Driver to drive?

On Oct 19, 11:38 am, UltimatePatriot
<UltimatePatr...@thebestcountry.org> wrote:
On Sun, 19 Oct 2008 07:06:47 -0700 (PDT), mpm <mpmill...@aol.com> wrote:
On Oct 18, 10:22?pm, UltimatePatriot
UltimatePatr...@thebestcountry.org> wrote:
On Sat, 18 Oct 2008 08:53:03 -0700 (PDT), mpm <mpmill...@aol.com> wrote:
It will be interesting to see who, if anyone, is endorsed by Gen.
Colin Powell tomorrow morning on Meet the Press.

? What would you like to bet on it?

?I'll bet $50 that it is not Obama.

Please make your check out to the Democratic National Convention, or
Planned Parenthood.
Or even "Joe the Plumber".  Maybe it'll help him with his back-taxes.
Thank you.

  Back taxes?  You're an idiot.  You believe all that bullshit the DP
started?  You are one gullible dipshit then.

  He hasn't endorsed a candidate yet, and you presuming his choice shows
that you are a presumptuous lil bastard, just like Obama is.
Clueless.
 
John Fields wrote:
Eeyore wrote:


I've made one decision though. If one outfit wants me it'll be Group
Technical Director.

My advice would be to take the one where you're likely to do the least
damage.

You would think they already have a know it all janitor. :(


--
http://improve-usenet.org/index.html

aioe.org, Goggle Groups, and Web TV users must request to be white
listed, or I will not see your messages.

If you have broadband, your ISP may have a NNTP news server included in
your account: http://www.usenettools.net/ISP.htm


There are two kinds of people on this earth:
The crazy, and the insane.
The first sign of insanity is denying that you're crazy.
 
On Sun, 19 Oct 2008 18:18:18 +0100, Eeyore
<rabbitsfriendsandrelations@hotmail.com> wrote:

John Fields wrote:

Eeyore wrote:

You're a babe in arms in this discipline.

---
You wish.

I cut my teeth on audio and was designing and building bridge amplifiers
in the early '60's, even before RCA came out with them, as I recall.

The world has moved on John.
---
As have I, while you guys keep struggling to lower THD to limits which
are so far beyond the threshold of audibility that the point of the
exercise becomes ludicrous.


JF
 
On Sun, 19 Oct 2008 20:07:08 GMT, "Kevin Aylward"
<kaExtractThis@kevinaylward.co.uk> wrote:


When I was young, I prayed and prayed to the Lord to get me a bike. After
many years, and no success, I realised that HE, doesn't work that way...So I
stole the bike, and preyed for his forgiveness...
---
Upon whom? ;)

JF
 
On Sun, 19 Oct 2008 17:53:36 +0100, Eeyore
<rabbitsfriendsandrelations@hotmail.com> wrote:

John Fields wrote:

Eeyore wrote:
John Fields wrote:

As it is, all you seem to be intent on doing is promoting yourself as
some sort of audio Guru who claims to greatness but who refuses to
submit proof.

Suit yourself. Everything I claim does what it does. All you have to do is
buy one and test it yourself.

---
Why buy when I can build?
---

It would cost you LOTS more to build one yourself and you wouldn't replicate the
pcb pattern which can be critical for top performance.
---
Ah, but since you don't hold the keys to the kingdom I might come up
with something even better, just for the fun of kicking your ass.

JF
 
On Oct 19, 2:38�pm, UltimatePatriot
<UltimatePatr...@thebestcountry.org> wrote:
On Sun, 19 Oct 2008 07:06:47 -0700 (PDT), mpm <mpmill...@aol.com> wrote:
On Oct 18, 10:22?pm, UltimatePatriot
UltimatePatr...@thebestcountry.org> wrote:
On Sat, 18 Oct 2008 08:53:03 -0700 (PDT), mpm <mpmill...@aol.com> wrote:
It will be interesting to see who, if anyone, is endorsed by Gen.
Colin Powell tomorrow morning on Meet the Press.

? What would you like to bet on it?

?I'll bet $50 that it is not Obama.

Please make your check out to the Democratic National Convention, or
Planned Parenthood.
Or even "Joe the Plumber". �Maybe it'll help him with his back-taxes.
Thank you.

