1920s vintage speaker with a guitar amp (Impedance problem)

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bzblues
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Joined: Tue Nov 10, 2020 4:01 pm

1920s vintage speaker with a guitar amp (Impedance problem)

Post by bzblues »

Hello everyone!

(I apoligize in advance if I ask noobie quiestions, but I'm a beginer in this matter)

I have a 1920s vintage speaker that is in a pristine condition! I intent to use this speaker with a small powered guitar amp that I've built. The guitar amp is called "ruby" wich is a 9v powered 1watt amp and it works well with 4ohm and 8 ohm speakers.

This vintage speaker is 1000 ohms and obviously doesn't work out porpperly with the guitar amp because of the impedance. So, I started to do some research and I found out that you would have to use a "step down" or "step up" impedance transformer. Now, here is when I hit the wall because its an unknown territory for me (yet)

I found out a website that allows you to calculate the type of transformer that you would have to use, but it seems that the results are not "realistic" but still, maybe I'm missing a few things.

What would you recomend to do in this particular scenario? again, its a small guitar amp (1 watt, 9V powered, works well with a 4ohm speaker) and I want to use it with this 1920's vintage speaker that is a 1000 ohm.

Is it possible to do?

Thanks a lot in advance!

Brian.
sluckey
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Re: 1920s vintage speaker with a guitar amp (Impedance problem)

Post by sluckey »

I'm thinking the 1000Ω is probably for the field coil, not the voice coil. Got a hi-rez pic?
bzblues
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Re: 1920s vintage speaker with a guitar amp (Impedance problem)

Post by bzblues »

Hello, everyone! thanks for the replys

Here are some pictures. I have 3 speakers of this kind and they all have the same type of coil and magnet. The screw in the back acts as a On/off switch I would say. You screw it and it makes contact and you can hear the speaker work. 

Sorry for the messy pics, its not easy to shove the cellphone. The back lits are not possible to open except for one. 

Here is more info about one of the speakers: http://earlywireless.com/celestion_c12_picinfo.htm

​​​​​​​Cheers! 
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pdf64
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Re: 1920s vintage speaker with a guitar amp (Impedance problem)

Post by pdf64 »

A photo clearly showing the component that the wires connect to would be beneficial.

Are there definitely only 2 wires from the speaker assembly?

Are any of the components magnetic?

I get the impression that it’s not the standard magnet / polepiece / voicecoil / former / cone design.
Maybe more akin to a cone attached to a solenoid slug assembly.
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bepone
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Re: 1920s vintage speaker with a guitar amp (Impedance problem)

Post by bepone »

if is 1k ohm really speaker impedance, then this is perfect for OTL tube amp! in cathode follower or in anode, tube can be some high current TV deflection, many many options, working on low voltages for this purpose 100-200V
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