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Dave Plowman (News) Dave Plowman (News) is offline
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Default SSM 2017

I have a home made amp in the workshop which gets heavy use. Since the end
of the last century.

It has balanced inputs, and for some reasons lost in the mists of time, I
used SSM 2017. Probably because I had loads.

On powering up at the end of last week, both had died. It has a +/- 15v
regulated PS entirely separate from the power amp - which appears fine. It
also feeds the pre-amp, and that is ok.

Only odd thing was heavy lightening we had on Thursday night - quite the
most spectacular I've seen in London. But the amp was switched off during
that - and nothing else in a house full of electronics seems to have
suffered.

Bit of a mystery.

--
*Gravity is a myth, the earth sucks *

Dave Plowman London SW
To e-mail, change noise into sound.
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Jay Ts[_4_] Jay Ts[_4_] is offline
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Default SSM 2017

On Wed, 23 Jul 2014, Dave Plowman (News) wrote:
I have a home made amp in the workshop which gets heavy use. Since the
end of the last century.

It has balanced inputs, and for some reasons lost in the mists of time,
I used SSM 2017. Probably because I had loads.

On powering up at the end of last week, both had died. It has a +/- 15v
regulated PS entirely separate from the power amp - which appears fine.
It also feeds the pre-amp, and that is ok.

Only odd thing was heavy lightening we had on Thursday night - quite the
most spectacular I've seen in London. But the amp was switched off
during that - and nothing else in a house full of electronics seems to
have suffered.

Bit of a mystery.


Do you remember the last time you had it turned on? Maybe it was damaged
before being powered off, and you didn't notice.

If you get a chance to analyze the problem, it might be interesting to
learn what failed.

For now, just a guess based on my own recent experience:

One thing about the SSM2017 and similar chips is that you need diodes
from the inputs to the plus and minus power supplies to protect against
transients. (For example, if phantom power for a mic preamp is turned on
when the XLR connector is pulled out, the transient that appeas on the
chip's inputs is much higher than the absolute maximum rating of the
chip.)

I had an INA163 chip fail in my M-Audio DMP3, and it was because the
designer failed to include four $0.02 diodes per channel to protect the
INA163, which cost over $7.50 to replace. The 1N4148 diodes are shown in
an example mic preamp circuit in the manufacturer's datasheet, with this
included in the discussion: "For additional input protection against ESD
and hot-plugging, four INA4148 [sic.] diodes may be connected from the
input to supply lines." Perhaps the word "may" was interpreted as
permission to omit them.

I guess that's what I get for spending only $100 per channel for a mic
pre. Fortunately, after I replaced the INA163, adding the diodes was
not hard.
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geoff geoff is offline
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Default SSM 2017

On 24/07/2014 4:02 a.m., Dave Plowman (News) wrote:
I have a home made amp in the workshop which gets heavy use. Since the end
of the last century.

It has balanced inputs, and for some reasons lost in the mists of time, I
used SSM 2017. Probably because I had loads.

On powering up at the end of last week, both had died. It has a +/- 15v
regulated PS entirely separate from the power amp - which appears fine. It
also feeds the pre-amp, and that is ok.

Only odd thing was heavy lightening we had on Thursday night - quite the
most spectacular I've seen in London. But the amp was switched off during
that - and nothing else in a house full of electronics seems to have
suffered.

Bit of a mystery.



I generally find TL0xx to be very fragile.

geoff
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Dave Plowman (News) Dave Plowman (News) is offline
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Default SSM 2017

In article ,
Jay Ts wrote:
Do you remember the last time you had it turned on? Maybe it was damaged
before being powered off, and you didn't notice.


No - it's normally playing the radio.

If you get a chance to analyze the problem, it might be interesting to
learn what failed.


For now, just a guess based on my own recent experience:


One thing about the SSM2017 and similar chips is that you need diodes
from the inputs to the plus and minus power supplies to protect against
transients. (For example, if phantom power for a mic preamp is turned on
when the XLR connector is pulled out, the transient that appeas on the
chip's inputs is much higher than the absolute maximum rating of the
chip.)


