In article , Don Pearce
wrote:
On Fri, 18 Feb 2005 09:24:07 +0000 (GMT), Jim Lesurf
wrote:

In article , Don Pearce
wrote:


Fear not. Most of the 'bad' Ge transistors are probably long-dead. The
ones that have survived this long are the cast-iron ones. ;-)

Slainte,

Jim

So how far along the bottom of the bathtub curve do you reckon it might
be? Cruising gently, or about to strike the plug hole?

Dunno. Not even sure if we started from the 'tap end' or not... :-)

My only real experience with Ge devices has been with things like AL102's
in sets made back in the 1960's. These seemed to show initially high rates
of failures as you'd expect. Indeed, the term 'firecrackers' might be
relevant here... :-)

But others seem to have endured. Not sure, but it makes me suspect that
there were wild, uncontrolled variations from one device to another in
things like how good the thermal/mechanical bonding between device and case
may be. Thus my suspicion that the worst ones mostly blew up as a result
of breakdown or runaway decades ago, but that those which still work have
very good (for such devices!) thermal properties.

Sort of survival of the fittest. Shame we can't breed better devices by
leaving a pair of AL102's in a dark room. :-)

Slainte,

Jim

--
Electronics http://www.st-and.ac.uk/~www_pa/Scot...o/electron.htm
Audio Misc http://www.st-and.demon.co.uk/AudioMisc/index.html
Armstrong Audio http://www.st-and.demon.co.uk/Audio/armstrong.html
Barbirolli Soc. http://www.st-and.demon.co.uk/JBSoc/JBSoc.html

On Fri, 18 Feb 2005 15:41:41 +0000 (GMT), Jim Lesurf
wrote:

In article , Don Pearce
wrote:
On Fri, 18 Feb 2005 09:24:07 +0000 (GMT), Jim Lesurf
wrote:

In article , Don Pearce
wrote:


Fear not. Most of the 'bad' Ge transistors are probably long-dead. The
ones that have survived this long are the cast-iron ones. ;-)

Slainte,

Jim

So how far along the bottom of the bathtub curve do you reckon it might
be? Cruising gently, or about to strike the plug hole?

Dunno. Not even sure if we started from the 'tap end' or not... :-)

My only real experience with Ge devices has been with things like AL102's
in sets made back in the 1960's. These seemed to show initially high rates
of failures as you'd expect. Indeed, the term 'firecrackers' might be
relevant here... :-)

But others seem to have endured. Not sure, but it makes me suspect that
there were wild, uncontrolled variations from one device to another in
things like how good the thermal/mechanical bonding between device and case
may be. Thus my suspicion that the worst ones mostly blew up as a result
of breakdown or runaway decades ago, but that those which still work have
very good (for such devices!) thermal properties.

Sort of survival of the fittest. Shame we can't breed better devices by
leaving a pair of AL102's in a dark room. :-)

Slainte,

Jim

Even the small signal devices were fragile. Remember those little blue
anodized clothes pegs you clipped on the leads before you soldered
them? I'm not sure whether that was a bit of overkill or not, - or
perhaps just testimony to the horrible quality of soldering irons of
the day and Ersin multicore solder.

Whatever, I lost plenty of power devices to runaway before I gave in
and pretty much always put in small (OK, not so small) emitter
resistors in desperation.

d

Pearce Consulting
http://www.pearce.uk.com

Thanks for your information. I also did a little Googling, and found
out:

1. Posting: Netscape 7 on Solaris is not a good idea - I was about to
finish this post and it crashed.

2. Age: According to [1], the driver transformer design was used in
the early days of the transistor, as power transistors weren't
available back then. This was from mid fifties until mid sixties.

3. Sound: Don Pearce said that about any newer amplifier would sound
better. Might very well be, but it seems it could also be worse.
According to [2], the sound of this driver transformer setup isn't all
that bad. I also compared the Nikko amplifier with a nine years old
Samsung max-440 miniset, and both I and someone else found that the
former sounded better, especially as it has full bass/treble/loudness
controls and not only three "equalizer" presets and a extra bass
function which is almost completely worthless.

4. Power: when the input is rated at 90W, the thing won't have too
much power - the Samsung miniset uses 90W for 20W RMS at 6 Ohm, a
Pioneer SX-450 uses 130W for 18W at 8 Ohm [4]. I would guess a
dedicated amplifier scores better, albeit due to the age not much...

5. Reliability: To my feeling the Nikko works just as well as when I
got it eight years ago, so to me it appears as quite reliable.
According to [3] however, transistors only last for 20 to 40 years on
average, so the thing would be at the end of its life - even more so
when germanium transistors are really less reliable than silicon ones.

I know almost nothing about hifi, so have I forgotten something? Is
there something very stupid in the above? No? In that case, I think
I'll stick with the Nikko for now:

- It's not *too* bad, and the sources and speakers that I have aren't
*that* good,
- It works,
- And it is small, only 30x20x8.

Or does someone know an amplifier that is cheap, just as small and
really better (also with better sound and with good potmeters, and
just as reliable)?

Daan.

[1] http://www.geofex.com/Article_Folder...mp/voxprot.htm
[2] http://groups.google.de/groups?selm=
20010226034901.02436.00000324%40nso-bk.aol.com
[3] http://www.diyaudio.com/forums/showthread/t-22225.html
[4] http://www6.head-fi.org/forums/showthread.php?t=102378

In article , Don Pearce
wrote:
On Fri, 18 Feb 2005 15:41:41 +0000 (GMT), Jim Lesurf
wrote:


Even the small signal devices were fragile. Remember those little blue
anodized clothes pegs you clipped on the leads before you soldered them?

