Today, I had a biggish Trace Idiot cross my bench. The owner's complaint was
that it produced a continuous buzz (the shop that had taken it in had
quizzed the owner about this, and they were adamant that it was a buzz
rather than a hum).

They claimed that it was unaffected by any of the controls on the amp,
except the "mute" button, which reduced this buzz, but only marginally.

I tried it, but apart from a slight mechanical buzz from the torroidal
transformer, whose bolt was not fully tightened, I could find no problem. I
phoned the shop to recheck the reported fault symptoms, and to see if it was
possible that it was the tranny buzz that the owner was hearing, but again,
the shop said that they had suggested this to the owner, but he was certain
that his buzz was coming from the speaker he had connected to it. Whilst I
was on the phone, I was idly poking at some very thin all-grey wire
interconnects that went between two boards stacked one above the other on
the back panel, and contained various effects send - receive jacks and level
controls, and the main board. If you tugged on one of them just right, the
sound actually went off - but still no buzz was produced. I followed the
wire bunch back to the rear- panel board, and was amazed to see the
termination block easily rock in the pcb. This was one of those slim white
blocks that looks for all the world like a plug / socket, until you look a
little closer, and see that it is just a termination for the wire bunch,
that solders straight into the board.

There are two of these on each of the two boards, so I removed both boards
from the rear panel to see what was going on. When I could see the
underside, I was stunned to see that all four blocks were just sitting in
'virgin' print. Not a jot of solder had ever been anywhere near any pin on
either of the two blocks, on either of the two boards. The actual 'pins' on
these blocks are made from a tail of metal that has been 'split' to form a
springy 'point'. Over the 8 or 10 of them that were in each block, they had
obviously provided enough friction to hang in the pcb holes, and enough
spring tension to make to the thru' plating in those holes. This amp is a
few years old, and is used regularly out on the road, and it is amazing that
this has never even caused the owner a problem with intermittency, let alone
falling out of the board completely.

What I don't understand though, is how this production error can have
occurred in the first place. I could perhaps understand that these
terminations had been called out for hand soldering as a pre-made cable
assembly, after stuffing and soldering of the rest of the board. It's then
fairly easy to see how the actual soldering could have been missed. However,
the board looked like it had undergone flow soldering, and had normal solder
mask over it. But the unsoldered contacts for the terminations were just
naked tinned pads, so how could these have been prevented from taking solder
during the flow soldering process ... ?

It's a mystery ... d:-\

Arfa

Arfa Daily wrote:
Today, I had a biggish Trace Idiot cross my bench. The owner's complaint was
that it produced a continuous buzz (the shop that had taken it in had
quizzed the owner about this, and they were adamant that it was a buzz
rather than a hum).

They claimed that it was unaffected by any of the controls on the amp,
except the "mute" button, which reduced this buzz, but only marginally.

I tried it, but apart from a slight mechanical buzz from the torroidal
transformer, whose bolt was not fully tightened, I could find no problem. I
phoned the shop to recheck the reported fault symptoms, and to see if it was
possible that it was the tranny buzz that the owner was hearing, but again,
the shop said that they had suggested this to the owner, but he was certain
that his buzz was coming from the speaker he had connected to it. Whilst I
was on the phone, I was idly poking at some very thin all-grey wire
interconnects that went between two boards stacked one above the other on
the back panel, and contained various effects send - receive jacks and level
controls, and the main board. If you tugged on one of them just right, the
sound actually went off - but still no buzz was produced. I followed the
wire bunch back to the rear- panel board, and was amazed to see the
termination block easily rock in the pcb. This was one of those slim white
blocks that looks for all the world like a plug / socket, until you look a
little closer, and see that it is just a termination for the wire bunch,
that solders straight into the board.

There are two of these on each of the two boards, so I removed both boards
from the rear panel to see what was going on. When I could see the
underside, I was stunned to see that all four blocks were just sitting in
'virgin' print. Not a jot of solder had ever been anywhere near any pin on
either of the two blocks, on either of the two boards. The actual 'pins' on
these blocks are made from a tail of metal that has been 'split' to form a
springy 'point'. Over the 8 or 10 of them that were in each block, they had
obviously provided enough friction to hang in the pcb holes, and enough
spring tension to make to the thru' plating in those holes. This amp is a
few years old, and is used regularly out on the road, and it is amazing that
this has never even caused the owner a problem with intermittency, let alone
falling out of the board completely.

What I don't understand though, is how this production error can have
occurred in the first place. I could perhaps understand that these
terminations had been called out for hand soldering as a pre-made cable
assembly, after stuffing and soldering of the rest of the board. It's then
fairly easy to see how the actual soldering could have been missed. However,
the board looked like it had undergone flow soldering, and had normal solder
mask over it. But the unsoldered contacts for the terminations were just
naked tinned pads, so how could these have been prevented from taking solder
during the flow soldering process ... ?

