- Thread Starter
- #41
Those 4 relays are power relays connection 120 or 240 mains voltage to the corresponding primary transformer wires.That’s great the firmware update fixed your thump. Totally agree, bad behavior is tolerated more in …
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Pontus turn on “thump”
- Thread starter gjpmho
- Start date
- Thread Starter
- #42
Thanks all for the insights and help. I’m planning to replace all electrolytic capacitors ( all with Nichicon UHE series except the 2 2700uF ones - with Panasonic FS series), relays (replacing with Omron and TE), and add heatsinks to the underside of all mosfets in the power section. I noticed some discoloration from heat stress in the PCB. If you look you’ll find heat sinks and larger surface areas for the mosfets to radiate in the newer versions of the Pontus. Heat is bad for components and heatsink will add some longevity. Anyway, I will be delightfully surprised if doing the above clears the thump, if anything it will be preventative maintenance and I’ll just live with turning on the DAC before my amplifier, or likely keep it on 24/7. And I don’t anticipate any alteration in the sound signature. This DAC is “grey” box without schematics and for some reason all the smd mosfets have been defaced. I’ll let you all know about the outcome. Good news is the Pontus is easy to disassemble. I followed Vinshine Audio’s (Alvin’s) teardown video. Make sure to wait a while for the million or so capacitors to discharge before disassembly.
Tip: use a hairdryer to loosen the glue that binds the transformers to the case.
Tip: use a hairdryer to loosen the glue that binds the transformers to the case.
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I don't think it will help anything if you replace the capacitors now. They are not old, just well conditioned by now. Maybe in ten years think about it. On the other hand there is a good chance to break someting while soldering the caps. Some of the unreplaceable integrated circuits may be harmed, just by electrostatic from soldering near it.
Chinese "developers" never release any schematics, if they do they never match the actual gear or have severe mistakes. Even as this degrades their products to throw away items. I try to explain why. A correct schematic shows in a few minutes which product they have made a copy of and what simple changes they have done to the original design just to bloat the PCB with important looking parts. Like using a zillion of caps where two or a small handfull would do the same and using different types just for the nice looks. The red WIMA copies are a proof of highest workmanship in Chinese minds, many of them, nicely placed in large droves, even better. Same for the usual clones of Nichicon or Elna "for Audio" etc.
In China copying something is paying respect to the real developer, they say. They are not capable to design something from scratch, that is what many others say. In fact it is better to copy a good design than to do an incompetent new one. It is not even illegal to copy some more than 20 year old DAC, amp or whatever design.
Chinese audiophiles always ask where the origin of the design comes from, it must be a well known western developer like Pass, Levinson, Johnson or brands like Krell, Goldmund or whatever. They don't trust their own designers. So to sell something in the own country, it has to be an "improved" copy of some legendary, western construction. A lot is snake oil and myth, this connects the Western and Eastern audiofools.
If you really want to get rid of the thumping noise, there is a simple, reliable solution. Find some ready made PCB with a timer and relais. The relais must short the output to ground directly or through a, maybe 200 Ohm, resistor, directly at the output terminals. If you use a resistor, solder it directly to the post. The timer is started once you switch on the DAC. The relais must be place near the output post, don't run long wires throug the case.
The only problem is to find the signal activating the output and using it to start the timer. It is best practice not to load that signal, so some high impedance switch should be used. I don't know about your abilities in electronics, but you seem to be quite carefull. Better ask here twice than do something "you thought it might work" and break something that can not be repaired.
I like to use the Ali PCB's for TTL signals that are dead cheap and small. Example: https://de.aliexpress.com/item/1005001700441473.html
Chinese "developers" never release any schematics, if they do they never match the actual gear or have severe mistakes. Even as this degrades their products to throw away items. I try to explain why. A correct schematic shows in a few minutes which product they have made a copy of and what simple changes they have done to the original design just to bloat the PCB with important looking parts. Like using a zillion of caps where two or a small handfull would do the same and using different types just for the nice looks. The red WIMA copies are a proof of highest workmanship in Chinese minds, many of them, nicely placed in large droves, even better. Same for the usual clones of Nichicon or Elna "for Audio" etc.
In China copying something is paying respect to the real developer, they say. They are not capable to design something from scratch, that is what many others say. In fact it is better to copy a good design than to do an incompetent new one. It is not even illegal to copy some more than 20 year old DAC, amp or whatever design.
Chinese audiophiles always ask where the origin of the design comes from, it must be a well known western developer like Pass, Levinson, Johnson or brands like Krell, Goldmund or whatever. They don't trust their own designers. So to sell something in the own country, it has to be an "improved" copy of some legendary, western construction. A lot is snake oil and myth, this connects the Western and Eastern audiofools.
If you really want to get rid of the thumping noise, there is a simple, reliable solution. Find some ready made PCB with a timer and relais. The relais must short the output to ground directly or through a, maybe 200 Ohm, resistor, directly at the output terminals. If you use a resistor, solder it directly to the post. The timer is started once you switch on the DAC. The relais must be place near the output post, don't run long wires throug the case.
The only problem is to find the signal activating the output and using it to start the timer. It is best practice not to load that signal, so some high impedance switch should be used. I don't know about your abilities in electronics, but you seem to be quite carefull. Better ask here twice than do something "you thought it might work" and break something that can not be repaired.