Yes - I do that when using it as a mic pre-amp. But this is fed at (near)
line level. It is also regularly hot plugged when I'm using it to test
things with a balanced output. Must have been done hundreds of times
without problems.

I had an INA163 chip fail in my M-Audio DMP3, and it was because the
designer failed to include four $0.02 diodes per channel to protect the
INA163, which cost over $7.50 to replace. The 1N4148 diodes are shown in
an example mic preamp circuit in the manufacturer's datasheet, with
this included in the discussion: "For additional input protection
against ESD and hot-plugging, four INA4148 [sic.] diodes may be
connected from the input to supply lines." Perhaps the word "may" was
interpreted as permission to omit them.


I guess that's what I get for spending only $100 per channel for a mic
pre. Fortunately, after I replaced the INA163, adding the diodes was
not hard.


Quite. I have a third one in the same enclosure used as a mic amp with
phantom power, for mic testing, and powered from the same PS. It is ok. It
does have the diodes. It is in a steel case to help with screening,
though.

If one had failed I'd have put it down to chance. But both at exactly the
same time (and after 15 years or so) is just plain weird, unless the PS
had thrown a wobbly.

--
*Of course I'm against sin; I'm against anything that I'm too old to enjoy.

Dave Plowman London SW
To e-mail, change noise into sound.
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Mike Rivers[_2_] Mike Rivers[_2_] is offline
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Default SSM 2017

On 7/23/2014 6:42 PM, Dave Plowman (News) wrote:
If one had failed I'd have put it down to chance. But both at exactly the
same time (and after 15 years or so) is just plain weird, unless the PS
had thrown a wobbly.


You mentioned that there was a thunderstorm prior to your discovering
the failure. That could have been the cause. Lightning can induce short
term power surges by putting a couple of thousand volts on to the power
ground when a lightning bolt hits the earth. That can attack your gear
through the power supply even if it's turned off.

--
For a good time, visit http://mikeriversaudio.wordpress.com


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Dave Plowman (News) Dave Plowman (News) is offline
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Default SSM 2017

In article ,
Mike Rivers wrote:
On 7/23/2014 6:42 PM, Dave Plowman (News) wrote:
If one had failed I'd have put it down to chance. But both at exactly the
same time (and after 15 years or so) is just plain weird, unless the PS
had thrown a wobbly.


You mentioned that there was a thunderstorm prior to your discovering
the failure. That could have been the cause. Lightning can induce short
term power surges by putting a couple of thousand volts on to the power
ground when a lightning bolt hits the earth. That can attack your gear
through the power supply even if it's turned off.


Yes - it's a nice tidy explanation for the two failing at the same time -
after all those years and the replacements are working normally.

Although just why these failed when everything else is ok - and it's not
the first thunderstorm I've seen here, although one of the most
spectacular.

--
*Who is this General Failure chap anyway - and why is he reading my HD? *

Dave Plowman London SW
To e-mail, change noise into sound.
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Sean Conolly Sean Conolly is offline
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Default SSM 2017

"Dave Plowman (News)" wrote in message
...
In article ,
Mike Rivers wrote:
On 7/23/2014 6:42 PM, Dave Plowman (News) wrote:
If one had failed I'd have put it down to chance. But both at exactly
the
same time (and after 15 years or so) is just plain weird, unless the PS
had thrown a wobbly.


You mentioned that there was a thunderstorm prior to your discovering
the failure. That could have been the cause. Lightning can induce short
term power surges by putting a couple of thousand volts on to the power
ground when a lightning bolt hits the earth. That can attack your gear
through the power supply even if it's turned off.


Yes - it's a nice tidy explanation for the two failing at the same time -
after all those years and the replacements are working normally.

Although just why these failed when everything else is ok - and it's not
the first thunderstorm I've seen here, although one of the most
spectacular.


It depends on how close you are to where the lightning goes to ground. A few
years back we had a bolt that hit about 50 yards from our home and took out
several pieces of gear. Almost took out one of my son's friends who was
stupidly playing a video game with a wired controller during the storm. It
took a few hours for his arm to recover from the shock.

