Oppo`s BDP105 - discussions, upgrading, mods... - Page 68 - diyAudio
Go Back   Home > Forums > Source & Line > Digital Source

Digital Source Digital Players and Recorders: CD , SACD , Tape, Memory Card, etc.

Please consider donating to help us continue to serve you.

Ads on/off / Custom Title / More PMs / More album space / Advanced printing & mass image saving
Reply
 
Thread Tools Search this Thread
Old 26th October 2013, 02:03 AM   #671
diyAudio Member
 
NorthStar's Avatar
 
Join Date: Oct 2012
Location: Vancouver Island, British Columbia - Canada
Will they make an Oppo BDP-105D?
__________________
~ Bob ~ Test Only Ω
  Reply With Quote
Old 27th October 2013, 12:59 AM   #672
diyAudio Member
 
zenelectro's Avatar
 
Join Date: Sep 2009
Quote:
Originally Posted by Joe Rasmussen View Post
Hi Terry

You don't know what I have here?

Something that is pretty good.

Cheers, Joe
So what is it Joe?
  Reply With Quote
Old 27th October 2013, 02:11 AM   #673
diyAudio Member
 
NorthStar's Avatar
 
Join Date: Oct 2012
Location: Vancouver Island, British Columbia - Canada
I wanna know too.
__________________
~ Bob ~ Test Only Ω
  Reply With Quote
Old 28th October 2013, 05:23 PM   #674
diyAudio Member
 
Join Date: Mar 2002
Location: Boulder Creek, CA
A very simple output stage can be made using the OPA1632. Simply remove all the opamps (this is for the two channel board only) and mount a pair of 1632s using the pads that have the funky LME49724s in them (outputs for the balanced outs). The 49724s and 1632s have the same pin out (they are both differential amps). You simply hook up the outputs of the DACs to pins one and 8 and use a resistor on each output leg back to the input with a cap across it for a single pole filter and then a single small resistor on the outputs directly to the output jacks. If you are just using just one of the outputs of the DAC then you will need a 1.8K resistor for feedback (for 2.2V out) and I like to use a 1000pf cap across it. Then a 47 ohm output resistor. You need to do this to both phases (you have to have both inputs hooked up and both feedback resistors hooked up for the part to work). You can use just the unbalanced outs or balanced....in either case there is no DC offset. Pin 2 on the part sets the output offset and it is grounded in this instance so you get no offset (well a few millivolts).

This output stage has simply one great opamp and one resistor in series with the signal. This is way better than the stock output stage. I have tried the 49724s as the IV diff amp but it sounds way bad....please use the mucho better 1632. Obviously, the quality of the feedback and output resistors are important as well as the feedback cap. Flavor any way you like.
  Reply With Quote
Old 16th November 2013, 09:04 AM   #675
Per is offline Per
diyAudio Member
 
Join Date: Aug 2001
Location: Herning, Denmark
I've searched the thread without finding something about digital multichannel out, like analog multichannel, but via digital via 8 rca. I know there is made boards for earlier model of Oppo. I'm thinking of using multichannel digital outs for minidsp or the likes...

Like this one: Audiopraise :: Specialist in digital electronics and signal processing
  Reply With Quote
Old 14th December 2013, 09:10 AM   #676
Coris is offline Coris  Norway
diyAudio Member
 
Join Date: May 2009
Location: Norway
Default A clock debate...

I have/get a dilemma about a clock signal...
So, I think to lunch here a quite theoretical question: How is best (audio point of view) to have the clock signal in a device, square or sine?

A square clock signal it may look more accurate as rise time, and better time definition, but it looks also very noisy (many high level harmonics). A sine signal is less noisy (harmonics), but quite bad rising time, and maybe enough difficult to get out of an modern (HF) oscillator... At least a logical circuit it should work on square clocks... but thinking at the amount of generated noises...

Some comments on this subject...?
  Reply With Quote
Old 14th December 2013, 10:30 AM   #677
Coris is offline Coris  Norway
diyAudio Member
 
Join Date: May 2009
Location: Norway
I mean clock signal coming from an oscillator...
  Reply With Quote
Old 14th December 2013, 03:41 PM   #678
eganz1 is offline eganz1  United States
diyAudio Member
 
Join Date: Mar 2013
Hi Coris,

The clock is designed to provide zero crossings at well defined time intervals, and with accurate long-term stability. Therefore the square wave is vastly superior in terms of jitter, being more resistant to applied voltage noise, as you know.

