EQUIPMENT HISTORY:
Everything I am describing below is IMPORTANT, read it please!
This amplifier is part of my "collection" of all things audio, both professional and consumer gear.
I have over the years collected together a LOT of quality audio equipment due to my business activities in pro audio post production although this Pioneer amplifier is really for general purpose consumer use, in fact it was occasionally used when we used to have "gatherings" for low - medium background and dance music.
It is simple to use and operate, reliable - nice little amplifier!
We have not used this amplifier for quite a while due to ban on gatherings but also we went "high tech" and just use a little Google box thingee to provide our general entertainment music.
But with all that said, this nice compact amplifier would also look just as good inside the house/loungeroom/office as it is easy to move around and in extremely nice condition.
So my wife says "for goodness sake, get rid of that mountain of gear" so them's my orders ... out they all go.
This equipment does have one very minor issue, and it is extremely important that the complete description is read in full.
THE CONDITION OF THIS EQUIPMENT IS CLEARLY STATED BELOW, BOTH COSMETICALLY AND ELECTRICALLY
There is no warranty, there are no returns - but I am very thorough and do not "gloss over" any issues I might discover!
PIONEER Stereo Amplifier
Model: SA-420
Released 1981 ~ 1982
Dimensions: 420mm x 94mm height x 267mm
Weight (unpacked): 4.6Kg (packed in the box) 5Kg
Australian version, fitted with Australian GPO plug (2 pin moulded with NO earth)
BASIC SPECIFICATIONS:
Power output 20W RMS per channel into 8 Ohms
Frequency response (3dB points) 10Hz ~ 60Khz
Damping factor: 30
Maximum Total Harmonic Distortion (THD) at full power into 8 Ohm load: 0.1%
Inputs: Phono (turntable), Tuner, AUX, Tape
2 section tone controls (Bass, Treble)
Balance control
Large Volume control
The tone & balance rotary controls have a nice positive centre indent
Loudness ON-OFF (Bass boost)
Front panel headphone socket
Rear panel Line out socket
OFF, A or B or A+B speaker switching at the front panel using a combination of two push switches
Speaker outputs are all spring loaded terminals.
COSMETIC CONDITION:
In a nutshell, Wow factor is 9/10!!!
Although used for our entertainment, this amplifier was always cared for both cosmetically and electrically (no shorting of the outputs for example!)
The front and rear panels are very clean
All metal case is straight and true
NO dents or bending!
NO major scratching at all, with the exception of the rear panel (left side) but it is not a major scratch.
Sides, top of the case and underneath are all in very good condition with no marks/scratches
All buttons and knobs are present and undamaged
I love these older knobs in particular, solid aluminium with a small plastic insert inside for the fluted control shaft. Much better than "metalised plastic" knobs
TESTING:
Ah this is the part that really matters....
Took a look inside (something that I always do to establish the general build quality and a visual inspection of the components for signs of trouble) and it is looking really great.
No visual signs of component stress and the electrolytics look to be in great shape (no bulging or leaking)
Extremely well laid out single PCB with plenty of space for cooling air circulation.
Clean and free of excessive dirt/dust both "on top" and underneath the PCB.
I can see no signs that anyone has been inside for servicing work, the output transistors look undisturbed since the 1980's!
Enough "looking", let's fire it up!
Testing undertaken at 240V AC input
Power ON switch working (locking) fine.
This amplifier does NOT have any protection relay, so don't wait for the "click" as you will never hear one!
Prior to connecting my precious Vifa loudspeakers, I checked both outputs for any dreaded DC voltage being present, none at all thank goodness! Never ever should you see DC voltages at your amplifier speaker outputs because if you connect your prized speakers to such an amplifier, your speaker voice coils suddenly turn into little heaters and then go POOF! This is something you must prevent at all costs - ALWAYS check an unknown amplifier for DC at the speaker outputs before connecting your speakers.
No issues at all on either channel (no AC or DC of any significance), so I connected my 8 Ohm test loudspeaker system.
The only indication that the power is on is the green lamps next to the input selection switch - there is no ON-OFF lamp indicator as such. Instead Pioneer indicate the amplifier is turned on by the position of the input selector.
Don't forget, these are incandescent lamps not LED's - this is the 1980's afterall!
MINOR ISSUE: It is here that I noticed the one and only issue - each input selection has a green lamp which lights up, depending upon which input is selected.
The lower-most lamp (AUX) is not working so it does NOT glow. I do not have a replacement lamp (8V 50mA lilliput type with flying leads) and I have not made any attempts to repair this. I do know that places such as Jaycar Electronics have similar lamps, if ever you wished to replace this lamp.
The other two input selections DO light up correctly.
This in no way affects the operation of the amplifier, but if you have the input switch in the most counterclockwise direction and that lower lamp does not light, you cannot tell that the amplifier is in fact turned on. Just leave the amp switched to the centre position and all will be revealed when you turn it on.
I checked both of the line level inputs (AUX,TUNER) and also the Phono input - nice, actually really nice on the Phono.
NOTE: This is an almost all discrete active device amplifier, no hybrid power output modules and the only integrated circuit is the Phono preamp using a 4558, an ordinary dual Op amp similar to a TL072.
I then removed all inputs and listened very closely with the Volume turned to maximum - barely any background hum at all, so the main filter capacitors look to be doing their job fine.
I also listened carefully for any "scratching" or breakup of the audio when rotating the controls such as tone, balance and volume. Nothing at all - nice clean audio adjustments.
SUMMARY:
40 years old and still going strong, good work PIONEER!
A compact, "not too heavy" amplifier which is very well "put together"
Treat it with respect (don't pour wine all over the top! I have seen that happen to other people's gear at a party - disaster!) and never allow the speaker outputs to be shorted together - the amplifier will not like it!
Audio is very good, perfectly suitable for most consumer un-demanding situations.
I can easily ship this equipment anywhere around Australia and shipped at the buyers expense UNLESS an order is created exceeding A$76, in which case the shipping ANYWHERE WITHIN AUSTRALIA is FREE. This is an automatic setting on this website.
