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Old 2nd May 2013, 08:46 PM   #1051
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Join Date: Jul 2012
Quote:
Originally Posted by Alterfalter
Hi,

while I am waiting for my Najda board to arrive I look at some PSUs

How about
1.) ASTEC DPT52
Mouser Electronics - Electronic Components Distributor
External PSU, no switching frequency specified, minmum load 0.1A for +12V

2.) ASTEC NLP65-7608J
Mouser Electronics - Electronic Components Distributor
Open Frame, 100Khz Switching Freq., requires minumum load to start up, foootnote 6

3.) ASTEC LPT 42
Mouser Electronics - Electronic Components Distributor
Open Frame, 110KHz Switching Freq., requires minimum load 0.2A for +12V

If possible I would rather use an external PSU. Any opinion if 1) is OK?
I guess the minumum load is requires to not fall out of the specified range.
Nick: Any opinion if Najda would be sensitive to (hopefully only a bit) overvoltage?

Uwe
Hi Uwe,

External PSU is fine, no problem at all.
I think you're right about the minimum load: the power supplies are probably out of specs if the minimum load condition is not satisfied.
Overvoltage on the 5V line is dangerous if you exceed 5.5V. Indeed, the 5V supply powers all digital chips (micro, SPDIF transmitter, glue logic) and most of these chips won't like anything above 5.5V.
Overvoltage on +/- 12V lines is less critical because most of the current drawn here goes through regulators.
Hi Nick,

thanks for the fast reply. I ordered the Astec DPT52 (external PSU). I will check all voltages with and without load before I connect to Najda.

BTW especially for European builders: All mentioned PSUs are available from German ebay for less than 15 EUR (new, not used).

Uwe
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Old 2nd May 2013, 09:31 PM   #1052
JLOP is offline JLOP  France
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Location: Luxembourg
Quote:
Originally Posted by Alterfalter View Post
BTW especially for European builders: All mentioned PSUs are available from German ebay for less than 15 EUR (new, not used).

Uwe
Plus a burnt Najda board
Thanks for making the guinea pig for us !

btw incredible prices !

BR
Jean-Louis
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Old 2nd May 2013, 09:37 PM   #1053
chaparK is offline chaparK  Luxembourg
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Location: Luxembourg
Quote:
Originally Posted by dahlberg View Post
When disscusing the ability to do settings in pairs you said that the obvious
pairs would be 1-5. 2-6, 3-7, 4-8 to get an equal load on both cores.
I belive that it would be nice to have the possibility to make stereopairs
that's the same as the spdif outputs as well. I do have three excellent
dac's so I will be using them. In a three way setup using the spif outputs
you will always get an uneven load anyway. As it seems now I will be using
channel 1-2 for basspanels (h/p, l/p + dipole-eq+delay) channel 5-6 for
tapped horn subs ( l/p) and channel 7-8 for the ribbons (h/p + delay).
All crossovers 4/ord LR.

Edit: No delay for the subs. I have'nt tried it yet so I might change the use
of channels.
Now I see, you were talking about linking. I was confused with all the pairs (linking, spdif, DSP load) we have mentioned recently. The linking is still under discussion, and the option I like the most so far is the one Jean-Claude (jcga) has suggested, which would allow setting pairs freely. The only problem now is where to locate the pairing control on the interface...

Quote:
Originally Posted by SunShade View Post
When you say a priori, a guess you mean hardwired? If that is the case, I have 4 I2S streams, 7+1 channels coming from a Dolby decoder. I'd like to use two Nadja boards, 2 I2S channels each. Each input audio channel should be mapped to two outputs - as my speakers are two ways.
In theory it should be pretty easy. Is there a way to do it in Najda / can you maybe provide a fixed in/out mapping for this application?
I understand. Let's keep this in mind and see if more people come with similar needs. However, taking 2 Najdas for a single multichannel setup is not ideal because you can't daisy-chain 2 units, at least for now.

