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Dave Moore
Guest
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 Posted:
Fri Dec 09, 2005 9:35 am Post subject:
The future of germanium ? ( diodes mainly ) |
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I'm interested in hearing the thoughts of ye experts
about the future of germanium.
Specifically, germanium diodes, as I have decided
to possibly take to market some of my old circuit
designs that used germanium diodes.
There would seem to be a number of semi-houses that
still manufacture them, however they certainly don't seem
to be a hot item at any of the popular distributers.
Another disturbing trend :-) is the so-called
*improvement* in leakage specs. This may
be an "improvement" for some applications,
but to those in the world of guitar amplifier
FX design, this could well be the death nell.
So what thinketh ye ? Will the good old leaky
Ge diode soon go the way of long since deceased
reptiles?
Thanks
Dave Moore
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John Popelish
Guest
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| Posted:
Fri Dec 09, 2005 9:35 am Post subject:
Re: The future of germanium ? ( diodes mainly ) |
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Dave Moore wrote:
| Quote: | I'm interested in hearing the thoughts of ye experts
about the future of germanium.
Specifically, germanium diodes, as I have decided
to possibly take to market some of my old circuit
designs that used germanium diodes.
There would seem to be a number of semi-houses that
still manufacture them, however they certainly don't seem
to be a hot item at any of the popular distributers.
Another disturbing trend :-) is the so-called
*improvement* in leakage specs. This may
be an "improvement" for some applications,
but to those in the world of guitar amplifier
FX design, this could well be the death nell.
So what thinketh ye ? Will the good old leaky
Ge diode soon go the way of long since deceased
reptiles?
Thanks
Dave Moore
How do silicon Schottky diodes sound in your designs? They will |
certainly be around for a while.
I am waiting for someone to come up with a germanium nitride
passivated germanium transistor. Moisture sensitivity of the old
unpassivated germanium transistors was one of their worst faults. |
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Dave Moore
Guest
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| Posted:
Fri Dec 09, 2005 9:35 am Post subject:
Re: The future of germanium ? ( diodes mainly ) |
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: Dave Moore wrote:
: > I'm interested in hearing the thoughts of ye experts
: > about the future of germanium.
: >
: > Specifically, germanium diodes, as I have decided
: > to possibly take to market some of my old circuit
: > designs that used germanium diodes.
: >
: > There would seem to be a number of semi-houses that
: > still manufacture them, however they certainly don't seem
: > to be a hot item at any of the popular distributers.
: >
: > Another disturbing trend :-) is the so-called
: > *improvement* in leakage specs. This may
: > be an "improvement" for some applications,
: > but to those in the world of guitar amplifier
: > FX design, this could well be the death nell.
: >
: > So what thinketh ye ? Will the good old leaky
: > Ge diode soon go the way of long since deceased
: > reptiles?
: >
: > Thanks
: > Dave Moore
: >
"John Popelish" <jpopelish@rica.net> wrote
in message news:w5udnZJVX-n6hATeRVn-vg@adelphia.com...
: How do silicon Schottky diodes sound in your designs?
Terrible :-) Technically they work, but
tonewise, they fail the old scientific "ear test".
They will
: certainly be around for a while.
I've certainly experienced some interesting results
during a few brief experiments with Schottky's and
intend to delve into their sonic qualities a bit more
deeply in the future.
Ah, if only there were enough time
in the day ( about 64hrs/day might suffice :-)
:
: I am waiting for someone to come up with a germanium nitride
: passivated germanium transistor. Moisture sensitivity of the old
: unpassivated germanium transistors was one of their worst faults.
How about the diodes? Same problem?
Most of the diodes I've been using to date were scrounged
from old TV and radio boards that were stored in
a rather humid environment.
They seem to be healthy AFAIK.
Thanks
Dave Moore.
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Meindert Sprang
Guest
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| Posted:
Fri Dec 09, 2005 9:35 am Post subject:
Re: The future of germanium ? ( diodes mainly ) |
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"Dave Moore" <valveless@last.net> wrote in message
news:rh9mf.48340$i7.47785@bignews2.bellsouth.net...
| Quote: | in message news:w5udnZJVX-n6hATeRVn-vg@adelphia.com...
: How do silicon Schottky diodes sound in your designs?
Terrible :-) Technically they work, but
tonewise, they fail the old scientific "ear test".
|
Can't you 'soften' a Schottly diode with a small series resistor and add the
leakage in reverse by adding a large resistor in parallel?
Meindert |
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Robert Baer
Guest
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| Posted:
Fri Dec 09, 2005 9:35 am Post subject:
Re: The future of germanium ? ( diodes mainly ) |
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Dave Moore wrote:
| Quote: | I'm interested in hearing the thoughts of ye experts
about the future of germanium.
