dtd

When you say ultrasonic, are we taking 20k+ range?

How does upsampling 64x DSD to 512x improve things?

Please do - will be interested how it sounds against a Mytek (if you still have one?)/

I suspect I have a defective transformer, but it doesn't sound like its getting worse. Transformers shouldn't hum.

Same here. Mild, barely noticeable.

Any alternative DIY designs worth considering? Out of stock.

Do you know if this issue is fixed yet?

This kills the DAC? I think I've plugged the firewire in, whilst it was on, and survived to tell the tale?!

Has anyone tried plugging the Mytek into an auto voltage regulator? If so any observations? I'm only using a cheap APC R-Line unit, and noticed better bass, less edgyness and a marked yet obvious lowering of noise floor. My unit has about 200hrs break in so far. I wasn't expecting much if any changes, but removing the regulator from the system does reap a difference - maybe I have some really nasty AC....

Can anyone from Mytek confirm if the Firewire port is galvanically isolated?

Actually the USB one certainly is performing galvanic isolation, it was recommended by another audio designer. So far, I've found the DAC won't work with the above adapter as mentioned.

Examples : FireWire Port Isolator - 6 pin - 6pin Male to 6pin Female - Eliminate bus power problems - USBFireWire.com - 877-522-3779 https://www.olimex.com/Products/Modules/Interface/USB-ISO/ - I have this final one, the DAC's USB 2.0 port wont go into full speed mode with this on the line. It prevents noises from the computer from 'infecting' the device connected on the other end. Some PCs/Laptops need it more than others. Defiantely a YMMY case.

You're right, its a tricky one with different scenarios. On one hand there might be small differences. On the other, if the Mytek is connected to a poorly earthed/noisy USB/Firewire ports or hubs then that in itself can cause noticeable differences. Think I better grab some isolators once the unit has broken in, and just test them back to back for a week.

Has anyone noticed any difference between the Firewire and USB2 inputs? I don't think I can tell them apart, but my unit is still breaking in too.

I also have the Mytek and Ncore NC400s. I removed the gain resistor and use the Mytek directly which works very well together. This lowers the amp's gain to approx 13db. I tried lowering the gain (-6db jumpers) on top of removing the gain resistor, and it hasn't made much of a difference to the sound quality. 13db gain + Mytek with -6db output jumpers engaged with output set to 0 = 100db~ on a pair of 89/db @1w efficient speakers. As for why it sounds worse at -35 than -10, that could be RF interference? Dropping to -35 means quite a lowering of output voltage, leaving it a bit exposed.