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 Quad
II... |
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The Quad II is one of the most highly respected mono-block hifi valve amps around. First introduced in 1953, it's still used by many enthusiasts. The Quad II has no user controls, and was originally designed to be housed out of sight. However, the engaging design coupled with the opportunity to see the glowing valves, usually means they're left very much on display. |
| The famous ID plates contain
the serial numbers (these examples being 42841
and 42891), the old Quad
logo, and manufacturer details - "Made
in Huntingdon, England by the Acoustical Manufacturing Company Ltd."
When purchasing Quad II's go
for pairs with close serial numbers to attain
a good match - and avoid
units before the 7000 mark as they're extremely
hard to pair-up.
Once again, illustrating Quad's ingenuity, even the screws holding the ID plates have a dual purpose - securing the double capacitor mounting inside the unit's casing. |
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Quad II's use five
valves (clockwise
from top left)...
The two Quad II's featured here are fitted with the original valves. For more info on these, check out the valves section... |
| Located on one side of the amp are the speaker and control connections. The large two pin socket on the left accepts mains power directly from the control unit, and it then returns high and low tension valve supplies via the six pin "jones" plug. This plug also accepts the preamp signal output from the control unit. The two remaining centre sockets are the speaker connections - the top one being the +ve (red) connection, and the bottom -ve (black). The Quad II was originally configured with a 15 ohm output impedance, but if necessary this can be modified to 8 ohm by changing a couple of tags on the output transformer. |  |
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The Quad II remains a benchmark
in hifi power amp design. These 15
watt work horses provide pure amplification
and are still very much sought-after. You
can find some interesting reconditioning of
Quad II's too, bringing them bang up to date
both in appearance, and electronics.
To see some examples of these, see the work
in progress section or check out
the "Quad Mod"
d.c.~daylight
page...
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