A New Take on the Classic Pass Labs D1 with an ESS Dac

[opc]

Iloveswan:

You posted that question a few pages back, and both myself and qusp answered you. Please read back before reposting the same questions.

Post 598 and 607

Thanks,
Owen

[Iloveswan]

Originally Posted by opc

Iloveswan:

You posted that question a few pages back, and both myself and qusp answered you. Please read back before reposting the same questions.

Post 598 and 607

Thanks,
Owen

sorry I am been too focus on reading other your words...
I will send some samples to QUSP to test the TC.

Thanks,

[qusp]

Hi guys, yeah Iloveswan, I suppose I can test one or 2 for TC,

btw guys I normally pay by visa debit card to Texas components, so haven't had to worry, but when I checked my payment after confirm payment I noticed a 5% 'convenience' fee had been added when i paid by paypal, one would think that with such prices these things would be covered as just the cost of doing business.........(at least do it in the background so I don't know lol), so I'm going to have to get you guys to add 5% of your orders and add to the fêts payment. Sorry for taking another bite at the cherry, but 5% of this order isn't loose change.

Speaking of which opc, have you got the mosfet matching/testing guidelines/parameters and circuit ready for me mate? Haven't got any mail from you.

Also guys, those who wanted extras like regs and caps from me, i'm making the orders this weekend, so we need to sort this out asap. Will send you all an email tomorrow, so those that need to make preparations to have paypal funds available, please do it now as I cannot afford the delays of last time, as a friend if mine in oz who is getting some things too, he needs to do it this weekend. Will make the Conrad order late this week sometime so if anyone else is keen, please act fast. I got details for the pricing on and cartage on the most appropriately sized model. Those who would like details please email me.

Think that covers it.

[qusp]

Oh btw received eta on shipping date, the r's will ship 30th of nov, so I will have them about 10 days after that, fedex express was nearly 100 bucks, so took international priority.

[stephen1212]

digi key no longer has the 22uF Epcos caps in stock. Does anyone have a recommendation for an alternate source or brand? Also what are people using for the "?" caps C32-33 C38-41 and C46-47 ? What is the formula to determine the value to choose?

[qusp]

The ? Caps form a plain vanilla rc filter, which you can find calculators for it all over the net and depends on the input impedance of the next stage and your desired bandwidth what exact value you need there. I dont think you want any cap recommendations from me what's your budget and what is the source resolution 44/48/96/192/384? I do know good value caps too, but that's a subjective term in itself so I need a budget before I make any suggestions.

[merlin el mago]

Originally Posted by qusp

The ? Caps form a plain vanilla rc filter, which you can find calculators for it all over the net and depends on the input impedance of the next stage and your desired bandwidth what exact value you need there. I dont think you want any cap recommendations from me what's your budget and what is the source resolution 44/48/96/192/384? I do know good value caps too, but that's a subjective term in itself so I need a budget before I make any suggestions.

For input impedance 1Meg & sampling 384kHz?

[merlin el mago]

@qusp
Please link me to spreadsheet or let me know the values.

Thanks in advance

Felipe

[qusp]

Originally Posted by merlin el mago

@qusp
Please link me to spreadsheet or let me know the values.

Thanks in advance

Felipe

Hi mate, I'll dig out a link to a calc online. You can find many rc filter calculators, some for speaker xo and others for opamp filters etc, all can be repurposed for this pretty straight forward filter. Sorry for lag, I'm still moving and on the iPad for all forum stuff at the moment; so don't have access to any of my research or links. I'm setting up the Mac today at some point, so will post details after that's done. In the meantime google is your friend. With 1meg inputZ you can pretty much treat it as infinite so should have little or no effect, it's the rc filter formed by ? And the r nearby, sorry don't have the schematic handy

[stephen1212]

The 22 uF cap loaded by the parallel combination of the 100K R and the input impedance of the following stage would be what you are mentioning. The formula is fc=1/(2 * pie *R* C) or fc=1/6.283185307*R*C
where fc is in hertz, R is in ohms, and C is in farads.

The only tricky part is that in this case = R total= 1/(1/R)+(1/100000) practically you could forget about the 100K as its effect will be less than the accuracy of the parts.

The other way to look at it is that the output unloaded has a corner frequency of 0.1 Hz

The "?" capacitor is on the input forming a low pass filter with the DAC output impedance. Does anyone know what the Buffalo II output impedance is? I am guessing with only 4 outputs +- L +- R that they are paralleling two outputs of about 190 ohms if I remember? so roughly 95 ohms?