Brownface Vibrato in the Gallery

[markm]

Hello all!
Here's a heads up that the Brownface Vibrato is up in the Gallery.
My build still has some slight speed issues but, I am awaiting the correct value Pot before I proceed any further.
The layout works as it is, it may need a few tweaks but I must say overall, It sounds Real Good a very nice tone and kinda of "creamy" I'd say. It sounds very "Vintage" to my ears.
On extreme settings it'll make you sea-sick!! 

Here's the link;
http://aronnelson.com/gallery/view_album.php?page=1&set_albumName=album76
It's the rather Large one, top left corner!! 
A BIG Thank you to R.G. for the design and the assistance in being able to see this project through.
The Complete schematic is here at R.G.'s site http://www.geofex.com/. While you're there, spend an extra few minutes
reading an article or two, you'll leave having learned Something......Guaranteed! 
Have at it fellas, and have a Great DIY day! 

[ulysses]

cool mate

will check it out.

RG checked the layout right? is the problem with the schem? Do you need and untainted eye check the layout?

thx for your work

cheers
ulysses

EDIT: hey mate, i just checked it out, i like the way you renamed the trannies to the pinout think i might do that from now on also

[ulysses]

i checked out geofx. there are two different circuits that start with ersatz fender pro vibe*/trem*

has rg converted two different circuits EA/P90 to have similar properties to the brownface?

do you know if RG has done any writeup on these circuits on geo? i couldnt find any more info.

http://www.youtube.com/watch?v=Ya9s_0f0eFE > is this the vibe or the trem?

cheers
ulysses

[R.G.]

The writeup is in a thread here. See if you can find it with a search.

Yes, I did two different versions of the Fender Pro/Concert vibrato. One was based on the Phase 90 and used the JFETs as gain modifiers for the opamps instead of phasing. The other was based on the EA tremolo.

The Fender Pro vibrato has a frequency/phase splitter done as some resistors and caps and two variable gain stages that amount to two tremolos running in parallel. The output of the tremolos are mixed back together, and that's the output. The two tremolos are fed opposite-phase LFO signals so when one's high gain, the other's low, and vice versa. The mixing of the two signals was done so any LFO signal in the mixed output would cancel and not provide a thump.

So I first did a P90 version, changing two phase stages to gain-changing stages and using the leftover opamps from the unused two phase stages to give a mixer and an inverted LFO output. This one has a way-wider LFO speed than the other.

There were the usual groans about JFETs being more like the "original" circuit, so I did an all-discrete version using all JFETs in the signal path modelled on the EA tremolo. There is an input buffer/gain stage to present a high impedance to a guitar; from there on, it follows the Fender circuit. There is  the same R/C frequency splitter, two EA trem circuits each of which does a variable gain on the split signal it gets, and an output mixer which combines the two outputs. I used an EA-tremo style LFO, and modified it to have dual out-of-phase outputs.

[markm]

RG checked the layout right? is the problem with the schem? Do you need and untainted eye check the layout?

Yes.
I had the pleasure of working with R.G. most of the weekend on this through e-mail.
He's very sharp.
He looked it over and with the exception of one thing I think, all was well.
I don't think my speed issue is the fault of the schem or the layout and I can't really say at this point because I don't have the correct Dual Gang hooked up to it at the moment.
What it does right now is at full speed, the LFO locks up.
After backing the pot off about an 1/8th of a turn, the LFO will start up again after a few seconds have passed.
Please feel free to take a look, I don't mind.
I have it from R.G. to try adjusting the 2 1K resistors to the speed pot to try and stop the LFO from stalling but, I am going to wait at the moment until I can get the correct Dual Ganger from smallbear.......couple of days probably.

[audioguy]

I cant wait to build this thing later this week!

[QSQCaito]

I'm ready to go buy my things later this weekend probably.

Hey Mark, is thera any chance you could get sound samples, it'd be cool D:

Bye bye

tbanks

DAC

[markm]

Hey Mark, is thera any chance you could get sound samples, it'd be cool D:

I wish I did but, I don't.
It's a nice build though, I really LOVE the sound of it. 

[ulysses]

thanks for the replies guys.

cheers
ulysses

[markm]

You are quite welcome ulysses.
Have you looked everything over?

[ulysses]

hey mark

i have not had time to look over it yet. besides, if rg says its good to go then im sure it is

will let you know when i have built one and post some sound samples prob this weekend.

cheers
ulysses

[theblackman]

mark your layouts are awesome thanks!

[markm]

mark your layouts are awesome thanks!

Thank you.
Amazing as it may seem, this circuit seems to be sinking into the abyss of the forum.
Too bad, it was alot of work. 

[reb]

Anyone willing to make a pcb of this for me?  (not looking for a freebe) I'd love to build it. 

Thanks,
Rob

[jakenold]

Don't worry Mark - me and probably others are building this as we speak. When the results are in, I'm sure this thread will flourish again!

[markm]

Don't worry Mark - me and probably others are building this as we speak. When the results are in, I'm sure this thread will flourish again!

Nahhhhh.
Not really worried.
Just that I was under the impression there were lot of folks after a circuit like this one.
Maybe not.
Either way, I need to get in contact with R.G. concerning the speed issue.
Over at Max setting it stalls the LFO.
Maybe it's a Cap issue??

[Ben N]

Mark,
Of course people are interested. But there are a lot of people here who pursue this hobby in the occasional moments that are available, which may  not be many. So be sure there are people who follow threads like this, but may have to put off building because of time... or because they need to order parts. Be patient: someone will build it, then someone else, then someone else--it'll be a standard around here.
Ben

[audioguy]

For me... I'll build it as soon as I can get those trannies from Mouser.

[John Lyons]

Looking good mark. The forum is pretty slow as of late over all.
I still need to finish up the heartbeat vibrato and then I'll give this a shot.
Thanks for the hard work and making it a reality!

John

[oldrocker]

As usual Mark great job.  You're really getting a super nice selection of layouts going here for us all.  I for one appreciate it and will get tons of use out of them in the future.   That vibtrato looks interesting.  I don't have a stand alone vibrato pedal so maybe I'll give it a shot.  Thanks.