Phase Array Speaker Bose 802

I discuss in this video: cross over, phase array, current limiting lamp and show you the inside of a Bose 802. The cross over is a low pass filter. Due to the difference in phase shift of one set of speakers vs the other, the speaker has a much broader wave front. This is not a Bose concept, but a concept of Karl Braun in 1905. It is just put to good use by Bose in their various speakers.
The Current Limiting Lamp is used in oscillator circuits to provide current stabilization. A lot of op-amp circuits use a neon lamp. In fact, there are quite a lot of "low-voltage (starved plate) vacuum tube compressors" that use a vacuum tube as a compressor. Basically, you can pull that vacuum tube out and put in a light bulb and accomplish the same "compression" characteristics. But, they use a vacuum tube because nobody wants a "light bulb" compressor.
Again, there is nothing new in speaker designs. Most all the concepts can be found in engineering texts from the early 1900's.
Original Work, Copyright 2015 James D. Whiteside, II all rights reserved, For consideration only, no reproduction without prior permission.

[@paulj0557tonehead]

I remember the first time hearing a Bose 802. I was 12 and it was Easter Sunday 1978. I was at King's Island in SW Ohio (you remember the Brady Bunch ep where cardboard tube with Mike's drawing gets swapped with the poster...). Anyway, I was sitting there eating an elephant ear concession snack with my parents and little brother, when up comes this little impromptu, 3-4 people music singing group with pre-recorded backing music. Their sound system was portable, and I just remember sitting there hearing the small Bose box with two holes pouring forth the cleanest most perfect fidelity I'd ever heard. I was a technically minded kid and yet I was absolutely baffled by what could be in that box, not knowing it was just speaker cones. When I did finally learn this it was 10 years later. It made me realize the significance of giving the consumer a mystery to keep them guessing.

[@tubical71]

Cool video, well explained!

[@djsimonrossprice9400]

Hello sir
Wonder if you can help.
I've been given 14 bose 802s mark 2 8 work fine but 6 dont work at all. Fuses are fine but no sound, any idea was to what i can do. Many thanks for your help.

[@deepblueharp]

The most common issue is that the braided lead from the speaker's wire terminal to the speaker cone has broke. They are fragile. You will need to remove one speaker at a time and inspect the connections and re-solder the connections. The braided cone cable is woven with very fine wires, fragile, and acts as a candle wick. Be careful when soldering. I suggest using 20ga solder wire and a fine tipped-heat controlled soldering iron set to 675F. Like a Weller WES51. Don't use a $24 solder iron, those make a mess. If the soldering station seems expensive, think of it like this: the $120 station is an investment because you will need it for other things. A tech will charge more than $50 to fix 1 speaker. If there are other issues you discover, please email me and I will try to help you further. Good luck, you can do this.

[@ssgeek4515]

Hi Simon Ross.I rewired mine completely with better filter caps inside.If one driver is blown it will break the circuit.Best way is to put a multimeter on inputs on low ohms and press each driver cone every one should cause the display to change - if not that driver is bad. Wiring in Mrk 2 each corner 1-4 then middle 4 is 5-8.Theres no lamp to pop only a ptc switch (thermistor ) so it's either driver fail or wiring.Lucky guy having them..Still the best for PA Speach outside 12db up vocal range.Mine 1987 date stamped

[@feetnframes]

Whats your thoughts on stacking these either vertical or side by side, I have seen both done, but i did wonder if placing say 2 stacks of 3 side by side if the would be phase issues

[@deepblueharp]

+John Simpson Stacking will not cause phase issues. However, wiring will. If the leads (Signal and Ground) are swapped on one speaker and correct on another speaker, that creates a phase issue.

[@djflex83]

can i run a pair of the bose 802 with crown XTi 4002 amp ?

[@deepblueharp]

+VDJ FLEX The amp delivers 650 watts per side. The Bose is good to 250 watts. I'd use a smaller amp.

[@DeanusMcWildthing]

Hi there. I have a pair. On the back they say Bose 802 Series II. I downloaded a series II manual and the wiring bares no relation to what I have. In fact what I see in mine is exactly what you show here, but I cannot find a series I manual online. The problem I have is that the top row of speakers has stopped working. All I get from the speaker is the High frequencies. No low end at all. What could be the cause of this?

[@deepblueharp]

See my video on Bose 802 Common Failure. You may very likely have a crack in a speaker lead. I place an audio source to the speaker and start wiggling each terminal wire until I find one that crackles. Once it is resoldered, the speakers row starts working again. I have repaired this failure a lot. Check the fuse, just in case. The capacitor would be a super rare failure. Update me when you get the speaker working.

[@ssgeek4515]

DeepBlueHarp Hi.I have series 2 pair that uses a polyswitch rather than a lamp,also two caps..20uf and 5uf.
it's almost impossible sourcing the correct replacement polyswitch.Markings are 0411 703 followed by B.Made in mexico.Bose,at least in the UK don't reply.Have diagram.will upload it sometime.

[@ganormand]

you mentioned another video on phase array...I couldn't find it

[@deepblueharp]

It is still in the making. I got distracted on my tone stack series.

[@djflex83]

so the crown XTi 2002 will be better .....

[@deepblueharp]

Yes.