If you're worried about radiated noise, then extra shielding should be the solution. Good high-frequency circuit design and local power supply bypassing also come to mind. Of course, this is a program that you and many of us have been pursuing.

So theoretically, I would say that you want to provide your best clock, and then fix the consequences.

Eric
  Reply With Quote
Old 14th December 2013, 04:30 PM   #679
Coris is offline Coris  Norway
diyAudio Member
 
Join Date: May 2009
Location: Norway
Hi Eric,

Thanks for your comment.

I feel the need to precise a little bit more my above thinking...
We have two (or more) black boxes. One is the oscillator (clock generator), the other one (or the rest) is/are the receiver(s) of that clock. The discussion is not what it is happen inside the "clock receiver" black box. This "receiver black box" it will anyway convert that clock signal on its input port to an square clock, to be used further in its circuits, and how Eric says/justified above, inside that device it have to be a square signal.

My dilemma is how is better to be done, when is to put a clock signal in to a "receiver device". There are some oscillators which it output a very fine sine clock frequency, and another ones which it output a square clock signal. Apparently, delivering to a device a sine wave as clock signal, it seems to be less noisy or cleaner signal to be processed further by the receiver device. In opposite, delivering to a device on clock input port, a square clock wave, it seems to induce in the same time some unwanted harmonics which it may (further) disturb the "receivers" inside processes, more "work" it may be necessary for the "receiver device" to clean up the clock signal, and so on.

So, how it may be more beneficial for an audio device/circuit (DAC or whatever audio processor) to get this clock signal on its input: as square or as sine wave?

I do hope now it may be better understood my enunciation of the problem...

Last edited by Coris; 14th December 2013 at 04:33 PM.
  Reply With Quote
Old 14th December 2013, 11:16 PM   #680
diyAudio Member
 
abraxalito's Avatar
 
Join Date: Sep 2007
Location: Hangzhou - Marco Polo's 'most beautiful city'. 700yrs is a long time though...
Blog Entries: 101
Send a message via MSN to abraxalito Send a message via Yahoo to abraxalito Send a message via Skype™ to abraxalito
Quote:
Originally Posted by Coris View Post
I have/get a dilemma about a clock signal...
So, I think to lunch here a quite theoretical question: How is best (audio point of view) to have the clock signal in a device, square or sine?
My own view is that sine is better than square for transmitting the clock around a circuit. This is for a couple of reasons beyond the one you mentioned about broadcasting harmonics around.

Firstly since the square clock is very wide bandwidth it requires great attention to the transmission line details - there's a requirement for a constant impedance over a wide bandwidth and reflections must be kept well under control.

Secondly since the square clock is such a wide bandwidth signal, the clock receiver must be similarly wide bandwidth, meaning that its susceptible to noise pickup. This is the corollary of your already stated observation that a square clock radiates more noise - its also more susceptible to noise.

Hence if I were to get really fussy about clock quality, I'd distribute a sine (you're right, you'd probably better start off with an analog rather than digital oscillator). I'd also filter the sine at the receiver with a bandpass filter (probably an LC tank of some kind). I'd also not use a comparator to convert sine into square, rather a limiter kind of circuit which amplifies the sine through a number of stages into clipping.
__________________
No matter if we meanwhile surrender every value for which we stand, we must strive to cajole the majority into imagining itself on our side - Everett Dean Martin
  Reply With Quote

Reply


Hide this!Advertise here!
Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
OPPO 93 and OPPO 95 - A warning. sandyK Digital Source 3 26th January 2012 06:53 AM
Discussions about your favorite or DIYD/T-amp v-bro Class D 0 13th January 2009 08:37 AM
Class D discussions mskeete Class D 16 19th March 2004 06:27 AM
Discussions on Balenced Amplifers theChris Chip Amps 24 6th January 2004 02:40 PM
Do opamps discussions also have to take place here? Bricolo Chip Amps 3 27th April 2003 08:39 PM


New To Site? Need Help?

All times are GMT. The time now is 11:31 AM.


vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2014 DragonByte Technologies Ltd.
Copyright ©1999-2014 diyAudio

Content Relevant URLs by vBSEO 3.3.2