Silicon Chip – May 2019

siliconchip.com.au Australia’s electronics magazine May 2019 73

Parts list – Bridge-mode Adaptor for Amplifiers

1 double-sided PCB, code 01105191, 79 x 44.5mm

1 UB5 Jiffy box (optional)

3 PCB-mount right-angle switched RCA sockets (CON1-CON3)

1 PCB-mount right-angle barrel power socket (CON4) AND/OR

1 3-way (or 2-way) mini terminal block (CON5)

1 8-pin DIL IC socket (for IC1)

4 3mm inner diameter, 6.3mm long untapped spacers

4 M3 x 16mm machine screws

4 M3 hex nuts

Semiconductors

1 LM833 or NE5532 dual low-noise op amp (IC1)

2 16V 1W zener diodes (ZD1,ZD2)*

4 1N4004 1A diodes (D1-D4)j

Capacitors

2 470μF 25V electrolytic*

1 220μF 10V electrolytic^

2 100μF 25V electrolytic*

6 22μF 50V electrolytic

1 100nF 50V multi-layer ceramic or MKT (code 100n, 104 or 0.1)

2 100pF 50V NP0 ceramic (code 100p or 100)

Resistors (all 0.25W, 1% metal film unless otherwise stated)

3 100kΩ (brown black yellow brown or brown black black orange brown)

3 10kΩ (brown black orange brown or brown black black red brown)

2 2kΩ (red black red brown or red black black brown brown)

1 1kΩ (brown black red brown or brown black black brown brown)

2 100Ω (brown black brown brown or brown black black black brown)

2 100Ω 1W 5%* (brown black brown brown or brown black black black brown)

this time, the maximum output pow-
er of the combined amplifiers will be
much higher!

Mounting it in a box

As mentioned above, you will need
to drill four 3mm holes in the base of
the Jiffy box. If you forgot to do that ear-
lier (using the PCB as a template) you
could instead make the holes where
shown in the drilling diagram, Fig.9.
You will also need to drill three
9mm holes in one side of the box for
the RCA sockets, plus a 7mm diameter
hole in the opposite side to access the
barrel socket. The positions of these
holes are also shown in Fig.9. You can
copy this diagram, cut out and stick the
copy onto the box and then mark and
drill the holes.
Ensure the template is aligned accu-
rately with the top, bottom and sides
and drill the holes accurately, starting
with a smaller pilot drill and then en-
larging to side with larger drill bits, a
stepped drill or a tapered reamer.
This ensures that the unit will fit
nicely in the box and look neat.
Once you’ve made the holes, de-
burred them and removed any de-
bris from the box, feed the four 16mm

All of these components

are commonly

available from your

normal parts suppliers.

The PCB (01105191) is

available from the

SILICON CHIP ONLINE SHOP.

j only two needed for single AC/

split DC supply

* only one required for single-ended

DC supply

^ only required for single-ended

DC supply

You will go a long, long way to find speakers with anywhere near

the performance of the SILICON CHIP – certainly in the do-

it-yourself world, and even compared to ready-built models.

Detailed, blind listening tests confirm they are at least as good as

• and some say better than – speakers costing ten times as much!
  At 486(w) x 864(h) x 580(d)mm each, you will certainly reuire plenty
  of room for the. They are most suitable for large listening
  areas, especially where you want high levels of crystal-clear sound.
  How high? Spectacularly high!
  They feature an etone or Celestion 15-inch woofer, teamed
  perfectly with a Celestion T5134 diecast horn tweeter and matching
  compression driver, plus a two-way first order crossover.
  Building the is well within the capabilities of the average
  constructor. They’re not cheap – they certainly won’t leave any change
  out of $1000 per pair (and probably a bit more!). But if you want
  exceptional power and performance, you can’t go past the.

Majestics

Majestics

Majestics

Majestics