroy the wall adaptor, don't ask!
The new item arrived yesterday and the replacement caps went in.
I replaced the power supply caps with Nichicons plus a couple of others
The sound is now quite dull and relaxed
Any advise on what is most likely to have caused such a dramatic change?
Cap choice, dry joints or wall adaptor.
Unfortunately I did.t listen to the new adaptor before swapping caps.
Any pointers gratefully received.
Regards Ian
I've just embarked on recapping my DacMagic.
I previously purchased Panasonic FC for power supply only to open up and find some are simply too large diameter and the others too tall. I installed the 1000ufs and left the lid off I also installed muse dc blocking caps.
The sound was extremely detailed, maybe a little too bright.
In the meantime I managed to destroy the wall adaptor, don't ask!
The new item arrived yesterday and the replacement caps went in.
I replaced the power supply caps with Nichicons plus a couple of others
The sound is now quite dull and relaxed
Any advise on what is most likely to have caused such a dramatic change?
Cap choice, dry joints or wall adaptor.
Unfortunately I did.t listen to the new adaptor before swapping caps.
Any pointers gratefully received.
Regards Ian
Give it a few days to settle in before deciding too much. Which DC blocking caps did you use, green bipolar electrolytic audio caps? Did you replace any caps that filter the dac chip reference voltage? If so, maybe not too surprising if you hear the new caps in that sensitive part of the circuitry. Putting a .01 wima polypropylene in parallel with caps that have a big effect on SQ might help the sound some, or not. Using Panasonic FM instead of Nichicons in sensitive positions might help.
You see, the danger in mass cap replacement without a schematic is you don't know which caps are the ones that tend to affect sound the most. You could change caps one at a time and then listen each time, or maybe try to visually reverse engineer the circuit, otherwise you may have to experiment after the fact to find which caps affect the sound the most by trying a small wima in parallel with each one, one at a time. Something like that.
Regarding the power adapter, you might try substituting a clean linear supply for test purposes. SMPS like wall warts can generate some RF noise which can sometimes cause problems. However, poorly implemented linear supplies can create their own problems. At least if trying different power supplies changes the sound you know there is something to possibly investigate there, whether or not it has anything to do with the cap replacement.
You see, the danger in mass cap replacement without a schematic is you don't know which caps are the ones that tend to affect sound the most. You could change caps one at a time and then listen each time, or maybe try to visually reverse engineer the circuit, otherwise you may have to experiment after the fact to find which caps affect the sound the most by trying a small wima in parallel with each one, one at a time. Something like that.
Regarding the power adapter, you might try substituting a clean linear supply for test purposes. SMPS like wall warts can generate some RF noise which can sometimes cause problems. However, poorly implemented linear supplies can create their own problems. At least if trying different power supplies changes the sound you know there is something to possibly investigate there, whether or not it has anything to do with the cap replacement.
My DACmagic has been downgraded to use on the television. To get a tidy installation, I removed the EI transformer from the wall wart and put it in an earthed die-cast aluminium box, enabling me to add a mains switch, then screwed the box to the underside of the table supporting the amplifier and DVD/digibox. While I was at it, I added a pair of 10nF capacitors to chassis (mains earth), one from each end of the transformer's 12V secondary. In combination with the existing 20pF of capacitance from primary to secondary, this made a common mode interference attenuator. It made the whole thing sound a lot nicer.
That won't help with investigating the audible difference due to aural memory fade during the time it takes to change caps. The switching has to be within couple seconds or it's a dud.
Thank you for the replies.
Yes I used UES blocking caps but that was at round 1 when I also changed the 1000uf power caps for FCs
At that point it did sound quite good, very detailed but overly bright for some CDs
This time I swapped out the 1000uf 50v for Nichicon UHW chosen for low esr and high ripple
I also swapped the 4 2200s for Nichicon UPW again chosen for esr and ripple.
I did swap the 2 1000uf 25v for the UHW 50v as above.
There is a single 220uf 50v which i swapped for a Nichicon UKW and a 470uf 50v for a Nichicon UKA
Behind each reg there is a 10uf 35v where I used Elna Silmic 2
My gut feeling is it could be swapping the power supply.
The DacMagic runs from an unregulated 12ac adaptor.
I've seen very expensive power supplies available but other than a toroid I can't see why they run from £120-400
Could I make a supply using an off the shelf toroid with maybe an input filter built into the IEC?
if that doesn't yield results maybe go back in and refit the original caps
Yes I used UES blocking caps but that was at round 1 when I also changed the 1000uf power caps for FCs
At that point it did sound quite good, very detailed but overly bright for some CDs
This time I swapped out the 1000uf 50v for Nichicon UHW chosen for low esr and high ripple
I also swapped the 4 2200s for Nichicon UPW again chosen for esr and ripple.
I did swap the 2 1000uf 25v for the UHW 50v as above.
There is a single 220uf 50v which i swapped for a Nichicon UKW and a 470uf 50v for a Nichicon UKA
Behind each reg there is a 10uf 35v where I used Elna Silmic 2
My gut feeling is it could be swapping the power supply.
The DacMagic runs from an unregulated 12ac adaptor.
I've seen very expensive power supplies available but other than a toroid I can't see why they run from £120-400
Could I make a supply using an off the shelf toroid with maybe an input filter built into the IEC?
if that doesn't yield results maybe go back in and refit the original caps
It's just a potential divider, but made with capacitors, the 20pF is the split bobbin EI mains transformer from the wall wart. The 10n you add yourself. A toroid will have much higher primary to secondary capacitance, perhaps 250pF. The original mains transformer is actually better!
