Zen-lightenment

[Geoff]

Nelson

You mention in your article that you bought and tested various types of lamp for use in this project and determined that a standard incandescent was the most suitable. For the benefit of those of us on the wrong side of the pond (and elsewhere) who have a 230V mains voltage could I please ask what other types of lamp you tested and with what results.

To give a similar resistance to a 120V 150W or 300W lamp, a 230V lamp would need to be 600W or 1200W, which is clearly impractical since they are not made in these sizes (150W is normally the largest).

A check of some main suppliers in the UK reveals that 110V lamps are only available in low wattages (eg 15W pigmy bulbs and 60W standard bulbs for safety handlamps etc), with one exception. 110V 300W and 500W tubular double-ended lamps are available but these are a tungsten halogen type for use in industrial floodlights and the like.

I am sure that there will be a number of people who would be glad of any further advice you can give regarding alternative lamp types.

Geoff

[sdman]

Nelson,

Now you have gone and done it!, and invented the Light Bulb
Amplifier(LBA). Looks like the great Sierra mountain air has done nothing to deteriorate your brain.

You realise you have opened up "Pandora's Box)" to a
multitude of questions such as, what brands,Westinghouse,
GE,Sylvania,Phillips,etc,etc,and then later someone will be saying that the GE seems to muddy the highs but gives a great low end response, the Westinghouse has great imaging,
etc.
Of course I am just funning you and would like to congratulate you on the new web site.

You have breathed some fresh air into this forum.

[Lisandro_P]

Originally posted by Geoff
To give a similar resistance to a 120V 150W or 300W lamp, a 230V lamp would need to be 600W or 1200W, which is clearly impractical since they are not made in these sizes (150W is normally the largest).

The largest 220v bulb commonly available is 300w, and uses a bigger base (i think is called "Goliath"). I have an OSRAM 300w 220v right here, and measures exactly 13 ohms (cold, of course), for whatever's worth.

[surf,sun&sound]

I just came from the new Pass site, great site! But that new "Zen-lightenment" amp is way to cool!!! I will have to build one of these just for the kicks! My only question is what is the rms wattage of this design?

Also I need to know what substitutes we can use for the bulbs, since I live "Down Under".

Surf, Sun & Sound

[Geoff]

Lisandro

220V 300W may be commonly available in your part of the world but they are not sold here in the UK where, as I said, 150W is the largest size listed in the suppliers catalogues that I have checked.

Geoff

[Lisandro_P]

Originally posted by Geoff
220V 300W may be commonly available in your part of the world but they are not sold here in the UK where, as I said, 150W is the largest size listed in the suppliers catalogues that I have checked.

Well, i'm in Argentina, so i guessed you could find them everywhere else You could use lamps in series instead of in parallel...

[Samuel Jayaraj]

Geoff,

Two 150w 220volt bulbs in series, would result in 110volt 300w equivalent with the resistance doubled. That is only obvious, and I know that you know this.

Hence, maybe Mr.Pass could tell us, what is the typical cold resistance (of the filaments) that is desirable.

[tortello]

No, it seems to me that two 220V/150W in series make a 440V/300W load...

[Geoff]

A single 120V 300W lamp will have a 'nominal' resistance of 48ohm. To achieve the same 'nominal' resistance at double the voltage rating will require four times the power ie 1200W. This could be achieved in the UK by using eight 150W lamps in parallel but is a little unrealistic if an acceptible 110/120V alternative could be found. Hense my question to Nelson about which other types of lamp he had tested.

Geoff

[vdi_nenna]

What happens when a bulb burns out?