[pinkfloyd4ever]

is it a bad idea to use only a sonicap for the output, like a .47uf or so?

 

[FallenAngel]

Quote:

Originally Posted by pinkfloyd4ever /img/forum/go_quote.gif is it a bad idea to use only a sonicap for the output, like a .47uf or so?

Absolutely not, it's great idea, why would it be bad?

Just make sure that you have an input impedance of 100K (50K will be OK, but not "perfect").

 

[pinkfloyd4ever]

I dunno, I thought it might not be enough capacitance cause it seems like everybody uses more like 47uf. I assume Gen 1 would be best? I think I'll actually go with 1.0uf since it's cheaper. Anyone ever tried bypassing BG NXs with a sonicap?

I use my alien with my Millett Max...anyone know its input impedance?

 

[FallenAngel]

Quote:

Originally Posted by pinkfloyd4ever /img/forum/go_quote.gif I dunno, I thought it might not be enough capacitance cause it seems like everybody uses more like 47uf. I assume Gen 1 would be best? I think I'll actually go with 1.0uf since it's cheaper. Anyone ever tried bypassing BG NXs with a sonicap? I use my alien with my Millett Max...anyone know its input impedance?

People use 47uF because it's the smallest BG they can find.

This is the short version of what value output caps for what value input impedance amps:

10K : 4.7uF
50K : 1uF
100K : 0.47uF

This is a "bast case scenario" value, but you can go a bit lower and in all likelihood never hear a difference.

I'm quite sure the Millet will be 50K, go with 1uF.

If you want, you can bypass a 1uF Gen 1 with a 0.1uF Gen 2, should be a nice result.

For the DAC, don't bypass BG with Sonicap, just use the Sonicap. If you're thinking of bypassing BG in the amp, that's another story, I haven't tried it.

 

[Pars]

The formula for the -3dB cutoff point on a filter (high pass in this case) is:

f = 1 / 2 * Pi * R * C

where C is in farads.

So for example, your 0.47uf cap with a 100K resistor to ground would give:

1 / 2 * 3.14159 * 100000 * 0.00000047

or 3.39 Hz

The filter will have some effect up to an octave or so above this.

 

[tomb]

Quote:

Originally Posted by pinkfloyd4ever /img/forum/go_quote.gif I dunno, I thought it might not be enough capacitance cause it seems like everybody uses more like 47uf. I assume Gen 1 would be best? I think I'll actually go with 1.0uf since it's cheaper. Anyone ever tried bypassing BG NXs with a sonicap? I use my alien with my Millett Max...anyone know its input impedance?

The other guys have given you good answers.

I can't speak from personal experience, but the GEN I is supposed to be fairly neutral, while the Sonicap Platinum is supposed to stand up there with the best. I have had direct experience with the GEN II, though, and it is not up to those standards, IMHO. It works pretty good bypassing ES's in the Alien, but it's still not as good as just the BG NX's by themselves. I wouldn't waste time using a GEN II by itself or bypassing BG NX's.

 

[FallenAngel]

Quote:

Originally Posted by tomb /img/forum/go_quote.gif The other guys have given you good answers. I can't speak from personal experience, but the GEN I is supposed to be fairly neutral, while the Sonicap Platinum is supposed to stand up there with the best. I have had direct experience with the GEN II, though, and it is not up to those standards, IMHO. It works pretty good bypassing ES's in the Alien, but it's still not as good as just the BG NX's by themselves. I wouldn't waste time using a GEN II by itself or bypassing BG NX's.

Cool, nice to know. I tried Gen1 with Gen2 bypass and Gen1 alone, I liked both quite a bit, a lot more than BG NX. I'll make sure to stay away from Gen2 alone.

 

[bhjazz]

Quote:

Originally Posted by MASantos /img/forum/go_quote.gif In terms of capacitance values, 47uf is a good choice for C13,C23,C33 and CL/CR, according to the suggested values by Alf in the parts list page.

Quote:

Originally Posted by Alf /img/forum/go_quote.gif C23, C33 positions accept capacitors up to 8mm. If you have a few extra dineros in your pocket, I would try 100uF Silmics here as the DAC may benefit from it.

Currently Digikey is out of the Panasonic 100uF. Backordered until May 13th or something crazy like that.

What is the difference between using th .47 or the 100uF? Handmade has them both in the SilmicII. Should I opt for that instead. Any comparisons between the Silmic and the Panny's here (what tweakers we all are, eh?)

Thanks!

 

[tomb]

Quote:

Originally Posted by bhjazz /img/forum/go_quote.gif Currently Digikey is out of the Panasonic 100uF. Backordered until May 13th or something crazy like that. What is the difference between using th .47 or the 100uF? Handmade has them both in the SilmicII. Should I opt for that instead. Any comparisons between the Silmic and the Panny's here (what tweakers we all are, eh?) Thanks!

The last one I built had 300uf Panasonic FM's at C13, C22 and C33, and 1000uf at C2. It works great, but I'm worried that the current inrush will bring down my PC's power supply.

Seriously, I can't really say it made much difference when tested - but I am certain it caused no problems or made the performance worse. I was trying to compensate for any issues with longer lead length while bending the leads at right angles so that the caps are horizontal and laid flat on the board. The 1000uf actually hangs horizontally off the edge of the board. It's 3/8" at it's thickest board height - an experiment to fit under a MAX board in a standard Hammond case. I'll post some pics tomorrow.

Bottom line, I think you can greatly upsize those caps to equal the low ESR of much more esoteric caps with good effect.

EDIT: It uses a panel-mounted USB jack with wire leads. Otherwise, the board-mtd USB jack results in about a 1/2" board height on its own.

 

[error401]

Quote:

Originally Posted by tomb /img/forum/go_quote.gif The last one I built had 300uf Panasonic FM's at C13, C22 and C33, and 1000uf at C2. It works great, but I'm worried that the current inrush will bring down my PC's power supply.

Every motherboard I've ever used current-limits the USB power rails to a couple amps at most per pair of ports. Your supply shouldn't have trouble.

 

[tomb]

Quote:

Originally Posted by error401 /img/forum/go_quote.gif Every motherboard I've ever used current-limits the USB power rails to a couple amps at most per pair of ports. Your supply shouldn't have trouble.

Duh. There were a few winkies there.

 

[bhjazz]

Quote:

Originally Posted by tomb /img/forum/go_quote.gif The last one I built had 300uf Panasonic FM's at C13, C22 and C33, and 1000uf at C2. It works great, but I'm worried that the current inrush will bring down my PC's power supply. Bottom line, I think you can greatly upsize those caps to equal the low ESR of much more esoteric caps with good effect.

Ah, the size. Hadn't thought of that...

Okay, then. Thanks for the info, Tom. I'll skip the Panny's and get the Silmics from Handmade. I'm happy to see that those two locations offer some options for uF.

 

[NumpXP]

i shot glassjar an email 2 days ago and still no response. anyone eager to point me a good BOM or any other kit seller?

(prefer to use mouser or/and digikey)

thanks in advance

 

[bhjazz]

There are four or five BOMs within this mega-thread. Yeah, I know: it's 117 pages! Just search for BOM. I seem to remember that a few of them were just for Mouser. And I know for sure that a BOM or two were split pretty evenly between Mouser/Digikey.

You will want to dig through the thread more, too. Since those BOMs were written, lots of experimentation has gone on with the design, and using some custom caps in CL and CR can make a big difference.

 

[pinkfloyd4ever]

I sent jeff an order form and a payment on the 17th and haven't heard anything back yet...anyone heard from him lately?