I like to use the Ali PCB's for TTL signals that are dead cheap and small. Example: https://de.aliexpress.com/item/1005001700441473.html
- Thread Starter
- #45
I’ll seriously reconsider changing the capacitors, it does currently work. Thanks for all this information and perspective.. What about only changing the 1000uF, 25V Chemi-con KRG capacitors? These are low profile with 1000hr endurance @105C. I know the endurance doubles every -10C. Guessing it didn’t get above 60C which is too hot to the touch. This DAC is 6 years old. I don’t know how many of these (61) are being used in standby mode. AFAIK, The previous owner kept it in standby mode when not in use.
- Thread Starter
- #46
Yes. +/- 7.2V if I recall. It’s suppose to be +/-7.4V. I figure that’s close enough.
- Thread Starter
- #48
Oh ok, the only labeled voltages I see are here.
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With 6 years the electrolytics are youngsters. Keeping them in standby will not shorten their life. These 1000 hours are at the worst conditions allowed by the data sheet. Even in such a case they still function, they only loose some capacitance. No 100% fail after such a test. Your DAC is overdimensioned about a hundred times from what I see. The DAC chip that is the basic part of it could even work in a Walkman disk player. There is no room for all these fancy parts...
This seems to be the power PCB. Can you do picures of both sides? There have to be some regulators. Maybe they are placed on the signal PCB and the power part is only dumb rectifier + capacitor. Usual voltages are 5 and 12 Volt, maybe 3.3 with newer integrated circuits.
- Thread Starter
- #51
There are no components on the other side of either PCBs.
Attachments
PS I forgot you have it disassembeled. So you can't measure voltages. Often they remove the writing from the most simple parts in such gear. This is the case here. Not a nice move...
Anyway, just by looking at it one can guess what part is what.
Anyway, just by looking at it one can guess what part is what.
I can't see any details on the pictures, there may be regulators on the DAC board. Maybe I expected too much from that construction.
Do you know what DAC Chip is used? I would have a look at the data sheet to see what voltages must be there.
If you assemble it into a working state, is the DAC PCB on top?
Do you know what DAC Chip is used? I would have a look at the data sheet to see what voltages must be there.
If you assemble it into a working state, is the DAC PCB on top?
- Thread Starter
- #55
- Thread Starter
- #58
No I’m going to leave it be, unless something is actually broken. But I’m convinced this is a design flaw, and I can workaround that. Thanks for your help! I just reassembled it with heatsinks, and it works. Also this is lead-free solder which is more challenging to work with IME. I looked at the Cyclon EP4CE22FT datasheet and couldn’t find a “mute” function. Another design flaw I spotted is the DAC PCB sags a bit. There is no support at the center. There’s enough clearance to avoid a short, still a support at the center would have been easy to implement imo.
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Sokel
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They have mixed a boatload of PSUs in there, both linear and SMPS looking to appear as a low noise design, right?
And low noise means low noise, at any state.
Does it sound sane to you that the opposite would occur, more so by design?
They, themselves admit that it's not normal. Something is asking for trouble in there, and it won't stay put at the current state, it will only get worst.
If you have some good gear upstream any potential failure can harm them too.
The 1VDC spice you measure with your DMM can very well be 15VDC, DMMs are not fast enough to catch such spikes. It did its job but your gonna need a analyzer to see the true extent, maybe some friend near you?
I think from your standpoint it is a wise decission to leave it alone. Maybe think about checking the regulated voltages on the DAC board, for peace of mind, but that may be all you can do. They should be a volt or so lower than the unregulated numbers on the board.
From what I see, there are programable IC's on the board, so the functions will be done in the software. I could not see any "normal" DAC parts. At least all functions after initial power up, like switching from standby to on, are software commanded. I'm pretty sure an update could solve your problem, if the manufacturer cared. There are all kinds of connectors on the board which may be there for this task, but only be used once, during assembly.
Anyway, all you could do would be some USB connected update and that will not be possible. You need some programmer directly connected to the board.
I think it is not wrong to suppose the manufacturer doesn't care too much for after sale service. So best is to leave it allone and use it as it is. If you break anythink a repair will be complicated or impossible.
PS from a technical view, there is a lot of useless material used in the build. The power supply is lowest electrical engineering, made impressive by using countless parts.
That doesn't say it can not sound fine, like most DAC's do.
From what I see, there are programable IC's on the board, so the functions will be done in the software. I could not see any "normal" DAC parts. At least all functions after initial power up, like switching from standby to on, are software commanded. I'm pretty sure an update could solve your problem, if the manufacturer cared. There are all kinds of connectors on the board which may be there for this task, but only be used once, during assembly.
Anyway, all you could do would be some USB connected update and that will not be possible. You need some programmer directly connected to the board.
I think it is not wrong to suppose the manufacturer doesn't care too much for after sale service. So best is to leave it allone and use it as it is. If you break anythink a repair will be complicated or impossible.
PS from a technical view, there is a lot of useless material used in the build. The power supply is lowest electrical engineering, made impressive by using countless parts.
That doesn't say it can not sound fine, like most DAC's do.
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