� Back taxes? �You're an idiot. �You believe all that bullshit the DP
started? �You are one gullible dipshit then.

ďż˝ He hasn't endorsed a candidate yet, and you presuming his choice shows
that you are a presumptuous lil bastard, just like Obama is.
You can also pay by Credit Card.
https://www.democrats.org/page/contribute/ChangeWeNeed

Unless you're the type who welshes on bets.... ?
 
On Oct 18, 11:03�am, MooseFET <kensm...@rahul.net> wrote:
On Oct 17, 5:51�pm, krw <k...@att.bizzzzzzzzzz> wrote:





In article <26b1f724-0411-4976-b8d4-6e8ab7be5a61
@w39g2000prb.googlegroups.com>, kensm...@rahul.net says...

On Oct 16, 8:05�pm, krw <k...@att.bizzzzzzzzzz> wrote:
In article <48F7ED96.BD3C7...@hovnanian.com>, p...@hovnanian.com
says...

Jim Yanik wrote:

"Paul Hovnanian P.E." <p...@hovnanian.com> wrote in
news:48F54EF8.A413A4B@hovnanian.com:

Kris Krieger wrote:

"Paul Hovnanian P.E." <p...@hovnanian.com> wrote in
news:48F4E02F.18E854FA@hovnanian.com:

Kris Krieger wrote:

"B. Peg" <bent_pe...@worldnet.att.net> wrote in
news:QL0Jk.3229$x%.1609@nlpi070.nbdc.sbc.com:

His holding back on his records is disturbing and I don't think
all the fuss is over grades.

The lawyer (Berg) who is pursuing him not being a naturalized
U.S. citizen, hence disqualifying him from the POTUS spot, may
be on to something and it may be apparent on his school records.

B~

Since when do school records contain citizenship info?

And since when does an individual born within the USA need to
become a naturalized citizen?

Well, as I wrote to JF:

When did that start, is what I meant (I guess I could have phrased it
better). �I just hadn't heard of that.

I don't know. But some people just bite on any rumor, no matter how
improbable.

I seriously doubt any candidate would have made it through a DoJ
background check with such a hole in their records.

since when does DoJ vet potential Presidential candidates?

Background checks. Try running for or being appointed to any federal
(and many state) offices without one.

Where is a background check mentioned in the Constitution?

While we are at it where is the FCC in the constitution?

The FCC clearly falls under the IC clause.

That would mean that the FCC would only be allowed to regulate radio
waves that cross state lines and wired communications that run across
state lines. �Either the FCC is operating beyond their allowed powers
or the IC clause includes things that don't go across state lines.- Hide quoted text -

- Show quoted text -
Well, you have to put the agency somewhere.
While it may not have been envisioned at the dawn of radio, signals
these days cross international borders, talk to submarines around the
world, even satellites flying high overhead.

Spectrum is finite, and for practical reasons, nations must engage in
treaties to utilize this resource efficiently and effectively. US
States are not able to execute these treaties, and thus, the FCC is
federalized. In other words, the States-rights argument is a non-
starter.

But again, when it comes to manufacturing equipment, regulating
safety, developing standards (i.e., DTV, cellular, etc..), there is a
very strong tie-in to commerce. So, having FCC under the Dept of
Commerce probably makes sense. (Even if you don't buy the "crossing
State lines" issue..) I mean, it makes more sense than say, putting
it under the Dept of Agriculture.

-mpm
 
On Oct 19, 12:47�pm, krw <k...@att.bizzzzzzzzzz> wrote:

If a radio wave cannot cross state lines it isn't regulated
(shielded inside an enclosure, for instance). �Once you let it free �
it's going to cross state lines, all on its own. ďż˝;-)
Technically, that statement is not true.
MRI machines and microwave ovens are two RF examples that come to
mind.
Both are enclosed. Both are regulated.

That said, I understood your point.
 
On Oct 19, 3:28�pm, "Jon Slaughter" <Jon_Slaugh...@Hotmail.com> wrote:
"mpm" <mpmill...@aol.com> wrote in message

news:211f87d7-5558-4901-aa6c-c45e987012b1@d1g2000hsg.googlegroups.com...
On Oct 19, 4:41?am, "Jon Slaughter" <Jon_Slaugh...@Hotmail.com> wrote:

Is there a cheap source for fiber optic that is't used for communication
but
lighting? I need it in small lengths(< 1 in but of course I can cut it)
and
don't mind imperfections. In fact I imagine even scrap would work. 1mm to
2mm in diameter too.

