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Old 18th November 2010, 05:21 PM   #121
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Ah, thanks.....
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Old 18th November 2010, 06:16 PM   #122
iwok is offline iwok  Poland
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Quote:
Originally Posted by Peter Daniel View Post
It's not a problem, it's normal. Usually there is a coupling cap in a DAC (0.01uF or similar) and you don't have to do anything. If DAC does not lock to your transport, install such coupling cap at the output.

Thanks Peter. My DAC communicates with the transport without any problem. I am just thinking if this constant voltage is not dangerous to my DAC when used for a longer time..
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Old 18th November 2010, 06:24 PM   #123
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I got my birdnest setup running today with the original trafo and a Vishay W02G diode bridge with a Evox-Rifa 1nF cap between each leg. Two Panasonic FC 1000uF / 25V caps and a MC7808C regulator. The C916 was replaced with a Panasonic FC 22uF / 100V cap.
The two output resistors were just some old ones taken from the drawer.

The 5 components suggested by Peter was removed.

The transport is feeding a DPA Enlightenment DX32 DAC.

Its cool when it works the first time, but I cant comment on the sound yet until I try it up against my DPA transport.
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Old 18th November 2010, 11:04 PM   #124
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Iwok: its not dc voltage - its the spdif signal, which is so fast that your dmm thinks that its dc.
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Old 19th November 2010, 05:12 AM   #125
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Quote:
Originally Posted by Kim Schultz View Post
I got my birdnest setup running today with the original trafo and a Vishay W02G diode bridge with a Evox-Rifa 1nF cap between each leg. Two Panasonic FC 1000uF / 25V caps and a MC7808C regulator. The C916 was replaced with a Panasonic FC 22uF / 100V cap.
The two output resistors were just some old ones taken from the drawer.

The 5 components suggested by Peter was removed.

The transport is feeding a DPA Enlightenment DX32 DAC.

Its cool when it works the first time, but I cant comment on the sound yet until I try it up against my DPA transport.
any reason why u need such a large deviation from the original value for C916?
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Old 19th November 2010, 07:41 AM   #126
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Commstech, no reason other than Peter recommend a 33uF or 47uf BG but I only had a 22uF if I wanted a Panasonic FC.

Ill see if I can find some BGs to experiment with another powersupply.
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Old 19th November 2010, 10:04 AM   #127
slawney is offline slawney  Germany
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Thanks Peter. You provide solid, easy-to-follow guidelines for this project.
If I may, I suggest putting a .27Ohm - .47Ohm 2-5 Watt resistor between the LM7808 V+output and the 1,000uF-470uF decoupling cap that follows it. LM78xx regulators are notorious for oscillating into low impedance loads and a low impedance cap like a large value Black Gate or Rubycon (esp. with a bypass) after a commercial regulator will result in oscillation. The added benefit of this resistor will be to provide a last low-pass RC filter for the supply before it reaches the active components. The resistor does not need to be low-inductance, in fact, inductance would add further HF filtering, which would be beneficial here.
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Old 22nd November 2010, 08:03 PM   #128
billo44 is offline billo44  United Kingdom
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Quote:
Originally Posted by Peter Daniel View Post
It's not a problem, it's normal. Usually there is a coupling cap in a DAC (0.01uF or similar) and you don't have to do anything. If DAC does not lock to your transport, install such coupling cap at the output.
That is my exact problem....
So excuse me for being 'a bit of a thicky' (there is no excuse really!) but... the (0.01uF or similar) cap goes across DOUT and GND after the output resistors? Or in line on DOUT?

DAC locks on to other sources OK. Using the built in DAC in an Onkyo Integra A-701 for now.

I can only think of electronics by using plumbing analogies, this will only get me so far I guess!

I'll probably have found out by the time anyone answers..... I'm on Japan time and at the start of the Labour Day holiday here.

regards all

Bill

Last edited by billo44; 22nd November 2010 at 08:10 PM. Reason: lack of clarity
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Old 22nd November 2010, 08:12 PM   #129
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You are up too early.....
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Old 22nd November 2010, 09:12 PM   #130
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Quote:
Originally Posted by billo44 View Post
That is my exact problem....
... the (0.01uF or similar) cap goes across DOUT and GND after the output resistors? Or in line on DOUT?l
It goes in line with output, after the resistors.
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