De-Lite strange problem

[Puffin]

1.6v

[stefanobilliani]

Originally Posted by Puffin

1.6v

OK , check if you can , what is the current draw of one channel ;
If it is 1.6Amp then R4 is still doing a good job .

At the input cap , you may want to apply some resistance to ground to control the charge .Say 47K.

[Puffin]

OK, will do that tomorrow. Thanks.

Rob.

[Puffin]

UPDATE:-



Well I think I have finally cracked it. Having had the situation of the light bulb staying lit when using an MP3 player (albeit it would dull - less volts?), but getting sound out, but no sound when connected to a Pre-Amp. The bulb would go out completely.

I made a new module. The first positive thing was that when it was all connected and I held the phono lead it buzzed as it was being grounded. This did not happen before. Connected a CD player to the pre-amp and bingo. The light bulb on that channel stays as bright as the other one (which is not currently connected) and looks like it should in the pic in the article by Mr Pass.

I did initally try a 15 Ohm resistor in place of the bulb (this is still on the heatsink). It worked but the resistor (high power alu clad) got blisteringly hot after a very short time.

I have also replaced the 1 Ohm resistor with a high power alu clad one and this gets mildly warm. The 3W wirewound ones I initally used got very hot.

There is still some hum, but much less. May move the PS to another box.

Now I can work on getting it finished.....Finally!

[Nelson Pass]

If you are literally building the circuit posted at the beginning of this thread,
then you are missing some elements. This was a simplified intermediate
schematic for tutorial purposes. You want to be sure that your circuit
corresponds to the more finished version.

[Puffin]

Originally Posted by Puffin

Improved De-Lite schematic




R4 is the 3W resistor I mentioned above.

I have used this schematic.

[Zen Mod]

small difference ;

so - either this (Fig.10) or Fig.7

[Puffin]

Originally Posted by Zen Mod

small difference ;

so - either this (Fig.10) or Fig.7

I said in post 7 that I had made new modules using the 20N FETs.

In the light of Nelson's comments I would like to know if the schematic in FIG 5 (The Improved Circuit) makes a proper working amplifier :-

QUOTE: You want to be sure that your circuit
corresponds to the more finished version.

[Puffin]

Originally Posted by Nelson Pass

If you are literally building the circuit posted at the beginning of this thread,
then you are missing some elements. This was a simplified intermediate
schematic for tutorial purposes. You want to be sure that your circuit
corresponds to the more finished version.

Please Mr Pass, don't leave me in the lurch

[Puffin]

Originally Posted by Puffin

In the light of Nelson's comments I would like to know if the schematic in FIG 5 (The Improved Circuit) makes a proper working amplifier :-

QUOTE: You want to be sure that your circuit
corresponds to the more finished version.