Although need it without the sheath or some easy way to remove it. Would
be
nice if it had a coating on it so I could handle it but a very thin one
that
was bonded to the fiber)

Thanks,
Jon

I think you definitely want to hook up with one of the Chinese Import
companies that deal in plastic fiber optic cable. �Here's a couple to
get you started...

http://www.tootoo.com/buy-Plastic_Fiber_Optic/http://www.tootoo.com/d-p12460465-Plastic_Fiber_Optic/

Google keywords: �China Import Plastic Fiber Optic.
You can also try acrylic.
------------

have you dealt with any of these chinese companies before? I'm a bit wary
about them for some reason.
No. And be advised they usually deal ONLY in high-volume.
But you can try going the "sample" route with them, and/or find out if
they sell to any distributors or value-added resellers, etc...

Anyone in manufacturing these days deals (at least in part) with the
Chinese or India.
No big deal. Just find a reputable company.
 
On Oct 19, 3:27�pm, "Jon Slaughter" <Jon_Slaugh...@Hotmail.com> wrote:
Here are some pics of a proof of concept. The quality sucks but shows whats
going on:

http://server6.theimagehosting.com/image.php?img=MVC-001S.48c.JPGhttp://server6.theimagehosting.com/image.php?img=MVC-002S.3ec.JPGhttp://server6..theimagehosting.com/image.php?img=MVC-003S.4a3.JPGhttp://server6.theimagehosting.com/image.php?img=MVC-004S.688.JPG

The first is with flash. It should be obvious which one is the fiber optic
and which one is the led on the surface. The fiber optic is running both red
and green while the lifted one is just red.

The fiber optic is much "tighter" but as the last picture shows, at a
different angle the green comes completely through and sometimes the red is
more prevalent(3rd link).

The fiber optic looks "nicer" because it looks more professional but that
might be just because of of the other being rigged(hot glued to hold it in
hole). The fiber optic method is much easier to do because I don't have to
"lift" the led into the hole but can put the led's on pcb.

On the other hand, the fiber optic is clearly not as bright and it is a bit
harder to see off angle. Increasing the diameter of the fiber optic core
should help a little and may help with "mixing" the colors beter.

So, the main thing I need to get my idea rolling is some fiber optic cabling
that solves the following problems(or where it can be easily modified to):

1. Mixes the colors better(so viewing at different angles do not give
different colors)
2. Disperses the light at the end a bit better
3. A thin jacket so that it will fit snug in the hole. (the one I used fits
very nicely but the jacket is 1mm thick. I'd like to reduce the jacket size
and increase the core size but same snug fit without screwing up the fiber
in some way)
4. A lot of light seems not to be going into the fiber. When I look
underneath the wood it is almost just as bright as what is above if not
brighter. �Seems pretty in efficient to me since I could probably get the
same brightness by using the "lifted" led at 1/3 power(or maybe 1/2) but
"lifting" the led has many of it's own problems.

I was also thinking of maybe having some type of "lenz" that fits on top of
the hole that can be pressed in that disperses the light and mixes it.
Although this complicates things by a few factors(mainly resourcing them and
extra cost).
A lens (note, not spelled "lenz"?) will improve the fiber-optic
results tremendously.
There was a company I used once before (I'm trying desparately to
remember their name....).

They make a lot of fiber-optic safety interlock switch stuff.
But they have discrete lenses available. Began with an "S", I
think..?
It'll come to me, or someone here will know them. Big company. USA.

I actually have a box full of misc plastic fiber optics, parts, fiber
reels, etc...
If I knew where it was in the warehouse, I'd ship it to you my regular
discount offer price:
That being, the cost of UPS shipping plus a single bottle of a decent
Belgian Ale! Ha!!

