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WhiskeyRebel

WhiskeyRebel

Registered thread killer
Today I picked up the Webcor reel to reel I won on Ebay.

A. It is all in one piece. Apart from a few scratches on case, some faded labels on the panel and some loose pins on the safety connector under the tube cover, it looks better than I had any right to expect.

B. It is a standalone powered tape unit. Each channel has its own little EL84 and output tranny feeding a little square-field-case speaker. It also has external speaker and external amp outputs.

C.There are no tubes missing. The EL84s are Webcor stamped and marked "made in Great Britain". The 12AU7 driver (apparently shared by both channels) is also Webcor branded. All the 12AX7s and 12AU7s on the input board are labeled Amperex. So there are no recently made firecrackers in the thing. Must be silicon rectified because there is no rectifier tube on the chart or in the deck.

D. I know I should not have plugged it straight into 120 and flicked it on but I couldn't resist. So I plugged an old Les Paul copy into one of the mic jacks, set it for monaural and WHHHOOOOOOAAAAAAAAAAA!!!!!!!!!!:guitar: Even if I never get the transport working, this thing works as a HELLACIOUS guitar amp!!! Absolutely MONDO gain and sustain for days. I'm talking Spinal Tap sustain. :rockon:

Of course I still would like to see if it can be run as tape deck. What is the right kind of oil to lubricate the mechanism, and how will I know where all the lubrication points are?

Now here is an interesting idea - could I run the external speaker jacks into 8-Ohm load resistors paralleled with a high-resistance voltage divider to extract a line-level signal that has the extra flavor from the EL84s and their OPTs? This thing could be a secret weapon for mastering my band's tracks. Dump the mix onto tape at 7 1/2 IPS with the meter yellow, then run it back through the output tubes with a little pepper on the level.......
 
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Find yourself an old output transformer (it need not be a brute! any small trany from a low powered amp will do) and one that has a primary impedance of 50K ohms to, say, 150 K ohms. Wire the output of the R2R speakers 8 ohms into this transformer's secondary 8 ohm (or 16 - 16 etc.) and the primary on the trany will be your input to the line level connections.

Of course this come with the usual precautions of; VOLUME CONTROL at minimum, test speakers connected, do not do this at home unless you are a licensed tech .. etc. :D

Paul
 
OK, I see where that would step the voltage down to line level and isolate it. Thank you for the tip.

Any recommendations on the type of oil to lubricate the mechanism?

Could I damage anything by running a guitar through it at a high enough gain to generate heavy distortion? That is, assuming the speakers do not fry out and cause it top operate without a load on the OPT secondaries.

Also, how much risk is there to damage this if I operate it without replacing any old electrolytic caps inside it?
 
Well I finally got the drive belt out of the thing. I had to unmount the capstan flywheel and slip it through the gap between the motor shaft and the chassis, because the stepped pulley on the motor shaft would not come off.

The belt is basically a large O-ring. Is there a shop locally in the Detroit area that carries lots of sizes of these, or should I expect to have to order one off the web?
 
That belt sounds like a nice one I have from an Ampex. I know its a long shot but what size do you need? What is the model # of you Webcor?
 
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The Webcor is a Coronet Regent. The circuit diagram says Model 2007. The belt has a diameter about 0.100" (2.54 mm) and its circumference is approx. 15.5". That's estimated by folding it as near to half as it will go and doubling the measured inside length. Amazingly it still has a slight amount of stretch and give to it and is not checked or brittle. I am not betting that it is at its original length though. I don't know how to find out what it is supposed to be.
 
Whiskey, do a Google search for tape deck belts. There is a page out there that sells them and explains how to measure them. IIRC, mark the belt with a pen (I used a piece of tape) and measure either with a flexible tape or a piece of string. If it had any pull when it was mounted (would spin something), subtract 5-10% of the length and that is approx the measurement you want.

I've used rubber o-ring stock and super glued the ends, works for me. Try a small plumbing shop (Mom and Pop type if there are any left) Bob
 
I will dig out the belt see if it could work.

The PRB cross has 1 belt listed for Webcor 2007 -
Replacement # OB14.0
Round Rubber Drive Belt
14.0 Inside Circumference
.103 Cross section
 
Thank you for the tip. There is a plumbing store called Warren Pipe around the corner. I can check there.

What is the PRB cross?

Man. 14.0" to 15.5" No wonder it only turns at one speed.
I have done some checking on standard O-ring sizes and there are a number that are close enough to try. Based on my measured size, 15.5 circ = 4.94 dia
#159 O-ring is 4.987 ID x 0.103 sect
#158 O-ring is 4.737 ID x 0.103 sect

If it has really stretched THAT far, 14.0 circ=4.45 dia
#156 is 4.237 ID x 0.103 sect
#157 is 4.487 ID x 0.103 sect

There are also standard sizes in the same circumferences with a nominal 1/8 sect but that brings the actuals section dia up to 0.139. That might have too much tension and side-load the bearings.

What material should I look for? Buna? Silicone? Neoprene?
 
WhiskeyRebel said:
B. It is a standalone powered tape unit. Each channel has its own little EL84 and output tranny feeding a little square-field-case speaker.
Click to expand...

There are a number of old tape units with quality single-ended amplifiers. A model of Roberts (770X?) has a pair of tube-rectified 6BQ5 amps, SE, with EF86 and 12AT7, IIRC. These RTRs often go cheaply, but are heavy for shipping. If you're in the right place...
 
The plumbing store did not have a large enough size O-ring but I found a store that did. I'll post a new thread with the info.
 
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