Specifically, germanium diodes, as I have decided
to possibly take to market some of my old circuit
designs that used germanium diodes.
There would seem to be a number of semi-houses that
still manufacture them, however they certainly don't seem
to be a hot item at any of the popular distributers.
Another disturbing trend :-) is the so-called
*improvement* in leakage specs. This may
be an "improvement" for some applications,
but to those in the world of guitar amplifier
FX design, this could well be the death nell.
So what thinketh ye ? Will the good old leaky
Ge diode soon go the way of long since deceased
reptiles?
Thanks
Dave Moore
One major "killer" go Germanium transistors was the use of Indium for |
doping; it made for a rather low temperature specification.
Late in the life of "flower power" transistors, a different doping
element was used - making the power transistors *more* temperature
resistant than "sand power" transistors.
But, sand power somehow won the day.
If you need lots of low Vf diodes and do not mind them being leaky
and having crappy breakdown voltages, then use schottky diodes. |
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Dave Moore
Guest
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| Posted:
Fri Dec 09, 2005 5:35 pm Post subject:
Re: The future of germanium ? ( diodes mainly ) |
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"Meindert Sprang" <mhsprang@NOcustomSPAMware.nl> wrote in message news:11piajus3tjt61a@corp.supernews.com...
: "Dave Moore" <valveless@last.net> wrote in message
: news:rh9mf.48340$i7.47785@bignews2.bellsouth.net...
: > in message news:w5udnZJVX-n6hATeRVn-vg@adelphia.com...
: >
: > : How do silicon Schottky diodes sound in your designs?
: >
: >
: > Terrible :-) Technically they work, but
: > tonewise, they fail the old scientific "ear test".
:
: Can't you 'soften' a Schottly diode with a small series resistor and add the
: leakage in reverse by adding a large resistor in parallel?
:
: Meindert
Actually, I'm planning to attempt to get the same
effects from generic silicon eventually.
Wherein, I expect to encounter
as with your suggestion, the same drawback, which is an
increased parts count and extended development time.
For some reason that I haven't yet taken the time to
understand, the schottky's introduce a rattling sound
when used in some of these circuits. Whether a damping
resistor will tame the abberrant carriers, dunno.
Time will tell I spoze and thanks to hurricane Katrina,
I have about half the time that I used to these days )`:
--DM-- |
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Dave Moore
Guest
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| Posted:
Fri Dec 09, 2005 5:35 pm Post subject:
Re: The future of germanium ? ( diodes mainly ) |
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"Robert Baer" <robertbaer@earthlink.net> wrote in message news:dybmf.922$QQ1.306@newsread3.news.pas.earthlink.net...
: Dave Moore wrote:
:
: > I'm interested in hearing the thoughts of ye experts
: > about the future of germanium.
: >
: > Specifically, germanium diodes, as I have decided
: > to possibly take to market some of my old circuit
: > designs that used germanium diodes.
: >
: > There would seem to be a number of semi-houses that
: > still manufacture them, however they certainly don't seem
: > to be a hot item at any of the popular distributers.
: >
: > Another disturbing trend :-) is the so-called
: > *improvement* in leakage specs. This may
: > be an "improvement" for some applications,
: > but to those in the world of guitar amplifier
: > FX design, this could well be the death nell.
: >
: > So what thinketh ye ? Will the good old leaky
: > Ge diode soon go the way of long since deceased
: > reptiles?
: >
: > Thanks
: > Dave Moore
: >
: >
: One major "killer" go Germanium transistors was the use of Indium for
: doping; it made for a rather low temperature specification.
: Late in the life of "flower power" transistors, a different doping
: element was used - making the power transistors *more* temperature
: resistant than "sand power" transistors.
: But, sand power somehow won the day.
: If you need lots of low Vf diodes and do not mind them being leaky
: and having crappy breakdown voltages, then use schottky diodes.
Hey, that's the best argument for schottky's I've heard yet :-) |
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Keith Williams
Guest
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| Posted:
Sat Dec 10, 2005 12:34 am Post subject:
Re: The future of germanium ? ( diodes mainly ) |
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|
In article <dG8mf.48335$i7.31501@bignews2.bellsouth.net>,
valveless@last.net says...
| Quote: | I'm interested in hearing the thoughts of ye experts
about the future of germanium.
