new Barber pedal teaser [Archive] - Telecaster Guitar Forum

11 Gauge

May 26th, 2012, 09:26 AM

Maybe a 2 mode Shredmaster?

No - the SM has 3 op amps, and this one only has one.

The Dirty Bomb was SM-derived, and that had a TL074 quad op amp.

The LTD used a JRC072 op amp - this one uses a 4558, so no "jFET input" op amp type.

At the upper LH corner, there is a 120pF cap strapped across a 1M drive control. Anything that big is going to be your main gain stage - both the pot value AND the cap value. The cap bleeds off fizzy treble. Something like a Tube Screamer uses a dinky 51pF cap, in comparison. So this is smoothing out the treble a bit more.

There is a quad of clipping diodes at the upper LH corner of the circuitboard. The big question is whether they are soft clipping in the NFB loop like the LTD, or are they shunted to ground? Kind of a big clipping threshold for diodes to ground, but Barber put 1N4148/2N7000 series combos (in parallel) with the Dirty Bomb, so the thresholds would be similar.

There are what might be a pair of clippers just to the above left of the op amp, and they (probably) would be shunted to ground. There is also a small value disk cap near them, which could be used to bleed off some top end sizzle. Even though you can't really go by physical size, there's a good chance it is a bigger value cap - possibly .001uF - .0047uF or so - also commonly used for shunted clippers (OCD uses .001uF IIRC).

One of the signal caps will have to be for an input cap, and one will have to be for a high pass filter at the first op amp stage. So the rest are for interstage and tone circuits. The electrolytic "canister" at the upper LH corner of the circuitboard is most likely the output cap - Barber favors those fancier "audio quality" electrolytic caps, and they rarely look like "standard" electros used for the filtering/biasing stuff, like the blue pair in the upper RH portion of the circuitboard.

So the rest of the caps are for EQ shaping. The pair of yellow-green ones above the op amp are possibly the same value, and there are other caps "in proximity" that might be, as well. When you see stuff like that and there are multiple tone controls, there is a likelihood of tone circuits like a Baxandall for treble and bass, or something like what is called a bridged t or twin t, which IS the contour control in a Shredmaster - it uses a .047uF/.1uF caps bridged with a .001uF to let you go from mid-heavy to scooped.

There is a small multilayer ceramic cap (yellow) not far above the white trimpot. Again, it is probably a smaller value (compared to the other signal caps), and may support one of the above tone circuit implementations. For something like the SM's contour control which has a .001uF bridging cap, that could be what the little yellow guy is.

All of this said, Dave didn't use the countour control in the Dirty Bomb, and he didn't use a Baxandall in the LTD (which is obvious, because it is a three knob pedal).

And - the LTD SR has a presence trimmer, and the little yellow cap is kind of close to that first trimmer, so it could be for a presence-type control.

While I dislike the trimmers, they allow Barber to really do a great job fine tuning the EQ characteristics with his stuff to make it more "sublime" or "integrated sounding." If it is indeed supposed to have a JCM800 sound, they really don't have as much distortion as we frequently reckon they do, hence the existence of only a single (dual package) op amp.

Whatever this dirt box is, I have little doubt of two things:

- it will probably sound fantastic

- it will probably be very affordable

Actually, there is a third - Barber is still using full sized pots. While I don't consider them to be clearly better than mini pots, they just kind of add a "visual value" IMO. Barber could do what so many other companies have done, and go to a circuitboard layout done by a computer that allows for pots with standoffs. This method "says hand built" to me, and it's one of the things I like about Barber.

Just realized - there is a 4.7K resistor just above the quad of diodes in the upper LH corner of the circuitboard. There is also a 4.7K resistor across an outer and "wiper" lug of what is clearly the drive pot. This means most likely that it behaves "like a boost" with the drive knob set to minimum - you see this with many newer drive boxes. The fact that the 4.7K is so close to that quad of diodes means most likely that they are soft clippers in the first gain stage's negative feedback loop.

...So...the little pair just to the left above the op amp are probably hard clipping diodes shunted to ground. They are smaller than the surrounding vertically mounted carbon comp and carbon film resistors, so they probably are diodes. Since they are "oriented anti-parallel" that is further evidence.

A lot of this might already be known to any pedal geek like myself who happened to take a gander inside the Super Sport (which I have not). So a lot of this is just from me doing a visual inspection from a photo. There may be info on the web about the particulars of the Super Sport. As much as I like Dave's stuff, the Dirty Bomb and SS aren't really my cup of tea, so I haven't investigated them much. But I figured I'd help as much as I can.


