>I must get round to buildign a secodn Williamson. A friend of mine had
>one and wanted to get a stereo pair but he never found a second one. He
>gave it to me in exachnage for repairs to his guitar amp. He also gave be
>some boxes of 'junk' which incuded a pair of new KT66s, other valves,
>valvholders, etc _and the Williamson mains and output transformers. In
>other words he'd got the hard to find bits to make his pair... His loss....
>
>-tony
>
I am seriously jealous... No not really, I'm glad for you. How terrific!
What are you waiting for? ;-)
Jonas
>
> I will have to find mine... From what I remember, it's a yellow cover and
> titled 'High Quality Sound Reprodcution'. It includes (I think it this
> order) the 5-20 (EF86, ECC83, 2*EL34, GZ32), preamp for the 5-20
> (3*EF86), FM tuner (I can't remember the full line-up, I am pretty sure
> the IF amplifiers are EF41s, the detector an EB91 with an EM80 tuning
> indicator), the pre-amps for the 5-10 (EF86) and the 5-10 itself (EF86,
> ECC83, 2*EL84, EZ81),
>
If you could find it and give me details of it, I can start looking. That
would be much appreciated.
> There were of coruse other FM tuners for the home constructor at one
> time, Some easier to align than others...
>
> I also have the GEC book on audio amplifiers. The _low power_ one is the
> Williamson (15W, 2*KT66 in the output stage). I think the highest power
> amplifier schematic in that book gives 1.1kW RMS into the speakers...
>
*Drool*
Another book I shall have to try and find...
Someday I must get round to building a valve amplifier.
Jonas
All,
This is starting to get further off topic as this is more a few years
into the future. I was reading the IEEE Spectrum for Feb and they have
a couple of pages about a move to 380V DC distribution for data
centres with a view to make it suitable for domestic use.
Simon
--
------------------------------------------------------------------------
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the utility of the final product."
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Hi all,
This is going to seem like a weird question......
Does anyone know why on almost all of the Acorn machines with disk
interfaces (including at least one non-Acord designed one), they gate
the drive select signals with the motor on signal. e.g. drive select is
inactive unless the moror is also on ?
This seems to be a peculiarity of Acorn as none of the other machines I
am familliar with do this (Dragon, CoCo etc), even when they use the
WDxa7xx type controlers. Though I guess cirtainly with the Atom / BBC
A/B it may be a requirement of the 8271, it seems odd that it was
carried over to the machines that only ever had 177x controlers.
Cheers.
Phill.
--
Phill Harvey-Smith, Programmer, Hardware hacker, and general eccentric !
"You can twist perceptions, but reality won't budge" -- Rush.
In the US, two separate 110 legs are delivered to the house. When we
need 220, the magic of constructive interference is applied, and we
get 220. The 220 is delivered to the appliance as two separate 110
wires, a neutral wire, and sometimes a separate ground wire for
safety.
Because of this arrangement, sometimes appliances (I believe, maybe
I'm wrong) will pull 110 from one of the legs to power electronics in
the appliance.
But I think european 220 doesn't work this way. Is one 220 leg
delivered to the house? And the electronics work off that 220 leg?
Or are two 110 lines delivered and every outlet gets the sum of those
two 110 lines?
If it's not two separate legs, I'm thinking that it will be impossible
to wire an american 220 appliance to work with european 220. Is this
right?
brian
>
> Depends on the 'take over' :-) It certianly says 'Made in Sweden' on th
> front and on the rating plate,
>
Asko took over Cylinda from ASEA or ABB, don't remember if it was before or
after the ASEA-Brown Boveri merger.
Maybe they drop the Cylinda part overseas for marketing reasons or
something.
> > I have always thought that the UK system was much more sensible. Not
> only
> > are all plugs and sockets earthed, fused and switched, but they are also
>
> I am not sure what sockets are still permitted over here, but the
> standard one is the 13A plug to BS1363, which is indeed earthed,
> polaraised, and cotnains a cartridge fuse.
>
I wouldn't know, but I certainly remember that my Uncle's house in Sleaford
had the old 3-pin round pin polarised and earthed sockets in the late 60s or
early 70s, all of them switched IIRC, and IIRC there were no two-pin sockets
at all. And the electrical installation must have been quite a few years old
then.
> Do socket outlets have to be switched? I would never fit one that isn't,
> but I thoguth unswitched ones were still available.
No switched sockets at all here, unfortunately, possibly with the exception
of sockets for electric irons in communal laundries in blocks of flats etc.
And coffee makers in workplaces etc are always connected through a timer,
since there have been fires caused by coffee makers boiling dry and the
protection device having failed closed-circuit. It is probably illegal to
run a coffee maker without a timer in a workplace.
>
> > polarised so it is impossible to switch live and neutral (provided the
> > electrician who installed them knew what he was doing). The Swedish
> plugs
>
> Sensible people check to make sure ;-). There are plenty of so-called
> 'electricians' who get this wrong.
>
I can well believe so. Many years ago I witnessed a very experienced
electrician getting the hair dryer treatment from his boss because he had
used a green/yellow piece of wire for a phase connection in an industrial
installation.
Here unfortunately there is no way of knowing which wire is live on the
appliance, since the plug can be connected either way round.
> I
> beleive that some countries (Germnany?) oftn have a pair of 16A socket
> outlets protected by a single 32A breaker. And you could plug a small
> appliance in to osme of those sockets with no other protecive devices in
> the circuit, even if the flexible cable to the devive is rated at 3A,
> say. No thanks!