It's a mystery ... d:-\

I've seen connections like this before- they appear to be solder-free
where the pins or stakes (the ones I saw were square) were just pressed
into plated through holes. I never figured it what the deal with those
were, but it seemed intentional. Why would one solder hundreds of other
joints, but skip just the weird connectors? If they did have a touch of
solder at the edges of the pins, why were the rest of the voids never
filled in?

Arfa Daily wrote:
Today, I had a biggish Trace Idiot cross my bench.

Sounds like the result of some kind of chemical assay...

0.3% Dummy
0.1% Fool
Trace Idiot

What I don't understand though, is how this production error can have
occurred in the first place.

I was going to blame a Chinese orphan having a bad day, but their Web
site says "Designed in Great Britain, assembled in the USA". Which is
an interesting division of labor.

However, the board looked like it had undergone flow soldering, and
had normal solder mask over it. But the unsoldered contacts for the
terminations were just naked tinned pads, so how could these have been
prevented from taking solder during the flow soldering process ... ?

Sometimes parts of the boards are taped off before they go through wave
soldering. If you dunked this whole board, some of the holes for the
ribbon cable would probably get filled with solder, which means somebody
would have to clean them out before they could install and hand-solder
the ribbon cable. Putting a piece of tape over the ribbon cable holes
means that they stay solder-free, ready for someone to hand-solder them
(or not, in this case). Another case would be something like a PC
expansion card, where the edge connector "fingers" would get taped off
before soldering.

3M has Kapton tape (5413 among others) that they specifically market for
this application and it's probably available from others as well.

Matt Roberds

I was going to blame a Chinese orphan having a bad day, but their Web
site says "Designed in Great Britain, assembled in the USA". Which is
an interesting division of labor.


** The Trace Elliot company has gone through several big changes.

Their factor in Essex closed in about 2002, since when the few remaining
products have been made in the USA, now by Peavey Electronics.

http://en.wikipedia.org/wiki/Trace_Elliot

Since AF will not say which pile of TE **** he has we have no idea where
it was made.


..... Phil

On 29/03/2014 06:00, Cydrome Leader wrote:

I've seen connections like this before- they appear to be solder-free
where the pins or stakes (the ones I saw were square) were just pressed
into plated through holes. I never figured it what the deal with those
were, but it seemed intentional. Why would one solder hundreds of other
joints, but skip just the weird connectors? If they did have a touch of
solder at the edges of the pins, why were the rest of the voids never
filled in?



Dave discusses these connections when doing an airbag controller
teardown and says that they are designed not to be soldered because it
creates a more reliable connection.

https://www.youtube.com/watch?v=kcxw...ilpage#t=17 6
if interested.

wrote in message ...

Sometimes parts of the boards are taped off before they go through
wave soldering. If you dunked this whole board, some of the holes
for the ribbon cable would probably get filled with solder, which means
somebody would have to clean them out before they could install and
hand-solder the ribbon cable.

You'd think the person who installed the cable would be the same person who
soldered it.

"Phil Allison" wrote in message
...




I was going to blame a Chinese orphan having a bad day, but their Web
site says "Designed in Great Britain, assembled in the USA". Which is
an interesting division of labor.


** The Trace Elliot company has gone through several big changes.

Their factor in Essex closed in about 2002, since when the few remaining
products have been made in the USA, now by Peavey Electronics.

http://en.wikipedia.org/wiki/Trace_Elliot

Since AF will not say which pile of TE **** he has we have no idea where
it was made.


.... Phil


It's not that I won't say - I just inadvertently omitted to. It was, in
fact, an AH1000-12GP12.

The story of how Peavey became involved is quite an interesting one. The
original Trace company went pear-shaped when all of their key employees
including designers, upped sticks and left to form Trashdown. That left a
cleaner, a van driver and the accounts girl at Trace ...

Gibson in America bought the Trace Idiot name, but sat on it for a couple of
years, before flogging it on to Peavey, by which time, any reputation that
Trace had enjoyed, had evaporated away ...

Eventually, Peavey brought out a range of equipment under the Trace name,
but it suffered a lot of production and after sales problems, and this
apparently just about finished off the Trace name as having any credibility
at all. GM audio remained somehow connected to the name in this country -
repairs maybe ? GM stood for Gary something - Mason, maybe. I believe he was
one of the original people from the Trace company, but that might be wrong.

I spoke to the owner of the shop that this came in via, and he is of the
firm belief that this amp dates from before the original break up, so is a
genuine all-British Trace, rather than any kind of badge job.

Arfa

It is common to get buzz when audio grounds fail open and depending on the connected equipment the buzz may manifest or not. It is very likely these unsoldered connections are the cause of an intermittent buzz.

"Arfa Daily" wrote in message ...



"Phil Allison" wrote in message
...




I was going to blame a Chinese orphan having a bad day, but their Web
site says "Designed in Great Britain, assembled in the USA". Which is
an interesting division of labor.


