Building a symmetrical PSU B1 buffer

Jump to Latest
CeeVee

CeeVee

Member
Joined 2006
Paid Member
korben69 said:
My mistake, the tansformer is 2x15v. 2x12 is a typo. Some Selectronic RCore are oversized as mine, 2x15v gives about 19.5v at the output...
Click to expand...

Hi Korben,

Why do we need more than 1A on the secondary of the trafo....i was planning to use a Selectronic 30VA Rcore...fits nicely in a 1U box ( i like compact units ).

Edit: ok read thread a bit more...sorry for jumping the gun.....Salas has answered this....15-0-15 30VA is enough ( as i expected )....
 
Last edited:
K

korben69

Member
Joined 2006
I don't know about return policy from Selectronic as I've bought mine more than 2 years ago for another project.

I've found "SHILCHAR" written on the RCore, this information point me to a WEB site, after some readings company seems to be established in India :
:: Shilchar Technologies Limited ::

I've forgotten to measure what voltage is supplied home by EDF, maybe more than 220VAC...

You're right CeeVee it fits nicely in a 1U enclosure, such as HiFi2000 one's.
 
Last edited:
M

Malka07

Member
Joined 2009
korben69 said:
Malka07, I'll send you a PM for my built, your help will be great. Very nice result, I like the "Zen look" !
I use a Mezmerize board not Hypnotize. I'll try a GoldMinireg as PSU for the 5V.
Your pics show that you've wired the LDR Output(L/R) to the Hypno Input(L/R).
How should I proceed with the Pot on the Mezmerize PCB ?
Should I just ignore it ? :confused: :confused:
Click to expand...

Hi Korben69, As i dont have a Mezmerize, im not too sure...but i think as you said just delete the pot on the Mez, and wire as i did. If you have a look at page 129 post 1289 of this thread you can see a pic of member William2001 lightspeed with Mes and Hypnotize...its difficult to see, but i think he just deletes the pot on the Mez board.

Let us know how you get on, and how it sounds with the Goldminireg :)

Alon
 
A

AndrewT

R.I.P.
Joined 2004
Hi,
Mez has 6 pads to connect the volume pot.
3 for left and 3 for right.
These 6 pads go to the 6 audio connections of the LDR half of an LED/LDR volume control, just like a normal volume control pot.
The LED half of the LED/LDR volume control needs the control voltages fed to it from a 5V supply and a real dual track 100k log law pot. These control voltage connections are just like George and Uriah have repeatedly posted for us.
 
M

Marra

Member
Joined 2009
Paid Member
Finally managed to read through all the posts.I'm really looking forward to receiving my Blue Hypno boards and starting my build.
Regarding the Selectronique R core transformers would I be better off going for the 12+12 secondaries as they seem to output more volts than spec or do I just strap the mosfets to the case and run hotrodded?
 
Salas

Salas

diyAudio Chief Moderator
Joined 2002
Paid Member
Marra said:
Finally managed to read through all the posts.I'm really looking forward to receiving my Blue Hypno boards and starting my build.
Regarding the Selectronique R core transformers would I be better off going for the 12+12 secondaries as they seem to output more volts than spec or do I just strap the mosfets to the case and run hotrodded?
Click to expand...

Run with 10R 5W and Mosfets cooled on the box's floor. Cheapest & easiest sinking. Fixes the thing down best for vibrations too since it grabs it from more points along its length.
 
A

AndrewT

R.I.P.
Joined 2004
if you intend running at the standard +-10Vdc then the 12Vac secondaries may be below recommended limit when mains is low.

I doubt the Rcores you have in mind are out of specification.

I used 15+15 for my DCB1. CCS set to 60mA and the CCS FETs run a bit hotter than I would like, but they could run permanently at that dissipation.
I choose to add a heatsink. The Shunt FETs do not need a sink. They only dissipate 10V * 40mA = 400mW
 
M

Malka07

Member
Joined 2009
Just wanted to give an update on my Dcb1/Optivol.

First of all i cut out a hole and installed a fan in the roof of my chassis. This helps keep the mosfets cool. At first i was running the fan at 12vdc...but i found that the fan was too noisey and was interfering with the music, so now im running it at 5vdc and the fan is now so quite, it is almost silent :)

An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.


I add some Granite to weight the top of the chassis down, so that there are no vibrations, as i hav'nt screwed the top of the chassis down yet...makes it easier to get inside as im still modding this wonderful pre amp ;)

Also as can be seen, i run the optivol, with a Salas Shunt Reg 5v, i also have up'd the currents on the Dcb1, i now run...

+PS 2.09v/6ohm = 348ma
-PS 1.73v/5ohm = 346ma

I check the heat of the mosfets after 2 hours of playing music...the heat is just warm, definitely hotter then before as before it was cold...but this is understandable as the fan is running slower...The sound of this preamp now is just AMAZING...adding the Salas Shunt reg to run the Optivol, improves it alot...and uping the current's from circa 250ma to 350ma also improves the SQ..i will now up the current's further, little by little making sure each time that the mosfets dont get too hot...but in my listening tests, every time i have up'ed the current's a noticible improvement can be heard. Well worth doing.

An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.


As im running circa 350ma now, would i gain improvements by changing the two 4700uf caps to two 10,000uf caps?

Thanks

Alon
 
You must log in or register to reply here.
Top Bottom