Author Topic: DIY boutique amps, pedals, mod kits, proto-type circuits, etc - Post them here! (Read 1817228 times)

vittobrat · « **Reply #8525 on:** December 25, 2015, 10:32:48 AM »

Quote from: lolwat on December 25, 2015, 07:25:45 AM

http://www.muzique.com/schem/mosfet.htm

As per the developer himself, replacing the 100uf capacitor with a larger value (220uf and up) achieves a flatter boost (the original circuit rolls off some bass).

Deeco Cubao carries a 2N7000 which works perfectly for this circuit.

Tnx po...

Has anyone in this thread ever made this kind of pedal?

lolwat · « **Reply #8526 on:** December 25, 2015, 04:51:27 PM »

Quote from: vittobrat on December 25, 2015, 10:32:48 AM

Tnx po...

Has anyone in this thread ever made this kind of pedal?

Me. Lol

cacophony · « **Reply #8527 on:** December 26, 2015, 03:59:32 PM »

all glued up ready for paint job

emil_murillo · « **Reply #8528 on:** January 06, 2016, 12:43:23 AM »

Hi Guys!

i wanna ask for some help po sana.. anybody near cavite po.. if you please help a friend of mine.. nasira ang LED ng pedal niya.. it's a hardwire supernatural reverb.. bale either the LED itself lang or the current limiter.. may reverb pa naman daw like as normal and nagsi-switch pa naman ng maayos so flip-flop circuit can be over rule na rin.. so here's his number ► 09255143071 - tim

i am counting on you guys bigtime.. so please kindly help po our friend, he's a forumite also.. so thanks in advance po!

-Emil

Freak · « **Reply #8529 on:** January 11, 2016, 07:13:59 PM »

Hi Guys, I need help where to source for I.C.s with part number M5201A or JRC 2120D... very badly needed. TIA

lolwat · « **Reply #8530 on:** January 13, 2016, 11:32:26 PM »

Good evening, I tried building a Jack Orman (amz-fx) MOSFET boost using a p-channel MOSFET (BS250) and as per testimonials from fellow D.I.Y. effects builders, the background hiss was indeed dramatically reduced to nearly zero (the BS170/2N7000 versions always had the background hiss even with the guitar volume rolled all the way down). The only downside is that this turns the pedal into a positive ground device, which will require a voltage polarity inverter circuit if you want to daisy chain with negative ground pedals.

What's more, changing the source capacitor to lower values turns the effect into a treble boost-type pedal minus the bass rolloff. In my case, using 100nf and 68nf capacitors in parallel, I am able to mimic the EQ curve of a Mesa Mark-series preamp set to Mr. John Petrucci's preferred settings, and plugging this into the front end of a distorted amp set to darker EQ settings produces a sound fairly reminiscent of Images and Words/Awake era sounds. I'll post a soundcloud demo as soon as I can.

Musikerochan · « **Reply #8531 on:** January 14, 2016, 03:38:55 PM »

^try mo using a negative ground supply. refer to Orman's positive power for fuzz face article.

changing the bypass cap to lower value will reduce the low end content, same with lowering the emitter cap in NPNs.

lolwat · « **Reply #8532 on:** January 14, 2016, 06:45:52 PM »

Quote from: Musikerochan on January 14, 2016, 03:38:55 PM

^try mo using a negative ground supply. refer to Orman's positive power for fuzz face article.

changing the bypass cap to lower value will reduce the low end content, same with lowering the emitter cap in NPNs.

I actually built a voltage inverter circuit alongside the booster one which allows me to daisy chain. The low end rolloff used to be a problem for me until I discovered that increasing the bypass capacitor value even to 220 microfarads solves the issue right away. Right now it serves as my new favourite type of "drive" pedal with the small cap

EDIT: Here's the uploaded demo: https://soundcloud.com/jolo-carrera/ibanez-laney-amz-fx

ubersam · « **Reply #8533 on:** January 15, 2016, 01:34:23 AM »

Quote from: lolwat on January 14, 2016, 06:45:52 PM

...The low end rolloff used to be a problem for me until I discovered that increasing the bypass capacitor value even to 220 microfarads solves the issue right away.

