Musiland MINI Power Mod: Less Jitter?
Most people’s idea to improve the power of a USB device is to replace the USB power with an external linear supply. Although this kind of mod would improve the incoming power to the device, the ultimate noise performance is determined by the local regulators that directly feed the chips.
Additionally, because I value the convenience of using USB power, I took a different route: I decided to replace the local regulators with low noise types. The factory regulators are AMS1117. The ones I am upgrading are LT1963. Noise density figures for the AMS1117 is approx 990 nV (3.3v regulator) and for the LT1963 is approx. 125 nV (3.3v regulator).
The AMS 1117 regulators are similar in noise performance as the very popular LM317 types. The LT 1963 are cousins of the LT 1763 used in Buffalo II. They have higher noise (but are still low noise) due to their higher current carrying capability.
Removed the existing regulators and large capacitors. The easiest way to remove the factory regulators is to cut the pins first. Or you can use a very small screwdriver and lift one pin at a time while applying heat.
Built a dual PS with two adjustable regulators: one for 3.3v and one for 1.2v. [Too much solder -not enough practice with soldering soic, but no bridging]
The voltage setting resistors are in the backside of the board. Input power to the regulators is taken from the connections of the original capacitors. Output power feeds the connections of the original factory caps. Basically, this replaces the factory local power supply (regulator plus caps) with the new power supply.
Some listeners may be able to discern differences in sound when changing a circuit element or improving the power supplies. I am not very good in discerning small differences in sound so I can’t definitely say that the upgraded Musiland sounds better than before. I can only say that it sounds “real good now”. Further, I can do some testing to determine if things have improved.
Previously I reported that when the Bufflao II DAC reaches steady state (about ~15-30 minutes after power-on), setting the DPLL bandwidth to “Lowest” or “Low” would result in several dropouts within each song; if I change the setting the DPLL bandwidth to “Medium-Low”, it would result in a single dropout every few/many songs. [The test was conducted with the Musiland MINI using the I2S connection to Buffalo II DAC]
With this power supply modification, I can report that the jitter performance of the Musiland has improved one notch. When setting DPLL to “LOWEST”, I would experience about one or two (sometimes more) dropouts every song. With DPLL setting at “LOW” I could actually enjoy dropout-free songs now and then. I can definitely say that the numbers of dropouts with LOW and LOWEST settings have markedly improved, indicating a reduction in signal jitter.
This is probably the most effective mod for the Musiland MINI, especially because it cost me less than $10
Note: the full power mode includes removing the power from the two DC-DC converters (to turn them off) that are used to power the output stage of the DAC.
Here is another photo showing both top an bottom of the board. I added some isolation (white plastic) to prevent the metal cans shorting connections in the back side of the board.
Here is a new summary of relevant mods I’ve done so far [link to original list of mods]:
- Tapping SPDIF [link]. The newer version of the device has enabled SPDIF through a mini-toslink interface. If you have a DAC that can take TTL-level inputs, you can feed the signal straight without level conversion -the SPDIF signal from the Musiland device is TTL-level (3.3v). In the case of Buffalo II DAC, you can bypass the comparator, removing another component from the signal path.
- Tapping I2S lines: You can do it without removing the factory DAC [link], or by removing the factory DAC [link].
- Disable DC-DC converters (which are switching regulators) [link]
The manufacturer is often improving the device driver. A new version improves upon the accuracy of the clock. Another newer driver adds HDCD decoding. I’ve found that the newest drivers are the best in terms of stability and functionality. Some people have indicated that the older drivers sound better. I can’t tell the difference.
The Musiland device is the only “hifi” consumer USB device I know that uses bulk mode transfer. Although many experts reject the idea of using bulk mode transfer because it is not real time, the advantage of bulk transfer over Isochronous-asynchronous transter is the guaranteed nature of the data delivery [meaning the protocol will resend a package in case the packet is lost or corrupted]. The advantage of Isochronous transfer over bulk is the guaranteed bandwidth; however if there is plenty of bandwidth available (for example, you are not maxing out the bandwidth of the USB connection by plugging in several devices), then guaranteed bandwidth is never an issue. In my extended use, I’ve never experienced lack of bandwidth even when using the computer for other tasks while playing music. If you worry about bandwidth, you can avoid sharing the USB bus with other devices by determining where the USB device is connected
Drivers can be found here:
- Official Release: Musiland Driver Downloads (look for USB). Site is in Chinese. The English language site points to a very old driver
- Officially released drivers: Musiland historical driver directory. Look for MlCyMON
- Latest driver (likely Beta): Musiland latest driver directory. Look for MlCyMON
- All device drivers here: Tam’sAudio Old and new Musiland Monitor Drivers. This directory is maintained by a retailer of Musiland products. All the drivers that have been released are here
- Installing the driver and using ASIO: http://bbs.musiland.com.cn/viewthread.php?tid=4813&extra=page%3D2 (Musiland forum entry. Must have account. Use google toolbar to translate)
- Firmware upgrade: http://coolfungadget.com/musiland/Update_Firmware.html