65 Suitcase TUBE amp question.

[rusto]

Have an early FR. Wondering what the two yellow-ish knobs in the lower right corner do.
http://www.flickr.com/photos/33536929@N06/3120080639/
Figured/found out that the pot in front of the middle transformer is for the bias. I'm pretty sure I messed with it (and the other knobs) years ago and nothing has blown up. I fiddled with them again a few days ago. Hooked up an ipod. Noticed nothing as I twisted dials. Tried to leave everything how I found it. Which was in the middle for each one.

[sean]

Hey Rustofunk,

Nice set of photos on flickr.  The tonebars look cool and unique.  I have never seen that type before.

I was scratching my head about the third pot on the namerail, and then I noticed that it was not connected to anything.

Why no photo in full glory with her silver top on?

sean

P.S. - sorry that I can't help on the knobs-on-amp question.

[Rob A]

The tonebars look cool and unique.

Yeah, it looks like they machined away part of a solid bar of aluminum. Thanks for the pics, sorry I'm no help either.

[james]

Here's an interesting clue...a VIBRATO PEDAL jack?? Maybe this is a custom job with the Fender Twin built-in like Kenneth Manning's Executone:

http://www.fenderrhodes.com/cgi-bin/gallery-display?id=4

[michaeltristan]

Well...  are those 6l6 power tubes?  does not look like a twin reverb however.   shuld be more preamp tubes if it were.  some kind of tube power amp 'tho.  Looks like a very interesting instrument you have there.

if you could list the tubes,  that could help identify the power amp.

[sean]

Aha!  Now I understand James!  
Or do I mean "Now I understand, James!" ?

He points out that one of the photos shows a jack labeled  "Vibrato Pedal" -


And the seemingly non-sequitur pointer to the Executone clearly shows a speed and an intensity knob.  And the pedal that the caption calls a "Volume Swell" pedal, is probably what we know as tremolo (variation in volume) on-off control.

But the 65 Suitcase has the pedal jack labelled "Vibrato Pedal".  I suspect it is the common misnomer (tremolo mistakenly called vibrato; vibrato mistakenly called tremolo).

This misnomer is repeated here:  http://www.fenderrhodes.org/ch11/fig11-8.jpg
This schematic shows a switch that turns the "vibrato" effect on and off, as well as two potentiometers that would control intensity and speed.  But this circuit creates variation in volume (with the variation of the two outputs out of phase), so it should not be called vibrato.

Anyway, this leads me to believe that it would be interesting to test the 65 Suitcase for tremolo.  I would bet that if you short the "vibrato pedal" RCA jack, it would turn on the tremolo, and maybe the two yellow knobs control speed and intensity/depth of the tremolo.

You can be certain that this 65 Suitcase does not have ping-pong-panning/stereo-tremolo, because all four speakers are wired in parallel.  See http://www.flickr.com/photos/33536929@N06/3120080587/sizes/l/

The 1/4" jack that was added to the side of the amp/speaker case above the input jacks looks like it is supposed to be a speaker output, but I can't clearly see if it is wired correctly.

Sean

[rusto]

Nice. You are indeed correct, Sean. I use a twisted off rca cable to activate the tremelo. (How would vibrato work anyways? I thought tremelo was volume modulation and vibrato is pitch modulation. Another post, I suppose!)
"Speed" and "Depth" controls, they are.
Upper phono jack: long story short.
The upper jack works as an "external speaker input" when the amp is off. It does not work with the keyboard plugged into it.
When it's still being used as an ext spkr and the Rhodes' amp is turned on, it adds about half (or maybe even a quarter) of the Suitcase amp's normal output.  Plus, it distorts easily. Though I could be wrong about the output being about half-ish. I'm using a Peavey Classic 20's Ext Spkr Output. I'm assuming the Rhodes amp is lowering the Ext Spkr's input to be able to run it through it's own amp. Perhaps if I was using an 80watt amp, the Rhodes amp's output would sound normal. Also, tremelo works with this setup.
Keyboard into the regular input + dummy plug into the top jack (adapter or cable plugged into nothing else) gets you NO sound at all.
Whadayathink of that?
For bonus points, check out my soon-to-be post about my student model.
Also, I added a pic "in full glory."

[Groove4Hire]

Hey... Congratulations!! You are the owner of one of the very first Sparkletop suitcases built! According to Kenneth Manning,. the very first Sparkletops were built with a tubeamp and no vibrato, only bassboost and trebleboost. Now, it seems there is a vibratofunction on the poweramp there but I've never seen one of these up close myself, only one on Ebay a few years back... These are almost to be regarded as prototypes. Take out the bottom left ke, you might find a stamp on the side of the key with the date and year... My guess would be 1964... My Sparkletop is from September 1964 and it has the solid state amp.

[rusto]

Yep. It's a low serial baby. Your knobs look like they're all metal. Could you take a close-up picture of them?
Forgot about the toobs. GE 6L6's and the pre has 2 12ax7's and 1 7025, all RCA's.