Fender Vibratone crossover

[surfkat]

I am trying to recreate the crossover network and relay switching of a Fender Vibratone cabinet. It looks like the crossover is active on the signal sent to the normal speaker and the Vibratone gets a full range signal. Then when the Vibratone is switched off the normal speaker gets a full range signal. Is that correct? I would guess that this LC circuit is a mid range cut, any idea of the frquency? I am not sure of the values of the components shown. The inductor is labeled "Mh 1.2". I guess that is Milli-henry and not micro-henry. The C2 capacitor is labeled 2.0 but does not specify uF, pF or nF. Any ideas on this stuff?

Also I am confused about the function of and need for C3, C4, C5 & C6  capacitors. Anybody care to explain to a noob like myself. Thanks for your help.

 

[PRR]

1.2mH and 2.0uFd would ring at 3,250Hz.

The tank goes high-impedance at resonance so the "normal speakers" will have a dip at 3KHz.

Can't know Q and bandwidth without impedance. Rough-assuming 8 ohms: dip starts at 1KHz and goes to 10KHz.

This is likely the band where the spinning-speaker has most effect, so you'd want to dip the stationary speaker.

> need for C3, C4, C5 & C6

C4 reduces turn-on click and switch arcing.

C5 C6 do the same thing for the motor speed relay contacts.

C3 is a spin-speaker low-cut cap. Ass-uming 8 ohms, 200uFd (spelled "MF") cuts below 100Hz.

> Ben Franklin never patented his inventions

The patent system we know didn't exist until late in Ben's life. Tommy Jefferson was opposed to patents, at least the way it was done in England. Later Tommy worked out a system he liked better.

 

[surfkat]

A Thousand Thanks for the perfect reply answering ALL of my questions including the ones I did not know I asked. It's funny you should mention Tommy J. because I just started reading a biography of him. Brilliant guy IMHO, as are you PRR. Now on to get that speaker baffle spinning...

 

[mg73]

Old topic but..

When my Vibratone cabinet is activated with my Superreverb I get distortion in the upper frequencies on the superreverb.
When I hit the pedal switch and disengage the VIbratone and just the Superreverb is activated it sounds fine in the upper frequencies .

I replaced the 2uf and the inductor but still the same problem,
any ideas?

 

[PRR]

Put 10 Ohms 10 Watts across the L and C.

But this may be unsolvable, if the superreverb dis-likes the impedance curve of the "crossover". Was it a recommended combo amp for the vibratone?

 

[CJH]

I realize this is an OLD post.. but here goes.
I'm planning a *small* vibratone build using a pull from an old transistor  organ. It's got  the Styrofoam cheese wheel with a 8" throat,  a 25W (50W-peak) 8"/4ohm Jensen (C8R). but with  the standard TWO speed Motor assembly. I intend this for use with two small vintage amps; a brown face Princeton and a '71 Deluxe Reverb that I recently rebuilt from a bizarrely modified and abused example .. acquired really *cheap*.
I found PRR's discussion above highly informative!! first I would like to maybe correct(?) an "assumption" then give my ideas on general considerations and my changes for my particular project.
The Fender Vibratone was a Silver Face era product. On the cover of the owners manual it is shown connected to a Twin Reverb. Fender rated these *large* Vibratone cabinets as good to 100 watts. Almost ALL Silver Face Fender amps with over 22W output were dual speaker - 4 ohm speaker Loads (EXCEPT Super Reverb with 4 speakers and a 2 ohm load). All the Smaller amps were single speaker and 8 ohm ( as are my examples). I am arguing that the physically large Vibratone was optimized for larger amps and a 4 ohm Load.  In fact the Vibratone Shipped with a 4 ohm speaker. 
I initially treated the C2 capacitor and the L1 inductor as first-order high pass and low pass filters respectively(sending Highs and Lows back to the Amp's speaker).  so into 4 ohms ( high power fender amps) the "dip" as PRR describes above would
begin at 530Hz ( the Low pass L1)  and goes to 20K Hz (the High pass C2), 
the resonance Frequency is 3.249Hz AND THE Q =6.124

To Get the SAME values into an 8 ohm load , L1 would be twice the value (2.4mH) and the the C2 Half the value (or 1uF).
The resonance frequency would be the same 3,249Hz and the Q also identical at 6.124
**These are the values I will use.**

The C3 capacitor is dependent on the Spinning speaker which for me ( currently) is 4 ohms so I won't change that.
For the Guy above with the Super Reverb to get the same frequency responses into 2ohms,  C2 = 4uf  and L1 = 0.6mH .

 

[CJH]

now to my actual questions..
...I have some more general electronics questions, best practices etc.  I'm going to use a relay with 12vDC coil. I have a 12v transformer/bridge rectifier/capacitor for the control circuit power.  The Schematic i the post at the top, appears to have an AC voltage controlling the relay;  shows a cap across the Low voltage relay switch labeled  01 ? and 1kv ? . and a cap in parallel with the mains switch  and caps across the 110vac to the motors C5,C6 ( on what appears to be the return leg?) and a Fuse in the mains leg opposite the switch. Some of this just looks wonky. 

For the Audio signal parts I will use audio crossover quality caps and inductor. But for these "noise suppresser??" caps, what values and types would be suitable? and general guidance on wiring it with a grounded 3 prong plug. 
????

 

[Khron]

Especially since those will be on the mains side, you're going to want X2-rated safety capacitors.