Anyone built the El Pistolero? How's it sound?

[bipedal]

Curious if anyone has feedback on how this one sounds: http://www.aronnelson.com/gallery/v/MarkMs-Gallery/album15/album76/EL_Pistolero_LAYOUT.png.html.

It's a nice simple layout for a MosFET booster that also uses FETs for clipping.  Looks like it be an easy circuit to tweak.  Does it offer sufficient output to tack on a simple tone control?

I'm out of parts right now, so was interested in hearing from anyone who "knows" this before I order anything.  Didn't see any previous discussion of this one when I searched the forum.

Cheers,

- Jay

[John Lyons]

I have not built it but I'm curious to hear what it sounds like.
So.....Bump!

John

[bipedal]

No prior builders on this one I guess...

I think I'll give it a go anyways for my next project -- should be a quick build -- and I'll post a build/sound report when I can.

My only pre-build concern is that this circuit's gain comes from a single BS170 tranny.  I'm not certain that it'll be enough to give it sufficient "oomph" for generating an output level much above unity.

Cheers,

- Jay

[John Lyons]

Fear not. The Zvex Super Hard on (among others) uses a single BS170 and there's plenty of gain there! Big boost.

I'm curious to hear what it sounds like. Please report back.

John

[MikeH]

After the clipping I'd guess it probably won't have enough for a full tone stack, but definitely enough for a tone control.  You could always add an output buffer...

[John Lyons]

A buffer wouldn't add back any level but another BS170 after the tone stack would!!

John

[trevize]

I'm not seeing clipping diodes, the 1n4739a surely is a zener diode, don't remeber how many volts, and it's not in the signal path.
D1 could be substituted with a Led for static protection. Look at the ROG peppermill or the mosfet booster.

[~arph]

The two BS170's Q2 and Q3 are wired as clipping diodes 

[ADR]

This is very similar to an idea I've been mulling over for a while, putting some kind of clippers on a mosfet boost front end.

The only question I have is about the gain pot, why 2k instead of the 5k for the mosfet boost? Going back to Jack Orman's page on the mosfet boost, he says that the source resistor is bypass by a large cap in series with the gain pot, and that the minimum resistance is when it's at maximum boost.

Also, why the 10uF cap instead of the 100uF? I assume it is related to the pot value and you prefer the sound.

As I don't have a 2k pot on hand, I'm going to go with the 5k and 100uF set up. If it doesn't work, I'll get the 2k pot next time at the electronic store.

P.S. MarkM, have you also experimented with asymmetrical clipping with the mosfets? Maybe tagging an extra 1N34a in one direction? Or maybe an LED to ground. I dunno, I'll just mash some ideas on the breadboard.

Thanks!

[John Lyons]

Mark M isn't here anymore (that we know of).
I have a diode clippser with FETs and a 1n34 as an asymetrical clipper and I think it sounds nice.
You can always put a 5k resistor across the 5K pot (across the outer lugs) and get a 2k5 linear pot.
Try 5K first. More gain range I would think but maybe it does not need it.

John

[ADR]

Thanks John. I forgot about the resistor on the pot lugs trick. Then again, it's been months since I built my last stompbox.

I'll try it out this weekend.

I'm keen to buildeither two of these, with one a variant with some different ideas, or maybe an electra distortion/trotsky drive.

[richon]

how did this go? 

[ADR]

After playing with it on the breadboard, I ended up changing the front end of the circuit, more or less a DOD250 with an LM741 IC, then the mosfet 2n7000 clippers and a recovery stage (like a rat) tacked onto the end. Running it into the AMZ minibooster sounds soooooo good after it. I may just shoehorn a miniboost into this thing and remove the recovery stage.

The mosfet front end was pretty good too, but I wanted a bit more midrange to the circuit, and the LM741 did the trick.

[bipedal]

Ah, I had forgotten to revisit this thread.  I finally built the Pistolero per the gallery layout, with the following changes:

- An SPST switch to make/break connection with the clipping diode pair
- A basic tone control prior to volume pot, using a 10k lin pot in series prior to output volume, with wiper -> .1 uf cap -> ground
- Used 1K instead of 2K pot for Gain.

With this arrangement, it gave a reasonably fat sound, but not a ton of extra boost beyond unity.  Quite useable sounds when gain and volume controls were maxed (nice bluesy sound with a single-coil Strat, a little muddy with humbuckers...), but when the gain was turned down below about 2:00 o'clock position, there wasn't much exciting happening.

When using the BS170s for clipping diodes, it was very hard to hear any difference versus when the clipping diodes were switched out.  It took a swap from the BS170s to other clippers (a red LED + 1N4148) to notice a tonal change.

Good potential in this simple circuit, but I suspect it would become a lot more versatile with the addition of a second gain stage.

- Jay

[ADR]

Good potential in this simple circuit, but I suspect it would become a lot more versatile with the addition of a second gain stage.

- Jay

Yep, I'm a relative latecomer to the whole DIYstomper thing, starting only 1.5 years ago. I only found out that the Shaka3 is kinda the same conclusion I came to after building this circuit. The minibooster, and other fet stages, tend to make some very organic and useful clipping stages. Not a fan of germanium diodes for clipping. But, I will experiment with the AMZ warp control ideas, in using a trim pot or resistor to tailor the diode clipping stage.

[bipedal]

Back again, to "re-revisit" this thread.  I built the Pistolero (single stage mosfet booster with 2 mosfets used as clipping diodes) with an added tone control at the end.  It was okay, but a bit dark and not particularly versatile.

So, I scrounged up some spare parts and added a low-parts-count booster -- essentially a Sekova Power Booster, except with a 2N3904 tranny -- to the front end of this design.  Whoa!  Initially the booster was driving the overdrive circuit too hard, so I added a voltage divider to tame the level going into the BS170 a bit (I think I'll use a pot next time for more versatility) -- and now I've got a moderate-to-high gain overdrive/distortion pedal that seems relatively warm and amp-like, is responsive to pick attack, cleans up nicely as guitar volume is rolled back, and has a lot of output.  Interesting combination of some grit from the BS170 being overdriven by the 2n3904 plus the clipping of the two additional BS170s used as diodes.

Still needs some value tweaking, but it's got potential.  It seems to like my single coil strat better than my humbucking tele -- more clear and crisp...
It's kind of fun when a "what the heck, lets see what happens when I add this" turns out unexpectedly well...   

I'm (slowly) working on a layout for this mash-up of designs, will post/share when ready.

- Jay