Stand-alone true pitch shifting vibrato for guitar

[Willabe]

Well now I'm beginning to see. But the part of that highly proprietary optocoupler that connects to those transistors is not a light bulb. Those four elements are CdS (cadmium sulfide) photo cells or photo resistors.

Ahh, my fault, wrong name again. I'll try to remember that.

The single light bulb inside that optocoupler that really connects to Q13 collector just shines on the four photo resistors to change their resistance at the LFO rate.

Yes, so since the photo resistors are driven by the single light source, all 4 are effected by how evenly or not that bulbs filament turns on and off. It's said it changes the "wobble" of the modulator.  

This is supposed to be part of the Univibes mojo.

IMO, it would be well worth trying to figure out how to change/adjust the "wobble" of the modulators in the Warbler. Can a light bulb be placed in series between the LFOs K and the SR string?

That's fun too. Don't fret. What's a trim plate?

Yeah it is great fun when I get it right. I'm a carpenter, I don't have much experience working with metals, but I'm getting better.  

Got to break a few eggs to make a cake. Face plate, ~$20, chassis, ~$50.    

I know your just trying to keep me grounded in common sense Sluckey, thank you.

Are you sure?  

Guess it depends which side of the modulator wave your on?      


               Brad      

 

[Willabe]

The univibe also phase shifts different frequencies in each stage, see the different capacitors used (15nf, 220nf, 470pf, 4.7nf).  I recall reading somewhere this was to simulate the Leslie rotating cabinets.

With the warbler it's all the same frequency, you get 2 phase shifts which are 180 degrees, and will produce a notch and thus a phaser sound if mixed with the original right there.  And then you also add another 90 degree shift, with the third stage, but still the same frequency so that's 270 degrees.

Yes! That's supposed to be the 2nd part of the Univibes mojo. Thanks for posting that point.

I didn't want to add that in to the conversation till I could post the first part right where the guys would understand what I was trying to say.

shoggoth , have you listened to the sound clips that Sluckey and Tubeswell have posted playing through their Warblers? They sound better than the Univibes that I've played through.

To me, anything that could be added and is either switchable and/or adjustable would only be a positive at this point.

I'm going to build it as is, which is IMO already a wonderful sounding effect and play with it from there.


            Brad          

[sluckey]

Willabe, I really don't know the answer to your question, so I just decided to mess with you a bit. It was all in fun. Too much free time these days!

I've been thinking about how the wave form you posted was slightly different top from bottom.

That's something I've noticed about all the phase shift LFOs I've looked at. None have been a perfect sinewave, but pretty close. I don't have a clue as to how the non symmetry might affect the sound. I suspect that the slight difference in positive and negative half waves would make very little difference in this case.

Here's an idea I have kicked around some. The original liquidator circuit (got the warbler idea from the liquidator) did not have an onboard LFO. Instead, he used a programmable function generator capable of complex modulation waveforms. I was gonna use my HP 3310B function generator to experiment with sine, square, and triangle/ramp waveforms. But my prototype warbler showed so much promise with the simple Fender LFO that I put the idea on hold and just never got back to it. My HP does not have adjustable dutycycle so I could not experiment with non symetrical waves anyhow. I may play with that yet.

But honestly, I'm so pleased with the warbler at this point that I really don't want to change anything else. You're gonna like it too. Now git 'er done. I want to still be alive to enjoy it with you!   

[Willabe]

Willabe, I really don't know the answer to your question, so I just decided to mess with you a bit. It was all in fun. Too much free time these days!

I know, your good in my book.    

Now git 'er done. I want to still be alive to enjoy it with you!    

Ok, ok.    

Going to my buddies house at 4:00PM tomorrow, that will break the damn.


   Thanks,  Brad    

[shoggoth]

shoggoth , have you listened to the sound clips that Sluckey and Tubeswell have posted playing through their Warblers? They sound better than the Univibes that I've played through.

