Oppo`s BDP105 - discussions, upgrading, mods... - Page 4 - 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 4th November 2012, 06:12 PM   #31
Coris is offline Coris  Norway
diyAudio Member
 
Join Date: May 2009
Location: Norway
Quote:
Originally Posted by stephensank View Post
Correct me if I am wrong, but, as I see the specs, all of these "32bit dac" chips from ESS & etc. are NOT 32bit dacs, but are 24bit dacs with 32bit digital filter on-board. I haven't ectually seen even a 24bit dac that's capable of genuine 24bit SNR/DNR.

Oppo's reasoning for use of 4x dac channels for headphone makes no sense. The dac chip does not see any 'extra load', as it's simply feeding a driver chip. They should have at least used, instead, 4 dac channels for the balanced outputs, which would have made good sense.

Appears that the 103 uses Nichicon caps in the dac/output stages, which I personally prefer over Elna. I find Elna's to be far too unreliable to use, even if they *maybe* sound a bit better for a given purpose(which I believe they don't, after caps are well broken in). Elna's are particularly short life in hot environments, which I expect the 105 will be.

As for the dc offset- in this sort of design, even very sloppy selection of parts will end up with totally insignificant output offset, unless the design is appallingly bad. But UL hates anything without dc blocking on output/input, so most makers use them even when they are not at all needed.

I don't know why people are at all impressed when they see Wima caps. I've known them to be terribly bad sounding caps for 25 years. Even after 1000 hours of break in, they sound hazy in signal path & grainy as ps bypass. I'd sooner use Panasonic polyesters than any Wima.
The ESS9018 is the most advanced audio DAC chip at this time, it have an 32 bit architecture, and can process on 32 bit resolution.

There is not the meaning of allocation of the DAC channels, the load(s) on it. The chip can deliver very good performances on every channel. The point with connecting 2 or more channels together is to obtain a very high accuracy of the resulting analogue signal, a max dynamic range, and to improve the SNR in the system. The output differential channels of ESS9018 can be connected together in multiple of 2. Oppo use 2 + 2 stereo ch for XLR, 2 stereo ch for RCA out, and 4 stereo ch. for headphone. In this configuration the only possibility to switch those 2 remaining ch (after having 2 for headphone) is between the headphone out and RCA out. One may chose to double the headphone or RCA in this design. Oppo explain the allocation they used as been necessary for have an independent volume control for the XLR/RCA output and for the headphone. I suppose they fix this separation of those volume controls in the DAC firmware and it divide the outputs of the DAC in two part for this propose. Maybe they have to chose this way to have those independent volume controls. I personally mean that it should be used an DAC chip more to maintain at least the same level of quality for the output signals (at the level of 95 model) and having in the same time an independent output for the headphone. Them choice downgrade the quality level for the stereo stage in my opinion...

The debate about Elna vs Nichicon will never end... The best is not to use at all caps in that places...

I share your opinion about the DC offset. The design or the components have to be very bad to have a dangerous or uncontrolled offset at the outputs. Is not difficult at all to chose a design which can assure a very low, almost 0 DC offset. Protection for the next input is made using resistors. But the opamp chips may have internal protection anyway. AC coupling in my opinion is a downgrade from the precedent models. The modders will have so a good job to do... Right?

Of course are many (betters) alternatives when about film caps. I think using just SMD film caps is a much better solution...
  Reply With Quote
Old 4th November 2012, 06:26 PM   #32
diyAudio Member
 
David Gatti's Avatar
 
Join Date: Mar 2004
Location: Melbourne, Australia
It would be interesting to hear reviews from the headphone crowd on the performance of Oppos headphone stage. I suspect most of the fanatics will stick to their dedicated headphone amps so it's a pity Oppo sacrificed performance to cater to them.

A while ago I ran temperature tests on the Oppo 93 and 95. Both maintained internal temperatures around 41 - 43 degrees C. I would be disappointed if the 103 & 105 are worse than that.
  Reply With Quote
Old 4th November 2012, 08:50 PM   #33
diyAudio Member
 
Join Date: Dec 2008
I had my heart set on the Oppo 105, so the comments here are very disappointing.

IMO there is no point in using the ess9018 DAC and then using WIMA coupling caps.

The unit could be AC coupled with transformers - but the cost of audio transformers - like Lundahl is quite excessive.
I see a person on DIYAudio winds his own.
Winding transformers is not difficult - the most difficult part is acquiring the magnet wire and cores.



How about other units that use the ESS9018 DAC ?

The W4S DAC2 looks well build and has a good power supply.

The Eastern Electric DAC plus isn't as well made as the W4S DAC2.
However, the Op Amps are in sockets and the output coupling caps are reasonably large.
.
  Reply With Quote
Old 4th November 2012, 09:03 PM   #34
Coris is offline Coris  Norway
diyAudio Member
 
Join Date: May 2009
Location: Norway
Quote:
Originally Posted by Uunderhill View Post

I had my heart set on the Oppo 105, so the comments here are very disappointing.


