Matrix Mini-i Balanced DAC+HP amp
Mar 29, 2011 at 9:26 AM Post #661 of 1,054

T.IIZUKA

Headphoneus Supremus
Joined
May 23, 2009
Posts
3,038
Likes
10
 
I remodeled the power supply part. 
 
1. I change three terminal regulators for a low noise product 
2. I change a bridge diode for an SBD bridge
 
 

 
Bridge Diode = SBD x 4
SBD http://en.wikipedia.org/wiki/Schottky_diode
 

 
Regulator
 
Fidelix Technical information
Nakagawa Shin made three-terminal regulator optimized for audio.
http://www.fidelix.jp/technology/3terminal%20regulator.html
(Japanese-text only)

 

 

 
I finish remodeling to mini-i with this remodeling.
 

 
 
Mar 29, 2011 at 10:26 AM Post #662 of 1,054

Gmatrixuser

New Head-Fier
Joined
Mar 29, 2011
Posts
5
Likes
0
Hi T.IIZUKA,
 
I read a lot about your mods and would like to thank you for sharing your ideas with us
smile.gif

 
My intention is to replace (resp. to bypass)  the power transformer and the both power regulators Type 7812 (+12 Volts) and Type 7912
(-12 Volts) by a separate symetric +/- 12V battery powered unit in a separate case (with control and charge system).
 
Do you know about the pin configuration of the power transformer?
Are the both power lines +12 V and - 12 V the only ones coming from the transformer?
All other regulatores are powered by this two lines, aren't they?
Or is there another power line coming from the transformer to the board?
 
There are only the two rectifiers that you replaced, aren't there?
 
Thanks for your answer
 
Alfred from Germany
 
Mar 29, 2011 at 10:50 AM Post #663 of 1,054

T.IIZUKA

Headphoneus Supremus
Joined
May 23, 2009
Posts
3,038
Likes
10
 
It is +12V and -12V that I changed.
 
 
It seems to be 12V and 9V.
 
palchiu -san 
>>Power Transformers... We should needs a 2x12V and 1x9V.
 
http://www.head-fi.org/forum/thread/441960/matrix-mini-i-balanced-dac-hp-amp/570#post_7152534
 
 
 
Mar 30, 2011 at 5:55 AM Post #666 of 1,054

Gmatrixuser

New Head-Fier
Joined
Mar 29, 2011
Posts
5
Likes
0
Hi T.IIZUKA,
 
thanks for the picture !
 
I saw that 3rd power feed from the tranformator in the VA2 edition also and I am wondering where the the 3rd rectifier is located on the board.
 
Did you measure this 9 V power at your board? AC at the transformer and DC near to it.
Ther would be a chance to measur it when the 7812 and 7912 regulators are away from the board.
 
Maybe at the weekend I will open my mini-i and will take a measurment of the transformer.
Because think to have DC without any noice (from batteries) will be the best to feed the mini-i with energy.
This was a mayor step with my Hiface !
 
At present my mini-i has got a "hum" like grumble. It comes from the transformator, but I don't know if this degrates the sound quality of the mnin-i .
 
Mar 30, 2011 at 6:00 AM Post #667 of 1,054

Gmatrixuser

New Head-Fier
Joined
Mar 29, 2011
Posts
5
Likes
0
Again friendly asking for reply by JTAM
 
Please, we have to have a kit for retrofit the old mini-i with remote contol
 
 
 
Dear JTAM,
 
I own a Matrix mini-i ordered from you last Year. It works perfect! 
 
My only mod is to add an OSCON cap 10V - 10myF direct to the TCXO (+3.3V).
 
I enjoy to listen to the very best sound quality via Netbook, modyfied battery powered Hiface, big old but perfect modded Luxman power amp 5M21 and German Görlich / Electro voice  Lautspeakers!
 
However JTAM,
 
we really have to have a remote control !
 
Please offer a kit / some parts to change (even with soldering works DIY) to enable all mini-i user to mod their V1 to remote control !
 
I hope to hear some positive news from you in this regard!
 
