How can you enhance Sijosae splitter precision without a trimmer?...

[Bill Sloman]

On Wednesday, December 16, 2020 at 10:07:12 AM UTC+11, John Larkin wrote:

On Tue, 15 Dec 2020 16:50:20 -0500, Phil Hobbs
pcdhSpamM...@electrooptical.net> wrote:

On 12/15/20 4:03 PM, John Larkin wrote:
On Tue, 15 Dec 2020 15:40:23 -0500, Phil Hobbs
pcdhSpamM...@electrooptical.net> wrote:

On 12/15/20 3:31 PM, John Larkin wrote:
On Tue, 15 Dec 2020 20:17:12 GMT, Steve Wilson <sp...@me.com> wrote:

jla...@highlandsniptechnology.com wrote:

<snip>

Jim W was pretty smart about a lot of things. He did tend to use a
crapload of parts sometimes.

Oh, he was great. I met him a couple times at the Foothill Flea Market
(also sadly gone) and he was nice, interested, but very shy. His two
books are wonderful. But I think he never got an EE education, so he
ran more on instinct than theory.

That doesn\'t follow. I\'ve never had an EE education, but you can get the theory out of books and papers.
If you do, you are an autodidact. Instinctive reactions are inherited - good luck with finding any that help you with electronics

There will be holes in that education - you tend to learn what you need to - but there are plenty of holes in formal electrical engineering courses.

Electronics has changed a lot since 1965 - when I started learning about it - and people who stopped learning about it as soon as they got out of university wouldn\'t be much use.

<snip>

--
Bill Sloman, Sydney

 

[Jasen Betts]

On 2020-12-14, Don <g@crcomp.net> wrote:

My proto-board needs a rail-splitter, built from parts on-hand, post
haste. A modded Sijosae splitter will work. How can you enhance its
precision without a trimmer?

Use the power pins of an op-amp to drive the transistors now organised
as common emitter

https://www.tubecad.com/2018/02/10/TLE2426%20Replacement%20Design%20Example.png

In this circuit the power to run the op-amp flows through the
transistor bases turning them on to assist the op-amp

As the power pins are involved you want a single op-amp in this
application, as if you use dual or quad the extra sub-parts won\'t
be usable.

The above image is taken from this blog post.

https://www.tubecad.com/2018/02/blog0412.htm

Which has lots of other good looking circuits too.

--
Jasen.

 

[Jasen Betts]

On 2020-12-16, Lasse Langwadt Christensen <langwadt@fonz.dk> wrote:

onsdag den 16. december 2020 kl. 00.14.17 UTC+1 skrev amdx:
On 12/14/2020 8:42 PM, Phil Hobbs wrote:
On 12/14/20 8:43 PM, Dave Platt wrote:
In article <ihuftfh1slneffn78...@4ax.com>,
John Larkin <x...@yy.com> wrote:

We don\'t know his actual \"modded\" circuit, but the Sijosae splitters
that show up in google searches look awfully soft and sloppy.

One site I read described them as significantly better than a simple
resistive divider, but significantly worse than any other buffered
circuit they described (typically op-amp-based). Price-wise that\'s
about how they fall, too. I guess you get what you pay for.

Unless the supplies are super accurate, I can\'t see much virtue in a
precise splitter. Downstream circuits shouldn\'t care much.

We don\'t know the requirements of the downstream circuits, either -
why precision seemed to be called for.



A resistive divider and a TCA0372.

Cheers

Phil Hobbs

For a breadboard... Use two wallwarts.

or find and old AC modem adapter and use a doubler

That\'s ok for powering a MC1488 (which is probably how the modem used it)
but bould be a bit noisy for running a synthesiser

--
Jasen.

 

[amdx]

On 12/14/2020 9:50 PM, jlarkin@highlandsniptechnology.com wrote:

On Tue, 15 Dec 2020 03:32:46 -0000 (UTC), \"Don\" <g@crcomp.net> wrote:

Phil Hobbs <pcdhSpamMeSenseless@electrooptical.net> wrote:
On 12/14/20 8:43 PM, Dave Platt wrote:
In article <ihuftfh1slneffn78vtj5lpljd5b6bmvsi@4ax.com>,
John Larkin <xx@yy.com> wrote:

We don\'t know his actual \"modded\" circuit, but the Sijosae splitters
that show up in google searches look awfully soft and sloppy.
One site I read described them as significantly better than a simple
resistive divider, but significantly worse than any other buffered
circuit they described (typically op-amp-based). Price-wise that\'s
about how they fall, too. I guess you get what you pay for.

Unless the supplies are super accurate, I can\'t see much virtue in a
precise splitter. Downstream circuits shouldn\'t care much.
We don\'t know the requirements of the downstream circuits, either -
why precision seemed to be called for.



A resistive divider and a TCA0372.
Unfortunately, there\'s nary a TCA0372 available in my parts bin. But,
there\'s a LM317, LM337, and a 3.3 V zener diode available, along with a
19 VDC wall wart from the bone pile. Beings so many think the Sijosae
splitter stinks, it may behoove me to move on to an adaptation of this
circuit:

https://i.stack.imgur.com/kPjJF.jpg

Danke,
Use two warts, or two 9 volt batteries.



Opps, just read your post a day late.

                             Mikek


--
This email has been checked for viruses by Avast antivirus software.
https://www.avast.com/antivirus