DexterMorgan said:
This is not correct. BCK goes to DCK. I deleted my previous post.
BCK is the bit clock, the bit clock goes to DCK.
The confusion arises because different manufactures (and people) refer to the same clock signal by different names.
When I designed the boards I did so with each part's datasheet in mind so the people could use the part's datasheet as a reference.
Cheers!
Russ
Russ White said:
At the AVCC pins you really only want a small capacitance because the supply is in a feedback loop, and you don't want he opamp driving a high capacitance. Its all actually very well thought out.
Riss
Russ
What about an earlier post suggesting increasing the VDD filtering cap C6 from 1 uF to 100 uF?
How much effect does this have?
Fred
fmak said:
Yes I did try that.
Well what it does is lower the Fc of the filter, but what I found what that when I look at it with the scope there was not much benefit in lowering the Fc to this extent. It did help a tiny bit. Any ripple was in the 80-160Mhz range, and the existing cap actually filters that very well.
So the honest answer is, not much difference.
Cheers!
Russ
Russ White said:
Yes I did try that.
Well what it does is lower the Fc of the filter, but what I found what that when I look at it with the scope there was not much benefit in lowering the Fc to this extent. It did help a tiny bit. Any ripple was in the 80-160Mhz range, and the existing cap actually filters that very well.
So the honest answer is, not much difference.
Cheers!
Russ
Yhanks; may try one of these Murata 'wonder' 10/22 uF smds that John W raved about in diyhifi.org. May help in this F range?
Russ White said:
This is not correct. BCK goes to DCK. I deleted my previous post.
BCK is the bit clock, the bit clock goes to DCK.
The confusion arises because different manufactures (and people) refer to the same clock signal by different names.
When I designed the boards I did so with each part's datasheet in mind so the people could use the part's datasheet as a reference.
Cheers!
Russ
Thanks Russ,
The USB->Buffalo works great now =)
Dex
Some PSU issues:
1/
Brian mentions in an earlier post that one way to go is to use 12V secondaries to drive the LCBPS and trim the output to 12VDC.
When I tested my LCBPS board (12V transformer) with a simple single power resistor load (330 ohms) I couldn't regulate the output lower than just below 14V (hitting the pots end position). Is this an indication of some kind of problem with my LCBPS?
Further, is there any real advantage in using 15VDC supply for the IVY as recommended, or is 12VDC just as great, or 14V as I have now for that matter?
2/
Also, I drive the SPDIF-convertor board with the buffalo VD-supply (LCDPS) at 6.0VDC, the manual states that 7.5VDC is preferred for the SPDIF-board. Again, does it really matter?
Thanks for your help,
Dex
1/
Brian mentions in an earlier post that one way to go is to use 12V secondaries to drive the LCBPS and trim the output to 12VDC.
When I tested my LCBPS board (12V transformer) with a simple single power resistor load (330 ohms) I couldn't regulate the output lower than just below 14V (hitting the pots end position). Is this an indication of some kind of problem with my LCBPS?
Further, is there any real advantage in using 15VDC supply for the IVY as recommended, or is 12VDC just as great, or 14V as I have now for that matter?
2/
Also, I drive the SPDIF-convertor board with the buffalo VD-supply (LCDPS) at 6.0VDC, the manual states that 7.5VDC is preferred for the SPDIF-board. Again, does it really matter?
Thanks for your help,
Dex
DexterMorgan said:
Yes, there is something wrong. You should be able to regulate it down to at least 3V. Is this problem the same on both sides of the supply? Check that IC1 is the LM317 and IC2 is the LM337.
12VDC should be fine, but you will get slightly better performance from 15V.
7.5v is a general recommendation when powering multiple modules to allow plenty of overhead for the receiver's on-board regulators, which are 3.3V. Really anything over 4.5V is fine.
luvdunhill: I'm sure brian/russ will jump in here, but the rule of thumb is that you need at least the same level of AC as the DC you want to achieve - you might get away with a volt, but often at the cost of poorer/noisier regulation (all of which is probably not the case with any of the TP supplies).
So for your 15VDC requirement you should be looking at 15VAC Tx, or even 18VAC (although you may need a little better cooling here).
Fran
So for your 15VDC requirement you should be looking at 15VAC Tx, or even 18VAC (although you may need a little better cooling here).
Fran
Actually I was thinking a little different for the regulator.
12.6V AC = 17.8V DC rectified, take off 0.7V for diodes, or use schotky diodes and it will be a little less. Still to be safe, you're looking at around 2V of regulator headroom. Not ideal, but likely OK as long as you don't need to pull a lot of current.
12.6V AC = 17.8V DC rectified, take off 0.7V for diodes, or use schotky diodes and it will be a little less. Still to be safe, you're looking at around 2V of regulator headroom. Not ideal, but likely OK as long as you don't need to pull a lot of current.
Russ White said:
Looking at the LCBPS the bridge has around 0.7 Vf and I could sub in a LM1086 which has a 1.3V drop-out voltage. I'm not sure what L1 and R1 will drop (don't know exactly what current I'll be drawing, but it's probably around 10mA, very low), but I could always omit them. I'm assuming this might have a greater chance of working than the Placid...
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