Alfred
  
 
Mar 31, 2011 at 10:20 AM Post #671 of 1,054

melie

100+ Head-Fier
Joined
Aug 23, 2010
Posts
107
Likes
12


 
Quote:
Yes. The headphone pre-amp works the same way via RCA or XLR. The XLR is reportedly the better quality output, too.
 
PA


 


 
Ok, so this could be ideal for monitors like a BX5a who have volume controle on the back? Also, how does it exactly work? If I for example have the volume on 20% when I turne the Mini-i of, will it still be on 20% when I turn it back on? And are there any strange resettes that occur like you can have with the windows volume controler?
The reason I ask this is because I'm going to buy the BX5a monitors which has the volume control on the back and I heart from a lot of people that you'll need some volume control other than the Windows one because it can reset to horrible loudness. So if I understand correctly the Mini-i (XLR is also a plus) would be an excellent pair with the BX5a? I'll be using the USB connection.

 
 
 
Mar 31, 2011 at 10:51 AM Post #672 of 1,054

panda-R

Head-Fier
Joined
Nov 7, 2009
Posts
84
Likes
13


Quote:
 

 
Ok, so this could be ideal for monitors like a BX5a who have volume controle on the back? Also, how does it exactly work? If I for example have the volume on 20% when I turne the Mini-i of, will it still be on 20% when I turn it back on? And are there any strange resettes that occur like you can have with the windows volume controler?
The reason I ask this is because I'm going to buy the BX5a monitors which has the volume control on the back and I heart from a lot of people that you'll need some volume control other than the Windows one because it can reset to horrible loudness. So if I understand correctly the Mini-i (XLR is also a plus) would be an excellent pair with the BX5a? I'll be using the USB connection.

 
 



YES! I am doing this with my KRK monitors. Works Great. 
 
Mar 31, 2011 at 12:28 PM Post #673 of 1,054

Ph1lerAudi0

Head-Fier
Joined
Oct 12, 2010
Posts
85
Likes
10
Panda-R and Melie,
 
if you have monitors with a volume control, wouldn't you want to then configure the MINI-I in straight DAC mode? By having 2 volume controls in the signal path you are degrading the sound a little more.
 
In my setup my Mini-I is the heart of my iTunes music server. I have the Mini-I in headphone amp mode with volume control. All other volumes are fixed. ITunes is at maximum, my amp is set at the right gain, etc. The only volume I ever adjust is on the Mini-I.
 
Just wondering.
 
PA
 
Quote:
YES! I am doing this with my KRK monitors. Works Great. 



 
 
Mar 31, 2011 at 12:31 PM Post #674 of 1,054

Ph1lerAudi0

Head-Fier
Joined
Oct 12, 2010
Posts
85
Likes
10
Oh and by the way, it is definitely worth the effort to spend a little extra on the XLR cables. At first I had some medium grade XLRs from Sam Ash audio. I decided to try some Blue Jeans cable XLRs. Those things made my Mini-I sing!
 
PA
 
Apr 2, 2011 at 6:22 AM Post #675 of 1,054

melie

100+ Head-Fier
Joined
Aug 23, 2010
Posts
107
Likes
12


Quote:
Panda-R and Melie,
 
if you have monitors with a volume control, wouldn't you want to then configure the MINI-I in straight DAC mode? By having 2 volume controls in the signal path you are degrading the sound a little more.
 
In my setup my Mini-I is the heart of my iTunes music server. I have the Mini-I in headphone amp mode with volume control. All other volumes are fixed. ITunes is at maximum, my amp is set at the right gain, etc. The only volume I ever adjust is on the Mini-I.
 
Just wondering.
 
PA
 


 


Yes, I would like to do that but I don't have a sepperate pre-amp and the volume on the BX5a's is at the back. Also, each speaker has it's own volume nob so it's pretty irritating to tune these things.. I would be going; Pc -> USB -> Mini-i -> Blue Jeans XLR -> BX5a Deluxe.
 

Users who are viewing this thread

Top