SONICS AS 331 1968
I picked up this pair of SONICS loudspeakers at an OP shop in Nambour (13th March 2009). I hadn't heard of this brand and the speakers looked very tired.
From the back it was clear that the cabinets were constructed from ply and they were stamped "Made in Japan"
I really was expecting to find a 3 way with perhaps some working drivers.
My feelings picked up noticing 5 ALNICO drivers in each box. Three tweeters a sealed mid and a 12in bass.
AND THEY ALL WORKED PERFECTLY
They sound incredibly sweet and detailed. VERY ALNICO. The bass is warm, tonal and nicely controlled. The mid and top are very musical and definitely have the ability to surprise
12in Bass shown above
horn supertweeter bottom left
The Walnut veneer has dramatically improved using Gilly Stephenson's Restoration wax
My Sonics speakers seem to be the AS-331s, they date back to 1968 ( I did think early 70's) There is actually quite a lot of info on the web.
The internal drivers are likely to be Coral.
http://www.audiokarma.org/forums/sho...d.php?t=142262
This link shows a US version with the grille off.
They really do sound very good indeed and they are very efficient
Pictures taken from this page show the front driver view
Added April 2010
Mine are actually quite different. Both bass and mid range have light brown coloured cones (concentric pattern on mid) The tweeter pair have black cones and square frames. The horn supertweeter appears to be the same as above
APRIL 2010
I have decided to rebuild my AS 331s. The veneer on one was pretty dry and a large piece has been missing since March 2009. The plan is simple.
I have opened them up, carefully removed all 10 drivers. Remove the glass fibre wadding, removed the front baffle, remove grille cloth and remaining veneer. Sand back repair defects, stain and treat with Danish oil.
Problems?
The front baffles are very difficult to remove. Half of the fixing screws were quite rusty, particularly the ones in hard to reach spots. I used WD40 which was really effective. The front cloths are held on with about 100 staples and many of these are quite corroded. On one speaker the twin tweeters appeared to be stuck in place and this took some time removing.
The veneer peeled off very quickly on all except the last surface. Here it appeared to be very fimly glued onto the ply. On one box the veneer had covered a dent filled with fibre glass. On the other one surface had quite bad cracking in the ply. It all required a lot of sanding.
I am still thinking about the final look but at the time of writing I am considering painting the front baffle a deep earth red soil tone to compliment the sandy coloured main drivers. Copper metal might look good. The main box will be stained and oiled to keep a more natural timber look. One side has a brilliant pattern which should look great.
With so many large paper cone drivers
I am thinking of making a protecting cover using a clear or smoky plastic. On when not in use and off for listening (with the idea that you can still see the drivers while they are protected)
sonics 12in bass superb deep dish
step one "after and before"
Note other alnico speakers in background
Working with the parts?
The front baffles were very dry. It is very difficult sanding the area around the tweeters because parts of the ply kept lifting. Working mainly by hand and going slowly obviously helps. At the start the various marks cuts and dents did not inspire much confidence. Things improve dramatically once you start using wood stain
I used a Wattyl "Nordic Pine" stain ( about 50:50 with mineral turps) The stain was rubbed in using steel wool. Colour uptake is dramatic, All the blemishes really add to the old world feel.
I really like the way the cabinets responded. Notice the chair rubber is a perfect way to protect one of the 4 tweeters during painting
This improved dramatically again once I used a single coat of Danish Oil.
The beading around the front has been replaced. These sections have been panel pinned onto PVA glue.
I loaded one of the baffles today (8th April 2010)
Wiring and fitting to the cabinets tomorrow
New Sonics AS311 crossover and cabinet upgrade Easter 2012.
I decided to re-build these speakers during a couple of weeks leading up to Easter 2012.
Key aspects of this upgrade included;
 new look SONICS sound amazing. the crossover box can also sit on the floor behind or as in picture
Replacing the original unbranded small grey crossover caps with a combination of Suntan polypropylene and Bennic non polar electrolytics. I really rate the sound of Bennic caps. The crossovers have now been rehoused in separate cases outside the speakers. The original inductors have been retained. The variable output super tweeter, and mid range pots have also been kept. The cap value are close to original. Original values shown below.Bennic 33uF replace the original 23.4uF, 3.3uF Suntan polys replace the 2.8uF
diagram created with Smart Notebook
The front baffles have been sealed internally with black silicone gutter sealant.
A range of sound absorping panels have been glued on the inside, including base (Yamaha felt) and foam rubber back and top panels.
Internal wiring has been replaced with a much neater mix of OFC, multi strand on the positive side and a single strand earth line. All old solder has been removed and all tags cleaned thoroughly with isopropyl alcohol before new wires attached.
The front baffles have been sanded back and finished with two coats of suede effect paint. The speaker cabinets have also been reworked slightly. Both tops in particular have received most attention.
The speakers are now angled slightly to help with listening alignment.
These speakers now sound amazing.
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