I've always demanded that everything gets unplugged during a lightning storm
if possible - and the cord is pulled away from the socket. Had a computer
fry when my son unplugged the cord but left it hanging an inch away from the
socket - the burn marks on the socket told the story.

Sean


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Scott Dorsey Scott Dorsey is offline
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Default SSM 2017

Dave Plowman (News) wrote:

One thing about the SSM2017 and similar chips is that you need diodes
from the inputs to the plus and minus power supplies to protect against
transients. (For example, if phantom power for a mic preamp is turned on
when the XLR connector is pulled out, the transient that appeas on the
chip's inputs is much higher than the absolute maximum rating of the
chip.)


Yes - I do that when using it as a mic pre-amp. But this is fed at (near)
line level. It is also regularly hot plugged when I'm using it to test
things with a balanced output. Must have been done hundreds of times
without problems.


You still need those diodes even when there's no phantom power involved,
because there is minimal static protection on the front end, and with repeated
static zaps, eventually the small protection diodes on chip will fail.

It's a cumulative effect over years, and the INA103 has similar issues.

You might have damage from a ground loop and a nearby lightning strike inducing
just a little too much voltage into an input that's already on the way out.

If you send me the chip I can pop it open and tell you for sure how it failed.
I'll be in London in a couple weeks as well.
--scott

--
"C'est un Nagra. C'est suisse, et tres, tres precis."
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Dave Plowman (News) Dave Plowman (News) is offline
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Default SSM 2017

In article ,
Scott Dorsey wrote:
Yes - I do that when using it as a mic pre-amp. But this is fed at
(near) line level. It is also regularly hot plugged when I'm using it
to test things with a balanced output. Must have been done hundreds of
times without problems.


You still need those diodes even when there's no phantom power involved,
because there is minimal static protection on the front end, and with
repeated static zaps, eventually the small protection diodes on chip
will fail.


Ah. Sadly, it's all now back together and working fine. And not the
easiest of jobs to remove and strip down.

It's a cumulative effect over years, and the INA103 has similar issues.


You might have damage from a ground loop and a nearby lightning strike
inducing just a little too much voltage into an input that's already on
the way out.


I've got plenty spares, so if it happens again I'll add the diodes. Have
put a note on my schematic to that effect.

If you send me the chip I can pop it open and tell you for sure how it
failed.


Sadly, went out in the rubbish, but thanks for the offer.

I'll be in London in a couple weeks as well.


Enjoy your stay. The weather is near perfect at the moment. Lets hope it
continues.

--
*A closed mouth gathers no feet.*

Dave Plowman London SW
To e-mail, change noise into sound.
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Don Pearce[_3_] Don Pearce[_3_] is offline
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On 24 Jul 2014 09:49:23 -0400, (Scott Dorsey) wrote:

Dave Plowman (News) wrote:

One thing about the SSM2017 and similar chips is that you need diodes
from the inputs to the plus and minus power supplies to protect against
transients. (For example, if phantom power for a mic preamp is turned on
when the XLR connector is pulled out, the transient that appeas on the
chip's inputs is much higher than the absolute maximum rating of the
chip.)


Yes - I do that when using it as a mic pre-amp. But this is fed at (near)
line level. It is also regularly hot plugged when I'm using it to test
things with a balanced output. Must have been done hundreds of times
without problems.


You still need those diodes even when there's no phantom power involved,
because there is minimal static protection on the front end, and with repeated
static zaps, eventually the small protection diodes on chip will fail.

It's a cumulative effect over years, and the INA103 has similar issues.

You might have damage from a ground loop and a nearby lightning strike inducing
just a little too much voltage into an input that's already on the way out.

If you send me the chip I can pop it open and tell you for sure how it failed.
I'll be in London in a couple weeks as well.
--scott


I've recently completed a design for the Echostar corp in USA. It
included a switched-mode power supply. Echostar put a very high spec
on lightning surge protection. 500 strikes of alternating polarity,
6000V at 3000A. That's 18 mega watts per strike. The equipment has to
be functioning within spec at the end of that.

