Sansui brand name

[Franc Zabkar]

On Sun, 6 Jul 2003 11:12:11 +1000, "Phil Allison"
<philallison@optusnet.com.au> put finger to keyboard and composed:

"Franc Zabkar" <fzabkar@optussnet.com.au> wrote in message
news2fegvg89qc59b6034fgmb1ofefvjo5mpa@4ax.com...
On Sat, 5 Jul 2003 16:11:41 +1000, "Phil Allison"
philallison@optusnet.com.au> put finger to keyboard and composed:

70s Sansui means the famous AU series in the minds of eveyone
except you.

The last Sansui amp I remember repairing was an AU4900. I was
surprised to find that its designer had created a full wave bridge
using eight 1A rectifiers connected as four pairs of diodes in
parallel. He/she was apparently under the misconception that the
bridge could now handle 2A. I was shocked to see such a fundamental
error from a high end (?) brand name. Fittingly the fault was shorted
rectifier diodes. Needless to say I rebuilt the bridge with four 3A
versions.



** Paralleled power diodes work fine.

Not at all. Look closely at the knee in the diode characteristic and
then tell us how current can be evenly shared by two parallel diodes
with even a *slight* mismatch in the I-V curve.

Hint: dI/dV is *very* large.


- Franc Zabkar
--
Please remove one 's' from my address when replying by email.

 

[Phil Allison]

"Franc Zabkar" <fzabkar@optussnet.com.au> wrote in message
news:jvlfgvc8s4624hug3vja0l01dp3j2pfsq2@4ax.com...

** Paralleled power diodes work fine.


Not at all. Look closely at the knee in the diode characteristic and
then tell us how current can be evenly shared by two parallel diodes
with even a *slight* mismatch in the I-V curve.

** Just try it Frank - you have NOT tried it.

Get two 1N4004 diodes from the same batch ( like any manufacturer
would) and TRY it.

I have - so I know.

I made over 100 guitar amps with this 25 years ago - not ONE
diode failed.



.................. Phil

 

[The Real Andy]

"Phil Allison" <philallison@optusnet.com.au> wrote in message
news:3f07dd82$0$30817$afc38c87@news.optusnet.com.au...

"Franc Zabkar" <fzabkar@optussnet.com.au> wrote in message
news:jvlfgvc8s4624hug3vja0l01dp3j2pfsq2@4ax.com...


** Paralleled power diodes work fine.


Not at all. Look closely at the knee in the diode characteristic and
then tell us how current can be evenly shared by two parallel diodes
with even a *slight* mismatch in the I-V curve.


** Just try it Frank - you have NOT tried it.

Get two 1N4004 diodes from the same batch ( like any manufacturer
would) and TRY it.

I have - so I know.

I made over 100 guitar amps with this 25 years ago - not ONE
diode failed.

It may well work, but it is very poor design.

 

[Mike Harding]

On Sun, 6 Jul 2003 20:07:03 +1000, "The Real Andy"
<ihatehifitrolls@yahoo.com.au> wrote:

"Phil Allison" <philallison@optusnet.com.au> wrote in message
news:3f07dd82$0$30817$afc38c87@news.optusnet.com.au...

"Franc Zabkar" <fzabkar@optussnet.com.au> wrote in message
news:jvlfgvc8s4624hug3vja0l01dp3j2pfsq2@4ax.com...


** Paralleled power diodes work fine.


Not at all. Look closely at the knee in the diode characteristic and
then tell us how current can be evenly shared by two parallel diodes
with even a *slight* mismatch in the I-V curve.


** Just try it Frank - you have NOT tried it.

Get two 1N4004 diodes from the same batch ( like any manufacturer
would) and TRY it.

I have - so I know.

I made over 100 guitar amps with this 25 years ago - not ONE
diode failed.

It may well work, but it is very poor design.

Agreed.

Mike Harding

 

[Phil Allison]

"The Real Andy" <ihatehifitrolls@yahoo.com.au> wrote in message
news:3f07f4c5$0$728$afc38c87@news.optusnet.com.au...

