The Mellotron Group

In a message dated 11/16/2009 6:30:53 P.M. Eastern Standard Time,  
pocotron@yahoo.com writes:

Very nice, Frank.  It's a clean machine.
   Here's a few nosey questions-
-Is that bar that the tapes pass over made of nylon?  Is the  friction it 
induces due to static build-up?
-What circuit is in the box in back of the control  panel? 
-Was the flywheel pulley belt standard sized?
 
  Thanks
  -Bruce Daily

 
Bruce, 
 
The roller guides on the tape frame were all difficult to spin. I fixed  
that. The roller guides that the tape return springs pass over were the same  
way. I fixed them. The nylon bars across the front and rear of the guides 
that  the tapes pass through at the head block are very smooth and cause 
little if any  friction. Whether or not they impart static electricity to the 
tapes remains to  be seen. I have not experienced any signs of that yet.
 
The flywheel appears to have the same diameter as any other at the point  
where the belt passes over it, but the diameter of the capstan is smaller 
than  that of a M-400. The M-400 capstan has a 20mm diameter and used 6004  
bearings while the 4-Track capstan has a 3/4" diameter and takes R-12  
bearings. The belt is stock and the drive pulley and timing sprocket are  stock.
 
If you look at the photos in the album I posted on the Yahoo site, you can  
see one of the 4 pre-amp boards. The pots are connected to the boards  
themselves. Here is a photo of what's inside. The preamp boards for each track  
plug into these edge connector sockets.

 
That's all that is up top except for the on/off switch and the pitch  
control pot. In the box below where the power supply is there is a SMS-3, a  
transformer, two capacitors and a few other components. Not a Bulgin anything to 
 be seen. It looks like all connectors are Molex connectors. Even in a 
standard  power supply, if you have an SMS 2, 3 or 5, you really only need the 
large 4000  microfarad capacitor and the 1600 microfarad capacitor next to 
it. The rest of  them can be used to make neat devices to shock the shit out 
of your friends or  even total strangers. Handle with care. The swell pedal 
connector is a DIN  connector.  All four tracks run to it and then to the 
lines out, much like  a M-400.
 
Notice the scientifically designed, human engineered, user friendly piece  
of Velcro to the right. This is the hook side; the loop side is attached to 
the  lid. This is to keep the lid closed if you happen to be playing 
outdoors in  heavy wind.
 
The 4-Track appears to have been designed and built by the Gilbert Company. 
 It is constructed very much like something one might build with an Erector 
 Set.
 
One last thing. There are seven 1/4" output sockets on the back of the  
cabinet. Three above four. As near as I can tell, they are configured as  
follows.
 
                    Left channel out.        Line out (normal  mono)        
 Right channel out
 
 
          Track A  (clean)         Track B  (clean)          Tack C  
(clean)          Track D  (clean)
 
By clean, I mean that the signal from the head stack does not run through  
the preamp and therefore the player has no control over volume or panning. I 
 suppose you could run the lines out through 4 separate volume pedals 
though. I  think the intent is to run the dry signal directly to a recording desk.
 
The left and right channels can be used for live performances and go  
through the swell pedal and allow panning of the separate tracks by the player  
during recording or live performance. The mono line out is for the guy who 
just  wants to plug it into his amp and make some noise.
 
I like it!
 
Frank