the 500 format and power supplies!

[pan60]

wow is this a touching subject or what:eek:

guys and gals lets chat about this.
1; please do don't poop on so other design, lets just cover the pros and con: )~
2; let's cover current draw as well as inrush current but please be civil :D
3; we can cover the validity of the bipolar voltage supplies. chat about head room, and try to explain the difference between a single rail or a bipolar rail supply.
4; also can we cover possible improvements to the power supplies;
are the any real benefits, any trades offs, / pros and cons?

now some know how i personally feel about the 500 format, it is very well documented, it is what it is.
i am cool with any product the will work in a standard API lunchbox.
and i am cool with those that don't i just disagree on how some are labeled.
so lets not be concerned with that BS on this thread, cool: )~

i will be asking some to chime in here as i get a chance, if you can, please chime in at anytime.
thinks guys and gals

[danetate]

The format arose out of an old console architecture. Old as in established - not old as in out of date. We are privileged to be able to participate with API in their design concept. I don't have any complaints. it's a good setup. Maybe it isn't perfect for everything, but it wasn't necessarily intended to be.

[[silent:arts]]

the problem is in the system :)
it was designed for custom build consoles.
no problem with calculating the PSU requirement.

today, open to others - API don't know how much power the 3rd party modules will need.

I'm sure all API racks will be fine with all API modules.
(while I have other experiences with the 200 series at work, which would be another story)

[LunchBoxHero]

The format arose out of an old console architecture. Old as in established - not old as in out of date. We are privileged to be able to participate with API in their design concept. I don't have any complaints. it's a good setup. Maybe it isn't perfect for everything, but it wasn't necessarily intended to be.

maybe the more knoweldgable (that would be most of you :D) can educate me on the history a bit here...

the format came from an older console design, which presumably supplied the necessary power to make those boards both coveted and great sounding. In many ways, API helped change the sound of popular music.

Why is it that now folks sometimes complain about the same format being ported over to something that is both portable and also captures that same sound? Was there a fundamental change in the way power was supplied to the modules when the format was moved from console to lunchbox?

Pan60, please feel free to move my thread if it takes us too far off topic!

James

[[silent:arts]]

if you design / build a console you know your power requirements.
you know the installed modules and you can use your calculator.

with an "open" standard, you don't know what your 3rd party modules require.
could be some mA, or too much for the PSU.
you don't know which modules your customers will install.

in the old days, designing a mixer, this was fixed calculably.

just my 2 cents (since I have to deal with it like API does)

[mikekeith]

One: in-rush of current; since these modules are not a power amp this should never be an issue..The lower end scale of loading the output is around 600 ohms, IF the output was driving its full +22dB output into 600 ohms that would create a current draw of less than 20ma, that is less than the idle current of the 990 op amp(25ma)..
Under a more common input load of 10K that same +22dB output would draw around 1ma...Not much..

Any module should have enough filtering/decoupling to handle that..Notice I said Module...

A phantom powered mic, IMHO... is far more likely of running out of current than a 500 series module...And that is not an issue either..

Having 10 times the current available than a module will draw will not some how make it sound bigger..At least I have never seen any evidence of this..
Yes you want a good power supply, I build my supply's to a very high level..IMHO, to isolate the audio circuits from the trash/noise on the AC line...What ALL good supply's should be doing...

Two: Headroom; API runs on the same +-16.5V either in the console OR Lunch Box..So headroom is the same...
Other modules...that depends..

[danetate]

maybe the more knoweldgable (that would be most of you :D) can educate me on the history a bit here...

I don't know when API started producing VPR rack units for their modules to be used outside of their consoles, but mine is a Datatronics (who owned API for a time) from about 1980 - quite a few years before actual lunchboxes came on the scene and long before the VPR Alliance was created. :)

[pan60]

i don't think it was anything API ever worried with as they knew their needs,
but now we have such a awesome collection of gear for the format, and being it is open more so now then ever, i think it would be nice to have a basic figure for many to work from.
this way people could crab something off the shelf and not worry, that is from the consumers point of view.

for the DIY guys this is all most likely little if any concern. if we need a bigger supply we most often would know it.

i think to many are concerned about power supplies and i am just not sure it should be a concern.

have have units from several manufacturers it i have not had any issues.

i know some have been concerned with inrush on some the Neve style module, but i have not seen a reason for concern?

just want to get everyones input and a super cool discussion: )~
so far we are off to a awesome chat:D

[mikekeith]

I don't know when API started producing VPR rack units for their modules to be used outside of their consoles, but mine is a Datatronics (who owned API for a time) from about 1980 - quite a few years before actual lunchboxes came on the scene and long before the VPR Alliance was created. :)

I found a schematic for the 500 Lunch Box supply, 3/81...
Still have lit from early 90's...
The early 6 space the supply was seperate..I remember that...

