SANYO HISTORY:
Founded by Toshio Iue (Japan) who was an inventor and closely associated with Matsushita prior to starting up Sanyo. In these early days the links between Matsushita (the Matsushita corporation used what are now well known brand names such as National, National Panasonic, Panasonic and Marantz) and Sanyo were close and this can be seen in some of the products released. So close in fact that Panasonic bought a major stake in Sanyo 2009, making Sanyo a subsidiary of Panasonic. In 2012 the brand name Sanyo removed from the market, Panasonic now had full control.
These were amazing times in Japan, having been devastated just two years earlier by two nuclear bomb attacks inflicted by the American military forces (1945) then occupation (by the Americans primarily) until 1952 - Toshio Iue managed to get Sanyo "off the ground" in 1947 while Japan was in such turmoil and the country remained under foreign occupation.
Sanyo began by designing and manufacturing electrical "nick nacks" and whitegoods and didn't enter the audio market until the late 1960's ~ early 1970's
Sanyo actually means "three seas" in Japanese, Toshio's vision was to expand his business across the oceans and become worldwide.
THIS MR-939 HISTORY:
This equipment came out of the Japanese factory (Osaka) in the period 1968 ~ 1970. While not up "there" with the semi-professional/professional world of ReVox, Studer and others of that ilk, this machine was aimed at a different marketplace, the "general purpose/consumer" market. As with so many other machines of this age, the Japanese paid a lot of attention to their equipment design and construction - cost cutting, lowering manufacturing costs etc had not yet taken grip of the Japanese manufacturers. That's why OLD Japanese audio equipment is considered quite good quality whereas audio products in later years were quite frankly, total rubbish - having been built to a tight manufacturing budget and aimed at budget customers.
This machine is in the former category, it would have been a very early product in the Sanyo line of audio equipment and would have had substantial manual assembly by the factory workers. The use of wooden cabinets and some plastic with heavy metal structure frameworks were used. The intended market was indeed worldwide, being capable of running on 100/117/125/220/240V AC supplies. USA was a large target market for Sanyo at this time.
When first released in Australia, this machine had a retail price of A$250 approximately. This was not an el-cheapo machine to consider purchasing because the average weekly wage in Australia 1970 was $115 (ABS statistics) so the buyer would need to think long and hard before buying one of these. There was also the stigma of being a Japanese product, the war was still quite fresh in people's minds (anti-Japanese sentiment was still quite wide spread) and Japanese products were not considered all that good. That original 1970's price of A$250 extrapolates to A$32,000 in today's money! (Based on products doubling in price every 7 years approximately)
We acquired this machine in the late 1990's for our business (post audio production) - not as a workhorse machine (for that we used Studer 810/820's) but more as a "fun, plaything" - it feels more comfortable playing around with a lower cost machine than very expensive Studer equipment!
The previous owners were also professionals in the audio industry and they looked after this machine. We did likewise, even though not critical to our work it was still desirable to "look after" our gear, this means it had the yearly lube job and generally kept in clean condition (heads/pinch roller etc)
I describe this machine in far more detail below, you will see that it is in such great condition even after all these years!
Amazingly we have never had to replace any major components, even after 50+ years of "life" - not bad Mr. Iue!
TAPE RECORDER MR-939
Made in Japan
1968 ~ 1970 period
3 Speed capable (7-1/2", 3-3/4" & 1-7/8" ips)
FRONT PANEL INPUTS/OUTPUTS
Headphone output (2 channel) 1/4" jack socket 8 Ohm or 10K Ohm
2x separate 3.5mm mono microphone inputs (0.3mV 50K Ohm impedance)
SIDE PANEL INPUTS.OUTPUTS
2x Loudspeaker outputs 3.5mm mono - up to 4W RMS each channel into 8 Ohms
2x AUX INPUT 3.5mm RCA - 100mV @ 300K Ohm impedance
2x LINE OUTPUT 3.5mm RCA - 800mV @ 2K Ohm impedance
1x 5 pin DIN socket for connection to similar European audio equipment (record and play inputs/outputs)
Manufacturer factory specifications:
Wow varies across each speed selected but the worse case is 0.3% @ 1-1/78" ips and best case 0.15% @ 7-1/2" ips
Hum & Noise maximum 30mV
Rewind/Fast Forward (1200Ft 7" reel) 2 minutes
Frequency response (3dB points) is 100Hz ~ 10KHz (7-1/2" speed) with the high end dropping off when the speed is decreased (5KHz @ 3-3/4" and 3KHz @ 1-7/8")
*** This frequency response information has been extracted from the Service Manual *** I see other sources indicating up to 15KHz @ 7-1/2" ips but I am taking a conservative approach to these figures
Crosstalk between channels better than 60dB
Headblock has two heads: Record/Playback & Erase
COSMETIC CONDITION:
Extremely well looked after (if I may say so!)