Yes. :-)

You've reminded me that I still have some 'fag packets' of very old
Newmarket transistors and some other antique devices in a drawer at work.
Perhaps I should put pictures on a webpage or donate them to a museum. :-)

Slainte,

Jim

--
Electronics http://www.st-and.ac.uk/~www_pa/Scot...o/electron.htm
Audio Misc http://www.st-and.demon.co.uk/AudioMisc/index.html
Armstrong Audio http://www.st-and.demon.co.uk/Audio/armstrong.html
Barbirolli Soc. http://www.st-and.demon.co.uk/JBSoc/JBSoc.html

In article , Daan
wrote:
[snip]

5. Reliability: To my feeling the Nikko works just as well as when I got
it eight years ago, so to me it appears as quite reliable. According to
[3] however, transistors only last for 20 to 40 years on average, so the
thing would be at the end of its life - even more so when germanium
transistors are really less reliable than silicon ones.

I would treat with care any assumption that "transistors only last 30-40
years". That is about the length of time they have been in wide domestic
use, and their typical lifetimes have probably extended over that period.
Also, as I commented in another posting, with early devices the spread of
devices means the poor ones tend to 'die young' leaving the more reliable
ones. If the transistors you have have worked OK thus far then - unless you
change their operating conditions - they are likely to continue to do so.

In my experience after a period of 30 years you are more likely to get
problems with things like electrolytic caps and connectors/switches/pots
than the actual transistors.

I know almost nothing about hifi, so have I forgotten something? Is
there something very stupid in the above? No? In that case, I think I'll
stick with the Nikko for now:

- It's not *too* bad, and the sources and speakers that I have aren't
*that* good, - It works, - And it is small, only 30x20x8.

Or does someone know an amplifier that is cheap, just as small and
really better (also with better sound and with good potmeters, and just
as reliable)?

If you are happy with the sound of Nikko and it continues to work, then I
would not personally see a reason to urge you to change to a newer amp.
Only change if the Nikko fails or you find some specific reason.

Slainte,

Jim

--
Electronics http://www.st-and.ac.uk/~www_pa/Scot...o/electron.htm
Audio Misc http://www.st-and.demon.co.uk/AudioMisc/index.html
Armstrong Audio http://www.st-and.demon.co.uk/Audio/armstrong.html
Barbirolli Soc. http://www.st-and.demon.co.uk/JBSoc/JBSoc.html

In article , Jim Lesurf wrote:
You've reminded me that I still have some 'fag packets' of very old
Newmarket transistors and some other antique devices in a drawer at work.
Perhaps I should put pictures on a webpage or donate them to a museum. :-)

When I was last in Munich, with a half-day to spare, I visited the
Deutsches Museum. The telecommunications, computers and microelectronics
galleries came as something of a shock. It was chilling to discover *in
a museum* semiconductor devices I had worked with as a young hobbyist,
computers I had used as a student, and kit I had seen brought to market
as state-of-the-art during my early career.

The model aircraft gallery was a far more pleasant piece of nostalgia
since it was one of my other hobbies before going to university.

Recommended if you find yourself in Munich. However I think they may
already have the sort of exhibits you offer.

--
John Phillips

In article ,
Jim Lesurf wrote:
I would treat with care any assumption that "transistors only last 30-40
years".

Yup. My first venture into electronics was a kit bought from Home Radio in
the '50s - basically a double tuned crystal set with a 'power' amp
designed around Repanco trasformers. The leaflet with the output
transformer showed a push pull stage using the same transformer, so I
bought the phase splitter one and added an extra output OC72. And lovingly
crafted a box for the whole thing in plywood covered in Rexine. Still
works... :-)

IIRC, OC 71/2s were about 7s 6d each. In today's money, perhaps roughly 7
quid. :-)

--
*I'm not as think as you drunk I am.

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

In article ,
Don Pearce wrote:
Even the small signal devices were fragile. Remember those little blue
anodized clothes pegs you clipped on the leads before you soldered
them? I'm not sure whether that was a bit of overkill or not, - or
perhaps just testimony to the horrible quality of soldering irons of
the day and Ersin multicore solder.

Well, perhaps the standard amateur soldering iron was the Solon 25 watt -
or an early Antex 15 watt. And I'll bet they both reached pretty high
temperatures. I've still got a Solon somewhere and could check.

I made a heatsink using a standard crock clip with copper wire soldered
into the jaws and copper plates to the 'handles' :-)

--
*Beauty is in the eye of the beer holder...

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

Daan wiffled:

5. Reliability: To my feeling the Nikko works just as well as when I
got it eight years ago, so to me it appears as quite reliable.
According to [3] however, transistors only last for 20 to 40 years on
average, so the thing would be at the end of its life - even more so
when germanium transistors are really less reliable than silicon ones.



As a matter of interest does the volume control work cleanly? The volume on
my flash new NAD gave up after only six months, but I've got a 70's JVC
receiver that I rescued from a skip that still works perfectly. They don't
make them like that any more?!


--
Despite appearances, it is still legal to put sugar on cornflakes.

Triffid wrote:

Daan wiffled:

5. Reliability: To my feeling the Nikko works just as well as when I
got it eight years ago, so to me it appears as quite reliable.
According to [3] however, transistors only last for 20 to 40 years on
average, so the thing would be at the end of its life - even more so
when germanium transistors are really less reliable than silicon ones.

As a matter of interest does the volume control work cleanly?

Well, yes and no. The volume control scratches quite loudly right after
turning the thing on. However, when I just wait a few minutes without
touching anything, as to let it "warm up", it works just fine.

The volume on my flash new NAD gave up after only six months, but I've got
a 70's JVC receiver that I rescued from a skip that still works perfectly.
They don't make them like that any more?!