Vibracaster - or "How to turn your Valvecaster into a Tremolo"

[frequencycentral]

Where did you learn about oscillators btw?

I've built a whole bunch for my modular synths. This one was my first PSO though, thanks go to R.G.: http://www.diystompboxes.com/smfforum/index.php?topic=70056.0

[Br4d13y]

so the circuit to make it a tremolo is an oscillator. correct me if i am wrong, but can i take one stage of your "crushed glass" as an oscillator, and make an all tube version? just a thought.

[frequencycentral]

so the circuit to make it a tremolo is an oscillator. correct me if i am wrong, but can i take one stage of your "crushed glass" as an oscillator, and make an all tube version? just a thought.

No - I tried that already! Not without major modifications. Besides, the Vibracaster oscillator is a sine wave, whereas the Crushed Glass oscillators are pulse wave with roughly 25% duty cycle. Sine is the classic wave for tremolo. The Crushed Glass oscillators are not very stable really - that circuit is tube terrorism, I came across the idea while I was torturing a breadboarded Valvecaster and it made a high pitched whine. They're best suited to just making an unholy racket on their own!

[Br4d13y]

i was hoping for an all tube tremolo, this is pretty close though, maybe i will look into it..........

[kurtlives]

Tubes need too high of a voltage to get them to oscillate. I would be silly to try and do it with a stompbox.

[Br4d13y]

Tubes need too high of a voltage to get them to oscillate. I would be silly to try and do it with a stompbox.

maybe we need to find some lower voltage tubes

[solderman]

Hi Rick or any one else who might know.
I really like the 5 knob Vibrocaster and plan to do a PCB and fit it in to a Hammond BB. (the 12AU7)
I especially like the like the idée to have a tremolo and booster combined.
I also happen to have a couple of MAX1044 voltage boosters in stock so I thought that I could let the filament and the LFO get 12V (direct from my 12V 800 mA wallvart) and the tube 24V to give it more headroom and fatter dist when I turn the gain up. Is that a good idee and if so do I have to change any resistor values by the tube?? Im a noob to tubes in pedas.

//Solderman

[frequencycentral]

Hi Rick or any one else who might know.
I really like the 5 knob Vibrocaster and plan to do a PCB and fit it in to a Hammond BB. (the 12AU7)
I especially like the like the idée to have a tremolo and booster combined.
I also happen to have a couple of MAX1044 voltage boosters in stock so I thought that I could let the filament and the LFO get 12V (direct from my 12V 800 mA wallvart) and the tube 24V to give it more headroom and fatter dist when I turn the gain up. Is that a good idee and if so do I have to change any resistor values by the tube?? Im a noob to tubes in pedas.

//Solderman

The MAX1044 has a maximum input voltage of 10.5 volts (although I have used one at 12 volts - my bad), so a LT1054s would be a better bet. I've tried plate voltages up to about 44 volts using a MAX1044 - looks good, as at low voltages tubes tend to 'round off' the tops of waveforms. Best bet would be to breadboard it and see if your ears think it's worthwhile.....

[solderman]

Best bet would be to breadboard it and see if your ears think it's worthwhile..... 

OK, Thanks Ill do that and get back with results

//Solderman

[kurtlives]

Finished my build last night....

Has some issues though...
I wired speed (3) and depth (3) backwards at first. Though I had them reversed the pedal still works but depth controls the speed and the speed control does nothing.

When I hook the connections up properly the tremolo does not work.


Also there is a slight volume loss when switching on the tremolo...Normal?

I would really appreciate if someone could look over my vero layout.

[frequencycentral]

Quote from: kurtlives on October 17, 2008, 08:48:02 AM<blockquote>Finished my build last night....

Has some issues though...
I wired speed (3) and depth (3) backwards at first. Though I had them reversed the pedal still works but depth controls the speed and the speed control does nothing.

When I hook the connections up properly the tremolo does not work.


Also there is a slight volume loss when switching on the tremolo...Normal?

I would really appreciate if someone could look over my vero layout.
</blockquote>


You're using the layout on page 4 of this thread right? Your ground jumper goes to L12, it should go to O12. That would screw up the speed control, and means the oscillator has no ground connection.

As for the volume loss:


Quote from: frequencycentral on September 23, 2008, 09:26:45 AM<blockquote>


</blockquote>

[kurtlives]

I am using the layout on pg 5 that Adriano and myself collaborated on.

[solderman]

i was hoping for an all tube tremolo, this is pretty close though, maybe i will look into it..........

Tubes need too high of a voltage to get them to oscillate. I would be silly to try and do it with a stompbox.

Hi
Here is one that made just that.
From the text of the ReadHead I assume the power circut are fairly the same for the Tremler.


The Swedish "Gooobliguugyy" meas:

"TREMLER
Tremler is a Tremolo/Boost pedal. loaded with two  6021:or
Its based on the Fenders Vibro-Champ. Currently running at about : 2.5-6Hz in tremolo."

From the Redhead
".. It is powered by an external 12VDC adapter, internal boosted to 165VDC.
There is no semiconductors in the signal path.
mind you, this is not a NanoHead clone."

in my opinion those are nice builds

//Solderman

[solderman]

Sorry
Forgot to add the link. here it is

http://www.zeta-sound.se/tube.html

//Solderman

[frequencycentral]

I am using the layout on pg 5 that Adriano and myself collaborated on.

Ok I'll look over it later in more detail, but it looked good on first glance and very similar to your layout on page 4 which I checked in detail. So you should check your build for wiring errors and solder bridges. Also post you voltages for the oscillator, mine are on page 6 - you need to stop the oscillator as I did by removing the speed and depth pot to get meaningful static voltages.