Specifically, germanium diodes, as I have decided
to possibly take to market some of my old circuit
designs that used germanium diodes.
|
One of my first tasks, as a Junior Engineer, at my PoE was to
redesign a boatload of circuits to eliminate Germanium diodes and
transistors (and schottkys were cheating). ...that was 30 years
ago.
| Quote: | There would seem to be a number of semi-houses that
still manufacture them, however they certainly don't seem
to be a hot item at any of the popular distributers.
Another disturbing trend :-) is the so-called
*improvement* in leakage specs. This may
be an "improvement" for some applications,
but to those in the world of guitar amplifier
FX design, this could well be the death nell.
So what thinketh ye ? Will the good old leaky
Ge diode soon go the way of long since deceased
reptiles?
|
I thought the dinosaurs were already dead.
--
Keith |
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Tim Williams
Guest
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| Posted:
Sat Dec 10, 2005 1:36 am Post subject:
Re: The future of germanium ? ( diodes mainly ) |
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"Robert Baer" <robertbaer@earthlink.net> wrote in message
news:dybmf.922$QQ1.306@newsread3.news.pas.earthlink.net...
| Quote: | One major "killer" go Germanium transistors was the use of Indium for
doping; it made for a rather low temperature specification.
Late in the life of "flower power" transistors, a different doping
element was used - making the power transistors *more* temperature
resistant than "sand power" transistors.
|
Hum, I don't see how that's possible- Ge has a lower bandgap than Si, so no
matter what you dope it with, electrons are going to bump through the
junction by thermal energy that much easier.
I recently saw mention that Intel(?) was going to try indium antimonide. I
looked up the bandgap and it's lower than Ge, as you'd imagine. I don't
know what the hell they're thinking...
Tim
--
Deep Fryer: a very philosophical monk.
Website: http://webpages.charter.net/dawill/tmoranwms |
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Rich Grise
Guest
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| Posted:
Sat Dec 10, 2005 1:37 am Post subject:
Re: The future of germanium ? ( diodes mainly ) |
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On Fri, 09 Dec 2005 17:09:28 -0600, Tim Williams wrote:
| Quote: | "Robert Baer" <robertbaer@earthlink.net> wrote in message
news:dybmf.922$QQ1.306@newsread3.news.pas.earthlink.net...
One major "killer" go Germanium transistors was the use of Indium for
doping; it made for a rather low temperature specification.
Late in the life of "flower power" transistors, a different doping
element was used - making the power transistors *more* temperature
resistant than "sand power" transistors.
Hum, I don't see how that's possible- Ge has a lower bandgap than Si, so no
matter what you dope it with, electrons are going to bump through the
junction by thermal energy that much easier.
I recently saw mention that Intel(?) was going to try indium antimonide. I
looked up the bandgap and it's lower than Ge, as you'd imagine. I don't
know what the hell they're thinking...
|
Maybe they're thinking of things that can do 5 GHz at about a volt Vcc. :-)
Cheers!
Rich |
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Tim Wescott
Guest
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| Posted:
Sat Dec 10, 2005 1:39 am Post subject:
Re: The future of germanium ? ( diodes mainly ) |
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Tim Williams wrote:
| Quote: | "Robert Baer" <robertbaer@earthlink.net> wrote in message
news:dybmf.922$QQ1.306@newsread3.news.pas.earthlink.net...
One major "killer" go Germanium transistors was the use of Indium for
doping; it made for a rather low temperature specification.
Late in the life of "flower power" transistors, a different doping
element was used - making the power transistors *more* temperature
resistant than "sand power" transistors.
Hum, I don't see how that's possible- Ge has a lower bandgap than Si, so no
matter what you dope it with, electrons are going to bump through the
junction by thermal energy that much easier.
I recently saw mention that Intel(?) was going to try indium antimonide. I
looked up the bandgap and it's lower than Ge, as you'd imagine. I don't
know what the hell they're thinking...
Tim
--
Deep Fryer: a very philosophical monk.
Website: http://webpages.charter.net/dawill/tmoranwms
InSb makes a dandy detector for 3-5 micron IR, though. You have to cool |
it to 77K before it really acts like a semiconductor, though.
Perhaps Intel is going to use little bits of InSb for heterojunction
transistors or something strange like that? It would make sense except
I think the only bipolars that Intel makes are the parasitic ones that
crop up in CMOS designs.
--
Tim Wescott
Wescott Design Services
http://www.wescottdesign.com |
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Jim Thompson
Guest
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| Posted:
Sat Dec 10, 2005 1:39 am Post subject:
Re: The future of germanium ? ( diodes mainly ) |
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On Fri, 09 Dec 2005 16:30:37 -0800, Tim Wescott <tim@seemywebsite.com>
wrote:
| Quote: | Tim Williams wrote:
"Robert Baer" <robertbaer@earthlink.net> wrote in message
news:dybmf.922$QQ1.306@newsread3.news.pas.earthlink.net...
