Next Build: BYOC's New Overdrive 2 Kit...

[duhvoodooman***]

As described in THIS POST, BYOC has redesigned their very popular Overdrive kit (Tube Screamer TS808 circuit clone), adding a number of new features and options. It even includes an integrated booster section that functions indepedently from the OD circuit and has it's own separate stomp switch. But the feature that grabbed my attention right away was the ability to build it as a MOSFET overdrive. If you're into overdrive pedals, you'll know that MOSFET-based OD's are all the rage, for their natural, tube-like response. The well regarded "boutique" MOSFET OD's regularly command prices in the $200 - $300 range. You've probably heard the names--Hermida Mosferatu, Fulltone Fulldrive 2 MOSFET, Blackstone MOSFET Overdrive, etc.

I already have a modified TS808 clone (IMO, one of the best you'll find--my Zonkin' Yellow Screamer mod!), but building a MOSFET version was something I definitely wanted to try. I managed to get two out of a handful of kits that Keith at BYOC still had available after his distributors ran him out of most of the initial production run. They were delivered this past Monday. One is for a Fretter who wanted one of these as a gift, but the other--that puppy is MINE!!

Looking through the build options, it turns out that MOSFETs can be used in 5 different places in this circuit:

• The input buffer
• The opamp
• The clipping stage
• The output buffer
• The boost stage

I did some looking into the pro's & con's of using MOSFET's in these various parts of the circuit and decided to go with them everywhere but the output buffer--sticking with a bipolar transistor there apparently gives the pedal better drive characteristics. The input buffer and clipping section will have the MOSFETs soldered in. The pedal comes with an opamp socket, so I'll start with the MC33502 dual-MOSFET opamp provided in the kit, though it also includes a JRC4558D and a Burr Brown OPA2134. And I decided to socket the entire booster section of the circuit (it's only 8 component spots), so that I can try both MOSFET and bipolar NPN trannies there, as well as play with the max. boost gain. The MOSFET is supposed to give a very clean, chimey boost, where the bipolar NPN will provide more drive and a slight degree of distortion. So I'll see which I like better, both alone and in combination with the main overdrive stage. Should be fun, mixing & matching.

Anyway, I started the build a couple of nights ago, and have it all together except for the jack and switch wiring, plus adding all the socketed components. Hope to finish it up tonight, 'cuz the rest of the weekend looks pretty well packed with family commitments. Will take some pics to post here, as well as the obligatory sound clip, once I've had a chance to play with it some and explore the sonic possibilities....

[tunghaichuan***]

Cool. I'll be very interested to see and hear the OD2 when you've finished it. I'm lousy with OD pedals, but if this is cool, I could always add another one.

BTW, have you ever checked out the Ibanez Mostortion? They are fairly rare. They came out in the same casing as the TS-10 Tube Screamer pedals. I got one on a blowout from Musicians Friend a few years ago. It only sounded OK, not as good as a normal Tube Screamer.

tung

[duhvoodooman***]

BTW, have you ever checked out the Ibanez Mostortion? They are fairly rare. They came out in the same casing as the TS-10 Tube Screamer pedals. I got one on a blowout from Musicians Friend a few years ago. It only sounded OK, not as good as a normal Tube Screamer.

Must admit, I've never even heard of that one before. Interesting. How long ago was this that Ibanez sold these?

[tunghaichuan***]

Must admit, I've never even heard of that one before. Interesting. How long ago was this that Ibanez sold these?

I believe these were sold from the late 80s to the mid 90s. I owned one when the first came out, sold it and got another one pretty cheap on a blowout from MF.

Here is some info:

http://filters.muziq.be/model/ibanez/10/mt10



Schematic is here. How close is it to the OD2?

tung

[duhvoodooman***]

BTW, I should mention this: For those of you who might be interested in this kit, either to build it yourself or have someone build one for you (now, who could that be?)--the 2nd production run is supposed to be available for sale on Feb. 9. The first one sold out in 48 hrs. Just sayin'....

[duhvoodooman***]

OK, I finished up the Overdrive 2 build on Fri. evening and had a little bit of time to play around with it yesterday. Very nice. Still recognizably a Tube Screamer-type overdrive, but the MOSFETs give it a nice warm, juicy kind of character. I've been playing around with the max and min gain trimpots inside and have it set up for the same minimum gain as a TS808 but a little more than twice the maximum. You have to be careful with this, because the max gain setting also affects the bass rolloff frequency of the pedal--dial it up too high, and you'll wash out the bottom end of the pedal, even at the highest of the 3 positions on the "Fat" toggle switch.