"Phil Allison" <philallison@optusnet.com.au> wrote in message
news:3f07dd82$0$30817$afc38c87@news.optusnet.com.au...

"Franc Zabkar" <fzabkar@optussnet.com.au> wrote in message
news:jvlfgvc8s4624hug3vja0l01dp3j2pfsq2@4ax.com...


** Paralleled power diodes work fine.


Not at all. Look closely at the knee in the diode characteristic and
then tell us how current can be evenly shared by two parallel diodes
with even a *slight* mismatch in the I-V curve.


** Just try it Frank - you have NOT tried it.

Get two 1N4004 diodes from the same batch ( like any
manufacturer
would) and TRY it.

I have - so I know.

I made over 100 guitar amps with this 25 years ago - not ONE
diode failed.

It may well work, but it is very poor design.

** That seems to be a non sequitur.

Plus irrelevant.

However well up to Andy Pambys usual standard.



......... Phil

 

[Phil Allison]

"Mike Harding" <mike_harding1@hotmail.com> wrote in message

It may well work, but it is very poor design.

Agreed.

Mike Harding

** Only an arsehole IT fuckwit like Harding could agree with Andy Pamby's
shite.



............... Phil

 

[Franc Zabkar]

On Sun, 6 Jul 2003 18:27:53 +1000, "Phil Allison"
<philallison@optusnet.com.au> put finger to keyboard and composed:

"Franc Zabkar" <fzabkar@optussnet.com.au> wrote in message
news:jvlfgvc8s4624hug3vja0l01dp3j2pfsq2@4ax.com...


** Paralleled power diodes work fine.


Not at all. Look closely at the knee in the diode characteristic and
then tell us how current can be evenly shared by two parallel diodes
with even a *slight* mismatch in the I-V curve.


** Just try it Frank - you have NOT tried it.

The only time one can legitimately parallel two or more PN junctions,
if ever, is when they are on the same die. In any case, a better
illustration of this principle would be to connect a bank of LEDs in
parallel. Some will be significantly brighter than others.

Get two 1N4004 diodes from the same batch ( like any manufacturer
would) and TRY it.

How would I measure the current in each diode without introducing load
sharing resistors (which would disturb the circuit being measured)?
And remember, it's not the shallow bottom end of the knee we are
talking about, it's the steep top end that is of interest.

I have - so I know.

I made over 100 guitar amps with this 25 years ago ...

A 26 (?) year old novice could be forgiven for making this sort of
mistake, but not a professional design engineer.

- not ONE diode failed.

Lucky you. I wasn't so fortunate. BTW, do you connect zeners in
parallel as well?


- Franc Zabkar
--
Please remove one 's' from my address when replying by email.

 

[The Real Andy]

"Phil Allison" <philallison@optusnet.com.au> wrote in message
news:3f07f92f$0$30821$afc38c87@news.optusnet.com.au...

"The Real Andy" <ihatehifitrolls@yahoo.com.au> wrote in message
news:3f07f4c5$0$728$afc38c87@news.optusnet.com.au...
"Phil Allison" <philallison@optusnet.com.au> wrote in message
news:3f07dd82$0$30817$afc38c87@news.optusnet.com.au...

"Franc Zabkar" <fzabkar@optussnet.com.au> wrote in message
news:jvlfgvc8s4624hug3vja0l01dp3j2pfsq2@4ax.com...


** Paralleled power diodes work fine.


Not at all. Look closely at the knee in the diode characteristic and
then tell us how current can be evenly shared by two parallel diodes
with even a *slight* mismatch in the I-V curve.


** Just try it Frank - you have NOT tried it.

Get two 1N4004 diodes from the same batch ( like any
manufacturer
would) and TRY it.

I have - so I know.

I made over 100 guitar amps with this 25 years ago - not
ONE
diode failed.

It may well work, but it is very poor design.



** That seems to be a non sequitur.

I think not, seems like a fair statement to me, i'm sure many others will
agree.

Plus irrelevant.