EDIT: While messing around and debugging it is possible that the oscillator will stop if not wired up correctly, to make it start again turn the power off and then on again.

[DiamondDog]

PSO bleeding would give a tick, no???

I'll get back to this later; I have to go into rehersals now for the silly season in OZ (ie Summer, beaches, parties, etc.) , so I'll be unable to do any serious soldering until the middle of February. Back to the The Tone God's Bullitt for now!

Good luck- you've done a great job on these circuits! I appreciate your work!

Cheers,

DD.

Correct, PSO bleeding would give a tick, so in you case it would be good as it would confirm the PSO is running. Shame that you have to wait so long to debug - that would do my head in! If I have an effect that need debugging I simply can't sleep until it's done!

...

Enjoy the beach and parties while I freeze my ass of through another British winter! 

Firstly, if having to wait to do a debugging does your head in, you need a hobby. Like a Frankenstrat, for example! 

WeI had a day off ( ) and I debugged it in about the same time as it takes to change a pot.

I just went with intuition, and one pot was only letting through 100K no matter what I did. When I opened it up afterwards, there was lots of little bits inside, and I'd say the wiper was dragging debris as it was turned. What did you say about being at zero degrees turn and being a straight valvecaster??

Change the pot- instant trem. I would like a level pot in there to balance it in my rig, so I'll go back and fiddle the valvecaster basics. But good job!

Interestingly, I saw the new schem version, and without the diode or electro, I didn't get any audible ticking. I'd suggest that people try without these two components, and if they need them, they know where to put them.

But that has to wait- there are beach, sun and good times to be had!

(Where abouts are you based in the UK? I know a band in the Middlesborough area, and the lead guitarist is uses my pedals. You may have to be quick to see them- from what I've heard they're on the verge of killing the egotist vocalist. The vocalist doesn't write the songs, but he's keeping the fees...)

[frequencycentral]

Good news Diamond Dog! Debugging often seems to be really simple things. Interesting that you didn't use the diode or cap to prevent ticking, I did find before my 'fix' that it was noticable with some amps but not with others, and also depended on what other pedals were before it and after it. Check it at HIGH volume. Maybe I'm just being precious, but I had to find a fix that prevented it ticking under ANY circumstances.

I'm in Coventry, UK - Middlesborough is a long way away - and then there's the language barrier too!

[solderman]

Hi and thanks all for the good info on this one (especially Rick who has design it)
After about 20+ projects I was beginning to wonder what type of project I should do next. Yet another distbox did not feel all that inspiring. Then I found this one and now I am really keen to build it. To do so I have made a DIY project file to etch a PCB. It is not verified yet so If someone spots an error, please yell.  (I only use PCB in my builds. I sort of fail every time I tried veroboard and such.) Since I have set out to only use Hammond 1590B for the big ones and then with the audio and power jacks on the top short side, to save pedal board space, I have made a PCB layout made to mount both the put:s and the tube socket on the PCD. I omitted the Tone put for space reasons and the Trem/OD switch but the 3,3uF cap is in. I happened to have a few MAX1044 in stock so I though that I use one to feed the tube plate side with 24V. I know the MAX1044 only suppose to be feed 10,5V max but 12V has been known to work so I have heard. There is actually two PCB:s. The second one is for the audio and power jacks but I am waiting for the PCB mounted power jacks I'v ordered so I have nothing to take accurate measurements from so and cant finish that boar yet. I'll post it as soon as I get the jacks.  So tomorrow I'm off to my local tube pusher to by me some 12AU7:s. As soon as it is ready (1-2 veeks) Ill post sound samples and info on my site.

Next step, when I find some where to buy 6111 and other subminis, I will try to shrink a Valvecaster to fit in to a Hammond 1590A.

Here is the project file and a pic of how I was thinking to assemble it all. I also submitted a link to the DIY file if anyone should care to use this as it is the only way I have found to print an accurate sized transfer to PCB from the DIY layout software and to show all the component values. (Some are missing on the pic)




How i am planing to mount it


DIY file
http://solderman.fatabur.se/Future%20project/VibraCaster.diy


//Solderman 

[frequencycentral]

That looks like a great piece of work solderman! One thing that occurs to me is that the circuit might operate differently with 24 volts to the plate and 12 volts to the oscillator, I'm not sure but I think the tremolo might not be as strong - I highly recommend you breadboard it before implementing it. The other alternative is the give the oscillator the same voltage as the plate - you would have to check the BC547C data sheet for its maximum voltage. With MAX1044 running at 12 volts, the output voltage will be about 22.6 volts, as each 1n4148 eats 0.7 volts. Be warned though - R.G. Keen castigated me for running MAX1044 above it's maximum operating voltage! It might run fine for a while then fail..........it might be fine, but it's not good engineering practice. You might be better to run the whole thing at 9 volts with the MAX1044, then use a few doubling stages from there. Good luck and post your results!

Rick

[solderman]

Thanks Rick
Thanks for the tip about 24V to the tremolo. Ill will test both with and without 24V to the BC547:s and check there limitations before soldering it down. Yes I know about the issue with MAX1044 and 12V not being good or best practice but Ill take my chances. 9V idée was something I haven't thought about. It would be in the range for the MAX1044 and yet raise the plait voltage a bit. It would give the plate around 17V and the BC547 9V.The fillment will drop to 9V though witch might be too low. The jumper in the charge pump is actually meant as a wire jumper, easy to put in or remove. If the charge pump wont work Ill just trough in the jumper and pull out the IC. I thought it would be more flexible this way. I can also see that I made a goof in the choice of components. The MAX1044 datasheet actually recommends fast schottky diodes like BAT85 (30V 200mA) instead of 1N4001. As soon as I have something working (or maybe not) Ill post the results.

//Solderman