Here are a couple of photos taken during the build. Clips to follow, when I have the time to do a couple.

Partially populated PCB; note the sockets on the right side, to allow switching the booster section between MOSFET and bipolar transistor configurations:



Completed PCB, except for mounting the socketed components:



Back of PCB, showing pot, toggle switch and dual LED mounting:



Finished pedal "gutshot":



Finished but unpainted pedal top:

[tunghaichuan***]

As always, excellent work. I'm in awe of your pedal building (and finishing) skills. : Have you thought of a name yet?

It looks like there are a few components missing from the PCB, mods to the basic design?

I'm definitely going to have to build this one.

tung

OK, I finished up the Overdrive 2 build on Fri. evening and had a little bit of time to play around with it yesterday. Very nice. Still recognizably a Tube Screamer-type overdrive, but the MOSFETs give it a nice warm, juicy kind of character. I've been playing around with the max and min gain trimpots inside and have it set up for the same minimum gain as a TS808 but a little more than twice the maximum. You have to be careful with this, because the max gain setting also affects the bass rolloff frequency of the pedal--dial it up too high, and you'll wash out the bottom end of the pedal, even at the highest of the 3 positions on the "Fat" toggle switch.

Here are a couple of photos taken during the build. Clips to follow, when I have the time to do a couple.

Partially populated PCB; note the sockets on the right side, to allow switching the booster section between MOSFET and bipolar transistor configurations:



Completed PCB, except for mounting the socketed components:



Back of PCB, showing pot, toggle switch and dual LED mounting:



Finished pedal "gutshot":



Finished but unpainted pedal top:

[duhvoodooman***]

Have you thought of a name yet?

Working on that! I definitely want to do some sort of word play on "MOS" or "MOSFET". Open to suggestions. So far, my short list of ideas include:

• MOSFETishist Overdrive
• Uno MOS-fet Overdrive (my current favorite)
• MOS Transit Overdrive
• Critical MOS Overdrive

It looks like there are a few components missing from the PCB, mods to the basic design?

Indeed. Depending on which sections of circuit are built to "stock" or MOSFET specs, certain resistors and diodes are used or left out.

[tunghaichuan***]

Working on that! I definitely want to do some sort of word play on "MOS" or "MOSFET". Open to suggestions. So far, my short list of ideas include:

• Critical MOS Overdrive

I like the one above.

tung

[thearabianmage]

To be fair, it's gonna be pretty hard to beat Mosferatu. . .

But I've got some suggestions:

MOSeltav - It's an OD!

MOStensibly Vintage OD

M.O.D. (i.e. Ministry of Defence - or Mosfet Over Drive)

My 2 cents. . .

Great build, by the way! Looks awesome!

[duhvoodooman***]

MOSeltav - It's an OD!

LOL! I like that one!!

[sunvalleylaw]

MOSeltav is good, or I like the Critical MOS one.

[tot_Ou_tard]

Beautiful work as always Vood.

It makes me wish that I was more into pedals.

Partially populated PCB; note the sockets on the right side, to allow switching the booster section between MOSFET and bipolar transistor configurations:

Bipolar transistors? That's the first that I've heard of silicon with mental disturbances. Probably makes a great pedal.

What else is there? Schizophrenic op-amps? Pots with OCD?

[marnold***]

Mos Tequila?

[tot_Ou_tard]

How about

MOS y Mas

(ie MOS and more)

The boost could be labelled Mas.

Here's "Mas y Mas" by Los Lobos for inspiration:



MOS y MOS

is also good as you have a lot of MOS.

or

MOS y MOS y MOS y MOS

since there are four places where you've used MOSFETs.

[scgmhawk]

There was an interesting article on BYOC in Premier Guitar that I was reading last night --might have been a back issue though, now that I think of it. The company is 3 people working out someone's house and it's really taken off. Pretty neat story.

[duhvoodooman***]

How about

MOS y MOS

is also good as you have a lot of MOS.

O-o-o-o-o-h, that's very good, Tot! : I think we have a worthy challenger to Mage's MOSal Tov! (the "correct" spelling)

[duhvoodooman***]

Bipolar transistors? That's the first that I've heard of silicon with mental disturbances. Probably makes a great pedal.

What else is there? Schizophrenic op-amps? Pots with OCD?

Pot's with OCD? How about the whole pedal:

[tot_Ou_tard]

Pot's with OCD? How about the whole pedal:

Yeah, I've often wondered about that pedal. All pedals tend to bring out the OCD in us. A little tweak here, a little knob twiddling there.