I just did (again), and yeah it sounds a lot nicer than the Univibe.

So the warbler puts it through three 90 degree phase shifts, you end up with a 270 degree shift.  Theoretically this would be roughly the same tone as a single stage with just a 90 degree shift.

Now I expect that in fact the saturable cores all have audibly different reactances, because I don't think the tones I hear in those clips are the same as you'd hear from just doing a single stage 90 degree shift.  So that's providing three shifted frequencies.  But that's all just a guess, only mixing in the first stage to the dry signal and seeing how it sounded would provide the proof of the matter I suppose.  The variance in capacitance values will also impact the frequencies generated.

[Willabe]

What's a trim plate?

Face/back plate. Could call it a dress plate.


             Brad    

[Willabe]

Well I just got back from my friends house.            

He did the art work in a vector program for the face/back plates for both the Warbler and GA-77.

Man is he good at what he does! It was a real pleasure to see someone with his experience and talent work in the vector program on a computer.

Next, call the engraver and e-mail him the files.


                Brad      

Edit; Looks bad because I cropped it in Windows 7 paint.

[Willabe]

Sluckey, turns out DAKA-WARE (Davies Molding) is still in business.

Look in here;

http://www.el34world.com/Forum/index.php?topic=15348.0



              Brad     

[shoggoth]

An aside - I'm working on taking a Zenith battery operated radio and changing into a guitar amp, using the tubes it came with as a design constraint.

I just listened to Sluckey's clips again, and they sound remarkably like the problem I'm trying to get rid of w/ the heptode tube (it's modulating the clean signal with some noise on the directly-heated cathode).  Maybe I should call it a "feature".

Of course it's fixed frequency in my heptode (presumably 120hz), as opposed to a varying frequency, and so can quickly become an obnoxious ring modulator sound depending on the intensity.

[HotBluePlates]

How do you have 120Hz in a battery operated amp?

An aside - I'm working on taking a Zenith battery operated radio and changing into a guitar amp, using the tubes it came with as a design constraint.

Do you also have the battery (batteries) it came with? If not, using the battery tubes may be a problem. I don't know cause I have no experience with them.

But it does remind me of the 25v or so battery required by the battery box of the first piezo guitar pickup (the Prismatone, as in Jerry Reed's Baldwin classical and the first Ovation guitars), which users swear by. If you don't have the old battery, you're S.O.L. So in that case, some guys rig up a small solid-state power supply to replace the battery.

[shoggoth]

How do you have 120Hz in a battery operated amp? Do you also have the battery (batteries) it came with? If not, using the battery tubes may be a problem. I don't know cause I have no experience with them.

No, I don't have the battery - the supply I built has a few issues I'm debugging, and thus the 120hz sneaking in where I don't want it.

[Willabe]

Went over and met the new engraver. She sure seems to know what she's doing as an engraver. I then e-mailed her the vector program face/back plate drawings. She was very happy with them because they were done in a vector rather than with a bit-map program.

Also went over to Johnsons Plastics, talked with them, got a full line catalog and ordered some color samples. Got them in 2 days and they look real good to me. I think I'm going to go with the reverse engraving stock to protect the color film and what ever gets engraved. The down side is you have to paint fill the engraving.     

I'm waiting on different colored knobs from AES, should be here Mon. or Tues. but I think I'm going with a black base with white lettering and markings. They do have a very dark blue, green and brown. They almost look like their black but would pick up and tie in with a blue, green or brown shade of tolex. White or cream colored knobs with light colored markings/lettering should provide easy to see controls on a dark stage.

I should have the plates in my hands by late next week.

Gonna warm up here next week into the high 30's/low 40's. So I can cut my eyelet/turret boards outside without freezing and get going on them while I wait for the dress plates.  



               Brad          

[Willabe]

Is this the best way to add a bypass chassis switch?

Or is it best to also lift the input/out put jacks ground feed wires to the jacks because of noisy ground current?