Relevant it is. Anyone who designs a circuit with components that rely on
batch tolerance should be termed a novice, ie. someone who has no idea about
what they are doing. It is very simpe to use the same concept, and make it
work without needing to worry about batch tolerance. A professional designer
will know how to do this. It doesn't take a genius to work it out.

However well up to Andy Pambys usual standard.

I see you have retalited with personal attacks, i guess that means i am
right.

Andy

 

[Phil Allison]

"The Real Andy" <ihatehifitrolls@yahoo.com.au> wrote in message
news:3f08b1c8$0$5428$afc38c87@news.optusnet.com.au...

"Phil Allison" <philallison@optusnet.com.au> wrote in message


It may well work, but it is very poor design.


** That seems to be a non sequitur.

I think not, seems like a fair statement to me, i'm sure many others will
agree.

** If it works well then ipso faco it is not poor design.



Anyone who designs a circuit with components that rely on

batch tolerance should be termed a novice,

** Done all the time in analogue design.

Matched input fets, matched output devices operating in
parallel - all batch matched.



ie. someone who has no idea aboutwhat they are doing.


** Get stuffed !!




It is very simpe to use the same concept, and make it

work without needing to worry about batch tolerance.

** Get stuffed !!



A professional designer

will know how to do this. It doesn't take a genius to work it out.

** What pompous drivel - but normal for Andy.

However well up to Andy Pambys usual standard.

I see you have retalited with personal attacks, i guess that means i am
right.

** Dream on wanker.



........... Phil

 

[Phil Allison]

"Franc Zabkar" <fzabkar@optussnet.com.au> wrote in message
news:dp5hgv8k9tch49chmvqpifnppvqcp705m2@4ax.com...

On Sun, 6 Jul 2003 18:27:53 +1000, "Phil Allison"
philallison@optusnet.com.au> put finger to keyboard and composed:


"Franc Zabkar" <fzabkar@optussnet.com.au> wrote in message
news:jvlfgvc8s4624hug3vja0l01dp3j2pfsq2@4ax.com...


** Paralleled power diodes work fine.


Not at all. Look closely at the knee in the diode characteristic and
then tell us how current can be evenly shared by two parallel diodes
with even a *slight* mismatch in the I-V curve.


** Just try it Frank - you have NOT tried it.


Get two 1N4004 diodes from the same batch ( like any
manufacturer
would) and TRY it.


How would I measure the current in each diode without introducing load
sharing resistors (which would disturb the circuit being measured)?

** Huh ? How about comparing temperature ?

How about measuring the drop across a few inches of wire ( ie a
few milliohms) .

In my case the 1A diode leads were twisted to ensure temp sharing.

I have - so I know.

I made over 100 guitar amps with this 25 years ago ...

A 26 (?) year old novice could be forgiven for making this sort of
mistake, but not a professional design engineer.

** Mistakes are things that DONT work - Frank.

I was well aware of the diode sharing issue back then.



............... Phil

 

[The Real Andy]

"Phil Allison" <philallison@optusnet.com.au> wrote in message
news:3f08c0e7$0$30822$afc38c87@news.optusnet.com.au...

"The Real Andy" <ihatehifitrolls@yahoo.com.au> wrote in message
news:3f08b1c8$0$5428$afc38c87@news.optusnet.com.au...
"Phil Allison" <philallison@optusnet.com.au> wrote in message


It may well work, but it is very poor design.

** That seems to be a non sequitur.

I think not, seems like a fair statement to me, i'm sure many others
will
agree.

** If it works well then ipso faco it is not poor design.

If thats the case, then those speakers that came with your computer are not
poor design, they work. Becasue it works, doesn't mean its good design, you
know this yourself. BTW, i think you mean "ipso facto".

Anyone who designs a circuit with components that rely on
batch tolerance should be termed a novice,

** Done all the time in analogue design.

Matched input fets, matched output devices operating in
parallel - all batch matched.

Done all the time by hifi designers who design for the idiots that think
they can hear the difference.