[danetate]

Lunchbox dating back to '81? I had no idea. Sure that wasn't a rack unit?

My Datatronix has a built in supply but no phantom power.

[mikekeith]

Lunchbox dating back to '81? I had no idea. Sure that wasn't a rack unit?

My Datatronix has a built in supply but no phantom power.

The Lunch Box was before any rack units..Which rack units? 3124?
It came with the B4...So yes.. It is very similar to what is used today..

[mikekeith]

I also have sold some 512b that were BEFORE the AES change of Pin 2 Hot...
Have a client that has a couple with Pin 3 Hot...

[raf]

Current inrush is caused by the initial instantaneous charging of any electrolytic caps across the power rails.

These capacitors are near zero ohms when discharged, so inrush currents can soar to the 10s of amps...

But, power supllies are pretty tolerant of inrush currents. That is usually not considered when sizing DC supplies under 200V DC.

I would be more concerned about headroom...

For example, 11 modules that follow the old spec of +/- 130mA per module will use 1.43A per rail when running. This is close to 1.5A, so the next logical size supply is a 5A supply which gives over 200% headroom. You NEVER want to run a supply anywhere near it's limits. I like 300% but is sometimes impossible.

All that aside, drawing 1.5A from a supply that maxes out at 3A will work just fine but run warmer than the previous example.

Obviously, the higher the headroom, the less stress inrush causes.

Roger
FCS

[mikekeith]

Current inrush is caused by the initial instantaneous charging of any electrolytic caps across the power rails.

These capacitors are near zero ohms when discharged, so inrush currents can soar to the 10s of amps...

But, power supllies are pretty tolerant of inrush currents. That is usually not considered when sizing DC supplies under 200V DC.

I would be more concerned about headroom...

For example, 11 modules that follow the old spec of +/- 130mA per module will use 1.43A per rail when running. This is close to 1.5A, so the next logical size supply is a 5A supply which gives over 200% headroom. You NEVER want to run a supply anywhere near it's limits. I like 300% but is sometimes impossible.

All that aside, drawing 1.5A from a supply that maxes out at 3A will work just fine but run warmer than the previous example.

Obviously, the higher the headroom, the less stress inrush causes.

Roger
FCS
Current Inrush:
ONLY at power up..People are NOT concerned about that...

[John Hardy]

Inrush current can be a problem if an individual card is being inserted into a frame that already has the power turned on. If the local power supply filter capacitors on a card are a large-enough value and low-enough impedance, it can take several amps of current to begin charging them. This can cause arcing at the edge connector, damaging the gold plating.

John Hardy
www.johnhardyco.com

[raf]

Current Inrush:
ONLY at power up..People are NOT concerned about that...

Well, not in audio at least.

And yes power up inrush is
the initial instantaneous charging of any electrolytic caps across the power rails

[danetate]

The Lunch Box was before any rack units..Which rack units? 3124?
It came with the B4...So yes.. It is very similar to what is used today..

No no, I mean the 500 VPR as opposed to the smaller Lunchbox with the handle on the side.

[raf]

Inrush current can be a problem if an individual card is being inserted into a frame that already has the power turned on. If the local power supply filter capacitors on a card are a large-enough value and low-enough impedance, it can take several amps of current to begin charging them. This can cause arcing at the edge connector, damaging the gold plating.

John Hardy
www.johnhardyco.com

+1..

[pan60]

how much dose certain transistors effect inrush current?
i have been told it could be a concern in some units?

i think most units fall far below the 130mA per slot as allotted, and only a small hand full ( at least that i am aware of ) would be close and only a couple that are more. so is headroom a concern in most settings?

i could see if if guys were running a lunchbox or rack full of power hogs. i just don't see that happening.
at least not soon.

raf, you still thinking about doing a more linear supply?
i think in one of our chats you mentioned it as a possibility.