If this is right, then I need to add Doug's relay boards which I have on hand.


              Brad    

[PRR]

> you have to paint fill the engraving

Use wax crayons.

[Willabe]

Use wax crayons.

Hmmm.....       Thanks PRR sounds that's a good idea. But.....

The Warbler chassis won't get hot enough to melt the wax, but what about on a combo amp with say a pair of 6L6's and a rectifier tube?


             Brad      

[plexi50]

Did you finalize the schematic? Cant wait to see your results ,pics. Think when i get time i have to build another using the updated schematic. I have one more transformer.

[Willabe]

Did you finalize the schematic?

Yes. I'm hoping to drill/punch out the chassis this week.


             Brad     

[PRR]

You can mix your own crayon with a hard wax, some white pigment (maybe even a crayon), and a dash of turpentine (check that against the plastic). Hardens as the turp comes off.

Seriously: this was often used in the old days. You scrape it in like spackling a wall-crack, scrub it off the flat.

Remember that softening wax on the stove can start a serious fire.

[Willabe]

Ok, I'll try it.

Thanks.


            Brad     

[DummyLoad]

davies molding chicken-head knob with the comb is part #2300 - pg. 33 in the 2013 catalog.

allied has them   -->click me!<-- and the price seems decent...

--pete

[Willabe]

Thanks Pete.

I called them today and they said minimum order is only 100 pieces and color match is a small added fee. The women took my info and said she'll get back to me with a quote.

I'd like to get a deep/dark blue chicken head knob. They do make a blue but I think it's to light in color. She said she'll send a sample.

I'm trying to match up the colors of tolex I like with the face/back trim plate material, knobs, handle, piping and grill cloth color.    

I did find the leather handle with "footman loop" hardware I like in 6 colors on line at http://www.goodcomponent.com/index.html

Sure looks like what mojo sells and Mesa uses.

I'd also like a nice dark brown and they still make that color. In fact they have a couple of browns they make.

I asked her if they still said Daka-Ware on the knobs underside. She said she thinks that they repaired the old molds and left that out when they did.

I called back the engraver today and told her the color of the face/back trim plate. She has to find out if the suppler has it in stock and will get back to me in a day or so with a price. If it's reasonable I'll give her the go ahead.    



             Brad    

[HotBluePlates]

davies molding chicken-head knob ...

allied has them   ...

So does AES, though it doesn't appear they tell you they're from Davies. I used the rose-colored ones for my Standel.

[Willabe]

Well I talked with the engraver today and she said I can pick up my face/back plates tomorrow around noon. She apologized for taking so long. Said they had family in from out of town for Easter.    

I also have cut my eyelet boards and have the templates taped on. They look good to me, will drill them out tonight and swage in the eyelets and turrets.


                    Brad        

[DummyLoad]

I'd like to get a deep/dark blue chicken head knob. They do make a blue but I think it's to light in color. She said she'll send a sample.

on stage a dark blue will appear to be black? medium blue?

i even like the chicken if the sauce is not too blue...     

--pete

[sluckey]

Brad, would you re-post your final schematic/layout? THX...

[Willabe]

OK, here they are including the blue chicken head secret sauce.

(I might not need the 2 shielded wire runs.)


                Brad      


Edit; PT eyelet board heater PT is wrong, should be a 229A 24v (6VA) at 500mA when wired for 12v. It's a little smaller than the 229B which is 12VA. I will post the corrected board later.

Edit; Fixed LFO pot labels as pointed out, thank you Pete.

[DummyLoad]

brad, you have the rate and depth pot labels reverses.

respectfully... 

--pete

[Willabe]

brad, you have the rate and depth pot labels reverses.

Thank you Pete, but you just scared the heck out of me.    

That would have messed up my face plate because I'd have to re-do my layout.     

Thankfully it's only on the LFO schemo. The layout drawing is correct and that's the drawing I used for the face plate.

