Page 107 - Hi-Fi World (January 2020)

OPINION

"My last pair of Quad IIs,

with all the leads, were

lethal"

Dave Tutt

A voltage DC with all else on the getting a Brennell reel-to-reel tape
couple of relics arrived
at the workshop this
same plug isn’t ever going to be
machine to pass its earth leakage
done today. It must be plugged
week. I suppose relics
test under PAT rules and you will
is not the right word as
see Bakelite isn’t a great product,
right in because exposed contacts
the design is still just
too dangerous not only for the
as valid today as it was
inside motors over 50 years old!

There is also the issue of
when new back in 1953. But many have 300 Volts DC on them – just especially used as an insulator
cat, but also for unsuspecting
modern hi-fi buyers would consider members of the family who might earthing. These amps were intended
valve mono-blocks that look closer just want to put some music on. to run with the partnering Quad 22
to industrial hardware rather unde- The connector can be removed and preamp which earthed the power
sirable – and of course there is the a gold plated phono socket fitted amps via the returns on the Jones
spouse aspect to consider too. onto a metal plate for the audio connector. If you are not using a
Bought at a local auction a pair – which looks so much better. The Quad 22 pre then where is your
of Quad II power amps with serial original plug and socket will be earth going to come from? Down
numbers reasonably close together noisy so unless you are desperate the screen of the audio cable!
they didn’t look too bad, but had to keep the Quad II looking This is another issue as your
a number of things to be done original, modification will improve pre might not be earthed in
that would bring them up to date safety and your listening pleasure. modern fashion – and to have
and make them work. You have to Otherwise the cost of an old 6 all that high voltage hardware
decide at an early stage how far blade Jones connector is liable to not earthed is not a good idea.
you are going to go with these be more than £30 and the phono Then if you earth both there may
amps. If you want to create a like- adaptors are £65 so a pair are a then be an issue with earth loops
new solution then the spray booth £150 addition to the bill before we because of the very thing you really
has to come out as the rust and start. shouldn’t leave off! Oh – and if
scratches needs to be sorted. That If, like the ones I have here, you you have them on separate mains
means a complete rebuild which I have no mains connectors that is plugs so they can be next to your
think, unless you just want to look also something of a problem too. speakers they really should have
at them, is a little extreme. They are rare, and only original mains switches on them too!
My feeling is, change the ones from the 50’s seem to be I feel with these sorts of amp
resistors as they are easy to do available and are also expensive we should obviously maintain
and relatively cheap and will have as well as being hard plastic or the basic structure of the thing
all changed in value anyway, so Bakelite – neither of which inspires but at the same time best not to
it makes sense. Any capacitor confidence. They are really not safe. compromise on safety. What was
that is split or looks like it has I know that sounds rather extreme acceptable in the 1950s is not okay
suffered due to heat should come but believe me, the reason these now! So new mains connectors are
out too. Like a lot of these old went out was exactly because they a must. The resistors are an easy
valved amps, the worst things are were dangerous. My last pair of replacement. There is really only
the connections, resistors and Quad IIs with all the leads when one crucial pair of caps that can be
capacitors that are miles from their they arrived were lethal. Damp replaced with modern equivalents,
indicated values – and of course ingress into Bakelite causes it to preferably with metal casing like
worn out valves. become conductive – and worse the originals. Then the Quad II
The Quad doesn’t have a when it does it tends to arc so you power amplifiers can be brought
simple audio line-in socket but a have plenty to make things nasty. up to running condition, providing
six pin Jones or Plessey socket I know people will say it's their output transformers are still
carrying heater and HT as well as never going to get damp but trust intact. If these have blown (fused
the audio. Unless you want 100% me, having had all sorts of ancient primary) due to valve failure then HI-FI SERVICE & REPAIR
Dave Tutt
authenticity this should come hardware with this material as an forget it. Money spent at auction +44 (0)7759 105932
out. It's a Health and Safety issue insulator I very soon realised it (or perhaps eBay) will be down the dave_london@hotmail.com
as much as anything: mixing high isn’t – a good insulator I mean. Try drain. www.tutt-technology.co.uk

www.hi-fiworld.co.uk JANUARY 2020 HI-FI WORLD 107