** The Trace Elliot company has gone through several big changes.

Their factor in Essex closed in about 2002, since when the few remaining
products have been made in the USA, now by Peavey Electronics.

http://en.wikipedia.org/wiki/Trace_Elliot

Since AF will not say which pile of TE **** he has we have no idea where
it was made.


.... Phil


It's not that I won't say - I just inadvertently omitted to. It was, in
fact, an AH1000-12GP12.

The story of how Peavey became involved is quite an interesting one. The
original Trace company went pear-shaped when all of their key employees
including designers, upped sticks and left to form Trashdown. That left a
cleaner, a van driver and the accounts girl at Trace ...

Gibson in America bought the Trace Idiot name, but sat on it for a couple of
years, before flogging it on to Peavey, by which time, any reputation that
Trace had enjoyed, had evaporated away ...

Eventually, Peavey brought out a range of equipment under the Trace name,
but it suffered a lot of production and after sales problems, and this
apparently just about finished off the Trace name as having any credibility
at all. GM audio remained somehow connected to the name in this country -
repairs maybe ? GM stood for Gary something - Mason, maybe. I believe he was
one of the original people from the Trace company, but that might be wrong.

I spoke to the owner of the shop that this came in via, and he is of the
firm belief that this amp dates from before the original break up, so is a
genuine all-British Trace, rather than any kind of badge job.

Arfa




I've seen a couple of the "new" trace power amps, and they are SMPS class D
chinese production line ****e, again.
Both had blown both power amp and power supply, and I couldn't/wouldn't fix
them.
I think they were 500 Watters, but possibly 350.

Nightmare.


The one you have would be old school.
If you look on the power amp PCB's you should find the name "Clive Button".
He designed most of the old stuff, as well as quite a few freelance odds and
sods for other manufacturers, e.g. Laney.


Cheers,


Gareth.

"Arfa Daily"

It's not that I won't say - I just inadvertently omitted to. It was, in
fact, an AH1000-12GP12.

The story of how Peavey became involved is quite an interesting one. The
original Trace company went pear-shaped when all of their key employees
including designers, upped sticks and left to form Trashdown. That left a
cleaner, a van driver and the accounts girl at Trace ...

Gibson in America bought the Trace Idiot name, but sat on it for a couple
of years, before flogging it on to Peavey, by which time, any reputation
that Trace had enjoyed, had evaporated away ...

Eventually, Peavey brought out a range of equipment under the Trace name,
but it suffered a lot of production and after sales problems, and this
apparently just about finished off the Trace name as having any
credibility at all. GM audio remained somehow connected to the name in
this country - repairs maybe ? GM stood for Gary something - Mason, maybe.
I believe he was one of the original people from the Trace company, but
that might be wrong.

I spoke to the owner of the shop that this came in via, and he is of the
firm belief that this amp dates from before the original break up, so is a
genuine all-British Trace, rather than any kind of badge job.


** So, that ribbon terminator is not some fancy connector, it needed to be
soldered and was not.

That PCB has only pots, jacks etc so my bet is they were all hand inserted &
soldered some time prior to the ribbon cable being installed. It is
remarkable that it survived for over 10 years with no problem until now.

OTOH - I have seen examples where tinned wires were placed into the holes
in pins of 8 and 9 pin vales sockets and left unsoldered for years.

Then create the most god awful intermittents and vibration sensitive
noises.


..... Phil

"Jeroni Paul" wrote in message
...
It is common to get buzz when audio grounds fail open and depending on the
connected equipment the buzz may manifest or not. It is very likely these
unsoldered connections are the cause of an intermittent buzz.


I repair this stuff all day every day, so am well aware of the problems that
intermittent grounds can cause with regards to hum / buzz. Like you, I would
have thought that the unsoldered connections may well have been responsible
for the owner's problems, but I have to say that even before I soldered
these joints, despite the fact that the connectors rocked easily in the
boards, the only symptom that manifested was intermittent audio, and only
then when these terminations were severely provoked.

Still, if the problem returns, at least I know one thing that it's *not* ...
d:-)

Arfa

Lee wrote:
On 29/03/2014 06:00, Cydrome Leader wrote:

I've seen connections like this before- they appear to be solder-free
where the pins or stakes (the ones I saw were square) were just pressed
into plated through holes. I never figured it what the deal with those
were, but it seemed intentional. Why would one solder hundreds of other
joints, but skip just the weird connectors? If they did have a touch of
solder at the edges of the pins, why were the rest of the voids never
filled in?



Dave discusses these connections when doing an airbag controller
teardown and says that they are designed not to be soldered because it
creates a more reliable connection.

https://www.youtube.com/watch?v=kcxw...ilpage#t=17 6
if interested.

interesting. I think the last ones like this I saw were on processor
modules for rather expensive computers. They were probably about aa decade
old.