Toshiba RT-7077

So here in Australia we don't have that much of a choice with what we generally call "Op (Opportunity) Shops" or secondhand stores, and the ones we have tend to be chains that are often overpriced or rarely get decent electrical products. I do have a local store that is just run by a guy that lives upstairs in the same building, and have occasionally come across some treasures. Hence, I was in there the other day and spotted this:



I do have a bit of a soft spot for Toshiba stuff, with my first partway decent system being an RT-7055 and buying a KT-4056 "Walkman" the following year, and I especially have a thing for digital tuners, even though it is almost impossible to get a good signal where I live.

This model had definitely caught my eye in catalogues as a kid, and in all honesty gave me the same feeling when I saw it now, but with no price on it. However at $30 it was mine!



I will post something about what I consider "must have features" back in the day, which wholly depended on what you wanted as a kid, but of course these units were always a compromise with pretty cheap decks on this model being offset by relatively high power and a digital tuner! It is in really good condition too, with most of the marks appearing to be stuff on the outside rather than scratches, so it should clean up next to perfect.



The sticker was true to its word, the only thing I have done to it so far was reseat the AM/FM switch which was not lined up correctly with the switch behind. All buttons and controls seem to be working correctly, although some definitely need some contact cleaner, and the fact the decks still play means at least the belts have not turned to goo!



Interestingly it has dual speaker connections that appear to come from dual amps according to the schematic. The bass speakers (that point down) are a much higher impedance than the main ones. No tweeters which is potentially a step down from my 1985 RT-7055, but who knows how good they actually were. It does have auxiliary in and require 2 AA batteries for the tuner memory on top of the obligatory 10 D cells! Yes, I know the speaker cables should be routed neatly in their place, but I need to pull it apart and clean it first.



This is it in the 1987 catalogue, 60 watts is more power than the top of the range model. I am interested in other's opinions, but I have found the P.M.P.O. rating divided by 10 is probably close to a sensible per channel output (so 6 in this case). It is interesting that the IC Logic control decks of many earlier Toshiba models seems to have been replaced with digital tuners on the top models by this time.

No price, but I would estimate that it might have been $300 to $400 back in the day. Service Manual is easy to get, but as seems to more often than not be the case, I can't find an instruction manual online. Please hit me up if you know where to get a copy!

 

If you have the service manual you can check out what amplifier ICs Toshiba used then find a datasheet which will usually give proper RMS ratings.

 

Wow, that does look snazzy! I think coloured systems (apart from black, grey and silver) were basically non-existent here for anything that had detachable speakers. I guess they were going for the "hi-fi system" look, and that was definitely what I was looking for at the time. I do often see Japanese models in red, even some of the smaller hi-fis.

My ability to read schematics is rudimentary at best, but I did manage to find the amplifier chip BA5406 which puts out 5W x2 into 3 Ohms when running on 12v, although with 0.3% THD at 0.5W I'm not sure what that means in terms of real power, not that I bought it for critical listening! Strangely, although there are two of these chips in the unit, it appears that only 1 channel of the second one is used for the DBSS with a combined L+R signal.

The service manual says it weighs 5.7kg (a bit over 12½ pounds) without the batteries, but mine weighs in at 5.87kg. I am not sure if the fuse that is exclusive to the Australian model could weigh 170g? Anyway, with its arsenal of 12 batteries I am sure you wouldn't be carrying it around on your shoulder for too long.

There does seem to be a direct lineage from my RT-7055 to this, with the former having better decks with IC logic controls and standard 2 way speakers, 1986's RT-7066 dropping the logic controls and moving to a digital tuner, and this model dropping the tweeters in favour of DBSS. I'm obviously going to have to pull out my old unit, and pray its belt has not yet turned to goo either!

 

Yes it was pretty common to use a second chip for the bass speakers. So figure about 10 watts into the main speakers and another 10 into the bass speakers, assuming they all had the same impedance. But you said the bass speakers are higher than 3 Ohms, so obviously they're not going to receive 10 watts. If for example they're 8 ohm speakers then they might get 6W instead of 10.

By the way, these figures were measured at 10% distortion, which would be horrible to listen to, but that's what nearly all the boombox manufacturers used on their datasheets.

 

I did expect something like this, thanks for the information. I think my "divide by 10" theory came about in the late 80s when everything was measured in P.M.P.O., like the 70s power wars but with distortion! Luckily if you read past the headline, some manufacturers (of hi-fi usually, not portables) would quote actual figures full spectrum and with low distortion into the actual speaker impedance, and it seemed to average out to about a tenth of the headline figure.

I am somewhat hesitant to pull the speakers apart if I don't have to, but the connections are labelled "3.2 to 8 Ohms" for the main and "16 to 32" for the bass, which appear to be in parallel so two 16s would be brought down to 8Ohms. Still throws any power figures into disarray, halving them at least. The woofers do have a different model number, but all a search furnished was that Sears was out of the main speaker.

Anyway, it sounds "of the era" to me, and I am more looking forward to cleaning up the switches and the unit itself to get it looking and working as it should!

 

Yeah PMPO is bullshit, no one actually measured it, they just put whatever number they wanted on the package, because they knew there was no law against doing so.

But amp chip datasheets provide legitimate RMS measurements, usually taken at 1,000 Hz and 10% distortion.

 

The RT-7096 would be from the year before, the RT-8097 would more or less be its replacement. The Model number appear to work along the lines of RT-X0YZ where X is 7 on detachable speaker models, 8 on all-in-ones, Y is the approximate level in the full line-up, and Z is the year.

Yes, I have a Pioneer Blue Line amp as a second amp in my main system and at good listening levels it is barely reaching 1 watt. Of course, with proper speakers with an efficiency around 90db/W/m that makes perfect sense.