UpTone Audio USB Regen Listening Impressions

[Alexis777]

I have ordered one last saturday... :-)

I hope to be one of the first customer.

I am wondering if I can connect the regen also with a clean 12 linear power supply..

I don't like the wall smpa :-(

I am very curious!!!

Ps. :-)

[Alexis777]

Thank you one and all for your orders. Woke up this morning to find there are only about 8 left unsold. Wow.

 

 

With regards to powering the REGEN from supplies above the 6-8V we silkscreened onto the case:

 

Below is a quickly edited version of what I wrote a couple weeks back in the other REGN thread, and this common question will be one of the very first to be addressed in the FAQ update of the web site the moment I catch my breath:

 

The REGEN has two expensive, ultra-low noise regulators (the wonderful TI TPS7A4700), one for 3.3V for the USB hub chip, and one for 5V for forwarding clean VBUS to the DAC for those that require it.

 

The +DC input voltage to the REGEN needs to be:

a) Above 6 volts since one of the regulators is being used to make clean 5V for any USB devices which need it;

but

b) Preferably below about 9V since we want the REGEN to be usable by those people whose DACs are entirely bus powered, and if one of those DACs draws the 500mA USB-spec allowed max., then the 4V drop from 9V to 5V is going to generate 2W of heat on a regulator with no heat sink. Such should be okay, especially since even bus-powered USB DAC/headphone amps are staying below the full 500mA spec.

 

On the other hand, if you have a bus-powered DAC drawing the full 0.5A allowed by the USB spec and you use a 12V PS, then the drop to get to 5V is 7V; 7V*0.5A=3.5 watts--perhaps a bit more than I would feel comfortable with. Probably okay, but I'd rather go to 9V or below.

 

If you DAC's USB input is NOT entirely bus-powered--say just powering your USB input for handshake, then a 12V or even greater supply could even be used, though there is no need. But it is hard to now just how much current your USB input will draw--unless you ask the manufacturer or find that your DAC works fine without ANY USB power.

 

If you don't need any bus power at all--or for sure only just for initial handshake--then you really don't have to worry. I think our USB hub chip draws less than 50mA at 3.3V, so it would be pretty hard to overheat that second regulator. (even 15V dropped to 3.3V will, at 50mA be only about 0.6w)

 

We are trying to keep the regulator for the 5VBUS from having to dissipate much more than 2.5W since it does not have a heatsink and is in a sealed enclosure.

 

As you know we will be including a 7.5V/2.93A/22W SMPS that I selected as best "sounding" for the price. Yes, our own JS-2 LPS beats it, but the REGEN sounds GREAT with just the stock supply.

As you can see, current capability for the REGEN's PS is really not the issue. The only reason I chose such a high wattage PS to include is that I found that size to be the sweet spot quality and output capacitance for current delivery--bass was better than on the little cheap ones, and MUCH better, and with clearer highs than on any of the available inexpensive linears (only wall warts; all the factory tabletop linears are unregulated units). Go figure…

 

 

 

Thank you very much for your fast reply...:-)

 

My dac is a MSB Analog, I think is it bus powered form the pc/mac...

 

A

[Alexis777]

I'd be interested to hear feedback from anyone using a filtered USB cable like the Totaldac D1. I haven't got a clue what's in their little box. A comparison to a less extravagant USB cable with a REGEN would be nice.

 

I am also curious. I have the Totaldac D1 Cable too and was not particolary impressed.. :-(