The Mini-A

Coulomb said:
jleaman said:



Yup,! Pretty expencive hobby, however im going to be building some audio stuff this winter, 😛

Jase

I see you put down a tarp so when you crash you can roll all the parts and take it home. 🙂


HAH! I wish, no when i crash i crash good 😛 the tarp is for trimming the servos adn doing hand's off, and stuff 😛
 
preamp for mini A

Ok , once again I build a mini as graduation gift great way to share. This time I will build integrated amp, looking for compact preamp design. Since it will probably be fed from a Ipod single ended would be ok, but balanced out would be a bonus. Any Ideas ?

Bill
 
Re: preamp for mini A

wirewiggler said:
Ok , once again I build a mini as graduation gift great way to share. This time I will build integrated amp, looking for compact preamp design. Since it will probably be fed from a Ipod single ended would be ok, but balanced out would be a bonus. Any Ideas ?

Bill


Balanced out from a ipod as a source, YUK! just use the analogue, and run a pot for a passive volume control.
 
Hi guys,

I got my mini-A boards from BrianGT and ordered all resistors with .125w rating other than the 3w source resistors. I found the .125w fits better on this small boards.
Are .125w ok for this application?

Albert

BTW I ordered some more at the same time for F4 & F5 too. Or I've to re-order them otherwise.
 
albertli said:
Hi guys,

I got my mini-A boards from BrianGT and ordered all resistors with .125w rating other than the 3w source resistors. I found the .125w fits better on this small boards.
Are .125w ok for this application?

Albert

BTW I ordered some more at the same time for F4 & F5 too. Or I've to re-order them otherwise.


You can stand them up like how i did, or use the smaller ones, the only resistors that matter for power/current are the main 3watt ones. Other than that you'll be ok.
 
Power Supply PCB

Hi,

just curious if anyone used resistors on the brian gt power supply pcb for the mini-a. There are footprints for up to 5 resistors per rail.

how do these .47 ohms in parallel help to reduce noise?
I see a similiar circuit on the F4/F5 power supply using 4 resistors per rail.

thx.
 
Re: Power Supply PCB

Bengali said:
Hi,

just curious if anyone used resistors on the brian gt power supply pcb for the mini-a. There are footprints for up to 5 resistors per rail.

how do these .47 ohms in parallel help to reduce noise?
I see a similiar circuit on the F4/F5 power supply using 4 resistors per rail.

thx.


I used 4 large resistors in parallel on my Brian GT PSU boards to drop a couple of volts in a CRC arrangement.

-David
 
You might want to play with PSU Designer 2 from Duncan Amp
Tools. When I pluged in a power supply using a 20v transformer
with 1 ohm source resistance ,25A bridge rectifier then a CRC
using 20,000 uf .1ohm 20,000uf and 20,000uf loaded at 1.5A the ripple was about 6db less than using just 2 20,000uf caps in parallel without the .1ohm resistor.
 
It sings!!

My Mini-A is finally done and has been singing for 3 days.
It wasn't as smooth sailing as I would hope, but each time it didn't work, I reread the
previous posts, looked at the schematic, took measurements, and tried whatever fixes that I thought would be the cause. I really learned a lot through out this kind of exercise. Casualties weren't that bad - 2 x ZTX450, 1 x IFP9610, and 2 fuses, plus a few drops of my precious blood ....

It is time to say thank you and a big cyber hug to Papa and Grey to share such fantastic design.

Here are a few photos of the naked and buttoned up Mini-A.

http://s257.photobucket.com/albums/hh207/fredvu/Mini-A/?action=view&current=mini-a-1.jpg
http://s257.photobucket.com/albums/hh207/fredvu/Mini-A/?action=view&current=mini-a-1.jpg
http://s257.photobucket.com/albums/hh207/fredvu/Mini-A/?action=view&current=mini-a-1.jpg

Thanks again!!
 
Re: It sings!!

pchw said:
My Mini-A is finally done and has been singing for 3 days.
It wasn't as smooth sailing as I would hope, but each time it didn't work, I reread the
previous posts, looked at the schematic, took measurements, and tried whatever fixes that I thought would be the cause. I really learned a lot through out this kind of exercise. Casualties weren't that bad - 2 x ZTX450, 1 x IFP9610, and 2 fuses, plus a few drops of my precious blood ....

It is time to say thank you and a big cyber hug to Papa and Grey to share such fantastic design.

Here are a few photos of the naked and buttoned up Mini-A.

http://s257.photobucket.com/albums/hh207/fredvu/Mini-A/?action=view&current=mini-a-1.jpg
http://s257.photobucket.com/albums/hh207/fredvu/Mini-A/?action=view&current=mini-a-1.jpg
http://s257.photobucket.com/albums/hh207/fredvu/Mini-A/?action=view&current=mini-a-1.jpg

Thanks again!!


Heat sinks aren't needed for the 3 fets that are on the amplifier board, they don't get that warm. Also make sure they are not touching if you keep them.



J'