EDIT: Here's the uploaded demo: https://soundcloud.com/jolo-carrera/ibanez-laney-amz-fx

Was the original roff-off with the 100uF too low? Too bassy? The AMZ mosfet booster will be my next project after I finish the one I started a year ago. Right now I'm just running sims in LTSpice.

lolwat · « **Reply #8534 on:** January 15, 2016, 07:50:58 AM »

Quote from: ubersam on January 15, 2016, 01:34:23 AM

Was the original roff-off with the 100uF too low? Too bassy? The AMZ mosfet booster will be my next project after I finish the one I started a year ago. Right now I'm just running sims in LTSpice.

The 100uf value for the capacitor took off too much low end that you could hear it if you listened carefully. This might end up being a good or bad thing depending on what you want your boost to do. In my case I couldn't stand it, so I experimented with higher values and ended up with a 470uf one for an essentially flat frequency volume boost. May I suggest socketing the bypass cap (as well as the transistor) for ease of swapping values.

Musikerochan · « **Reply #8535 on:** January 15, 2016, 08:46:46 AM »

is this the one with the 1nF input coupling cap? raise it to 10nF to compensate for the low end roll-off. i imagine the 470uF is slightly bigger and likely to crowd the other components.

lolwat · « **Reply #8536 on:** January 15, 2016, 08:59:40 AM »

Quote from: Musikerochan on January 15, 2016, 08:46:46 AM

is this the one with the 1nF input coupling cap? raise it to 10nF to compensate for the low end roll-off. i imagine the 470uF is slightly bigger and likely to crowd the other components.

Orman actually has an alternative schematic which calls for a 47nf input cap, but even with a 100nf or even 1uf input cap, the low end rolloff doesn't change too much, until you increase the source bypass capacitor. In my experience, even a 220uf cap brings back the bass that the original value loses.

ubersam · « **Reply #8537 on:** January 15, 2016, 09:21:46 AM »

Quote from: lolwat on January 15, 2016, 07:50:58 AM

The 100uf value for the capacitor took off too much low end that you could hear it if you listened carefully.

Weird. In simulation, using all the stock values, the response curve is pretty much flat from 20Hz to 20KHz. The low end roll-off point is around 14Hz. That's low enough to be used with a bass. In calculation, the roll-off is around 0.6Hz. Maybe the flatness of the response gives the impression of not having enough bass, or rolling off the bass. Maybe there's a wrong value somewhere. Have you checked the output cap? If you have something smaller than the 100nF in the schem, that would affect the roll off too. A 10nF output cap will roll-off around 150Hz.

lolwat · « **Reply #8538 on:** January 15, 2016, 09:31:14 AM »

That can't be right. Orman specified the rolloff to be around 30 or so hertz with the bypass capacitor straight to ground. He was saying it was enough for standard E-tuned guitars, but then i could hear my low B get left behind whenever i engage the pedal at stock values.

EDIT: wrong values

ubersam · « **Reply #8539 on:** January 15, 2016, 01:50:45 PM »

The simulation is good. It comes close to Jack's description. The curve shows the bass starts rolling off around 30Hz. But 30Hz is not the cutoff frequency. The technical cutoff frequency, the frequency 3db below the max, is around 14Hz. Calculating the cutoff frequency using the source R & C values in fc=1/(2*π*R*C), results in 0.6Hz, which is too far from what the sim says. I think there is a parameter that I'm missing in the calculation, but I haven't figured that out yet. Maybe it's the Ciss or the Coss of the mosfet.

lolwat · « **Reply #8540 on:** January 15, 2016, 02:28:15 PM »

Quote from: ubersam on January 15, 2016, 01:50:45 PM

The simulation is good. It comes close to Jack's description. The curve shows the bass starts rolling off around 30Hz. But 30Hz is not the cutoff frequency. The technical cutoff frequency, the frequency 3db below the max, is around 14Hz. Calculating the cutoff frequency using the source R & C values in fc=1/(2*π*R*C), results in 0.6Hz, which is too far from what the sim says. I think there is a parameter that I'm missing in the calculation, but I haven't figured that out yet. Maybe it's the Ciss or the Coss of the mosfet.