I'll fix that and repost.


            Brad    

[Willabe]

Well I picked up my face plates for both the Warbler and GA-77 and I'm very happy with them.   

The hash marks are a little long, going inward to the center on the Warbler, but the knobs will cover them.

I'll find my camera, take a picture and post with a knob or 2 sitting on them.


                Brad      

 

[Willabe]

OK, here's a couple of photos of the face/back plates.

Sorry about the glare from the sun through the window but I think you can get the idea of what they look like?

The back plates have the protective clear film removed to see the color a little better.

The 2 knobs on the left on the GA-77 are cream, 3rd is white. Knobs on Warbler plate are also cream color and a dark blue mini chicken head from AES. I need to get a few dark brown CHs from Weber speaker to see if I like them better than the cream. (I know you can't see the colors very well, will do better next time.)

I like the font style but my friend might have made the letters a little too thick, but he can thin them back to their original thickness for future builds. He thought it would make the words easer to read on stage.

Notice the small pilot center holes for the tip of the brad point bit. I need a 1/8" pilot hole through the plate and chassis for the step bit. 

Their reverse engraved and she used the smallest cutter she had for the pilot holes. The tip of the brad point when seated all the way down into the hole seems snug with no slop or play side ways/left/right. It should be self centered.



                  Brad        

[Willabe]

on stage a dark blue will appear to be black? medium blue?

Yes, tis true.

I'm kinda thinking more about what the amp will look like in the light of day or in the house under normal living room lighting.


                   Brad     

[Willabe]

Drilled out the chassis and face/back plates today. Still need to drill out for the eyelet/turret boards and choke.

Here's some pictures, sorry I need to work on getting the glare out. You can't even see the eyelet/turret boards.


                Brad      

[sluckey]

Lookin' good!

[Willabe]

I finished punching and drilling the chassis. I still need to drill a couple holes for the safety and chassis circuit grounds, plus any holes for a solder lug terminal, maybe 2 or 3.

I scratched up the back side of the chassis a bit. Can I sand it out with 220 grit on an orbital sander? It's an aluminum chassis.

Sluckey you polished your's, looks beautiful, how'd you do that? Fine grade grit sand paper on an orbital sander and then hit it with a car orbital buffer with some buffing compond?

Here's some pictures.


             Brad            

[sluckey]

Sluckey you polished your's, looks beautiful, how'd you do that? Fine grade grit sand paper on an orbital sander and then hit it with a car orbital buffer with some buffing compond?

That's basically what I did. But I was more low tech. I used 330, 400, and 600 wet/dry silicon carbide paper with water lubrication. Hand sanded in a straight line until scratches were gone then progressed to a finer grit. Then I used some military metal polishing compound applied by hand. Then buffed the compound off with a buffing wheel in my hand drill motor.

Your method will probably work better. Don't know that I'd start with 220 grit though, unless the scratches are really deep.

[Willabe]

Don't know that I'd start with 220 grit though, unless the scratches are really deep.

The scratches are not very deep. I'm not used to working with metal so in my mind 220 grit for wood is pretty fine. Wet sanding makes for a better result because of the slurry effect when sanding. I can do that. I have a 5" orbital sander but I don't have an orbital car buffer. It's going inside a cabinet so it doesn't have to be polished to a mirror finish, but I'd like to not see any difference, more or less, then the rest of the chassis. I just want to even it out again.

Thanks for the info Sluckey.


              
               Brad            

[plexi50]

Man that looks beautiful! Your really got the passion going on. I need a jump start

[Willabe]

Thanks Plexi.

It's looking good but it still has to fly.

James Taylor, "sweet dreams and flying machines in pieces on the ground".

              Brad     

[sluckey]

Any progress?

[Willabe]

Some, sanded the chassis. Looks fine now.

My wife's sick with the flu, taking care of her.

Maybe I can get some wiring done today?


             Brad     

[Willabe]

Ok, major progress today.