NO damage to the sturdy casing
NO damage to the vinyl coverings, not even a cut or scratch!
Very clean
VU lamps WORK! After all these years and those little meter lamps still operate on both channels
All labelling is clean and clear - none has rubbed off
There is a security ID code etched into the face panel on the right-hand side (lower section) - I cannot remove this but it doesn't "jump out" at you anyway.
LOUDSPEAKERS (2)
Detachable from the case, when not in use these clip lock onto the front of the MR-939 making a nice compact (but heavy) package and protects the tape-recorder front side.
Plywood casing, black stiple vinyl covered
Metal side and corner pieces are formed aluminium, not metallic plastic!
Plastic is used for the loudspeaker grille
Internal pocket (with a vinyl, locking flap) holds the speaker lead and any accessories
One speaker in each cabinet, 4" wide range, 8 Ohm impedance and 4+W RMS power handling
Speaker lead is 2.7m long and terminated with a 3.5mm plug
Cabinet dimensions: 230mm Wide x 130mm Deep x 340mm Height
One side of the cabinet has 3x rubbet feet so that it can safely be placed on a level surface and the loudspeakers will not move.
CONDITION:
Very good
NO rips or cuts to the vinyl covering
All metalwork is unscratched, unmarked
NO case damage at all
Speaker leads are in very good condition, no previous repairs and original 3.5mm plugs (shiny)
WHAT I AM SUPPLYING:
SANYO MR-939 Tape Recorder (as described)
2x Loudspeakers with leads
2x spool locks (rubber push on devices, vital for stable playing of tapes)
2x 7" ORIGINAL SANYO plastic spools, one even has the Sanyo "Demonstration Tape" sticker attached (but the audio material has been erased)
These reels have SANYO stamped into the plastic
1/4" to 3.5mm headphone socket adaptor (gold plated!)
2x AUX input leads - RCA male to RCA male
One spool is fully loaded (but does not have a leader spliced onto it) - I think this was AMPEX tape, not sure because it was a long time since I have seen our Sound Engineer playing with this machine. The tape has been machine erased and now only contains my test audio material.
Service manual (should you request this) in pdf format. This manual is commonly available online but I am happy to copy the pdf to a CD-r or print it out for you as well (19 pages). It could be useful in the future and does have full schematics which are of an average quality, parts lists and probably most useful of all is the lube and general maintenance procedure.
WHAT THE MANUALS DON'T TELL YOU
The record/playback head AND the erase heads are what Sanyo terms as 4 track, but in reality this machine should be considered as a 4 track/stereo machine, 1/4 track if you like.
You cannot record 4 tracks all at the same time, no bouncing between tracks is possible with this design. You can record two tracks (stereo) in one tape direction and then reverse the tape feed (switch spools) and you can record the other two tracks but never all 4 tracks at the same time. The same goes for playback, you can only ever play 2 tracks at the one time, not 4 tracks together.
However the erase head is also 4 track and is configured so that you can use each of the two tracks being recorded separately, including the erase feature. The inputs and outputs, recording controls for each track are totally separate and by using the Sound On Sound switch on the side of the machine, you can record one track, rewind and then record OVER the first recording without erasing the original recording. The Sound On Sound switch effectively turns OFF the erase head so that the record head records onto the already existing recording on the tape. This is what the guy in the video I found online is talking about, recording an instrument on one channel, perhaps a click track on the other channel and then adding another instrument over the top of the first recording, tricky to get right otherwise you will end up with a pretty messy recording with sync problems.
If you would like to read all the nitty gritty about tape basics, have a look HERE
The manufacturers specifications are by no means "high end" but good (for the day) and sufficient for the intended market of this machine. It is pretty clear that if you are recording a musical instrument(s) then 7-1/2" ips is the only way to go, otherwise you are really getting into Lo Fi stuff.
Auto stop (tape ends - runs out) but it stops with the pinch roller still engaged, it is not a good idea to leave it in this condition (unattended) as the pinch roller will eventually develop a flat spot.
NOTES: Obvious omissions/limitations compared to a professional machine (besides the lower specifications)
These points are only noted so that a prospective buyer knows the limitations to expect from this machine (this is NOT a fault list)
Maximum 7" reel size not 10.5" as found on pro equipment
NO tension arm system at all - the system is only just sufficient to do the job, most of the work is done by the pinch roller but I noticed the supply reel tends to play a bit of "catch up" at times.
