desertrat748
Super Member
What we have here..
Can a DAC this cheap really be this good? Yes it can! (…but with a little effort.)
knotscott
Super Member
Thanks for clarifying. Rather than risk damage, on the occasions when one of my sons brings a laptop for source music, I'll just switch in the Topping DAC and live with the lower fidelity.
oranda
Active Member
Actually looking at the picture more closely and digging a bit more, it appears that adapter is made with the intention of providing power through one side and data through the other. I didn't see the little labels on the thumbnail for each of the female connectors. Does the green light turn on if no power is provided through the "PD100W" port even if the source device is plugged in?
knotscott
Super Member
Yes. I plugged the PC into the audio headphone input, and disconnected the PSU. The greenlight stayed on, and the music continued to play even without the outboard power supply plugged in. I'm a little surprised....does that mean there's a 5V conflict going into the outboard PSU?
oranda
Active Member
Not sure. Sounds like there might be unless there is some smarts built in that senses voltage on the power line and switches the other input voltage off. Hubs are smart enough to regulate the voltage correctly, but I'm not sure about that adapter.
knotscott
Super Member
Maybe I could measure the voltage on the power input side when it's unplugged from the PSU... Assuming a measurement of 5V there would indicate the potential problem you mentioned. Either way, it's not worth the risk to me...I'll just unplug the PSU, and let it run off the PC when the time comes.
There's trouble in paradise. I received the SU1 directly from Apos (and beat the tariff). I also found a Yamaha DVD-S2300Mk2 in mint condition locally. I listened to it through the analog RCA while waiting for the SU1 to arrive. The sound was not terrible but not great either. But, it played whatever discs I put into it without a hiccup (at least 10 CDs). The SU1 finally arrived and I was excited to hook it up to the digital coax jack on my player. The sound was considerably better than the internal dac in the Yamaha. Here's where the trouble part comes in to the story. The signal started cutting out randomly for about 2 seconds. The same disc might play perfectly one time and cut out 5 or more times on the next play. This does not point to defective discs. Again, this only started happening when I put the SU1 in the system. I opened the player and cleaned the lens with some Windex. This had no effect. I'm starting to be suspicious of the SU1. I think I'll have to buy a different cheap DAC and see if the cutting out continues. If the SU1 is indeed defective I'm very happy I didn't start the surgery, which would have voided any warranty.
oranda
Active Member
Sounds like its either:
1. A bad coaxial jack on the Yamaha;
2. A bad digital coaxial cable, or
3. A bad SU-1.
If it were the power supply to the SU-1, the lights on the SU-1 would cut out. Hope you get to the bottom of this and great to see you on this adventure as well!
I have seen more than a few DACs use unique schemes in V supplies that anything would be an upgrade.
But they ofen cause problems after modifications. A good buck voltage replacing the knock off TIs is preferred to messing with them.
I hope you get to the root of this.
But they ofen cause problems after modifications. A good buck voltage replacing the knock off TIs is preferred to messing with them.
I hope you get to the root of this.
Last edited:
Well, the SU-1 is defective. I substituted a $13 dac for it and although it sounds like a transistor radio it works perfectly. I'm in contact with Apos to rectify the situation. I am surprised that an electronic item with no moving parts can come out of the factory defective. Law of averages, I guess.
They skip out on a lot of parts. I have an SMSL and the chassis sits above and shorts if I put it on other equip.
Customer service from Apos is first-rate. They emailed a prepaid shipping label and will refund the purchase amount. I opted to buy a second one from a seller on Amazon that can be delivered same day. The tariffs are looming large and the proposed de minimis fees are punishing. Will they take effect as proposed? I dunno but did not relish spending an extra $100 and/or 145% tariff. May 2 is the proposed date and I am assuming the article has to land in the US before then, not the day it leaves the warehouse in China.
oranda
Active Member
Nice to know the return was straightforward. I've heard that from others about Apos as well.
oranda
Active Member
Wow, crazy. I've had 4 SU-1s and a C100 and zero issues both before and after mods. Well, at least Amazon has a nice return policy.
oranda
Active Member
Either way, huge bummer! Yes, hope you can bag a decent one.
desertrat748
Super Member
I’m not trying to be negative here or sound rude in any way but I don’t think it’s the su-1 at this point.
Maybe some incapable w something in your system or some other issue that you might be unaware of? Are you sure it’s being switched to the proper output or the connections are secure on both ends? Last thought is could you take it to a friend’s house or do you have a separate system to try it out?