	Telecaster Guitar Forum > Other Discussion Forums > The Stomp Box > new Barber pedal teaser PDA new Barber pedal teaser rhoydotp May 24th, 2012, 04:17 PM saw this on their Facebook page https://fbcdn-sphotos-a.akamaihd.net/hphotos-ak-snc7/576362_463050413720955_1161727295_n.jpg https://fbcdn-sphotos-a.akamaihd.net/hphotos-ak-ash3/s720x720/579786_463049880387675_162659963760003_1748948_138 5093293_n.jpg from the man himself: It contains just as much JCM800 as the Super Sport with some added tricks, not to mention 2 channels at 3.7" wide. There is an extra fun midgrange control on top and note shape located to the interior. We have been giving it a workout over the last few days and Ronni is putting together another prototype. E5RSY May 24th, 2012, 04:52 PM Wow! Way too many knobs, switches and lights for me. But, I bet it sounds good. filmix2 May 24th, 2012, 05:01 PM Tri-color trimpots. Nice touch. Chiogtr4x May 24th, 2012, 05:38 PM Just finished jammin' (well, I was by myself...) with Strat>Direct Drive> old DR. what a great combo! Barber OD's rock! JesterR May 25th, 2012, 05:42 AM I should stop read this kind of topics. I just do not need new dirt pedals. But I love Barber and love dirt pedals. czech-one-2 May 25th, 2012, 09:17 AM Maybe a 2 mode Shredmaster? I think I want one,even though I just sold my shredmaster!:shock: I think I need G.A.S. therapy... Chiogtr4x May 25th, 2012, 12:53 PM I rememeber years ago (now) on TGP Dave B teased the idea of perhaps creating his take on a "Fuzz Face," but also commented he liked original designs- Still, I'd be into this as it would be well-made and affordable... BWNadeau May 25th, 2012, 02:29 PM "You may commence firing sequence..." :mrgreen::mrgreen::mrgreen: Carvalho Diablo May 26th, 2012, 04:04 AM Look a lot like a Burn Unit. Fantastic pedal that one. studio1087 May 26th, 2012, 07:15 AM Return of the 1/2 Gainer? It looks like my 1/2 Gainer. Love the 1/2 Gainer. 11 Gauge May 26th, 2012, 09:26 AM Maybe a 2 mode Shredmaster? No - the SM has 3 op amps, and this one only has one. The Dirty Bomb was SM-derived, and that had a TL074 quad op amp. The LTD used a JRC072 op amp - this one uses a 4558, so no "jFET input" op amp type. At the upper LH corner, there is a 120pF cap strapped across a 1M drive control. Anything that big is going to be your main gain stage - both the pot value AND the cap value. The cap bleeds off fizzy treble. Something like a Tube Screamer uses a dinky 51pF cap, in comparison. So this is smoothing out the treble a bit more. There is a quad of clipping diodes at the upper LH corner of the circuitboard. The big question is whether they are soft clipping in the NFB loop like the LTD, or are they shunted to ground? Kind of a big clipping threshold for diodes to ground, but Barber put 1N4148/2N7000 series combos (in parallel) with the Dirty Bomb, so the thresholds would be similar. There are what might be a pair of clippers just to the above left of the op amp, and they (probably) would be shunted to ground. There is also a small value disk cap near them, which could be used to bleed off some top end sizzle. Even though you can't really go by physical size, there's a good chance it is a bigger value cap - possibly .001uF - .0047uF or so - also commonly used for shunted clippers (OCD uses .001uF IIRC). One of the signal caps will have to be for an input cap, and one will have to be for a high pass filter at the first op amp stage. So the rest are for interstage and tone circuits. The electrolytic "canister" at the upper LH corner of the circuitboard is most likely the output cap - Barber favors those fancier "audio quality" electrolytic caps, and they rarely look like "standard" electros used for the filtering/biasing stuff, like the blue pair in the upper RH portion of the circuitboard. So the rest of the caps are for EQ shaping. The pair of yellow-green ones above the op amp are possibly the same value, and there are other caps "in proximity" that might be, as well. When you see stuff like that and there are multiple tone controls, there is a likelihood of tone circuits like a Baxandall for treble and bass, or something like what is called a bridged t or twin t, which IS the contour control in a Shredmaster - it uses a .047uF/.1uF caps bridged with a .001uF to let you go from mid-heavy to scooped. There is a small multilayer ceramic cap (yellow) not far above the white trimpot. Again, it is probably a smaller value (compared to the other signal caps), and may support one of the above tone circuit implementations. For something like the SM's contour control which has a .001uF bridging cap, that could be what the little yellow guy is. All of this said, Dave didn't use the countour control in the Dirty Bomb, and he didn't use a Baxandall in the LTD (which is obvious, because it is a three knob pedal). And - the LTD SR has a presence trimmer, and the little yellow cap is kind of close to that first trimmer, so it could be for a presence-type control. While I dislike the trimmers, they allow Barber to really do a great job fine tuning the EQ characteristics with his stuff to make it more "sublime" or "integrated sounding." If it is indeed supposed to have a JCM800 sound, they really don't have as much distortion as we frequently reckon they do, hence the existence of only a single (dual package) op amp. Whatever this dirt box is, I have little doubt of two things: - it will probably sound fantastic - it will probably be very affordable Actually, there is a third - Barber is still using full sized pots. While I don't consider them to be clearly better than mini pots, they just kind of add a "visual value" IMO. Barber could do what so many other companies have done, and go to a circuitboard layout done by a computer that allows for pots with standoffs. This method "says hand built" to me, and it's one of the things I like about Barber. Just realized - there is a 4.7K resistor just above the quad of diodes in the upper LH corner of the circuitboard. There is also a 4.7K resistor across an outer and "wiper" lug of what is clearly the drive pot. This means most likely that it behaves "like a boost" with the drive knob set to minimum - you see this with many newer drive boxes. The fact that the 4.7K is so close to that quad of diodes means most likely that they are soft clippers in the first gain stage's negative feedback loop. ...So...the little pair just to the left above the op amp are probably hard clipping diodes shunted to ground. They are smaller than the surrounding vertically mounted carbon comp and carbon film resistors, so they probably are diodes. Since they are "oriented anti-parallel" that is further evidence. A lot of this might already be known to any pedal geek like myself who happened to take a gander inside the Super Sport (which I have not). So a lot of this is just from me doing a visual inspection from a photo. There may be info on the web about the particulars of the Super Sport. As much as I like Dave's stuff, the Dirty Bomb and SS aren't really my cup of tea, so I haven't investigated them much. But I figured I'd help as much as I can.