Olds Dad

Anyone out there techno savy with the OE radios in these old beasts (I'm talking the tube radios here - '55 Olds specifically)

I understand that the tube style with the separate power unit (DC to AC vibrator) use 4 ohm speakers as opposed to modern 8 ohm.

I need to replace my rear speaker (seems to be a 6 x 9).

Are these available? Anyone ever have them reconed? Any advice?

The front speaker is a round guy (behind the clock bezel) - not sure if there's a replacement for that one..

I guess I don't really understand the 4 vs 8 ohm piece

oldcutlass

The ohm rating is impedance. I am almost certain that your car had 8 ohm speakers.

Olds Dad

Just spoke with Greg at
http://www.turnswitch.com/speakers.htm

very knowledgable and helpful - GM "Tube" radios were all 4 ohm setups - the transistors were 8 ohm (sometimes referred to at 10 ohm)

He has all the speakers for 50's GM stuff on the shelf in either 4 ohm or 8 ohm configurations - very reasonable prices too

Russ P in MD

It's my understanding that modern speakers are mostly 4 ohm. From what I've read, if you use a lower ohm rated speaker on an older radio, the radio will eventually fry. I think the factory radio in my 67 Camaro was set up for 10 ohm 6x9 and 4x10 speakers. One work-around would be to wire up a pair of 4 ohm newer speakers in series, to run with an older 8 ohm radio.

There are several places around that recone, I think they can pretty much do any size. It's not cheap, so it may be less $$$ to replace. The guy Greg you are talking with is considered one of the "go to" experts for this older radio stuff.

BILL DEMMER

another work-around would be to mount an amplifier that can accept a high-level(speaker) input, and use any speaker you want.


bill

MDchanic

Tube output stages are not nearly as sensitive to speaker impedance as transistor output stages. Just about any speaker that makes noise should work fairly well.

And, yes, many, if not most, modern aftermarket car stereo speakers are 4Ω.
8Ω is the older standard.

The lower the impedance (resistance), the more easily current will flow through the speaker.
The more easily current flows, the more current will flow.
The more current that flows, the greater the force exerted by the voice coil on the magnet.
The greater the force, the more the movement of the cone.
The more the movement of the cone, the louder the sound,

BUT...

The more current flowing through the speakers, the more current flowing through the output transistors, which, if they are not designed for it, will overheat and burn up.

So modern amps with more stable, durable, heat-dissipating transistors can handle lower speaker impedances. Tubes behave differently than transistors, so this is not an issue to the same extent.

- Eric