Hi Thank you for the reply
So rather than a cordial would you say something like the transformer below could be a better option?
Could the filter below offer any benefit?
https://uk.rs-online.com/web/p/chassis-mounting-transformers/0504672https://uk.rs-online.com/web/p/iec-filters/3864188
Regards Ian
So rather than a cordial would you say something like the transformer below could be a better option?
Could the filter below offer any benefit?
https://uk.rs-online.com/web/p/chassis-mounting-transformers/0504672https://uk.rs-online.com/web/p/iec-filters/3864188
Regards Ian
The RS transformer is a split bobbin, which is what you want. Go for it. Mains filters are for preventing the interference you've created in your kit from reaching the mains. They rarely do anything useful in the other direction. A 300J 275V MOV wouldn't hurt across the mains, but make sure you precede it with a fused IEC guzzinter (suggest 1A timed fuse).
Cool so would that be these?
https://uk.rs-online.com/web/p/varistors/6694370https://uk.rs-online.com/web/p/iec-connectors/8117213?cm_mmc=UK-PLA-DS3Ahttps://uk.rs-online.com/web/p/cartridge-fuses/0563558Is 1a enough as the day calls for a 1.5a supply and many people say go for higher
https://uk.rs-online.com/web/p/varistors/6694370https://uk.rs-online.com/web/p/iec-connectors/8117213?cm_mmc=UK-PLA-DS3Ahttps://uk.rs-online.com/web/p/cartridge-fuses/0563558Is 1a enough as the day calls for a 1.5a supply and many people say go for higher
1A mains fuse is perfectly adequate. The IEC is fine. The varistor is a bit weedy. https://uk.rs-online.com/web/p/varistors/1389301 should do. Don't forget the 10n (plastic) capacitors to chassis from the transformer secondary. They're the important bit.
Thanks
May I ask what's a bit weedy? I was looking for the v and energy ratings.
I note the one you kindly listed is 275J and also out of stock.
I could hunt for something a bit beefier on all fronts
Also will any pp 10nf cap suffice as its only seeing 12v ac
May I ask what's a bit weedy? I was looking for the v and energy ratings.
I note the one you kindly listed is 275J and also out of stock.
I could hunt for something a bit beefier on all fronts
Also will any pp 10nf cap suffice as its only seeing 12v ac
If I read the data sheet correctly, it was only 100 joule. Sorry, didn't spot the 275J one was out of stock. You want a nice high energy rating so that it can absorb spikes for a long while. Varistors have a limited life and as they absorb energy, their trigger voltage falls. Eventually, they trigger on mains peaks and that's why you need the 1A mains fuse. RS seem to specify varistors a bit oddly. Normally, they go by their RMS voltage rating (you want 275V for a long life on 240V mains), but RS appear to specify by peak to peak voltage, so 275V translates into 778V. Individual data sheets may be more sensible.
Yes, pretty much anything plastic will do on the 12VAC.
Yes, pretty much anything plastic will do on the 12VAC.
Hello everyone, I am in the process of recapping and modifying my DacMagic for 2 channel HIFI use.
A couple of questions:
Does anyone have a circuit diagram?
I use the optical input and wondered if the signal still goes through an input coupling cap (c8) that I could bypass.
I assume the replacement of the SMPS with a linear is a large and complicated / expensive job for a cheap out of date DAC?
interestingly I have soldered an XLR connector onto my old RCA interconnect and effectively bypassed the OP275 that combines the Hot and cold XLR outputs, and connected this just to ground and the Hot. Most people's opinion here seems to be this is better, so far (with very limited running in) I prefer the original RCA.
Thoughts?
A couple of questions:
Does anyone have a circuit diagram?
I use the optical input and wondered if the signal still goes through an input coupling cap (c8) that I could bypass.
I assume the replacement of the SMPS with a linear is a large and complicated / expensive job for a cheap out of date DAC?
interestingly I have soldered an XLR connector onto my old RCA interconnect and effectively bypassed the OP275 that combines the Hot and cold XLR outputs, and connected this just to ground and the Hot. Most people's opinion here seems to be this is better, so far (with very limited running in) I prefer the original RCA.
Thoughts?
There would be no benefit from bypassing a cap in the optical input circuitry since the signal at that point is purely digital. Besides, such a cap might be there to protect the input of the SPDIF receiver that processes the optical input signal.
Don't know what the power supply looks like for that dac, so don't know what might be involved in replacing it.
Connecting an XLR output before the OP275 may result in a DC bias voltage present on the XLR outputs. If someone were to bypass a DC blocking cap at the input of the next audio device, say, maybe a preamp or power amp, presence of a foreign DC bias at that point could introduce a considerable amount of distortion, to say the least.
Don't know what the power supply looks like for that dac, so don't know what might be involved in replacing it.
Connecting an XLR output before the OP275 may result in a DC bias voltage present on the XLR outputs. If someone were to bypass a DC blocking cap at the input of the next audio device, say, maybe a preamp or power amp, presence of a foreign DC bias at that point could introduce a considerable amount of distortion, to say the least.
Thanks for the reply - so my understanding of the circuit is that the balanced outputs, do not run through the OP275 in normal operation, and so taking the Hot and Ground is not really changing much from a DC isolation perspective, it would I have thought been the coupling cap that was tasked with this on the output?
For the digital input coming from the Optical input then if this is coming through C8 then I would assume that it's completely unnecessary for the optical circuit - although not on the SPDIF. I also am not sure why a digital signal should be impervious or insensitive to the quality and components in it's path, but admittedly I don't actually know this to be the case.