P.S.
John Hardy, how is you project coming along, any news to report?

[John Hardy]

The inrush current is basically caused by any capacitors that need to be charged up at various points in a circuit. These are typically the on-card filter capacitors for the power supplies. The higher the value of an electrolytic capacitor, the more energy it can store when charged up by a power supply. This results in higher current being required to do the charging. if the inrush current is high enough as someone is plugging a module into a frame where the power is already turned on, there will be an arc between the circuit board and the edge connector. This will damage the circuit board contacts and the edge connector fingers.

So, the basic question is, how much filter capacitance can there be before you have an arcing problem that damages things? 22uF? 47uF? 100uF? 220uF? 470uF? 1,000uF? Higher capacitance is better for providing power supplies with a lower impedance (lots of local energy available), but tradeoffs may have to be made in a modular situation due to the possibility of arcing.

Series diodes and protection devices can add resistance to the power supply path that can reduce the inrush current, but the added resistance also increases the overall impedance of the power supply. Of course, you can increase the value of the filter capacitors to compensate...

There are "hot-swap" circuits available that provide a gradual ramping of current during power-up, but they can be tricky to use.

John Hardy

(500 series: finishing CAD conversion software...)

[mikekeith]

Inrush current can be a problem if an individual card is being inserted into a frame that already has the power turned on. If the local power supply filter capacitors on a card are a large-enough value and low-enough impedance, it can take several amps of current to begin charging them. This can cause arcing at the edge connector, damaging the gold plating.

John Hardy
www.johnhardyco.com

Right, but that is not what people are concerned about OR referring to..
Its in the normal state, some think that a strong peak will demand MORE current than the supply can provide...

And this is not a problem...IMHO..

[mikekeith]

how much dose certain transistors effect inrush current?
i have been told it could be a concern in some units?

i think most units fall far below the 130mA per slot as allotted, and only a small hand full ( at least that i am aware of ) would be close and only a couple that are more. so is headroom a concern in most settings?

i could see if if guys were running a lunchbox or rack full of power hogs. i just don't see that happening.
at least not soon.

raf, you still thinking about doing a more linear supply?
i think in one of our chats you mentioned it as a possibility.

P.S.
John Hardy, how is you project coming along, any news to report?

What is a MORE linear supply?
The above could be tested VERY easy..Simply put a serious load on the output, drive the amp with a dB below clipping 40Hz signal and see what you get..IF the level drops with a 600 Ohm load versus a 5K load and If so how much..., IF it has a transformer output it will have a dB or two drop across it..so you need to be BEFORE it...
By the way I have done this test MANY times on various op amps...I prefer more like 200 Ohms...

It puts a REAL demand on the amp,supply, PCB rails, connections, ect....
BUT in real life with low level loads that mic pres, Eq's ect see this should not be a concern...And IM not concerned IF I do see a small drop in level..say less than a dB..My .02cents..

And ALL should be aware that you should NEVER remove/insert a module WITH OUT powering down..This goes for consoles..No difference..

[John Hardy]

2; let's cover current draw as well as inrush current but please be civil

John Hardy

[pan60]

The inrush current is basically caused by any capacitors that need to be charged up at various points in a circuit. These are typically the on-card filter capacitors for the power supplies. The higher the value of an electrolytic capacitor, the more energy it can store when charged up by a power supply. This results in higher current being required to do the charging. if the inrush current is high enough as someone is plugging a module into a frame where the power is already turned on, there will be an arc between the circuit board and the edge connector. This will damage the circuit board contacts and the edge connector fingers.

So, the basic question is, how much filter capacitance can there be before you have an arcing problem that damages things? 22uF? 47uF? 100uF? 220uF? 470uF? 1,000uF? Higher capacitance is better for providing power supplies with a lower impedance (lots of local energy available), but tradeoffs may have to be made in a modular situation due to the possibility of arcing.

Series diodes and protection devices can add resistance to the power supply path that can reduce the inrush current, but the added resistance also increases the overall impedance of the power supply. Of course, you can increase the value of the filter capacitors to compensate...

There are "hot-swap" circuits available that provide a gradual ramping of current during power-up, but they can be tricky to use.

John Hardy

(500 series: finishing CAD conversion software...)

i am glad you all know how to make this stuff work: )~

[raf]

raf, you still thinking about doing a more linear supply?
i think in one of our chats you mentioned it as a possibility.