Headblock covers are plastic, not metal (no shielding)
Plastic reel tables, friction grip "hub"
Braking system needs to be used carefully, if you return the big transport control lever back to STOP too slowly, the tape brakes can release but the motor is still feeding tape so you end up with tape spill. Just nice positive use of the transport lever alleviates this problem.
RECHECKING - TESTING:
As this machine has been safely stored away for quite a while, I took it out and checked it out within the limits of my test equipment (which means none as it all has been previously sold now!) Stupido!
I don't even have a head demagnetiser any longer so these tests are made without demagnetising the heads.
Any audio tests have needed to be made aurally, I no longer have equipment to test frequency response, wow etc
All audio tests made at 7-1/2" ips and input was by using the AUX inputs on the side (line level inputs)
Source audio (for these tests) was an excellent punk/post punk/new wave CD "24 Hour Party People" that I had to hand.
First test was Fast Forward & Rewind. Both function fine, tape travel is smooth and even. Complete reel rewind was just under 2 minutes.
NOTE: After using the machine for a number of hours doing these tests, I noticed on REWIND that the Take Up Reel started "squeeking" I suspect there may be a drive belt issue here (warms up and stretches a bit) - Funny enough though, tried it after recording the Right side and no squeeking at all - another intermittent.
Checked the 3 speeds (always turn the transport lever to STOP before changing speeds - never do this in "mid stream") - all 3 speeds are operating fine.
Mechanical tape travel counter is working fine
Next audio tests were made at 7-1/2" ips
I used the tape in the photographs, first erasing it completely (all four tracks, set on RECORD with Sound On Sound set to OFF and with no audio input) so I could test the erase functionality and then I recorded my test material onto this tape, across various channels.
I did notice that one pass on ERASE still left some previous audio behind, much lower level but it can be heard. Either multiple passes or a bulk eraser might be better.
Recorded on the left channel only, the whole tape length.
Audio monitoring is active while recording, so you can hear what is being pumped into the recorder. Recording level was smooth in operation, set for the sweet spot between maximum and overdrive.
You can also listen to the other track which has no audio input and I can hear very low level "breakthrough" of the source material while recording.
Then I noticed an intermittent fault, yes siree there is a small issue. The right channel meter "dances" at times, so I turned up the monitor volume and there is "crackling" AT TIMES on this channel. I suspect this is a noisy pot or switch, I adjusted the right channel controls and now the "crackling" has disappeared. I have made no effort to explore this further except that after another 3 hours, this noise did not reoccur. Looking at the schematic, before this meter are a number of switches - a good clean might be in order here.
I then played back my recording, all fine - not too bad quality actually (all things considered - source material is highly compressed but there you go. Highs are good, if anything I feel the lows were a bit lacking)
I repeated the recording on the other channel (Kylie Minogue - Fever) - same results minus that crackling issue which has disappeared for now.
If you are looking for these recordings on the supplied tape, set the counter to 000, fast forward to around 035 - Kylie kicks in first on the right channel and she is followed by Joy Division on the left channel.
Audio quality on both loudspeakers is very good (but keep in mind the frequency response of the machine isn't "great"), hum free and without any undue distortion - audio output is working fine.
VU meters both work as do the respective back lights.
Main transport lever works smoothly
Fan on the rear of the motor runs without excessive noise, no funny noises here
While running in either Play/Record or RW/FF there are no unusual noises (but see my notes above re an intermittent issue I noticed).
OVERALL IMPRESSION:
As you can imagine, I have spent hours running tape back and forth/flipping it over etc and in my judgement this is still a nice "fun" machine for non-demanding audio use - it certainly looks pretty cool!
A good maintenance refurbish inside might be on the cards, spray the signal path switches and pots for good measure. Check that drive belt too, it may be stretching a bit.
It sounds as good as you could expect, not high end for sure but not terrible either. A nice tape enthusiasts or musicians "toy".
WHILE THIS VIDEO MAY BE USEFUL TO SEE THE MR-939 IN OPERATION, HE HAD NOT FED HIS TAPE PROPERLY, COMPLETELY MISSING THE TAPE GUIDE ON THE TAKE-UP SIDE. IT IS IMPORTANT TO CORRECTLY FEED THE TAPE THROUGH THE TRANSPORT SYSTEM TO ENSURE A NICE TAPE/HEAD RELATIONSHIP AND PREVENT EXCESSIVE WEAR ON THE RECORD/PLAYBACK HEAD IN PARTICULAR
WORK IN PROGRESS, SHOULD BE COMPLETED TONIGHT! (11th November 2021)
