Brunetti Mercury

[Battery Acid]

this! I tend to use 1/2 supply voltage as a basis, and tweak to taste from there. I got a much louder output and the decay of the notes is now perfect. I'm really impressed by this bad boy, thanks a lot for the layout!

[motterpaul]

Battery - I like it too. What are you playing through? Especially what kind of amp (wattage, output tubes) - on high or low gain input ,etc.


I love this pedal too, but I could use more sustain. It is good but I want notes that ring for as long as I can hold them.

[Battery Acid]

Try biasing it a little hotter! The one I made sustains like crazy, going into controled feedback if I want it to. First I tried it with 2n5458, but I liked it much better with J201's. I'm running it thru a Marshall JTM30 loaded with JJ 6V6's and a heavilly moded korean Epiphone Les Paul Custom (PAF pickups, gotoh parts, etc etc)

[motterpaul]

Yup, I have had a couple of those JTM 30s. They are decent amps. Which channel are you using? clean or higher gain?

[Battery Acid]

I'm pretty happy with it. Here in Brazil, guitar amps prices are crazy high, and I've got a pretty good deal on this one. Sounds loud enough for pub gigs (and I tend to play with it mic'd, anyway), great clean sound, not too heavy to take it to gigs hehehe. Usually I go with clean channel, but when I'm lazy, I gig using only my wah and klon, and use the higher gain channel!

[strassercaster]

Nice layout I did the one from sabrotone before i saw this one. I like it a lot but it seems a little too dark. I used 2b5457 and its not as wooly as the real one. Its one of the best pedals i have ever made. How can I get some brightness back? Would the 3n3 cap make it bright by going smaller. I know it will cut less treble if i go smaller but will that help brighten it up a bit? Just trying to decide if its done or not . I really like it and have a bad habit of taking great pedals apart  to tweak and then not getting back to them for months ha ha

[Frank_NH]

I changed that last cap from 3.3nF to 330 pF in order to preserve the treble.  You can always roll off the treble using the treble (Bite) control...

The Sabrotone layout didn't have the JFET trimmers, and I thought it best to have those in order to dial in the J201s.  I also did this version with the LT1054 charge pump, which I prefer to the standard 7660, 1044 charge pumps.

[motterpaul]

I was using the pedal yesterday at a jam and I found that I had the treble rolled almost all the way off. Of course it depends on where tones are set on other things, but I found it to be in a workable range.

[Frank_NH]

You could put that cap on a switch and then choose which value you want based on your gear.  I tend to favor more treble than less, but then I've been playing a Telecaster lately...(ha)

[strassercaster]

thanks . I have a couple friends that are digging the one i made already. it took forever to get it sounding good.. i didnt know the jfets needed to matched. once i matched them biasing wasnt to bad. i heard whenever you do jfets its kind of oike tonebenders you should keep the original bias resistors and keep plugging transistors till its right and self biasing. im curious as to how they do mass production for circuits like this. trimmers are the way to go . if i make anymore im going to use your layout. the sabrotone layouts always seem to take me longer to make as well . the seperate cut and link layout saves a lot of time and possible mistakes from happening not to mention the values on the board make for less chance of error and easier troubleshooting in the event of an error.


so i have been asked what this would compare too. i would giess its similar to a bsiab but that would be a guess. what is this based or modeled after ? is it just a jfet version of one of their amps? ill try the 3n3 mod when i get it back letting a friend check it out

mh frined says this is good for cutting heads hence the name and artwork ha ha

[Frank_NH]

The JFETs don't have to be "matched" here.  The trimmers are there to permit you to dial in the proper bias at the drains of Q1 and Q2 (~ 9-10V).  As long as you have good JFETs this should work.

Good looking build Strassercaster!  

By the way, this is different than a BSIAB, or really most overdrive/distortions in that it uses the op amp to overdrive the JFET gain stages.  This is similar to overdriving an amp with a tube screamer, which is what I thought was interesting about this design.  I also found the tone controls to be very effective.

Alex has a new layout on the main page, so you can build it again for your other guitar-playing friends!  

[motterpaul]

Well, I just did a hearing test and found out mine start to fade at about 11k, which for age is actually not bad at all, I am lucky I have never had serious hearing issues; no tinnitus, etc. I do have people tell me my guitar is too bright, sometimes, though. I am learning to tone that down.

[strassercaster]

Well thats good. I have full blown tinnitus. Day and night some days are better than others. I was in a car accident last year hasnt stopped since.

[Battery Acid]

I just built another Mercury Box, now to the original specs (250kA volume pot), and the balance between treble and bass it's perfect using the 3n3 capacitor