I wouldn't write off fiber optic until you marry it up with a flush
mount lens of some sort.
I think you will be very impressed. Also, just to mention, the human
eye is much more sensitive to green than red. (You'll have to play
with color/luminosity issues, even with LED's)

And one word of caution, if you're handling glass fiber-optic, brush
up on fiber safety first. You don't want that stuff in your skin or
eyes. (And depending on what you're driving the fiber with -- you
don't want to perform amateur RK surgery either.. :) Though I'm sure
you're driving with LED's and not collimated lasers, etc...
Besides, I don't think I've ever seen glass fiber at the cross-
sectional diameter your project requries, but you never know. Just be
aware you can't pluck glass fiber out with tweezers. You'll end up in
the E.R. :(

-mpm
 
On Sun, 19 Oct 2008 20:07:08 GMT, "Kevin Aylward"
<kaExtractThis@kevinaylward.co.uk> wrote:

John Larkin wrote:
On Sun, 19 Oct 2008 10:07:41 GMT, "Kevin Aylward"
kaExtractThis@kevinaylward.co.uk> wrote:

John Larkin wrote:
On Fri, 17 Oct 2008 18:06:47 -0700 (PDT), Allen Bong


Hi Graham,

Is this a good audio amp using HexFET for a starter?

http://users.otenet.gr/~athsam/power_amplifier_45w_hexfet_eng.htm

The driver and output stages use IRF9540 and IRF540 and the opamp
is LF411. THD is 0.2%. Power supply is +/- 30V.

I like it because the PCB design is included.

Allen


Not too bad,

Yes. "not too bad" in the strict sense of the phrase. That is, it is
a bad design, but not so bad as to be totally unusable. However,
this does depend on the definition of "good" somewhat. Assuming we
give meaning to the term "average", then this design can not in any
reasonable way be classed as a "good" or even an average design".
It is a quick knock up, that serious audio designers don't even give
a second look to, well except when commenting on how bad it is.

except for the biasing. Iq could have been set by a
pot+resistor from IC1 pin 4 to 7, and the DC offset trim should be
into the opamp, not fighting it.

A "good" audio amp, imo, will have at most, only one trim pot, and
this is to set the output bias.


The biasing/crossover of this type of circuit is potentially
perfect, in that both stages run at some idle current and signal
makes one pick up,

For very high speed, audiophile performance, this output device
configuration is very poor. The gates of the transistors are
connected via two much speed lag. This usually results in very,
large shot through currents when hit by 100n pulses.

but leaves the opposite side idling. As opposed to a lot of
circuits where conduction on one side actively shuts off the other.

DC bias on the output fets depends on their thresholds, not so good;
closing local loops on the fets (with more opamps) would be better.

Oh...a sure-fire recipe for disaster, if done correctly...It will
generate additional de-stabilising poles. That particular technique
can be useful for reducing LF. distortion, but it does it at the
expense of BW, i.e. higher HF distortion. I would be surprised if
this "design" could stand having its HF IMD compromised any further.

My NMR and MRI gradient amps use a similar topology... the driver
opamp has its supply rails cascoded to make signal currents, and the
upper and lower power stages are active current mirrors. I'd argue
that adding an opamp per power fet makes things faster, stability
better, and compensation simpler, since the gate/Miller capacitance
disappears...

And your argument would be incorrect I am afraid to say. I have already
outlined these issues recently in another post.

There is no such thing as a free lunch. You cannot achieve better stability
by using extra feedback loops in this manner. The transfer function of the
op-amp and fet combined will cause considerable grief. Only if you roll off
the system much earlier will it be stable.

each fet now looks like a very fast, pF input
capacitance, DC-perfect device, and essentially disappears from the
overall loop dynamics.

Unfortunatly not. Consider a two stage amp circuit, one first stage, being
the conventional gain stage, followed by a second stage connected with a
local loop to make a CLG of unity. Additionally, the second amp connecting
back to the 1st (via a beta network if used) to form the composite. Now
calculate the system loop gain by breaking both feedback connections *at
once* an compare it with the 2 stage system both running open loop. The
transfer functions are identical. So, having the two stages means at least 2
roll offs. That is including an *additional* op-amp (to get better lf
performance) around the mosfet, will generate an additional pole that would
not have been there. Therefore the system is inherently more unstable.

I suggest you actually perform the *detailed* simulations of these type of
circuits.

I point out two circuits

http://www.kevinaylward.co.uk/ee/circuits/VeryLowDistortionAmp1.jpg
http://www.kevinaylward.co.uk/ee/circuits/VeryLowDistortionAmp2.jpg

They are similar, but one has a local feedback loop around the output
devices, one doesn't. One has better LF accuracy, one can be stabilised to a
higher UGF. Which is which?