I only floated the DIY thing as an example... That was linear. And only good up to around 1/2A with the heatsinks I used and 1.5A regulators.

Haven't used one, but what's wrong with the BAE power supply? Certainly cheap enough at $250?? Doubt I could meet that pricepoint with small production... Actually doubt you could DIY it cheaper.

For my mastering setup, a master PSU powering several rackmount boxes, I will probably use some industrial rail mount switchers, like +/- 48V @ 5A and a 5V relay and illumination supply @ 10A... Someday...

This kind of thing is DIY 101 as long as you are good with 120/220V wiring safety practices.

My main concern about all out DIY is the lack of high output regulators... The 338T is 5A, just barely enough for an 11 space rack if you want headroom and low operating temperatures. 350 is ok, but smallish too... 317/337 is 1.5A MAX, so eh...
Then you are into pass boosting with bulk transistors. There goes your DIY simplicity and cost savings.

Not sure what people think a PSU should cost.... But the BAE looks good in concept. Caveat being I haven't tortured one in person.

Even if you buy open frame linears it's going to get spendy in a hurry once you put them in a box.

rf

[raf]

Almost forgot, there is no such thing as safe hot swapping if you give a s**t about your gear, IMHO:D

[John Hardy]

I wonder how many times people plug a module into a powered-up frame, intentionally or accidentally.

[danetate]

Six times.

[John Hardy]

Correct!

[pan60]

What is a MORE linear supply?

i can't remember just what we were chat about or the details.
just brought is up as i thought it might ad to the topics.


I only floated the DIY thing as an example... That was linear. And only good up to around 1/2A with the heatsinks I used and 1.5A regulators.

Haven't used one, but what's wrong with the BAE power supply? Certainly cheap enough at $250?? Doubt I could meet that pricepoint with small production... Actually doubt you could DIY it cheaper.

For my mastering setup, a master PSU powering several rackmount boxes, I will probably use some industrial rail mount switchers, like +/- 48V @ 5A and a 5V relay and illumination supply @ 10A... Someday...

This kind of thing is DIY 101 as long as you are good with 120/220V wiring safety practices.

My main concern about all out DIY is the lack of high output regulators... The 338T is 5A, just barely enough for an 11 space rack if you want headroom and low operating temperatures. 350 is ok, but smallish too... 317/337 is 1.5A MAX, so eh...
Then you are into pass boosting with bulk transistors. There goes your DIY simplicity and cost savings.

Not sure what people think a PSU should cost.... But the BAE looks good in concept. Caveat being I haven't tortured one in person.

Even if you buy open frame linears it's going to get spendy in a hurry once you put them in a box.

rf

i just happy to remotely remember something about it in on of our chats, so i thought i would ask: )~


Six times.


Correct!

LOL
:eek:

so glad to see you guys in here offering your expertise: )~
you guys rock!!!!

thanks
pan

[Denyle]

There's nothing at all wrong the BAE power supplies. FWIW, it's an open frame linear in a box, a IHBB15-1.5 from International power to be specific. Add to that a 500ma, 48v linear if you need phantom power. It stays cool, has no fans or massive heatsink and 3A seems a realistic benchmark.

[pan60]

There's nothing at all wrong the BAE power supplies. FWIW, it's an open frame linear in a box, a IHBB15-1.5 from International power to be specific. Add to that a 500ma, 48v linear if you need phantom power. It stays cool, has no fans or massive heatsink and 3A seems a realistic benchmark.

i have a BAE here and n issues from it.
from what i have seen, i think any of these would be fine.
i have A-Designs, API, BAE, even a OSA ( which i hear some are okay some are not, mine has been fine. ), and a old Aphex that Avedis was kind enough to go through for me.
i want to get one of Andrews from purple, but i just have to save my pennies a bit longer.

[raf]

There's nothing at all wrong the BAE power supplies. FWIW, it's an open frame linear in a box, a IHBB15-1.5 from International power to be specific. Add to that a 500ma, 48v linear if you need phantom power. It stays cool, has no fans or massive heatsink and 3A seems a realistic benchmark.

Ok, that's what I have in my bench supply. I put it in a Nema elctrical box...
Ugly! Have it bolted onto the end of the bench with 2 4 pin XLR connectors right there at hand. Actually, it does have a massive heatsink for the 2n3055s though, the entire frame is the heatsink.