Protection includes a gas discharge tube and a pair of huge varistors.
That is followed by star grounding to prevent voltage buildup along
series lines. Instills a great design discipline.

Seems a useful spec though - never had a failure even in the stormy
bits of the mid west.

d


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mcp6453[_2_] mcp6453[_2_] is offline
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Default SSM 2017

On 7/24/2014 9:49 AM, Scott Dorsey wrote:

You still need those diodes even when there's no phantom power involved,
because there is minimal static protection on the front end, and with repeated
static zaps, eventually the small protection diodes on chip will fail.

It's a cumulative effect over years, and the INA103 has similar issues.

You might have damage from a ground loop and a nearby lightning strike inducing
just a little too much voltage into an input that's already on the way out.

If you send me the chip I can pop it open and tell you for sure how it failed.
I'll be in London in a couple weeks as well.


There are plenty of SSM2017's on eBay, but a lot of them are from China. Are these real SSM2017's, or are they fakes?

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Scott Dorsey Scott Dorsey is offline
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Default SSM 2017

mcp6453 wrote:
On 7/24/2014 9:49 AM, Scott Dorsey wrote:

You still need those diodes even when there's no phantom power involved,
because there is minimal static protection on the front end, and with repeated
static zaps, eventually the small protection diodes on chip will fail.

It's a cumulative effect over years, and the INA103 has similar issues.

You might have damage from a ground loop and a nearby lightning strike inducing
just a little too much voltage into an input that's already on the way out.

If you send me the chip I can pop it open and tell you for sure how it failed.
I'll be in London in a couple weeks as well.


There are plenty of SSM2017's on eBay, but a lot of them are from China. Are these real SSM2017's, or are they fakes?


I cannot imagine people would be bothered to make fake SSM2017s, but these
days you can never be sure. I mean, we are getting fake 2N3055s for God's
sake. And fake CAT5!

Buy from Mouser or Digi-Key, don't ever buy electronics parts from dodgy
dealers on Ebay. And if you're replacing an SSM2017, try buying the
pin-compatible replacement from THAT Semiconductor instead. It sounds
better to my ears, and doesn't cost any more. Burr-Brown also has a
replacement, the INA163, but I like the THAT one better.
--scott

--
"C'est un Nagra. C'est suisse, et tres, tres precis."
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Jay Ts[_4_] Jay Ts[_4_] is offline
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On Sat, 26 Jul 2014 21:38:23 -0400, mcp6453 wrote:

There are plenty of SSM2017's on eBay, but a lot of them are from China.
Are these real SSM2017's, or are they fakes?


I would assume they are counterfeit. It's the safest assumption, whether
true or not. Even if they have authentic parts, have they stored them and
will they ship them in proper ESD-safe packaging? If you send a message
to the seller in China and ask them, can they even reply in sensible
English?

I suggest you replace the SSM2017 with another chip. Look into the TI
INA217. Then you can purchase from a reputable distributor and know what
you are getting.

http://www.mouser.com/ds/2/405/sbos247b-125904.pdf

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On Sat, 26 Jul 2014, Scott Dorsey wrote:

And if you're replacing an SSM2017, try buying the
pin-compatible replacement from THAT Semiconductor instead.


The chips are THAT 1510 and THAT 1512:

http://www.thatcorp.com/datashts/THA..._Datasheet.pdf



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geoff geoff is offline
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Default SSM 2017

On 27/07/2014 2:49 p.m., Scott Dorsey wrote:


I cannot imagine people would be bothered to make fake SSM2017s, but these
days you can never be sure.


They don't. They make fakes 1458/741s or whatever and stencil SSM2017
onto them.

geoff



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Dave Plowman (News) Dave Plowman (News) is offline
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In article ,
mcp6453 wrote:
There are plenty of SSM2017's on eBay, but a lot of them are from China.
Are these real SSM2017's, or are they fakes?


If you've read the entire thread, you'd know they date from the last
century.

--
*WHY IS THERE AN EXPIRATION DATE ON SOUR CREAM?

Dave Plowman London SW
To e-mail, change noise into sound.
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