** Get stuffed !!
** Get stuffed !!
** What pompous drivel - but normal for Andy.
However well up to Andy Pambys usual standard.
** Dream on wanker.

I see you have retalited with personal attacks, i guess that means i am
right.

I rest my case.

 

[Phil Allison]

"The Real Andy" <ihatehifitrolls@yahoo.com.au> wrote in message
news:3f09018e$0$5434$afc38c87@news.optusnet.com.au...

"Phil Allison" <philallison@optusnet.com.au> wrote in message


It may well work, but it is very poor design.

** That seems to be a non sequitur.

I think not, seems like a fair statement to me, i'm sure many others
will
agree.

** If it works well then ipso faco it is not poor design.

If thats the case, then those speakers that came with your computer are
not
poor design, they work. Becasue it works, doesn't mean its good design,
you
know this yourself.

** Is that the best you can do ??

Anyone who designs a circuit with components that rely on
batch tolerance should be termed a novice,

** Done all the time in analogue design.

Matched input fets, matched output devices operating in
parallel - all batch matched.

Done all the time by hifi designers who design for the idiots that think
they can hear the difference.

** Is that the best you can do ??

I rest my case.

** You never had one in the first place.



.......... Phil

 

[Franc Zabkar]

On Mon, 7 Jul 2003 10:42:48 +1000, "Phil Allison"
<philallison@optusnet.com.au> put finger to keyboard and composed:

** Paralleled power diodes work fine.

Remember this post, Phil?
http://groups.google.com/groups?hl=en&lr=&ie=UTF-8&selm=BTjs7.39391%24Bs5.25212%40newsfeeds.bigpond.com

======================================================================
Franc Zabkar <franczabkar@dinggoblue.net.au> wrote in message
news:3bb0f8b6.1763826@news.dingoblue.net.au...

Hmmm, the words "Sansui amp" and "parallel" have jogged my memory. I
recently repaired a Sansui model AU-4900 amp whose only fault was a
failure of several diodes in the power supply rectifier. This was not
surprising given that the designer had constructed a bridge using
eight 1A diodes arranged in four parallel pairs. I always thought that
Sansui was an up-market brand, but after seeing this basic design
error it appears that they are no better than the rest.

Franc, I have seen them do much, much worse.
Regards, Phil
======================================================================

It seems you alter your stance to suit the occasion.


- Franc Zabkar
--
Please remove one 's' from my address when replying by email.

 

[Phil Allison]

"Franc Zabkar" <fzabkar@optussnet.com.au> wrote in message
news:8ecigv0bcih9shpbmcll5vm1ogfoqqsalm@4ax.com...

It seems you alter your stance to suit the occasion.

** You will have to explain yourself here Franc.

Making wild assertions over and over is no substitute for real
evidence.



........... Phil

 

[Trevor Wilson]

"Phil Allison" <philallison@optusnet.com.au> wrote in message
news:3f0938b2$0$5431$afc38c87@news.optusnet.com.au...

"Trevor Wilson" <trevor@rageaudio.com.au> wrote in message
news:3f09365e$1@news.comindico.com.au...


**What worse things have you seen them do, Phil?


** The alleged "crime" of using power diodes in parallel is very
minor - if a crime at all.

**It's just characteristic of the company. Which was my point in the first
place.

My remark must be seen in that light.

**I did.

The plastic chassis with inadequate heatsinks every semi over
run
to the wall amps they released in the 80s constitutes a hanging offense
IMO.

**Wasn't that part of my original complaint about Sansui amps? Pastic
chassis parts and stupid output device mounting systems (amongst a whole
host of other stuff). It's what I said in the first place. Sansui was at the
forefront of churning out crappy hi fi, during the late 70s and 80s. That
was when they destroyed their reputation.


--
Trevor Wilson
www.rageaudio.com.au

 

[Phil Allison]

"Trevor Wilson" <trevor@rageaudio.com.au> wrote in message
news:3f094406$1@news.comindico.com.au...

