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O2 AMP + ODAC - Page 104

post #1546 of 3453
Quote:
Originally Posted by orangecr View Post

I just got one from JDS Labs. I would have gotten the Mayflower just because of that apparently insignificant detail. 

hahaha I've had the JDS Labs one, it just never made sense from the beginning. Why would you ever put the ac adapter in the front, it must have made the design easier.

 

EDIT: Also lmfao @ "uglyjoe" in this FS thread  http://www.head-fi.org/t/666964/spc-occ-cooper-hybrid-cable-made-by-chris-himself-headphone-lounge


Edited by kskwerl - 7/4/13 at 7:41pm
post #1547 of 3453
Quote:
Originally Posted by kskwerl View Post


mayflower is selling an O2 with the power adapter on the back panel. which is very nice compared to having it on the front (which looks horrible IMO). its the same amp with no sonic difference just the ac power on the back label. His desktop variants of the O2 are nice as well.


The pictures on their webpage show the power adapter in the front:

http://www.mayflowerelectronics.com/black-objecective2---mayflower-edition.html

post #1548 of 3453
Quote:
Originally Posted by BenF View Post


The pictures on their webpage show the power adapter in the front:

http://www.mayflowerelectronics.com/black-objecective2---mayflower-edition.html

 

http://www.mayflowerelectronics.com/objective2-with-rear-power.html

post #1549 of 3453

Is Mayflower the only game in town doing an O2+ODAC that has a pre-out from the ODAC using RCA on the back? 

 

I am looking for that exactly, but don't understand why Mayflower charges such the premium compared to the JDSLabs build....

post #1550 of 3453
Quote:
Originally Posted by Ultimate Mango View Post

Is Mayflower the only game in town doing an O2+ODAC that has a pre-out from the ODAC using RCA on the back? 

I am looking for that exactly, but don't understand why Mayflower charges such the premium compared to the JDSLabs build....
mayflower is a smaller operation/ company
post #1551 of 3453

It looks like Mayflower's O2/ODAC combo is actually $30 cheaper than JDS Labs, unless I'm missing something?  


Their "desktop" version is more expensive, though.  

 

I think JDS Labs can do a "desktop" version for $25 more, but the only difference is a bigger case with a 1/4" output jack.  I think the Mayflower desktop version has that plus RCA inputs.  

 

Maybe someone else can verify all that.  

post #1552 of 3453
post #1553 of 3453

Speaking RCA cables, does it provide any audible advantage over a regular 3.5 mm cable? I plan to use the ODAC and hook it up to an amplifier that only has RCA inputs. My ODAC has the RCA output option but I don't have a RCA-RCA cable. I was planning to use a 3.5 mm miniplug to RCA though, which I do have, and I was wondering if this is OK to use.

post #1554 of 3453

Probably "technically better" (inaudibly so) channel isolation, but other than that, no.


Edited by Tus-Chan - 7/9/13 at 12:47pm
post #1555 of 3453

anyone know if these are good with production software? I've looked everything but haven't found much info on this. I need something for both Mac and PC with quality at least as good or better than my current Apogee ONE.

post #1556 of 3453
I've bought the O2/ODAC combo from Epiphany Acoustics. It comes with a 230/12V AC transfomer. I am a little confused that the designer is so worried about the 12V AC transformers, and recommends at least 14V AC for the transformer, for the 7812 and 7912 regulators to have headroom for regulation in case of ripple on the DC voltage. The 12V AC is a RMS value mening that rectified though a full-wave rectifier the DC level will be approx. 17V DC leaving plenty of room for regulation. Is it me misunderstanding something here? :) (I guess so...the designer seems very capable :))
post #1557 of 3453
Quote:
Originally Posted by DonJunker View Post

I've bought the O2/ODAC combo from Epiphany Acoustics. It comes with a 230/12V AC transfomer. I am a little confused that the designer is so worried about the 12V AC transformers, and recommends at least 14V AC for the transformer, for the 7812 and 7912 regulators to have headroom for regulation in case of ripple on the DC voltage. The 12V AC is a RMS value mening that rectified though a full-wave rectifier the DC level will be approx. 17V DC leaving plenty of room for regulation. Is it me misunderstanding something here? :) (I guess so...the designer seems very capable :))

 

It is slightly less than 17 V because there is a 0.6-0.8 V voltage on the rectifier diodes. Also, the voltage drops under load, especially since only a half-wave rectifier is used with 2*470 uF capacitors on each rail. Finally, the AC voltage is not guaranteed to be accurate either.

The 12 V/200 mA power supply is enough for headphones that do not need a lot of current, but it may not be enough under heavy load (when using inefficient low impedance headphones).


Edited by stv014 - 7/10/13 at 6:07am
post #1558 of 3453
Quote:
Originally Posted by stv014 View Post

 

It is slightly less than 17 V because there is a 0.6-0.8 V voltage on the rectifier diodes. Also, the voltage drops under load, especially since only a half-wave rectifier is used with 2*470 uF capacitors on each rail. Finally, the AC voltage is not guaranteed to be accurate either.

The 12 V/200 mA power supply is enough for headphones that do not need a lot of current, but it may not be enough under heavy load (when using inefficient low impedance headphones).

 

Thank you for the clarification. It's true it's only a dual polarity half wave rectifier. There may be room for some improvement on the PSU part (and perhaps better decoupling on supply of the DACs, as close a possible), even though the designer states that it won't matter and may cause the sound to worsen to e.g. improve the capacitor bank size with low ESR/ESL capacitors :) I have ordered a 15V AC 1A adapter..just to be sure :) I use Denon d2000 which is low-impedance
Edited by DonJunker - 7/11/13 at 3:47am
post #1559 of 3453
Quote:
Originally Posted by stv014 View Post

 

It is slightly less than 17 V because there is a 0.6-0.8 V voltage on the rectifier diodes. Also, the voltage drops under load, especially since only a half-wave rectifier is used with 2*470 uF capacitors on each rail. Finally, the AC voltage is not guaranteed to be accurate either.

The 12 V/200 mA power supply is enough for headphones that do not need a lot of current, but it may not be enough under heavy load (when using inefficient low impedance headphones).

I don't understand any of the technical discussion here,

but this is what I wanted to know:

 

 

Quote:

The 12 V/200 mA power supply is enough for headphones that do not need a lot of current,

but it may not be enough under heavy load (when using inefficient low impedance headphones).

Thanx for the last  beerchug.gif sentence.


Edited by JakeJack_2008 - 7/11/13 at 9:28am
post #1560 of 3453
I just received the Mayflower O2 with power adapter on the rear panel. sonically its obviously the same and I'm very happy with it. the front panel looks much cleaner without the power adapter.
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