Anyway, that International HBB15-1.5 can only (just) deliver 1.5A @ 15V.
More like .8 @ 17V with low enough ripple to be worth using.... I tested this myself. (as you adjust voltage up current capacity goes down) For example this same supply will deliver 1.7A @ 12V. There, of course, was no rating at a 17V output. It is capable but not documented.

That's what I was thinking earlier. It would not actually power 11 modules if they all drew the 130mA maximum.

So you need the, what is the next step up... looking in Mouser, 3A.
I like the Sola Hevi Duty Silver Line supplies. Have installed many, many of these supplies in extremely hostile conditions with zero failures.
Those are seeing daytime temps to +160 degrees F.

The real reason I like the Sola is the terminal blocks! No soldering out in the wind!

That BAE supply is a bargain though. And probably not have any problems driving 11 real world modules, barring power hogs.

rf

[Denyle]

Out of curiosity, how pretty does the output need to be? The modules have filtering as well. Is a diode and a 1000uf cap going to smooth it out? Sure, the electronics geek in me says it needs to be as clean as possible but in practice, I can't say I've ever heard anything that made me want to measure ripple of the psu.

[raf]

Nah, 1000uF is way over what you need.
On my builds that use DOAs that will be required to deliver high currents, I have used 220uF. Until you are drawing a lot more current than 500 stuff allows, 100-220 uF is fine after a 1N4003 or a 1R 1W resistor.

I am pretty particular about noise+ripple but you are not going to hear the effect of higher noise until you get close to maximum current capacity. Then it would be slightly higher hum component. Might show up earlier on an analyzer plot.

In the 500 format, power is simple in a single module unless you are using DC/DC converters or Class A.... Then grounding etc gets more critical.
For bipolar powered stuff, piece of cake.

Also, I have heard that some are concerned about symmetrical current draw. Would make sense right? No, There are no penalties for asymmetrical power draw, Many circuits use the negative supply for biasing only, therefore just sip at the neg supply rail.

If you look at many commercial supplies, they already know this and provide, say, 500mA on the negative rail and 1.5A on the positive.

500 modules are forced to use the positive rail for things such as relays and LED power. This puts a disproportionate load on the positive rail. Consequences? Not at all, as long as the rails don't poop out.

My 2 cents at least...
rf

[danetate]

We're using the negative rail for some of the LEDs.

[raf]

Yup

Lots of ways to skin a cat.

Just have to keep within limits like anything else.

danetate,
I was looking at your opto design, clean! Nice layout.

Good luck with that!

rf

[danetate]

Oh thanks. Is that the de-esser you are talking about?

[raf]

I was referring to your 545 Optical Disrupter...
Great name btw!

[danetate]

Ah. Thank you sir. Not too clean when the IN switch gets hit and the REDUCTION knob turned up though!

There is a discussion going on about this under Show and Tell btw.

[raf]

Well, nothing wrong with that! People looking for non-clean compression all the time. I'd like to hear one.

rf

PS, yeah didn't want to veer this thread so much...
Over to show and tell.

[pan60]

what about some unit that may choose to use incandescent lights as opposed to the LEDS, not sure anyone is, but their were some at some point.
still nothing to worry with?

[mikekeith]

what about some unit that may choose to use indecent lights as opposed to the LEDS, not sure anyone is, but their were some at some point.
still nothing to worry with?
They go out a lot, and draw far more current, take up more space and are slooooowwww..

[pan60]

i have taken LEDs and added a resister to replace incandescent before.
any reason for concern in doing that for the various 500 format cards?

[mikekeith]

i have taken LEDs and added a resister to replace indecents before.
any reason for concern in doing that for the various 500 format cards?
no. last longer..

[pan60]

cool thats good!
:D

[ajwells]

Incandescent lamps, like big electrolytics, when they are first powered on present an almost zero ohm resistance, and pull a huge amount of current until they come up to brightness. This might not seem like a big deal, unless you have, say, a lighted pushbutton switch, which you are turning on and off, like a bypass switch. every time you push the switch and the lamp lights, it spikes the current that is pulled from the power supply. Replacing incandescents with leds is a great idea, if you can do that. However, normally you wouldn't be switching things in the middle of a session, so any pops or clicks that an incandescent lamp would cause would not go on the session. Also, if you have a well regulated power supply, the regulators should take care of any transients in the current or voltage.

