[joneeboi]

That's a good point. I'm thinking about the load capacitance on the TLE. The PIMETA v2 gets away with very little capacitance on the output, and the Mini^3 puts two 100uF capacitors on it. We could probably put very little across it in this case, providing more room to the rail-to-rail capacitors.

 

[cobaltmute]

I should note that based on what I just said above, on my second board I'm going to decouple the 0V on the DCP from the rest of the board. I expect that it will drop the current draw of the board significantly.

EDIT: On second thought, I may not do this See my comment in post 470

 

[DKJones96]

At 70ma of idle current the DCP020509 is only running at 32% load and is somewhere around 75% efficient giving you a total of 54.25ma. Still missing about 15 tho...

How are you going to decouple the 0v?

Has anyone gotten the Bantam/Carrie pair cased successfully? I don't know what the heck is going on with mine but on the table it's fine, I can pick it up, wiggle the two boards around, hit it to the table(frustration) and it stays playing fine. Once I stick it in the case moving or even touching the usb causes a pop sound from the earphones and music stops and windows doesn't see the bantam anymore. I've even held the bantam and moved the usb cable around with no issues.

Damn thing just went to static when I was trying to change the volume.

 

[nightanole]

Im still building, i was planning on doing the dual 100uf fm caps on the vground and then my huge caps across the rails, like the mini3 does, should i also isolate the dcp zero volt pin?

 

[cobaltmute]

Quote:

Originally Posted by DKJones96 /img/forum/go_quote.gif At 70ma of idle current the DCP020509 is only running at 32% load and is somewhere around 75% efficient giving you a total of 54.25ma. Still missing about 15 tho... How are you going to decouple the 0v?

There are four traces around the ring that connect it to the ground plane. Either a knife or possibly a Dremel. I suspect the knife as the Dremel will not be fine enough.

Big Warning I just realized that the USB jack on the Bantam is grounded as well as the case will be from the Carrie. This mod may not work at all as the case might/will tie the two together anyways.

Quote:

Has anyone gotten the Bantam/Carrie pair cased successfully? I don't know what the heck is going on with mine but on the table it's fine, I can pick it up, wiggle the two boards around, hit it to the table(frustration) and it stays playing fine. Once I stick it in the case moving or even touching the usb causes a pop sound from the earphones and music stops and windows doesn't see the bantam anymore. I've even held the bantam and moved the usb cable around with no issues.

Are you casing it with panels or just sliding it in? Sounds like you might be shorting something through the case.

 

[cobaltmute]

Quote:

Originally Posted by nightanole /img/forum/go_quote.gif Im still building, i was planning on doing the dual 100uf fm caps on the vground and then my huge caps across the rails, like the mini3 does, should i also isolate the dcp zero volt pin?

Do not isolate the 0V pin at this time. If you note in post 470, I realized that once Carrie gets into the case, it likely won't make a difference.

 

[Billyk]

Quote:

Has anyone gotten the Bantam/Carrie pair cased successfully? I don't know what the heck is going on with mine but on the table it's fine, I can pick it up, wiggle the two boards around, hit it to the table(frustration) and it stays playing fine. Once I stick it in the case moving or even touching the usb causes a pop sound from the earphones and music stops and windows doesn't see the bantam anymore. I've even held the bantam and moved the usb cable around with no issues.

My 1st one is all cased up and running great. I do only have plastic end caps though. I am using it at the office between my PC and a chip amp been listening to it for several days now. Works flawlessly and sound very very good.
I am waiting on a grubdac board for build #2.

 

[DKJones96]

Don't do it cobaltmute! The DCP is essentially a high speed step-up transformer with a built in rectifier. If you cut the traces to the output gnd it won't work at all. These units are designed to have complete isolation so the output hv has no path back to output gnd through input gnd.

And I'm not using the end plates, they come in tomorrow. It's just in the case. I'll eventually get it figured out.

 

[joneeboi]

C8 underneath the Bantam can short to the case. It's happened to me before.

I'll have to mull over the grounding circuit before I can give you a definite answer, cobalt.

 

[DKJones96]

Strangely enough, if I use a piece of paper underneath the boards it does this, but if I stick a piece of tape underneath it doesn't... tape it is I guess.

 

[Billyk]

I find that the plastic from those disposable containers from the market cut up and work well as an insulator. I have used it in my cmoys and anything in these little Hammonds.

 

[keyid]

Quote:

Originally Posted by DKJones96 /img/forum/go_quote.gif Has anyone gotten the Bantam/Carrie pair cased successfully? I don't know what the heck is going on with mine but on the table it's fine, I can pick it up, wiggle the two boards around, hit it to the table(frustration) and it stays playing fine. Once I stick it in the case moving or even touching the usb causes a pop sound from the earphones and music stops and windows doesn't see the bantam anymore. I've even held the bantam and moved the usb cable around with no issues. Damn thing just went to static when I was trying to change the volume.

My bantam/carrie is working great except for the 80mv spike when turning off the amp/computer. Ill be completing the grubdac by end of the week. I got the boards and 2707 just waiting for mouser.

 

[cobaltmute]

Quote:

Originally Posted by keyid /img/forum/go_quote.gif My bantam/carrie is working great except for the 80mv spike when turning off the amp/computer. Ill be completing the grubdac by end of the week. I got the boards and 2707 just waiting for mouser.

Cool that you got the boards. I was thinking people might start getting them tomorrow.

There is no clearance issues with the Grub in the case. I slipped my combo into the case last nite and specifically looked at that.

 

[Billyk]

Quote:

Originally Posted by keyid /img/forum/go_quote.gif My bantam/carrie is working great except for the 80mv spike when turning off the amp/computer. Ill be completing the grubdac by end of the week. I got the boards and 2707 just waiting for mouser.

How do you set yourself up to see that? I want to check mine.

 

[stwspoon]

Quote:

Originally Posted by cobaltmute /img/forum/go_quote.gif I'm going to recant that last post. I metered that Carrie alone at pulling 70mA of idle current Let's do some math on that DCP020509 = 23mA AD8397 = 9mA/amp = 18mA OPA690 = 6mA TLE2426 = 150 microA TL750L08CLP = 1mA Total should ~= 51ma (23ma for the DCP + 25mA*1.15 for efficiency loss in the DCP for the on board components). Where is that other 20mA going?

I'm not sure you accounted for the DCP input output voltage difference and efficiency at light loading.

DCP power out = 25 ma * 9 v = 0.225W (~ 12% load for a 2W DCP)
Efficiency at 12 % load via data sheet fig 5 is ~ 65% for DCP0212
DCP power in = 0.225 W / 65% = 0.346 W
DCP current in = 0.346 W/5V = 69.2 ma

To check this, power down the DCP (ground the sync pin) to see what else is drawing current.