Pass "DeLite" Amp from BAF

Jump to Latest
Variac

Variac

diyAudio Editor
Joined 2001
BurningAmp.org
Paid Member
I had some 300w bulbs for a never built enlightened Zen, and cold they seem to measure about 4 ohms,.. I remember the bulbs at the show being big, but marked 150w So maybe Nelson can "enlighten" us. I realize that the bulb's resistance changes a little when it gets hot, but it isn't going up that much...I don't think..
hmm

Mark

/Anyway , I suspect it is 150w bulbs..
 
Last edited:
flg

flg

Member
Joined 2005
Well, I've posted this before but it may be of interest now ;)
 

Attachments

  • BulbTest Graph.PNG
    BulbTest Graph.PNG
    15.7 KB · Views: 1,398
flg

flg

Member
Joined 2005
I did not try any "dynamic" testing but I think your right :bulb: It would be interesting to see at least some pulse testing types of response. Maybe I'll get off my butt this weekend and try something:smash:
Hey as long as I have your attention, what do you think I should try? I haven't really thought about it much. Hmmm
Start with an amp or so (Idle current) and hit it with a step up to 2A? A step down to 0A. See what the rise time/fall time looks like? We could calculate Thermal Capacitance or whatever :bulb:
 
Last edited:
Michi124

Michi124

Member
Joined 2003
tryonziess said:
The ceramic bases are extremely common. Hundreds of old apartment buildings here
have these bulbs hanging from the ceiling on all of the hallways.
Click to expand...
Thanks, Tad. I really like those bases a lot better than the ones available here.
Since I'm lacking the resources to come over to the US to vandalize old apartments
- could someone please name a supplier for NEW ones that are NOT attached to old ceilings? :D
 
scott wurcer

scott wurcer

R.I.P
Joined 2004
flg said:
I did not try any "dynamic" testing but I think your right :bulb: It would be interesting to see at least some pulse testing types of response. Maybe I'll get off my butt this weekend and try something:smash:
Hey as long as I have your attention, what do you think I should try? I haven't really thought about it much. Hmmm
Start with an amp or so (Idle current) and hit it with a step up to 2A? A step down to 0A. See what the rise time/fall time looks like? We could calculate Thermal Capacitance or whatever :bulb:
Click to expand...

That's a good start. I would expect second harmonics to be way up there if there is much modulation. My grandmother only had two outlets in her whole basement so I used to buy 300 Watters so I could see, they got HOT!.

Maybe there's a way to work a panel light into the input to compensate. :D
 
Last edited:
Steve Dunlap

Steve Dunlap

Member
Joined 2008
Variac said:
I had some 300w bulbs for a never built enlightened Zen, and cold they seem to measure about 4 ohms,.. I remember the bulbs at the show being big, but marked 150w So maybe Nelson can "enlighten" us. I realize that the bulb's resistance changes a little when it gets hot, but it isn't going up that much...I don't think..
hmm

Mark

/Anyway , I suspect it is 150w bulbs..
Click to expand...

A 300W bulb should be 48 ohms when hot, assuming 120V RMS line.
 
Variac

Variac

diyAudio Editor
Joined 2001
BurningAmp.org
Paid Member
Well, we aren't running the bulbs at full output, or close to full output, so they won't be as hot as Scott's Grannies basement and I guess not the 48 ohms that 120v might give.

So Nelson's amp has two 150 w bulbs I believe - one for each channel. right? (its a stereo amp) And he calls the bulb out as 20 ohms.

So I guess my 300w bulbs have less resistance, so it looks like I'll have two 300's per channel in series. Appears that more wattage is more linear. I'll then have a "300W SED" amp which has specs like a "300B SET" amp. Hope they still glow enough though..
 
Last edited:
flg

flg

Member
Joined 2005
As my experimenting showed also ;) For the 300W: 25V/1.1A = 22.7 ohms
There definatly seems to be some non-linear functions at work with the heating etc.
I'm going to try to experiment with some bulbs and the heating elements and their response to rapid changes to applied voltage/current this weekend if possible. I don't have any ability to do THD at the moment but some curves/scope pics in the audio bandwidth rather than several seconds might uncover something interesting :confused:
 
You must log in or register to reply here.
Top Bottom