One major "killer" go Germanium transistors was the use of Indium for
doping; it made for a rather low temperature specification.
Late in the life of "flower power" transistors, a different doping
element was used - making the power transistors *more* temperature
resistant than "sand power" transistors.
Hum, I don't see how that's possible- Ge has a lower bandgap than Si, so no
matter what you dope it with, electrons are going to bump through the
junction by thermal energy that much easier.
I recently saw mention that Intel(?) was going to try indium antimonide. I
looked up the bandgap and it's lower than Ge, as you'd imagine. I don't
know what the hell they're thinking...
Tim
--
Deep Fryer: a very philosophical monk.
Website: http://webpages.charter.net/dawill/tmoranwms
InSb makes a dandy detector for 3-5 micron IR, though. You have to cool
it to 77K before it really acts like a semiconductor, though.
Perhaps Intel is going to use little bits of InSb for heterojunction
transistors or something strange like that? It would make sense except
I think the only bipolars that Intel makes are the parasitic ones that
crop up in CMOS designs.
|
On microchips the fastest bipolar devices currently made are SiGe,
typically with fT » 35GHz.
...Jim Thompson
--
| James E.Thompson, P.E. | mens |
| Analog Innovations, Inc. | et |
| Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
| Phoenix, Arizona Voice:(480)460-2350 | |
| E-mail Address at Website Fax:(480)460-2142 | Brass Rat |
| http://www.analog-innovations.com | 1962 |
I love to cook with wine. Sometimes I even put it in the food. |
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Robert Baer
Guest
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| Posted:
Sat Dec 10, 2005 4:05 pm Post subject:
Re: The future of germanium ? ( diodes mainly ) |
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|
Keith Williams wrote:
| Quote: | In article <dG8mf.48335$i7.31501@bignews2.bellsouth.net>,
valveless@last.net says...
I'm interested in hearing the thoughts of ye experts
about the future of germanium.
Specifically, germanium diodes, as I have decided
to possibly take to market some of my old circuit
designs that used germanium diodes.
One of my first tasks, as a Junior Engineer, at my PoE was to
redesign a boatload of circuits to eliminate Germanium diodes and
transistors (and schottkys were cheating). ...that was 30 years
ago.
There would seem to be a number of semi-houses that
still manufacture them, however they certainly don't seem
to be a hot item at any of the popular distributers.
Another disturbing trend :-) is the so-called
*improvement* in leakage specs. This may
be an "improvement" for some applications,
but to those in the world of guitar amplifier
FX design, this could well be the death nell.
So what thinketh ye ? Will the good old leaky
Ge diode soon go the way of long since deceased
reptiles?
I thought the dinosaurs were already dead.
Not too sure; i found a CK722 that is still good! |
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Guest
|
| Posted:
Sun Dec 11, 2005 5:05 pm Post subject:
Re: The future of germanium ? ( diodes mainly ) |
|
|
Dave Moore wrote:
| Quote: | Actually, I'm planning to attempt to get the same
effects from generic silicon eventually.
Wherein, I expect to encounter
as with your suggestion, the same drawback, which is an
increased parts count and extended development time.
For some reason that I haven't yet taken the time to
understand, the schottky's introduce a rattling sound
when used in some of these circuits. Whether a damping
resistor will tame the abberrant carriers, dunno.
Time will tell I spoze and thanks to hurricane Katrina,
I have about half the time that I used to these days )`:
--DM--
|
Silicons have the same nonlinear effect as Ges, but it occurs over a
small V range with a large V offset added, making it much tougher to
use for audio distortion than ge. Biasing them with a constant current
might help, but you've got 2 diodes to bias with 2 different Vs to get
symmetry. I'd stay with ge!
What production volumes are you looking at? If its only small, you may
be able to get a batch of ge diodes or trs off ebay or similar.
I dont know whether youve played with copper or selenium diodes, those
have similar uses, but again are even harder to find. Muggins here has
a batch of miniature metal signal diodes somewhere I've never found a
use for.
NT |
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Guest
|
| Posted:
Sun Dec 11, 2005 5:09 pm Post subject:
Re: The future of germanium ? ( diodes mainly ) |
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|
Tim Williams wrote:
| Quote: | I recently saw mention that Intel(?) was going to try indium antimonide. I
looked up the bandgap and it's lower than Ge, as you'd imagine. I don't
know what the hell they're thinking...
Tim
|
very low voltage for power saving? Would have many uses in computers
etc. Ge tr circuits can run happily on 0.5v supplies.
NT |
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