The fundamental trade off here is basic physics, there is an inherent
constraint of H(Power, Accuracy, Speed) = 0, e.g.
http://www.kevinaylward.co.uk/ee/cmospafl/cmospafl.html


You just can't just get better LF performance, and expect to get it all. It
don't work that way. Like,....


When I was young, I prayed and prayed to the Lord to get me a bike. After
many years, and no success, I realised that HE, doesn't work that way...So I
stole the bike, and preyed for his forgiveness...

Now just pile on as many opamp+fet pairs as you
need. DC balance and current sharing become as good as the opamp
offset voltages, microvolts if you like, so fet gate threshold
variations and transfer curves don't matter any more. So use very
small source resistors and cut losses.

For LF, the op-amp approach is very nice, for HF, its not so nice.


My amps often work in pulse mode, when doing chemical NMR. They settle
to PPMs of the target value (which is current, since we're driving
gradient coils) in 10's of microseconds.

This is very slow, by about 2 orders of magnitude at least. At this slow
speed, op-amps are probably a good choice. You just clobber with a big cap.
By fast, I meant at the < 100ns level.

Kevin Aylward
www.kevinaylward.co.uk
Oh, my mistake. I somehow imagined that this thread had "audio"
somewhere in its title.

How about this?

http://www.highlandtechnology.com/DSS/T860DS.html

Next rev I'll fix that little undershoot.

John
 
On Sun, 19 Oct 2008 20:07:08 GMT, "Kevin Aylward"
<kaExtractThis@kevinaylward.co.uk> wrote:

John Larkin wrote:
On Sun, 19 Oct 2008 10:07:41 GMT, "Kevin Aylward"
kaExtractThis@kevinaylward.co.uk> wrote:

John Larkin wrote:
On Fri, 17 Oct 2008 18:06:47 -0700 (PDT), Allen Bong


Hi Graham,

Is this a good audio amp using HexFET for a starter?

http://users.otenet.gr/~athsam/power_amplifier_45w_hexfet_eng.htm

The driver and output stages use IRF9540 and IRF540 and the opamp
is LF411. THD is 0.2%. Power supply is +/- 30V.

I like it because the PCB design is included.

Allen


Not too bad,

Yes. "not too bad" in the strict sense of the phrase. That is, it is
a bad design, but not so bad as to be totally unusable. However,
this does depend on the definition of "good" somewhat. Assuming we
give meaning to the term "average", then this design can not in any
reasonable way be classed as a "good" or even an average design".
It is a quick knock up, that serious audio designers don't even give
a second look to, well except when commenting on how bad it is.

except for the biasing. Iq could have been set by a
pot+resistor from IC1 pin 4 to 7, and the DC offset trim should be
into the opamp, not fighting it.

A "good" audio amp, imo, will have at most, only one trim pot, and
this is to set the output bias.


The biasing/crossover of this type of circuit is potentially
perfect, in that both stages run at some idle current and signal
makes one pick up,

For very high speed, audiophile performance, this output device
configuration is very poor. The gates of the transistors are
connected via two much speed lag. This usually results in very,
large shot through currents when hit by 100n pulses.

but leaves the opposite side idling. As opposed to a lot of
circuits where conduction on one side actively shuts off the other.

DC bias on the output fets depends on their thresholds, not so good;
closing local loops on the fets (with more opamps) would be better.

Oh...a sure-fire recipe for disaster, if done correctly...It will
generate additional de-stabilising poles. That particular technique
can be useful for reducing LF. distortion, but it does it at the
expense of BW, i.e. higher HF distortion. I would be surprised if
this "design" could stand having its HF IMD compromised any further.

My NMR and MRI gradient amps use a similar topology... the driver
opamp has its supply rails cascoded to make signal currents, and the
upper and lower power stages are active current mirrors. I'd argue
that adding an opamp per power fet makes things faster, stability
better, and compensation simpler, since the gate/Miller capacitance
disappears...

And your argument would be incorrect I am afraid to say. I have already
outlined these issues recently in another post.

There is no such thing as a free lunch. You cannot achieve better stability
by using extra feedback loops in this manner. The transfer function of the
op-amp and fet combined will cause considerable grief. Only if you roll off
the system much earlier will it be stable.

