Fault finding, BCL Clone, help needed.

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Mayday

Mayday

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Joined 2004
agdr said:
A lot of power transistors have fairly low DC current gain, like 10x or 20x, which can suck too much drive current out of whatever is powering them, often requiring another transistor just to drive the power transistor. But the DHX54's are an exception with fairly high DC current gains, right up there with the small signal BC558/BC548 they originally specified.

For your shunt regulators that chain of parts is correct.

For your LT voltage regulators though the big trick there, when using a positive regulator chip on each rail (along with using the isolated secondary transformer) is to tie the grounds together *after* the regulators. So for each power rail you would have isolated secondary -> rectifier -> filter caps -> regulator chip. Then the output of regulator #1 becomes your V+. The ground of regulator #1 and the output of regulator #2 tie together to become your system ground (that is why the xformer secondaries have to be isolated), and then the ground of regulator #2 becomes your V- rail.
Click to expand...
Thanks for your help :)
I have a few 547's and 548's at home...they will not work in the shunt reg?
Also have some bd139 and bd140, got them as spares for the bcl clone.
By DHX54, are you referring to d4xh11's?

Yes I know about the hook up for the LT1083 reg board.
I have a 2x15VAC 1.5A toroidal transformer for that.
I started looking at other regs since I was hoping to be able to use the 12-012VAC I have laying around.

Completely new to spice, so my first attempt at a simulation was, let's say, less than a success ;)

Was trying to simulate the circuit with a 300mA load on each rail. (the shunt reg)

Will have read up on spice and watch some tutorials.
 
Mayday

Mayday

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Joined 2004
agdr said:
Mayday -

Mooly has a helpful LTSpice writeup here:

http://www.diyaudio.com/forums/software-tools/260627-installing-using-ltspice-beginner-advanced.html

The BC547 and BC548 transistors would work, if their current and power dissipation is enough for what you are doing. They are rated for 100mA.

Yeah I got that transistor number scrambled! :eek:
Click to expand...

I meant as the "lower" transistor, still having D4xH11 on the "outputs" on the shunt.
So BC547/D44H11 on pos. side for example.
Or should I rather go D4xH11 for all transistors?
The shunt will need to provide current for:
4pcs TIP41C
2pcs 2N2222
3pcs 2N2907
in the JHL Class A headphone amplifier.


I meant no offence by my question about the transistor number, I actually looked for the dhx45 :)
 
Mayday

Mayday

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Joined 2004
Got the LT1083 dual rail regulator tested with a pair of parallel 395R resistors per rail.
Set it to 15.08V on each rail. Thanks to my good friend Dave for all advice, you're the man buddy.
I'll hook it up to the bcl clone another day as I'm tired now and have a fever.
Anyhow, it's always nice when there's no blue smoke or popping capacitors...or electrocution lol
 
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futureboy

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Joined 2010
ClaveFremen said:
attachment.php
Click to expand...

I think you can try change regulator to LT1085 and LT1185 for better result.
Pin configuration is the same, just change few resistors and capacitors.

sorry for bad english. :(
 
Mayday

Mayday

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Joined 2004
I've now cut the PS part of the board off using dremel and a good cutting disk.
It powered on fine with a temporary 7812/7912 supply.
The LT1083 supply is mounted and hooked up in the chassis though.
Hopefully I'll have time to leave it on for a couple of hours tomorrow to see if caps still get too hot.
 
Mayday

Mayday

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Joined 2004
This what's left of the PCB.
Notice the old Philips NE5532 in the opamp socket for now :)
I will swap it for something better later if it doesn't perform better than the more modern 5532's I've heard.
An externally hosted image should be here but it was not working when we last tested it.


I've since taking that pic de-soldered the screw-terminal and soldered in wires for connecting with HP-jack.

Perfboarded LT1083 dual rail Vregs, 4.7uF input caps and the very exclusive chassis (former ATX PSU).
An externally hosted image should be here but it was not working when we last tested it.
 
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