I wired up the PSU, IEC with self contained fuse, 2 PTs, 2 power switches, safety ground, B+ snubber and dc stand off.

Bent the leads on the radial B+ caps so they fit into the turrets.

Stuffing the main circuit board right now.


            Brad    
  

[tubeswell]

Fun isn't it?

[Willabe]

Yes!

Main board now has the 3 stage shifter parts stuffed, still need to add the fly leads from the board to the tube sockets.

LFO and CF driver is next.


       Brad    

[Willabe]

All right, a little more progress. I got the LFO/CF driver on the eyelet/turret board stuffed and laced up the B+ filter caps turrets in parallel for the CLC .

I forgot to say in the last progress report that I tested both PT's for B+acv and they where fine.

More tomorrow hopefully, my wife has been very ill with a stomach/intestinal virus for 4 days now. I think she's finally past it now.


        Brad    

[Willabe]

Since my color scheme on this build is a blue face/trim plate with a blue jewel pilot light, I'd like to go with a blue K LED for the vibe indicator.

I found 2 at RS with nice a chrome bezel, just like Doug sells, but a just a little bit bigger in diameter.

Question, will they work? Here's the spec's,

1. > 5mm, 5v, 30mA, 300mcd, 24 deg. viewing angle.

2. > 5mm, 3.7v, 20mA, 2600mcd, high intensity, 30 deg. viewing angle.

See any problems using either of these?


                   Brad      

  

 Edit; added LED viewing angle.   

[sluckey]

I experimented with about 10 different color and voltage LEDs. They all seem to work, but the higher voltage LEDs would drop out at slower and faster speeds. IOW, they operated over a narrower LFO frequency range in that particular circuit. Too narrow for my liking. They may be fine in another circuit though, or you may be able to tweak the warbler circuit to work better.

Reds, yellows, and orange (the under 2 volt LEDs) work very well with no fuss. Radio Shack has an assortment pack of LEDs that contains some yellow that look more like an incandescent bulb. The LED casing is clear with no diffuser. That's what is in my warbler. I have an orange diffused LED in my revibe. It really looks more like gold color to me.

EDIT... I recommend using red initially. Then when everything is working fine, start experimenting with different colors.

[Willabe]

Ok. I'll pick up a red LED at RS today that will fit the bezel I got from them.


               Thanks,   Brad     

[Willabe]

Got some more done, here's some pictures.

Forgot to say I fired up the 2 PTs, separately with a variac and monitored the voltage with a meter. All was fine.  

The brown, orange and green on the underside of the eyelet/turret board are the K connection for the SR coils. I left them long and kept the grid connections short and twisted with the K wires. Hammond had these wires running next to each other but didn't bother to twist them. The red and black bias coil wires were run away from these wires, I'll do the same. I'm using the same colors for the SR wires because I have the same colors they used. This way it will be easy to wire it up with Hammonds drawings.

These wires, except for the short K wire run will be run down against the chassis and away from any eyelets/turrets in the circuit board. B+ wires are down against the chassis also. I'm using 3/8" stand offs.

The 2 power switches are only tempt in. I only had SPST on hand and want to use DPST to kill both primary (+/-) wires for safety.

I hope to get the board, tube sockets and SR coil wired up today and maybe some of the controls.


        Brad    

[Willabe]

I don't have a 500K for the mix pot on hand. I can use a 1M with a 1MR across the o/x ends of the pot until I get 1, right?

I got a couple of red LED's from RS that fit the bezel I bought there. I have 4 red LED's I bought from Doug, but their 3mm (15/64" chassis hole) and I drilled out the chassis for the RS 5mm (5/16" chassis hole) bezels.

1.8v, 20mA, 120mcd, 40 deg. viewing angle.

1.7v, 20mA, 3000mcd, 12 deg. viewing angle.
  

             Brad    

[Ed_Chambley]

Killer Brad.  Man this is looking great.