If adding a gate driver per fet makes the fet bandwidth substantially
greater, why doesn't that reduce phase shift and make the overall loop
more stable, or allow a wider bandwidth for a given phase margin?

That's exactly what it does.

And it makes the fet transfer curve look linear, which also helps
stability.

each fet now looks like a very fast, pF input
capacitance, DC-perfect device, and essentially disappears from the
overall loop dynamics.

Unfortunatly not. Consider a two stage amp circuit, one first stage, being
the conventional gain stage, followed by a second stage connected with a
local loop to make a CLG of unity. Additionally, the second amp connecting
back to the 1st (via a beta network if used) to form the composite. Now
calculate the system loop gain by breaking both feedback connections *at
once* an compare it with the 2 stage system both running open loop. The
transfer functions are identical. So, having the two stages means at least 2
roll offs. That is including an *additional* op-amp (to get better lf
performance) around the mosfet, will generate an additional pole that would
not have been there. Therefore the system is inherently more unstable.
Not if the "additional" pole is at a much higher frequency than the
previous pole inherent to the capacitances of a heap of fets driven by
some wimpy resistive source. Increasing the bandwidth of the output
stage - the serious speed problem - by, say, 20:1 has got to help the
overall loop.

There's no free lunch here: we're adding GBW, and paying for it. But
not much, since opamps are cheap.

I suggest you actually perform the *detailed* simulations of these type of
circuits.
Been there, done that, sold and selling a lot of the results.

You see, I actually *build* my designs.

John
 
On Sun, 19 Oct 2008 13:29:17 -0700 (PDT), mpm <mpmillard@aol.com> wrote:

On Oct 19, 12:47?pm, krw <k...@att.bizzzzzzzzzz> wrote:

If a radio wave cannot cross state lines it isn't regulated
(shielded inside an enclosure, for instance). ?Once you let it free ?
it's going to cross state lines, all on its own. ?;-)

Technically, that statement is not true.
MRI machines and microwave ovens are two RF examples that come to
mind.
Both are enclosed. Both are regulated.

That said, I understood your point.

Both radiate, dipshit. THAT is NOT enclosed.
 
On Sat, 18 Oct 2008 13:15:17 -0500, "Jon Slaughter"
<Jon_Slaughter@Hotmail.com> wrote:

osr@uakron.edu> wrote in message
news:cda72500-4a0e-478b-9b8e-8ce12a8898f0@c60g2000hsf.googlegroups.com...
On Oct 18, 12:34 am, "Jon Slaughter" <Jon_Slaugh...@Hotmail.com
wrote:
"mpm" <mpmill...@aol.com> wrote in message

news:f3df757a-fd95-428f-9796-b1defd671db5@u65g2000hsc.googlegroups.com...
On Oct 17, 11:54?pm, "Jon Slaughter" <Jon_Slaugh...@Hotmail.com
wrote:

Any help would be appreciated,
Jon

Problem solved. (Depending on how comfortable you are thinking outside
the box.. :)
I'll email it to you....

-mpm

-----

Ok... lets hope it is the solution ;)

Right now I just hot glued the led in the hole.. it works nice except it I
can't do it on the guitar neck with good results(actually it probably will
work ok but rather use something else). Of course the colors are not mixed
great and I still have the wiring problem(it can be done but is tedious).
The led pipe stuff seems like the way to go... only if I could actually
find
some that small.

Thanks... I'll reply to the email once I get it if I have any questions,
Jon

3 mm plastic fiber optic is cheap, easy to work with , and a short
length contact coupled to your multicolor led will work fine. So will
a short piece of acrylic rod.

Steve Roberts

---------

Will this give approximately the same effect as "lifting" the led or will it
reduce the viewing angle signficiantly?

Actually I do have some fiber optic cable from a small "kit" I brought once.
Is the stuff easy to cut or will it shatter?
Is it glass or plastic?
 
Jan Panteltje wrote:
The free spaces between US digital TV stations can now be used for wireless services.
In spite of failed tests ;-)

In German:
http://www.heise.de/newsticker/US-Regulierer-will-den-Weissen-Raum-oeffnen--/meldung/117556

That has been around since a long time. Our church uses wireless mikes
as a secondary UHF user. Of course we made sure that this doesn't bother
anyone. Love thy neighbor :)

DTV is a whole 'nother ballgame. It falls apart every other night around
here. And when it goes then most of the channels turn into a blocky
Picasso, not just one.