I forgot to mention I also use it as some sort of preamp for things other than guitar, which means i need all the flatness i can get haha. I use LTSpice for the simulations.

If it helps, with a maximum level of +33db somewhere after 50hz or so, i get +29-30 near the 20hz area of the spectrum. In any case it's too bothersome a change to my ears, hence my choice of a higher bypass capacitor value.

ubersam · « **Reply #8541 on:** January 15, 2016, 02:54:22 PM »

Quote from: lolwat on January 15, 2016, 02:28:15 PM

I use LTSpice for the simulations.

That's what I use. Which mosfet model are you using? I'm using the one I found at DIYStomps... I tried the one from Fairchild but it generates a 4 pin device, which I am to lazy to figure out how to turn to a 3 pin device.

lolwat · « **Reply #8542 on:** January 15, 2016, 06:32:11 PM »

Quote from: ubersam on January 15, 2016, 02:54:22 PM

That's what I use. Which mosfet model are you using? I'm using the one I found at DIYStomps... I tried the one from Fairchild but it generates a 4 pin device, which I am to lazy to figure out how to turn to a 3 pin device.

Cool! I use the 2n7002, the sot23 version of the 2n7000 (essentially the same as a bs170).

cacophony · « **Reply #8543 on:** February 04, 2016, 03:56:49 AM »

shielded my pickguard using the cheapo aluminum tape from hardware store. poked the holes using a 2.5mm drill bit. x-acto knife for a clean cut

bakit? · « **Reply #8544 on:** February 05, 2016, 01:02:50 PM »

who can help me with my peavey classic 50? Pots issues lang naman and gusto ko mag work yung drive channel nya since binypass nung previous owner. Please?

walanakamingyelo · « **Reply #8545 on:** February 10, 2016, 07:36:18 AM »

Quote from: bakit? on February 05, 2016, 01:02:50 PM

who can help me with my peavey classic 50? Pots issues lang naman and gusto ko mag work yung drive channel nya since binypass nung previous owner. Please?

Tapon mo sa bahay ko. maaayos yan wahahahahaha

Pero kailangan mo talaga ipatingin pre

Ralph_Petrucci · « **Reply #8546 on:** February 10, 2016, 10:25:38 AM »

Quote from: bakit? on February 05, 2016, 01:02:50 PM

who can help me with my peavey classic 50? Pots issues lang naman and gusto ko mag work yung drive channel nya since binypass nung previous owner. Please?

dalhin mo na siguro kay mangraul yan paps.

dominant_chord2005 · « **Reply #8547 on:** February 11, 2016, 04:00:04 PM »

I dunno if I am in the right forum page but I was wondering if anyonme among you guys near Commonwealth QC who does mods and rehousing pedals. I wass wondering if anybody can help me rehouse my SD2 and seperate the 2 gain channels...just like the radial tone bone. Any help is appreciated...Nanghinayang lang ako sa BOSS SD2 ko di ko magamit dahil nasira ung volume and tone controls nya. Thanks guys ...u can PM me here or thru my fb page elmo.comia. Thanks...

ubersam · « **Reply #8548 on:** February 12, 2016, 01:28:53 AM »

Got curious about the SD2 so I googled it and found schematics... I also found this:

sargento · « **Reply #8549 on:** February 12, 2016, 01:26:36 PM »

Quote from: dominant_chord2005 on February 11, 2016, 04:00:04 PM

I dunno if I am in the right forum page but I was wondering if anyonme among you guys near Commonwealth QC who does mods and rehousing pedals. I wass wondering if anybody can help me rehouse my SD2 and seperate the 2 gain channels...just like the radial tone bone. Any help is appreciated...Nanghinayang lang ako sa BOSS SD2 ko di ko magamit dahil nasira ung volume and tone controls nya. Thanks guys ...u can PM me here or thru my fb page elmo.comia. Thanks...

Eto sir, re-cased by PIE Custom

http://talk.philmusic.com/index.php?topic=334142.0;topicseen

News:

Author Topic: DIY boutique amps, pedals, mod kits, proto-type circuits, etc - Post them here! (Read 1817228 times)