Favorite Jfet Overdrive?

[PhiloB]

Have a friend that is set on a Jfet overdrive.  What would you recommend?  All he can say is that he likes the 'Liquid sunshine' OD but can't get any more specific than that.  What say you?

Thanks


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[Haberdasher]

azabache from rog is highly regarded but i have yet to build one.

i built a liquid sunshine once, it didn't sound half bad iirc.

[PhiloB]

Thanks, would Josh's (1776) Brittania be a good option? 
I'll have to have a good look at the Azabache.


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[Haberdasher]

i guess it just depends what sound he wants.  the 1776 brit emulates something vox-y, and i understand the azabache is very fender-y

[mmlee]

I'm a big fan of  the azabache, been using it ever since I built it.

[pietro_moog]

plexi drive. very nice.

[midwayfair]

I heart FETs.

The Britannia is absolutely amazing. I like the Azabache better but mainly because I prefer the tone shaping in it over that of the Britannia.

The Britannia is a little better direct to a console and as an all-purpose OD. The scoop on the Azabache is better for more midrange heavy amps, though, and you can't get that out of the Brit. One thing I highly recommend is socketting at least the last set of diodes in the Azabache -- I ended up with an asymmetrical arrangement there, and a slightly lower gain FET, to get a bit more headroom.

Ultimately, I'm pretty partial to the Snow Day, though.

[jubal81]

I think it'd be good to know what kind of amp he's playing through. That seems to make a bit of a difference with these.


My favorites are the CB30/Galileo, Black 65, SVT and Plexi Drive. A 2-in-1 with a boost for pushing it would be a  great idea, too, because these respond VERY well to that. I've been using a Silver Pony specced Klone lately as a boost and it's really great for that.


I thought the Azabache sounded pretty good, the Britannia was not my cup of tea, but I think the Britannia is designed to go with a solid state amp. They both had that diode noise in the decay, which seems ironic to me because avoiding that should be one of the benefits of a JFET design and I don't really understand why ROG put those diodes in there.

[midwayfair]

which seems ironic to me because avoiding that should be one of the benefits of a JFET design and I don't really understand why ROG put those diodes in there.

It's complicated. Diodes aren't hard clipping when they are connected directly to the gate of a JFET, but they do prevent the signal from hard clipping the JFET's input (remember, once the signal exceeds |Vp|, the JFET hard clips). Someone explained it on DIYSB, either in the Azabache or Britannia thread. The clipping waveform looks very different, too, with a much slower turn-on and the front of the wave significantly more compressed than the next couple milliseconds.

There's another way of doing it with a single diode connected to the negative feedback of the emitter (it goes Emitter > resistor > bypass cap + /resistor/base diode  > ground). I don't have a link handy.

But notice I didn't use them in the Snow Day, even though I actually think they sounded good that way (I'm not sure what the "diode sound" is on the decay, but I assume it's the slightly swirly/cold sound) and made for good tube emulation. The thing is, it matters which type of tube distortion you want to emulate. Power tubes and preamp tubes have different harmonic profiles, and push-pull circuits have far less odd order harmonics than single ended. So building a FET drive that sounds like a cranked power amp is different from one that emulates an overdriven preamp.

I should say too that I don't really like any JFET drive at high levels of distortion, so I think we are on opposite sides of the taste fence on most of these.

[PhiloB]

After talking with him further, sounds like he would like the Azabache.  Is there an etchable project somewhere?


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[ggarms]

Here's the link to the etch mask:

http://runoffgroove.com/azabache-pcb.pdf

[mmlee]

TH Customs also has a fabbed board.  I did the cap change that's mentioned in the ROG article about the highs.

[PhiloB]

Thanks guys


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[Muadzin]

I've tried many overdrives, way too many, but once it got on my board NOTHING has managed to kick off my Dirty Little Secret. One of Madbean's old Grapevine boards.

[PhiloB]

I've been wanting to build the DLS for myself for a while.  My buddy is set on a Fender Amp OD sound.  Seems like the Azabache fits the bill.



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