--
Regards, Joerg

http://www.analogconsultants.com/

"gmail" domain blocked because of excessive spam.
Use another domain or send PM.
 
"mpm" <mpmillard@aol.com> wrote in message
news:f51614ef-03e3-4746-b329-8decbc42bdae@t54g2000hsg.googlegroups.com...
On Oct 19, 3:27?pm, "Jon Slaughter" <Jon_Slaugh...@Hotmail.com> wrote:
Here are some pics of a proof of concept. The quality sucks but shows
whats
going on:

http://server6.theimagehosting.com/image.php?img=MVC-001S.48c.JPGhttp://server6.theimagehosting.com/image.php?img=MVC-002S.3ec.JPGhttp://server6.theimagehosting.com/image.php?img=MVC-003S.4a3.JPGhttp://server6.theimagehosting.com/image.php?img=MVC-004S.688.JPG

The first is with flash. It should be obvious which one is the fiber optic
and which one is the led on the surface. The fiber optic is running both
red
and green while the lifted one is just red.

The fiber optic is much "tighter" but as the last picture shows, at a
different angle the green comes completely through and sometimes the red
is
more prevalent(3rd link).

The fiber optic looks "nicer" because it looks more professional but that
might be just because of of the other being rigged(hot glued to hold it in
hole). The fiber optic method is much easier to do because I don't have to
"lift" the led into the hole but can put the led's on pcb.

On the other hand, the fiber optic is clearly not as bright and it is a
bit
harder to see off angle. Increasing the diameter of the fiber optic core
should help a little and may help with "mixing" the colors beter.

So, the main thing I need to get my idea rolling is some fiber optic
cabling
that solves the following problems(or where it can be easily modified to):

1. Mixes the colors better(so viewing at different angles do not give
different colors)
2. Disperses the light at the end a bit better
3. A thin jacket so that it will fit snug in the hole. (the one I used
fits
very nicely but the jacket is 1mm thick. I'd like to reduce the jacket
size
and increase the core size but same snug fit without screwing up the fiber
in some way)
4. A lot of light seems not to be going into the fiber. When I look
underneath the wood it is almost just as bright as what is above if not
brighter. ?Seems pretty in efficient to me since I could probably get the
same brightness by using the "lifted" led at 1/3 power(or maybe 1/2) but
"lifting" the led has many of it's own problems.

I was also thinking of maybe having some type of "lenz" that fits on top
of
the hole that can be pressed in that disperses the light and mixes it.
Although this complicates things by a few factors(mainly resourcing them
and
extra cost).
A lens (note, not spelled "lenz"?) will improve the fiber-optic
results tremendously.
There was a company I used once before (I'm trying desparately to
remember their name....).
-------

What I found was led pipes and lenses. This is really what I need but I
can't find them at the proper size. (They are all for the large TH like leds
or large SMT)

====
They make a lot of fiber-optic safety interlock switch stuff.
But they have discrete lenses available. Began with an "S", I
think..?
It'll come to me, or someone here will know them. Big company. USA.
------

I don't know. I haven't dealt with fiber optic. It seems like my solution
is probably the best even if I can't work out the kinks perfectly, at least
for getting a prototype done. Although I'd rather get it right the first
time if it's not too much trouble.

I've already ordered 200 of the rgb led's and hopefully it won't be too hard
to get a pcb for them going. I got a 100$ fender squire comming. Hopefully
I'll be able to start on the circuitry sometime soon. Shouldn't be too
difficult but going to be hard to integrate into the guitar because enough
surface area needs to be left so the neck can stick well and if it needs to
be removed again it doesn't ruin the circuit. I think it shouldn't be that
bit of a challenge though when I get too it.

=======
I actually have a box full of misc plastic fiber optics, parts, fiber
reels, etc...
If I knew where it was in the warehouse, I'd ship it to you my regular
discount offer price:
That being, the cost of UPS shipping plus a single bottle of a decent
Belgian Ale! Ha!!
-----

That would be nice ;) But I wonder if the Belgian Ale is good for you? ;)



====
I wouldn't write off fiber optic until you marry it up with a flush
mount lens of some sort.
I think you will be very impressed. Also, just to mention, the human
eye is much more sensitive to green than red. (You'll have to play
with color/luminosity issues, even with LED's)
----

I've been looking for lenses but it seems they are all too big. The fresnel
type seem to be what I want but I can't find them at the size I need(at most
about 2mm).