Quote:
Originally Posted by Alterfalter View Post
I ordered the Astec DPT52 (external PSU). I will check all voltages with and without load before I connect to Najda.

BTW especially for European builders: All mentioned PSUs are available from German ebay for less than 15 EUR (new, not used).
That's great Uwe, thanks. Please let us know how it goes.
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Old 2nd May 2013, 10:29 PM   #1054
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Location: Sweden
Quote:
Originally Posted by dahlberg
No that's not possible. I will be using the built in digital volumecontrol of the dacs
(BuffaloIIIse). They have different buffers/analog outputs, but are identical in all
other aspects. The gainstructure will be rougly tuned using the I/V resistor in the
"Broskie unballancer" buffers. I'm using TP's "IVY III" buffer for the subchannels.
I can control the volume of all three with one 10k-pot and I saw no
reason to exclude the volumechip from the "Najda" it may come in handy some day.
Quote:
Originally Posted by Ryssen View Post
Hmm,so maybe the built in buffert in the volume control vill degree the sound,didnīt think of that..
It seems that I have developed a silicon allergi in my old days Actually
there can be many god things done with op-amps and I have heard some I
even liked a lot over the years but I can't help it, I just like the tubes .

These op's? I really don't know, I haven't started it yet The users that has
commented on SQ seems to be satisfied and maybe I'm just doing overkill here.
On the other hand, I'm aiming for fantastic and overkill seems to be working so.........
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Old 2nd May 2013, 10:31 PM   #1055
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Quote:
Now I see, you were talking about linking. I was confused with all the pairs (linking, spdif, DSP load) we have mentioned recently. The linking is still under discussion, and the option I like the most so far is the one Jean-Claude (jcga) has suggested, which would allow setting pairs freely. The only problem now is where to locate the pairing control on the interface...
Thanks
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Old 3rd May 2013, 06:18 AM   #1056
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Location: Italy
Quote:
Originally Posted by chaparK View Post
I understand. Let's keep this in mind and see if more people come with similar needs. However, taking 2 Najdas for a single multichannel setup is not ideal because you can't daisy-chain 2 units, at least for now.
.
Thanks. I don't see the need to daisy-chain 2 units. I can semply feed BCLK, LRCLK + serial data of two I2S channels to one unit, and BCLK,LRCLK+ serial data of the other two I2S channels to the other unit, can't I?
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Old 3rd May 2013, 08:41 AM   #1057
UrSv is offline UrSv  Sweden
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I don't know if anybody has asked so far but what is the meaning of the name Najda?
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Those who say it can't be done should not stop those who are doing it.
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Old 3rd May 2013, 10:47 AM   #1058
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Join Date: Dec 2001
Location: South Sweden
Quote:
Originally Posted by dahlberg View Post
It seems that I have developed a silicon allergi in my old days Actually
there can be many god things done with op-amps and I have heard some I
even liked a lot over the years but I can't help it, I just like the tubes .

These op's? I really don't know, I haven't started it yet The users that has
commented on SQ seems to be satisfied and maybe I'm just doing overkill here.
On the other hand, I'm aiming for fantastic and overkill seems to be working so.........
Unfortunately building a DSP operating in the 100s of MHz might be a bit to much with tubes despite the facts that second generation computers used said tubes (first used relays and other mechanical devices)
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Old 3rd May 2013, 10:49 AM   #1059
Julf is offline Julf  Europe
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Join Date: Oct 2011
Location: Amsterdam, The Netherlands
Quote:
Originally Posted by rikkitikkitavi View Post
Unfortunately building a DSP operating in the 100s of MHz might be a bit to much with tubes despite the facts that second generation computers used said tubes (first used relays and other mechanical devices)
The power bill would not be fun, but it would keep the house warm in the winter.
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Old 3rd May 2013, 10:53 AM   #1060
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Location: Sweden
God thing I'm not building the actual dsp then
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