> [...]
Sockets and lighting circuits here are usually protected by a 10A fuse in
the switchboard. Modern switchboards have miniature breakers for each
circuit, the kind with both a magnetic and a thermal trip. Older
installations only have a fuse. If you connect a shaver or something to the
socket and the shaver shorts out, I suppose it is possible that the
insulation on the shaver cable might melt before the fuse blew (shavers
usually have a 0.5 mm2 cable).
>
> But more seriosuly, I feel I might well die from electrocution. After all
> I work on mains-powered stuff most days and something could go wrong.
> But
> this doens;t mean I am not going to be sensible about it and use RCDs etc
> if I think they could help.
>
Actually it might not be a bad way to go provided the voltage and current
were high enough.
> > I don't intend to bring it about by electrocution in the bathroom. And
of
> > course the RCD goes on the end of the lead outside the bathroom. I would
> > want one even in a dedicated darkroom.
>
> I have a dedicated darkroom (it's a little hard treating a DeVere 504
> enlarger as a temporary device :-)), but I still have (and want) an RCD
> on the incoming mains to it.
>
Sadly I only have a 35mm enlarger, I am hoping to modify it to take 6x6
negatives. But I also have quite a few old 6x9 negatives which would be nice
to print. Happily for me, enlargers are cheap second-hand nowadays :-) (as
is old audio gear, Revox A77s or B77s can be had for very reasonable prices
for example. I have a very nice Marantz amplifier which I got cheap, and a
Technics FM tuner which probably weighs nearly as much as the BC-312
shortwave receiver I used to have).
Jonas
> > I am not that surprised given that at some time (in the past 20 years?)
ES
> > lampholders appear to have become legal in the UK (I'm sure they never
> used
>
> Weren't they? I am pretty sure I've seen reference to them in quite old
> (1950s) electrical engineering books over here. Maybe not used on
> domestic installations, thohhg
>
> > to be) and they have a large _easily_touched_ metal part that could
> randomly
> > be connected to live or neutral (I suspect that if Tony found himself
having
Not easily touched with the bulb in place, I hope? Over here (Sweden) all
bulbs are ES and all holders have an insulating exterior. If you remove the
bulb and poke your finger inside with the holder live, you may well get a
shock, since mains sockets aren't polarised here. Most people don't usually
do that however, not even the cognitively challenged.
The bulbs don't wobble about in an ES holder, IIRC they do in a bayonet
holder. The French use bayonet holders and that IMO says a lot about that
type of holder.
Jonas
>
>> SPX graphics adapter which was plugged into a very nice VR297 monitor (Sony
>> Trinitron). I plugged out the monitor cable from the back of the Vaxstation
>> for some reason. When I plugged it back in I felt a zap. On investigating,
>> the earth pin in the IEC plug going into the monitor didn't seem to be
>> making proper contact for some reason. The monitor didn't mind a bit but one
>
>I've neve seen that happen. Normally it's due to a wire having fallen off
>in one of the connectors. Of course tend to prefer the rewirable IEC
>sockets so I can check the wiring and make sure the contacts aren't bent
>open/
>
After unplugging and reinserting the plug (line socket?) once, I couldn't get
it to fail to make contact again. The connector was moulded but it was possible
to squeeze the contacts by inserting a small flat screwdriver between the
contact and the body. I decided it was better to discard the lead and use
another.
(I fitted a rewirable IEC connector on the vacuum cleaners lead after the cable
failed near the original moulded connector. The new connectors body is too
flexible and the rubber strain rellef sleeve regularly works free from it...)
>
>> I traced the connections on the graphics card and found the RGB outputs came
>> directly out of a large, probably expensive, difficult to replace and rare
>> looking BT459 RAMDAC :-(
>
>I asuem that's a Brooktree part from the number. They are not mormally
>custom chiups, you even find them (although probably not the right one)
>on old VGA cards.
>
Yes, it's a Brooktree part. I don't come across that many old VGA cards and
any that I have come across don't use it. If anybody has an old card with
a BT459 that they are willing to give/sell me, I would have a go at changing
it. A quick tally shows it to have 132 pins but it looks like they are 0.1in
spaced so I should have a realistic chance of dealing with it.
Maybe I should put this in another posting as the people with large stashes
of BT459s and think this is an off-topic discussion about mains voltages
might not realise we have drifted back on topic again :-)
>
>There is a locking assembly avaialble, but few manufacturers seem to use
>it. And it doesn;t work with moulded scokets (see above ;-)).
>
I've seen a simple wire retaining mechanism (on Cisco 1U high kit I think)
which seems to do the job and works with almost any leads, moulded or not.
However, I'd prefer something that just felt a bit more secure without
needing this extra mechanism.
>
>What mains connector do you prefer?
>
Given that almost all the kit I use has IEC connectors, I don't really have
any I prefer, just ones I don't like that much :-)
I once bought variable bench power supply at a ham rally for a very small
price. The obvious snag was that it didn't have a mains lead and the mains
input connector was an oblong thing a little flatter than an IEC chassis
mounted connector. I removed the original connector, made the hole a little
larger and fitted a new IEC connector. There's no shortage of IEC leads and
I don't want to end up needing a selection of different power leads for
different items. Sometimes it's easier to put up with something I'm not
than keen on. Even if they don't feel that secure, I can't argue with the
sheer numbers in use and the small number of reported problems with them.
Regards,
Peter Coghlan.
