[BrianDonegan]

I just added links for pre-orders of the next round...

 

[rockcod]

Quote:

Originally Posted by BrianDonegan /img/forum/go_quote.gif Here are some revised drawings, still works in progress. Switched to curved lines as I think they are easier to follow visually (just taught myself about Paths in PhotoShop). Will be improving the line color selection. Will probably go with Purple for digital... Single DAC to Ballsie: Dual mono DAC to Ballsie: These and others, including power diagrams, will be up on the site soon.

What difference can I expect in Single DAC to Ballsie v.s. Dual mono DAC to Ballsie? Or simply Single DAC v.s. Dual mono DAC?

Also, can I connect both USB and SPDIF receivers to the DAC? Of course, I will use only one at a time. One more question, when will the TORX board available?

 

[MrMajestic2]

Quote:

Originally Posted by hellomai /img/forum/go_quote.gif i would connect the two transformers in parallel.

I dont think thats a good idea with the Ballsie supply due to its virtual ground design. But maybe Brian can shed more light on this.

 

[MrMajestic2]

Quote:

Originally Posted by fordgtlover /img/forum/go_quote.gif Thanks for that. Once again, the diagram helps immensely. Like the OP, I am a visual person. The second part of my issue relates to the transformers. It would seem that I would need two transformers. Is that correct? If so, does this mean that I need two power inlets into the case, one for each of the transformers? Are there other options to supply power to two transformers from one power inlet? cheers

Im struggling with the same problem. Im torn between using two intakes or putting the transformers inside the case. If using two intakes, which means 8 wires in total, the power switching becomes troublesome. If the transformers are inside the case, then the switch isnt a problem, but interference might be.
If two intakes is too many for you, you could always use the 8-pole version of the Neutrik Speakon connector, but that would make a hefty umbilical. Im thinking of going dual intake and constructing a relay switch inside the case for the Ballsie supply.

 

[amb]

You can parallel the primary side of the transformers. After all, that's what happens if you had multiple IEC and then plug them all in to the AC wall outlets.

 

[MrMajestic2]

Quote:

Originally Posted by amb /img/forum/go_quote.gif You can parallel the primary side of the transformers. After all, that's what happens if you had multiple IEC and then plug them all in to the AC wall outlets.

Oh yeah, of course. I was thinking of the secondary side when using external transformers.

 

[fordgtlover]

I found this post on the Twisted Pear Forum

"The DAC's LCPS (LCDPS) cannot use a center tapped transformer, because the center tap will become the + rail of first supply, and the - rail of the second supply (two distinct supplies on the board). When you connect them to the DAC, the grounds from each supply meet, and you are basically shorting + and -.

The Ballsie's Dual Supply (now LCBPS) does the opposite. The two center secondaries of your dual secondary transformer are joined to form a virtual center tap, and the center (Ground) rail of the supply.

Therefore, when you attach your transformer to both supplies, the Ballsie's power supply is turning your transformer into a center tapped transformer, and that causes a problem on the DAC supply. In the end, you need separate transformers.

The alternative, is use the single transformer to power the Ballsie supply, then use a single set of its secondaries to power both sides of the DAC supply - this will prevent the center tap shorting situation."

http://www.twistedpearaudio.com/foru...?g=posts&t=174

 

[BrianDonegan]

Quote:

Originally Posted by rockcod /img/forum/go_quote.gif What difference can I expect in Single DAC to Ballsie v.s. Dual mono DAC to Ballsie? Or simply Single DAC v.s. Dual mono DAC?

Technically speaking, dual mono will give you better SNR than a single DAC (120dB vs 117dB) and better channel separation. Adding the Ballsoe will give you normalized SE outputs and more current drive. As for subjective changes, I will leave that for others to comment.

Quote:

Also, can I connect both USB and SPDIF receivers to the DAC? Of course, I will use only one at a time. One more question, when will the TORX board available?

You will need a switch of some sort so that one one I2S bus connection is present at a time. We are hoping to get our multiplexer (Beagle) out soon. I'm building a DAC for Burning Amp with both I2S and S/PDIF inputs, and using a simple relay board to switch between the two (two DPDT relays to switch the 3 clocks and 1 data line, with shared grounds). You could also use a 4-pole rotary switch.

The beagle will use multiplexer ICs to do the switching digitally.

The Torx kit will be available at the same time as the other modules, I just need to get it up on the site. I'll offer it as a prebuilt unit as well.

 

[BrianDonegan]

Quote:

Originally Posted by MrMajestic2 /img/forum/go_quote.gif Im struggling with the same problem. Im torn between using two intakes or putting the transformers inside the case. If using two intakes, which means 8 wires in total, the power switching becomes troublesome. If the transformers are inside the case, then the switch isnt a problem, but interference might be. If two intakes is too many for you, you could always use the 8-pole version of the Neutrik Speakon connector, but that would make a hefty umbilical. Im thinking of going dual intake and constructing a relay switch inside the case for the Ballsie supply.

Unless your case is particularly small and cramped, I would not worry too much about interference from the trafos. Especially if you are using balanced outputs, which will cancel any common mode interference (that's the point).

In either case (ha, pun intended), you can just parallel the primaries of the two transformers. No need to use two IEC connectors, as it would not give you any advantage.

 

[MrMajestic2]

Quote:

Originally Posted by BrianDonegan /img/forum/go_quote.gif Unless your case is particularly small and cramped, I would not worry too much about interference from the trafos. Especially if you are using balanced outputs, which will cancel any common mode interference (that's the point). In either case (ha, pun intended), you can just parallel the primaries of the two transformers. No need to use two IEC connectors, as it would not give you any advantage.

Well, my case is kind of cramped, but dual transformers is possible. The double input idea was for external transformers housed in a separate case.