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Hello there,
I have a Beomaster 6000 4-channer reciever. Restored it quite deeply I might say, making even the boards #07 Level amplifier, #10 Tone amplifier and #16 SQ Decoder altogether new, including PCBs. Though changing all the components to new ones, not only the capacitors
Because had occasionally weird cracling noices on one channnel and low level on the other. Did not want to bother to seek and find that fault. Quessed it would be a transistor or resistor somewhere which behaves oddly when the temeprature rises. Also the pertinax PCBs of these three were a bit warped, maybe causing those problems also…
And by doing these reproduction boards preventing the same fault on an another channel. In the nearest future perhaps, just after having this fault repaired. And there are four different channels creating possible problems…
But, I noticed it says on a sticker on the with screws detachable bottom cover plate, under which the SQ-module is installed, that ’4-2–4 SQ matrix decoder fitted. Type: BASIC’
The question arises, on the days way back then, what kind of other SQ modules were available to be chosen fo this Beomaster?
Is there anyone on the lines who knows? And if there is, please, help me find some information of those SQ modules so that I can reproduce also these variations. Would like to hear how they sounded…
BR Jouni
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I had one of those – the technical manual on site is the one I scanned in I think! There was a service manual as well though will have to see if I have the scan of that. As you know, the 6000 deals with two types of quad formats – SQ, as mentioned which is a matrix form of quad and CD4 which has 4 discrete channels. The input for that would be from a Beogram 6000 or 3400 but would require either a MMC6000 or 5000 cartridge as the rear channels are pressed at very high frequencies on the LP and then decoded back to the correct frequency. I had all of these in my time – I think I still have the cartridges and the BG6000 (though this was water damaged when at Bellac and has been converted into the totally mythical BG4001 and the CD4 module given to Tim Jarman! I confess to not being massively impressed with SQ – I do have a couple of LPs and CD4 was better but still not really my cup of tea. The BM6000 was quite a design for the time – always thought it looked like the Medical bed in the original Star Trek! Of course, as you well know, the innards are joyfully low tech! Very good looking set – the matching Beocord 5000 was of course only stereo and absurdly complex. I think I still have one somewhere but will be non operative! The quad fad was hamstrung by the cost and the lack of media so didn’t last that long. The Beomaster 3400 was in some ways rather easier to live with – though it did have the most bizarre tuning scale – I guess, as Tim states on Beocentral, that they had to do something to fill in the space! I think both the 6000 and 3400 on the Beocentral site were mine! To answer you question however, I do not think alternate SQ decoders were offered – not in the UK anyway.
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Thanks, mcevedy for you thorough story
I do have BM6000 as is mentioned here before. I do also have by me restored BG6000 with MMC6000. So, I have experienced both SQ and CD4 coded LP’s. IMHO, SQ (and also the third and also matrix decoding specification i.e. QS) coding is more forgiving to imperfections on a LP than CD4 is. But CD4 is far more precise in channel separation, and thus more loyal to the studio mixing reproduction…
I also have restored this over-engineered, complex and for an engineer like myself intriguing BC5000 which sure enough is only a two channel tape recorder/player. Although I do not right away understand why on the BM6000 there are two separate DIN connector for ‘TAPE4’ input enabling to connect four channel tape recorder/player. Might this be due to the fact that BM6000 was designed in that time when four channel HiFi was to be mainstream and this enabled to connect e.g. some BC reel-to-reel tape player with four-track head. The similarly designed than BM6000, the BC5000, I think, was made afterwards when it was already seen that people actually do not want to pay four channel equipments right after they have just purchased HiFi stereo. So B&O “downgraded” this way its top of the line equipment series in all silence. But this is me guessing
Still remains the riddle from the beginning. What does it mean when on the bottom of my BM6000 it says that the SQ-decoder inside it is “BASIC”…? I hope somebody could lighten this a bit
Jouni
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