Hell, I'm having a hard time finding cheap fiber optic with a core of about
1.5-2mm ;/ I'm going to hit the local stores tomorrow and see if I can't
find any in a hobby shop.

======
And one word of caution, if you're handling glass fiber-optic, brush
up on fiber safety first. You don't want that stuff in your skin or
eyes. (And depending on what you're driving the fiber with -- you
don't want to perform amateur RK surgery either.. :) Though I'm sure
you're driving with LED's and not collimated lasers, etc...
Besides, I don't think I've ever seen glass fiber at the cross-
sectional diameter your project requries, but you never know. Just be
aware you can't pluck glass fiber out with tweezers. You'll end up in
the E.R. :(
------

Really? I imagine the silica dust is harmful to the lungs but that develops
over long term exposure? Yeah, I'm not using lasers or anything but simple
led's so I don't have to worry about that. Mostly I just need to cut the
fiber optics to size. (used a razor blade to cut what I had and it worked
fine although the end wasn't perfectly smooth and flat)



Do you know if I were to strip the fiber optic's jacket off and insert it in
the wood if the wood will change the refraction causing it to be less
efficient? Or if the wood will some how weaken the fiber optic? (although
that shouldn't matter too much as it's short and not being moved once in
place)
 
Eeyore wrote:

Jamie wrote:


Eeyore wrote:

John Fields wrote:

Eeyore wrote:

John Fields wrote:

You make those claims and then, conveniently, fail to back them up
because of the restrictions you claim are placed upon you by copyright
and contractual limitations.

Fine. Pay me and I'll do something similar for you and you'll own the
copyright.

---
Pay you???

Thanks, that's the best laugh I've had all day!

Well, let's face it, you don't have the necessary skills.


Make sure you have a shovel, you'll need it for that hole
your about to dig for your self.


I'm quite sure that JF is far too out of touch with the technology currently
used in the best audio amplification.

Also, it has to be economic to manufacture. That's easily half of it.
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
that being the case, then it must be shit you're making!
I think any beginner can accomplish that.

http://webpages.charter.net/jamie_5"
 
Jamie wrote:

Eeyore wrote:
John Fields wrote:
Eeyore wrote:
John Fields wrote:

As it is, all you seem to be intent on doing is promoting yourself as
some sort of audio Guru who claims to greatness but who refuses to
submit proof.

Suit yourself. Everything I claim does what it does. All you have to do is
buy one and test it yourself.

---
Why buy when I can build?
---

It would cost you LOTS more to build one yourself and you wouldn't replicate the
pcb pattern which can be critical for top performance.

LOL!!
the crap is getting deep!
You clearly haven't the tiniest clue about the economics of high-volume manufacturing.
Or the importance of pcb layout. Not to mention the cost savings of offshore
manufacturing too.

One product of mine (in its various channel sizes) sold over 100,000 units.

Graham
 
Kevin Aylward wrote:

Eeyore wrote:
Kevin Aylward wrote:

A "good" audio amp, imo, will have at most, only one trim pot, and
this is to set the output bias.

I was delighted with the consistency of my D Series of bipolar amps.
No trim pots at all. Designed out in the design process. In fact the
entire amp had not one trimpot. That means faster production and
final test plus a cost reduction.

It would be a good idea if those lateral mosfet makers had current sense
transistors so that a current mirrored, push pull, source follower can be
done.
Motorola did a mosfet with a current sense terminal. Doubtless only N-channel
though.

Graham
 
Kevin Aylward wrote:

I point out two circuits

http://www.kevinaylward.co.uk/ee/circuits/VeryLowDistortionAmp1.jpg
http://www.kevinaylward.co.uk/ee/circuits/VeryLowDistortionAmp2.jpg

They are similar, but one has a local feedback loop around the output
devices, one doesn't.
I'm a great believer in local feedback. Linearises stages nicely and improves HF
and phase response. If you need to, you can make up some lost overall gain with
jellybean transistors (or ICs) at the front end.

Graham
 

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