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/diy/ - Do It Yourself


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How do I read the circut here? Does anyone know what the numbers are indicating?
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I dont, i hope you get it working though. Very cool piece.
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50 through 13,000 may be impedance taps. Signal from amplifier might have been high voltage, say 100 V, so selecting lowest tap (50 Ohms) resulted in highest volume, and 13,000 Ohms the lowest.
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To test, hook black (negative) lead from amp with 8 Ohm output impedance to "common", and red (positive) to 50, then to 125, 320, etc. Volume should decrease with higher numbers.
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>>1510175
This is what I was thinking, especially as they all seem to terminate onto what appears to be a transformer on the left of the device.

OP, where do the 2X etc taps terminate?
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>>1510177
Also, post any numbers you can see on it.
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>>1510175
>>1510177
yes, this is part of a PA (public address) system the idea is to keep "voltage high and current low" for better transfer of power (same idea applies to power generation and transmission power lines) this was very common during the tube era.
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>>1510176
It had been hooked up to a fire/ems scanner using the 50 and 125 terminal which produced a good sound. I guess my question would be what voltage can I run through it? Does it need an amplifier?

I want to use it as an alarm for when my wood boiler over heats. Would sending 24v(zone valve current) through it ruin it or produce a sound?

Pic is the name plate on the horn cover.
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Here is the unit with the horn cover on it.

>>1510177
As far as I can tell everything terminates to the block on the left except for two wires. I can’t easily trace them out by eye and using a tester doesn’t work as it reads as if everything is connected together. It does produce a static type sound when I use the tester on the terminals 50-13000. Only the x2 numbers etc. short out to the two connections in the middle.
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Sending DC into it will blow it out. This is an audio device and needs to be fed with an AC signal in the range of roughly 200 to 8,000 Hz. For an audible alarm signal you're better off with a Sonalert or equivalent device.
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>>1510175
This anon is correct.
NBR-115 was used on almost all navy ships for a long time. Sadly I don't have jack when it comes to the installation guides.
"X" is 100,000
The scale is Ohms (impedance) for matching.
While NOT the same.. 70V PA systems are similar in design.
https://www.bogen.com/support/productcatalog/pdfs/SysDsgn.pdf
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>>1510163
This an bump and if you fuck ut up beyond repair cobble a bluetooth speaker in it and call it done.

Pieces like this are becoming my life.

I gave 30 bucks for an 8 track player i didnt even want the other day. I got room to store it. Wtf happens if i have a heartbroken friend with a busted ass sentimental 8 track in 20 years? Or i randomly descide to build a 72 chevelle 4x4? Gonna need this 8 track.

Go ahead.

Price a new one...


Okay fine. Fuck. The new tefurbs are 60 bucks.

Wtf ever.

I got one for cheap
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>>1510539
Posts non potatoe pic.

Has sense enough to vlur serial numbers cosmetically.

Either FBI or legitimate non-autist.

FBI please leave.

Only autists here.
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>>1510797
THIS.

OP you seem smart enough to not blow this bitch. And if you do we still may be able to build or source a voice coil.

Pleasr only give this up to good friends or family if ever
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>>1510797
Just out of curiosity, could you connect line voltage from a wall outlet to it? I doubt it, but wonder what it would do?

>>1510925
My Dad had got it from my grandfather who served in WWII. It wont be leaving the family in my life time, I can tell you that. I’ve also got his original B-17 wool flight jacket and chaps as well as his headset from his days as a mechanic on the B-29, which I need to build a display case for, but that is another project.
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>>1511028
>Just out of curiosity, could you connect line voltage from a wall outlet to it? I doubt it, but wonder what it would do?

Likely fry it.

See if you can find a part number or diagram printed on that transformer can.
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Oh.. and that wire is Kapton-A. It gets fragile with age.



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