The odds of two in a row being bad seems unlikely. I think it’s possible that it is something else that is being overlooked.
mrehorst
Super Member
Back when I was in engineering school, one of my profs once told the class "if there are no measurements, there is no engineering".
The SMSL SU-1 has a built in switching supply that powers the circuits from the 5V input. If the built in switching supply doesn't put any audible noise on the output of the DAC when powered via a USB port on a computer or dongle, how does an analog 5V supply improve the DACs output? Or is this one of those mysterious things we can hear but can't measure?
If an analog power supply provides so much improvement, why would you stop there and not power the small, low-powered device with a rechargeable battery? It takes less than 1A to power it. A battery would surely be even better than an analog power supply connected to the AC line. A couple 18650 cells, or even 3 or 4 AA alkaline cells will power the DAC for many hours.
But that's taking the easy way out. Anyone truly interested in squeezing the best possible performance out of the DAC would bypass the internal switching supply with batteries. Surely that would offer even more improvement than using an analog 5V supply (or battery) and the internal switching supply. I see +0.9V, +3.3V, +5V, and +/- 12V marked on the PCB. A pair of 3S or 4S 18650s would provide the +/-12V, and a few linear regulators off the +12V battery would provide the other voltages, and probably power the thing for weeks between charges, and surely provide even more improvement in the SQ.
The SMSL SU-1 has a built in switching supply that powers the circuits from the 5V input. If the built in switching supply doesn't put any audible noise on the output of the DAC when powered via a USB port on a computer or dongle, how does an analog 5V supply improve the DACs output? Or is this one of those mysterious things we can hear but can't measure?
If an analog power supply provides so much improvement, why would you stop there and not power the small, low-powered device with a rechargeable battery? It takes less than 1A to power it. A battery would surely be even better than an analog power supply connected to the AC line. A couple 18650 cells, or even 3 or 4 AA alkaline cells will power the DAC for many hours.
But that's taking the easy way out. Anyone truly interested in squeezing the best possible performance out of the DAC would bypass the internal switching supply with batteries. Surely that would offer even more improvement than using an analog 5V supply (or battery) and the internal switching supply. I see +0.9V, +3.3V, +5V, and +/- 12V marked on the PCB. A pair of 3S or 4S 18650s would provide the +/-12V, and a few linear regulators off the +12V battery would provide the other voltages, and probably power the thing for weeks between charges, and surely provide even more improvement in the SQ.
Last edited:
Señor Desert Rat, I can see where you are coming from. In the early stages of this saga I didn't even consider the SU1 was at fault. Since the disc player was new to me I first thought there was an issue with it. A rather tricky operation to get access to the lens to clean it and reinstalling the tray in the proper orientation ensued. This didn't fix it. Kind of bummed that I had to go through that!
So here are the facts:
Player worked perfectly through analog output with a sample size of at least 10 discs.
Inserted DAC in the chain and skipping ensued.
I am using a Jameco linear p.s. which is 5v 1a. I had a 5v 3a switching block lying around and powered the SU1 with that on the slight chance the SU1 needed more current. Still skipped and sounded markedly worse.
Swapped out a $13 DAC in the same position as the SU1 (same coax and p.s.) No skipping at all.
The only conclusion I can posit is the SU1 is at fault.
To me it seems akin to a car company recalling 500,000 vehicles due to a bad bolt. Maybe the upcoming tariffs are putting pressure on the Chinese factories to push out as much product as possible and QC is suffering. Who knows?
If you can reach a different conclusion based on what I outlined above I'm all ears.
I sent an email to the rep at Apos who is handling the return of the first unit reporting the failure of the second unit. If they made a bad batch of SU1s then surely I'm not the only one to experience this. Whether they'll admit it is another matter.
So here are the facts:
Player worked perfectly through analog output with a sample size of at least 10 discs.
Inserted DAC in the chain and skipping ensued.
I am using a Jameco linear p.s. which is 5v 1a. I had a 5v 3a switching block lying around and powered the SU1 with that on the slight chance the SU1 needed more current. Still skipped and sounded markedly worse.
Swapped out a $13 DAC in the same position as the SU1 (same coax and p.s.) No skipping at all.
The only conclusion I can posit is the SU1 is at fault.
To me it seems akin to a car company recalling 500,000 vehicles due to a bad bolt. Maybe the upcoming tariffs are putting pressure on the Chinese factories to push out as much product as possible and QC is suffering. Who knows?
If you can reach a different conclusion based on what I outlined above I'm all ears.
I sent an email to the rep at Apos who is handling the return of the first unit reporting the failure of the second unit. If they made a bad batch of SU1s then surely I'm not the only one to experience this. Whether they'll admit it is another matter.