Pass "DeLite" Amp from BAF

[Tea-Bag]

DeLite on chalk board was running at 50 volts, assuming that may mix things up a bit.

 

[Variac]

I seem to recall from previous efforts getting about 20 ohms
from my bulbs when run at 30V or so.

Nelson, I know you are still working things out, but are the bulbs you used 150w? And likely to stay being 150w? That's what I remember, but if it is confirmed, then at least everyone can obsess over getting the bulbs while you get some breathing room on the design

 

[flg]

You often will find an interesting point around 1 KHz where
the bulb will sing a bit.
Charming.

What is that, 2nd harmonic? Mechanical resonance? Or an inductance from the coiled up filament?
Sounds like a tube thing actually

 

[Rodeodave]

Yap, they do ring. I noticed that with my Zen-lite amp. I think it's the AC-current through the filament changing it's temperature/length. I first thought I was tripping but it kind of makes sense...
Concerning bulbs and their resistance...maybe it's time to reread the Zenlite article.

http://www.passdiy.com/pdf/zenlite.pdf


(btw, I sourced my bulbs when I was on holidays in Mexico, 300W 115V, plus sockets. Luckily still have four in spare...)

 

[scott wurcer]

I missed this one, it covers a lot of questions. I see Mr. Pass is also a Roger Corman fan, I've seen nearly all of them and once did a retrospective of both the Poe cycle and the early sci-fi in separate summers around 1970.

 

[Nelson Pass]

A few years ago, as a Christmas present, my wife arranged
for me to lunch with Roger Corman. He is really an amazing
guy.

 

[Steve Dunlap]

I think I have seen most of the Roger Corman films also. I worked in the local movie theater in high school so I could get in for free. I loved the cheap SiFi movies. I still do. Do you remember who played the patient in the dentist office in Little Shop Of Horrors?

 

[scott wurcer]

Wilbur Force, Jack N. no peeking required. You know your hooked when you start doing the Dick Miller sightings.

 

[Nelson Pass]

Aaaahhh... "Bucket of Blood", the big Dick Miller vehicle.

Last seen in "The Twilight Zone Movie"?

 

[Steve Dunlap]

Last seen here.

Trail of the Screaming Forehead (2007)

 

[flg]

Powerful you have become, the dark side I sense in you.
-- Yoda

 

[jacco vermeulen]

big Dick Miller

1984 Terminator : there's a 15 day wait on the handguns, but the rifles you can take right now.

 

[Variac]

This has been already mentioned, but I couldn't find it just now. Check out
http://www.passdiy.com/pdf/zenlite.pdf

to catch up on light bulbs, power supply and other relevant issues, as well as the same old crazy ideas: more power, balanced.....

mark

EDIT: I couldn't find the link because it was posted by Rodeodave on the previous page! I was looking earlier in the thread. well, here's another excellent and relevant and already mentioned link:

http://passlabs.com/pdf/articles/sweet_spot.pdf

 

[Variac]

You will have to forgive the occasional lapse.

I have a purchasing manager, a big budget, and indulgent
business partners, so I don't think twice about ordering up
two different types of parts, or even the antique light bulbs.

That entices me to forget that not everyone is so blessed.

On the other hand, somebody needs to do it, if only to
provide vicarious entertainment. A little adventure won't
hurt you at 5% of the price of audiophile interconnects.

I would prefer to hear about all the options. I heard the DeLite at
Burning Amp and the mosfets used sounded good enough for me to order 4 from the group buy. If something "better" comes along I certainly want to hear about it also. Would add to the fun to compare various devices..

 

[Variac]

Oh yeah, I found some huge 20 ohm wire wound resistors at a surplus place.. Sure they wouldn't glow or look cool like a bulb, but they look kinda cool in their own right, and should be more rugged, compact and linear. BUT they are probably really inductive- is that bad for the "load " resistor? A little bad? really bad? Not bad at all?

Inquiriung reader wants to know..

 

[wrenchone]

One way to find out - clip leads are your friend... I have other plans for the Ixys fets when I get around to them. I'm still all caught up with the fets that have pilot lights, if you know what I mean.

 

[JPeitzman]

I am glad someone brought this one back up because I am going to build one of these I think. I needed an excuse to buy some parts from Mouser and they now have these parts available for $9.96/FET. I think I will throw them on with a bag full of JFET's and mixed passives. I wanted to ask though, how big should that 1R be(?), the picture looks like 100watt. Thanks!


James

 

[wrenchone]

It would be interesting to try both standard resistors and light bubs as loads. Is there a little magic due to the modulation of load resistance via signal current? The bulbs can be found at Mc Master-Carr, or consult your phone book for that dusty little electrical supply house in your city...

If they have the bulbs, they may also have the cool retro ceramics sockets, too, a good idea for things that get hot as a matter of course.

 

[Variac]

Just wondering if there were an obvious theoretical problem. I found bulbs and sockets quite a while ago at a local electrical supply shop that caters to electricians, when I was considering building Nelson's previous "Enlightened Zen" amp. So I will have bulbs, but I haven't bought the resistors yet, wanted to check first.. might make christmas present amps!

 

[Rodeodave]

I measured one of the bulbs (115V 300W) I am using in my Zenlite. See attachments.