Trouble with my Aleph-X

anders.a · 13th January 2006, 07:13 PM

I’m about to start my Aleph-X and having trouble. I’m using a light bulb for inrush current protection.
Without connecting to the board the power supply is ok. The light bulb starts glowing and slowly it’s getting weaker until it won’t glow anymore. But when connecting it to the PCB about halfway when slowly racing using a variac the light bulb won’t totally stop glowing. There’s a faint constant light that won’t go away.
I’m using Kristjans board.

Anyone knows what the problem is?

Holger Barske · 13th January 2006, 07:33 PM

Well, maybe it's a stupid idea, but:
When you connect the amplifier to the supply, it draws current, I suppose. So why shouldn't the bulb give some light when there's current flowing through it...?

anders.a · 13th January 2006, 07:35 PM

That would be a relief.

Netlist · 13th January 2006, 07:49 PM

Quote:

Originally posted by anders.a

Without connecting to the board the power supply is ok. The light bulb starts glowing and slowly it’s getting weaker until it won’t glow anymore.

When powering up, the glow of the light bulb is actually the charging of the supply capacitors made visible. When no amp connected, the caps remain charged but have nothing to supply their current to. Hence the light stops glowing when the caps are fully charged.

/Hugo

steenoe · 13th January 2006, 07:52 PM

Quote:

I’m using a light bulb for inrush current protection.

If you want to get rid of that light bulb, I think I have a spare Thermistor I can send you

Well, I see the purpose of the bulbs in the ZenLight, but as current inrush limiter.... well okay its maybe pretty cool, but ... Send me an email if you want it

Steen

anders.a · 13th January 2006, 07:57 PM

Netlist
Yes but shouldn’t the light slowly fade away? What happens now is that the glow slowly fading until there’s a faint constant glow.

steenoe
The light bulb is only temporally.

steenoe · 13th January 2006, 08:01 PM

Quote:

The light bulb is only temporally.

Oh, that explains!! I was rushing into things as usual

Sorry 'bout that

The offer stands, nonetheless

Steen

Netlist · 13th January 2006, 08:18 PM

Because this is a class A amplifier it constantly draws a huge amount of current. It is heavily biased, simply explained, it draws the maximum current that it can deliver at all time. Therefore the light bulb will always be able to burn, be it only a little bit. Try increasing the current draw of the amp, you should notice more glow.

/Hugo

anders.a · 13th January 2006, 08:21 PM

Thanks. I was afraid I did some stupid soldering mistake on the PCB. And now what’s the next step? To monitor the temperature (max 60C)? Measure voltage somewhere? Setting absolute and relative DC?

Netlist · 13th January 2006, 08:29 PM

What you described till now is normal behaviour. Which does not mean the amp is perfectly working. Now is time to do some DC measurements. I'm looking forward to see some picture and hear you rave about the sound.

/Hugo

13th January 2006, 07:13 PM	#1
anders.a diyAudio Member Join Date: Dec 2004 Location: Sweden	Trouble with my Aleph-X I’m about to start my Aleph-X and having trouble. I’m using a light bulb for inrush current protection. Without connecting to the board the power supply is ok. The light bulb starts glowing and slowly it’s getting weaker until it won’t glow anymore. But when connecting it to the PCB about halfway when slowly racing using a variac the light bulb won’t totally stop glowing. There’s a faint constant light that won’t go away. I’m using Kristjans board. Anyone knows what the problem is?

13th January 2006, 07:33 PM	#2
Holger Barske diyAudio Member Join Date: Jan 2001 Location: Ruhrgebiet	Well, maybe it's a stupid idea, but: When you connect the amplifier to the supply, it draws current, I suppose. So why shouldn't the bulb give some light when there's current flowing through it...? __________________ Best regards: Holger www.holgerbarske.com - Deutschsprachiges Paradise-Support-Forum

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13th January 2006, 07:35 PM	#3
anders.a diyAudio Member Join Date: Dec 2004 Location: Sweden	That would be a relief.

13th January 2006, 07:57 PM	#6
anders.a diyAudio Member Join Date: Dec 2004 Location: Sweden	Netlist Yes but shouldn’t the light slowly fade away? What happens now is that the glow slowly fading until there’s a faint constant glow. steenoe The light bulb is only temporally.

13th January 2006, 08:18 PM	#8
Netlist diyAudio Moderator Emeritus Join Date: Jan 2003	Because this is a class A amplifier it constantly draws a huge amount of current. It is heavily biased, simply explained, it draws the maximum current that it can deliver at all time. Therefore the light bulb will always be able to burn, be it only a little bit. Try increasing the current draw of the amp, you should notice more glow. /Hugo

13th January 2006, 08:21 PM	#9
anders.a diyAudio Member Join Date: Dec 2004 Location: Sweden	Thanks. I was afraid I did some stupid soldering mistake on the PCB. And now what’s the next step? To monitor the temperature (max 60C)? Measure voltage somewhere? Setting absolute and relative DC?

13th January 2006, 08:29 PM	#10
Netlist diyAudio Moderator Emeritus Join Date: Jan 2003	What you described till now is normal behaviour. Which does not mean the amp is perfectly working. Now is time to do some DC measurements. I'm looking forward to see some picture and hear you rave about the sound. /Hugo