.
To have a better "picture" of the 105 player you may also get known with comments/infos in this thread/forum:

Official OPPO BDP-103/BDP-105 Anticipation Thread

Some more (real) informations (review, impressions/comments) may come out when the player will be in fact on market...
  Reply With Quote
Old 4th November 2012, 09:32 PM   #35
diyAudio Member
 
David Gatti's Avatar
 
Join Date: Mar 2004
Location: Melbourne, Australia
It might be worth waiting for the Nuforce versions where hopefully these issues are addressed .... at a premium no doubt.
  Reply With Quote
Old 4th November 2012, 09:33 PM   #36
qusp is offline qusp  Australia
diyAudio Member
 
qusp's Avatar
 
Join Date: Oct 2009
Location: Brisbane, Australia
Quote:
Originally Posted by Uunderhill View Post
I had my heart set on the Oppo 105, so the comments here are very disappointing.

IMO there is no point in using the ess9018 DAC and then using WIMA coupling caps.

The unit could be AC coupled with transformers - but the cost of audio transformers - like Lundahl is quite excessive.
I see a person on DIYAudio winds his own.
Winding transformers is not difficult - the most difficult part is acquiring the magnet wire and cores.



How about other units that use the ESS9018 DAC ?

The W4S DAC2 looks well build and has a good power supply.

The Eastern Electric DAC plus isn't as well made as the W4S DAC2.
However, the Op Amps are in sockets and the output coupling caps are reasonably large.
.
if they wanted to meet some sort of analogue specification, using transformers would not be the way to attain it...they can for sure sound pleasant enough, but measured performance is shithouse with es9018 and output TX
  Reply With Quote
Old 4th November 2012, 10:56 PM   #37
diyAudio Member
 
David Gatti's Avatar
 
Join Date: Mar 2004
Location: Melbourne, Australia
Oppo BDP-95 vs Oppo BDP-105 final stereo output stage:

Click the image to open in full size.

Click the image to open in full size.
  Reply With Quote
Old 5th November 2012, 11:27 AM   #38
mvc is offline mvc  United Kingdom
diyAudio Member
 
Join Date: Jun 2004
Location: Cambridge
I'm still a bit puzzled about the allocations of the dac channels to the outputs.
Coris said "Oppo use 2 + 2 stereo ch for XLR, 2 stereo ch for RCA out, and 4 stereo ch. for headphone", but that adds up to 10 channels. Others say that there's 2 for RCA, 2 for XLR, 2 for headphones and 2 to ground. Someone from Oppo said that there are 4 channels dedicated for headphones. But the specs mention that the RCA level is 2.1V and the XLR is 4.2V. This seems to indicate that 2 times 2 channels are used for XLR, 2 channels for RCA and then the remaining 2 for headphones. That would make sense.
  Reply With Quote
Old 5th November 2012, 12:39 PM   #39
Coris is offline Coris  Norway
diyAudio Member
 
Join Date: May 2009
Location: Norway
Quote:
Originally Posted by mvc View Post
I'm still a bit puzzled about the allocations of the dac channels to the outputs.
Coris said "Oppo use 2 + 2 stereo ch for XLR, 2 stereo ch for RCA out, and 4 stereo ch. for headphone", but that adds up to 10 channels. Others say that there's 2 for RCA, 2 for XLR, 2 for headphones and 2 to ground. Someone from Oppo said that there are 4 channels dedicated for headphones. But the specs mention that the RCA level is 2.1V and the XLR is 4.2V. This seems to indicate that 2 times 2 channels are used for XLR, 2 channels for RCA and then the remaining 2 for headphones. That would make sense.
Yes, sorry. It were wrong allocation from my side. The right whole number is 8 (channels for ESS9018).
Anyway one may read the Oppo`s answer about this allocation.
XLR output is differential, and then 4,1v from only one differential channel of the DAC. Is correct. XLR is for R and L channels = 2 DAC channels. RCA is single ended and then 2,1v. This it need 2 DAC channels for stereo RCA output. It remain again 4 channels (2+2) which goes to headphone coupled in parallel.

Last edited by Coris; 5th November 2012 at 12:45 PM.
  Reply With Quote
Old 5th November 2012, 12:50 PM   #40
mvc is offline mvc  United Kingdom
diyAudio Member
 
Join Date: Jun 2004
Location: Cambridge
Thanks for the answer.

So, am I correct in now assuming that any single
channel on the Sabre DAC can be either differential
or single ended? I had assumed that a truly balanced
output would need two DACs.

Oppo seem to make the point that "The balanced output
features a true differential signal path all the way from the
DAC to the 3-pin XLR connector", which seems to suggest
a double DAC setup, or not?

Maarten
  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 10:09 PM.


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