Off subject here, one of the recommended mods on a Dynaco PAS3 preamp is to replace the power lamp with an LED/resistor because the lamp pulls enough current that it causes the filament voltage to sag, since it's on the same circuit.

[mikekeith]

Sorry A.J. but not correct..
A cap charging is FAR more initial current than a lamp...
And if it was the same you would hear it on that module..esp if you were in #1 slot, further from the supply...

What do you consider a large cap? 4700uf? Larger?

[Wireline]

Not to be Satan, but when does the amount of power draw, heat, and space of several 500 power chassis all connected to a patchbay scheme start to use more current than a small bucket oriented console, ala the Mark VIII?

(jes asking)

[mikekeith]

Not to be Satan, but when does the amount of power draw, heat, and space of several 500 power chassis all connected to a patchbay scheme start to use more current than a small bucket oriented console, ala the Mark VIII?

(jes asking)

It doesn't..The 2520 will draw the same, same voltage...
But in a console the modules WILL draw more current..more op amps ect..

[ajwells]

Sorry A.J. but not correct..
A cap charging is FAR more initial current than a lamp...
And if it was the same you would hear it on that module..esp if you were in #1 slot, further from the supply...

Yes, you are correct, caps do indeed pull more initial current than lamps. I'll be the first to admit that i'm not familiar with vintage API modules, so I don't know specifically what Pan60 was referring to when he was replacing lamps with LEDs. But I'm not sure that there is an application where you would be switching an electrolytic on and off of the power supply rails, (unless there was a can on the phantom supply in a mic pre, but those usually have resistors in series to limit the current,) where there would be with a lighted switch. So yeah, apples and oranges here, sorry.


What do you consider a large cap? 4700uf? Larger?

Large cap is a relative term here, I was meaning large in the 500 series realm for power supply rails within a module. We're using 10 uf caps on the rails on our modules, and we've had no problems. But large caps? I'd consider those 2 farad trash cans they put in car trunks for the stereos as large. But we're obviously not going to find those in a 500 series module.

But back to the general discussion, if you're running modules that are VPR compliant, you should have no problems with the lunchbox power supply. I think that's been said before.

Sorry for the misunderstanding.

[pan60]

as i said before no names mention as this is a great unit, and we all know just how a rumor can distorted spread and evolve to a totally different meaning from the original discussion.

i have a unit that using incandescent lamps, and the are all powered off of one rail.
the current draw far exceeds the VPR Alliance guidelines, the latest generation uses LEDs and the current draw seems to be well with in specs.

i can only imagine that the size and wattage of the bulbs would have a lot to do with stable current draw as well as inrush current draw?

[pan60]

P.S.

i think i have incandescent correctly spelled now?
:eek::eek:

[danetate]

Pan, our eyes are trained to overlook your spelling. :o

[pan60]

LOL
i tried spell check, but it don't speak hillbilly: )~
i did tell it to learn words for a long time, but that just makes it as bad a speller as me. :eek:

[mikekeith]

as i said before no names mention as this is a great unit, and we all know just how a rumor can distorted spread and evolve to a totally different meaning from the original discussion.

i have a unit that using incandescent lamps, and the are all powered off of one rail.
the current draw far exceeds the VPR Alliance guidelines, the latest generation uses LEDs and the current draw seems to be well with in specs.

i can only imagine that the size and wattage of the bulbs would have a lot to do with stable current draw as well as inrush current draw?

I can NOT think of one good reason to use lamps instead of LED's..in a readout that is..

[danetate]

I can NOT think of one good reason to use lamps instead of LED's..in a readout that is..

I can't either. In fact, aren't they going to outlaw incandescent bulbs altogether in a few more years? I don't know if that applies to little tweezy ones, but it sounds ominous.

[ajwells]

I believe the tweezy ones are immune from that directive, as are the halogen lamps that are used in stage lighting.

It would be nice if someone would make a direct plug in LED replacement for the tweezy lamps, i know of a couple of Echolab switchers that could desperately use some.

oh well.

[Denyle]

I actually prefer the way you spelled it the first time. :D
Polite light bulbs are so boring.

[pan60]

some of the new LEDs are cool as the are not so focused.

you guys should do a thread on converting your incandescent bulbs to LEDs when they go out.

a tiny resistor and LED will fit the old incandescent bulbs frame so why not?