Lightbulbs as ccs

DavesNotHere · 10th December 2011, 04:54 PM

Has anyone used ordinary incandescent light bulbs as ccs in their tube amps?

toprepairman · 10th December 2011, 04:58 PM

Frequency response DC to , well maybe 2 or 3 Hz within a few dB kinda says it all.

Yvesm · 10th December 2011, 05:00 PM

Not yet !
Just as load for Mosfets . . .

In the very old time, it was common to add a small light bulb in parallel with the loudspeaker to produce some "expander" behaviour !

Yves.

Soonerorlater · 10th December 2011, 05:59 PM

Quote:

In the very old time, it was common to add a small light bulb in parallel with the loudspeaker to produce some "expander" behaviour !

Wow, Far out man, that was me in the 70's!...........

DavesNotHere · 06:21 PM

I've been thinking, the light bulb has been in and out of audio/visual electronics for more than 25 years. I first saw it as a troubleshooting tool for high voltage DC switch-mode regulators in televisions back in the late 80's. Peavy prototyped an eq that had light bulbs on each tuning frequency to show peaks in the audio signal as a tool to spot positive feedback (was changed to leds in final design because of recovery time). crossovers used one to protect horns in stage monitors (still used today, but on below 500W designs). Guitar amps from time to time have them, but they were solid state based. and I saw the zen amp designs just a few minutes ago.

DavesNotHere · 10th December 2011, 06:18 PM

I wonder if someone has took a futterman otl, substitute the bottom row with lightbulbs.

Cobra2 · 10th December 2011, 06:26 PM

I have played with the thaught of using some GM70 tubes (filament) for a DeLite-amp...(or Zen..)

Arne K

ErikdeBest · 10th December 2011, 07:02 PM

Not yet, but doing some back of the envelope calculations with small (10W at 220V) bulbs they may actually sort of work. At 220V a 10W has about 5k resistance, pulling 45mA. Parafeed EL84?

v4lve lover · 10th December 2011, 07:41 PM

light bulbs where used as plate load for tube burn in . a very bright bulb would indicate a shorted tube

tomchr · 10th December 2011, 07:57 PM

An ideal CCS (Constant Current Source) has infinite output impedance. A small light bulb will be a few hundred ohms -- pretty darn far from ideal. So for a CCS, it's not a good candidate.

Used as a plate load for wonky distortion effects may be another story.

~Tom

10th December 2011, 04:54 PM	#1
DavesNotHere diyAudio Member Join Date: Jun 2011	Lightbulbs as ccs Has anyone used ordinary incandescent light bulbs as ccs in their tube amps?

10th December 2011, 06:17 PM	#5
DavesNotHere diyAudio Member Join Date: Jun 2011	I've been thinking, the light bulb has been in and out of audio/visual electronics for more than 25 years. I first saw it as a troubleshooting tool for high voltage DC switch-mode regulators in televisions back in the late 80's. Peavy prototyped an eq that had light bulbs on each tuning frequency to show peaks in the audio signal as a tool to spot positive feedback (was changed to leds in final design because of recovery time). crossovers used one to protect horns in stage monitors (still used today, but on below 500W designs). Guitar amps from time to time have them, but they were solid state based. and I saw the zen amp designs just a few minutes ago. Last edited by DavesNotHere; 10th December 2011 at 06:21 PM.

10th December 2011, 06:26 PM	#7
Cobra2 DIY ! diyAudio Member Join Date: Apr 2002 Location: Stavanger, Norway	I have played with the thaught of using some GM70 tubes (filament) for a DeLite-amp...(or Zen..) Arne K __________________ Ars longa, vita brevis

10th December 2011, 07:02 PM	#8
ErikdeBest diyAudio Member Join Date: Mar 2003 Location: Itoculo	Not yet, but doing some back of the envelope calculations with small (10W at 220V) bulbs they may actually sort of work. At 220V a 10W has about 5k resistance, pulling 45mA. Parafeed EL84? __________________ my surname is indeed 'de Best': neither misspelling nor snobbism! Ask SY!

10th December 2011, 07:57 PM	#10
tomchr diyAudio Member Join Date: Feb 2009 Location: Greater Seattle Area	An ideal CCS (Constant Current Source) has infinite output impedance. A small light bulb will be a few hundred ohms -- pretty darn far from ideal. So for a CCS, it's not a good candidate. Used as a plate load for wonky distortion effects may be another story. ~Tom __________________ "50 % of the game is mental and the other 50 % is being mental. I've got that part down, no problem." http://www.neurochrome.com/audio

10th December 2011, 04:58 PM	#2
toprepairman diyAudio Member Join Date: Nov 2010	Frequency response DC to , well maybe 2 or 3 Hz within a few dB kinda says it all.

10th December 2011, 05:00 PM	#3
Yvesm diyAudio Member Join Date: Jul 2004 Location: Ardeche	Not yet ! Just as load for Mosfets . . . In the very old time, it was common to add a small light bulb in parallel with the loudspeaker to produce some "expander" behaviour ! Yves.

10th December 2011, 06:18 PM	#6
DavesNotHere diyAudio Member Join Date: Jun 2011	I wonder if someone has took a futterman otl, substitute the bottom row with lightbulbs.

10th December 2011, 07:41 PM	#9
v4lve lover diyAudio Member Join Date: Aug 2010	light bulbs where used as plate load for tube burn in . a very bright bulb would indicate a shorted tube

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