How much should I spend on a new DAC

I have 1 DAC that cost $3300 and another that cost $14000 (but with built-in streaming). In terms of the DAC sound, I like both equally. The higher priced DAC showed me that the laws of diminishing returns seem to be very strong for DACs.

With my lower cost DAC I use a Sonore OpticalRendu (fibre) for streaming and that is equivalent to the built-in fibre streaming in the more expensive DAC. The oR can be found from $1-$2K.

Would anyone here with engineering background will bother to explain how the network streamer affects the sound quality, or can point to any research or documentation from the web? Thanks

UpTone-J.Swenson EtherREGEN ’white paper’.pdf (shopify.com)

John Swenson’s Tech Corner – UpTone Audio

This guy created the Optical Rendu too.

I use a EtherRegen from a network switch. A short Ethernet cable goes from the switch to the ER. I use the ER from B > A and the A side sends a fibre optical stream to my OpticalRendu. That goes by USB to my lower cost DAC. I have 2 of these DAC and selling 1.

My higer cost DAC has fibre built-in and the plan is to get a FMC (like a ER) and connect the fibre directly to the DAC.

The FMC is not a must but it does improve the clairity of sound a bit.

It is not just 1’s and 0’s since analog cables like Ethernet can carry network noise into the DAC. A glass fibre cable cannot carry this noise. Ed Mietner says the same thing on his web site. Switching power supplies like on a network switch also have analog noise, as does a computer connected to the network. I have all of this noise and more. However, I use fibre to stop it just before the DAC. It is so easy to hear the difference in sound. That is why I only use fibre for all my setups (4).

@jetter My new PEachtree GAN1 amp only has 1 input, it is a SPDIF. To get my Fibre stream into that amp I bought a $499 Sonore UltraDigital. I also bought a WyWire SPDIF cable with BNC on one end and SPDIF on the other. The UltraDigital comes with a BNC adapter so if your cable is RCA on both ends the adapter can be used. I connected 1 of my Sonore OpticalRendu's with the UltraDigital and had beautiful, streamed music. The UltraDigital gets its power from the USB out of the opticalRendu. 

I may not use the UltraDigital if I sell 1 or my OpticalRendu's because my new Livingroom DAC has SPDIF streaming output, which can go directly into my PeachTree GAN1.

The GAN1 will be used only for headphones. A switch on the DAC allows to change the streaming outputs.