"Phil Allison" <philallison@optusnet.com.au> wrote in message
news:3f0938b2$0$5431$afc38c87@news.optusnet.com.au...

"Trevor Wilson" <trevor@rageaudio.com.au> wrote in message
news:3f09365e$1@news.comindico.com.au...


**What worse things have you seen them do, Phil?


** The alleged "crime" of using power diodes in parallel is very
minor - if a crime at all.

**It's just characteristic of the company. Which was my point in the first
place.


My remark must be seen in that light.

**I did.


The plastic chassis with inadequate heatsinks every semi over
run
to the wall amps they released in the 80s constitutes a hanging offense
IMO.

**Wasn't that part of my original complaint about Sansui amps? Pastic
chassis parts and stupid output device mounting systems (amongst a whole
host of other stuff). It's what I said in the first place. Sansui was at
the
forefront of churning out crappy hi fi, during the late 70s and 80s. That
was when they destroyed their reputation.

** You likely saw the offending Sansui models way earlier than other
techs like myself and Bob.

Late 70s release translates into early 80s in the experience of techs
who are not doing warranty.



............. Phil

 

[The Real Andy]

"Phil Allison" <philallison@optusnet.com.au> wrote in message
news:3f090684$0$729$afc38c87@news.optusnet.com.au...

"The Real Andy" <ihatehifitrolls@yahoo.com.au> wrote in message
news:3f09018e$0$5434$afc38c87@news.optusnet.com.au...
"Phil Allison" <philallison@optusnet.com.au> wrote in message


It may well work, but it is very poor design.

** That seems to be a non sequitur.

I think not, seems like a fair statement to me, i'm sure many others
will
agree.

** If it works well then ipso faco it is not poor design.

If thats the case, then those speakers that came with your computer are
not
poor design, they work. Becasue it works, doesn't mean its good design,
you
know this yourself.

** Is that the best you can do ??

You have given plenty of examples of poorly designed equipment in this NG
that worked. The speaker example was the first one that came to my mind. You
are either a hypocrit or you have no concept of electronics design in which
case you could be forgiven for thinking that a working circuit is not a poor
design

 

[Phil Allison]

"The Real Andy" <ihatehifitrolls@yahoo.com.au> wrote in message
news:3f097539$0$30820$afc38c87@news.optusnet.com.au...

"Phil Allison" <philallison@optusnet.com.au> wrote in message
news:3f090684$0$729$afc38c87@news.optusnet.com.au...

"The Real Andy" <ihatehifitrolls@yahoo.com.au> wrote in message
news:3f09018e$0$5434$afc38c87@news.optusnet.com.au...
"Phil Allison" <philallison@optusnet.com.au> wrote in message


It may well work, but it is very poor design.

** That seems to be a non sequitur.

I think not, seems like a fair statement to me, i'm sure many
others
will
agree.

** If it works well then ipso faco it is not poor design.

If thats the case, then those speakers that came with your computer
are
not
poor design, they work. Becasue it works, doesn't mean its good
design,
you
know this yourself.

** Is that the best you can do ??

You have given plenty of examples of poorly designed equipment in this NG
that worked. The speaker example was the first one that came to my mind.
You
are either a hypocrit or you have no concept of electronics design in
which
case you could be forgiven for thinking that a working circuit is not a
poor
design

** Seems it was.

Oh well.


................. Phil

 

[The Real Andy]

"Phil Allison" <philallison@optusnet.com.au> wrote in message
news:3f097790$0$30568$afc38c87@news.optusnet.com.au...

** Seems it was.

Oh well.


................ Phil

Such a smug reply..............

 

[Phil Allison]

"The Real Andy" <ihatehifitrolls@yahoo.com.au> wrote in message
news:3f09fc6d$0$26635$afc38c87@news.optusnet.com.au...

"Phil Allison" <philallison@optusnet.com.au> wrote in message
news:3f097790$0$30568$afc38c87@news.optusnet.com.au...
** Seems it was.

Oh well.


................ Phil

Such a smug reply..............

** Which is one itself.



........... Phil