Dark Esbat Boost

[Chuck D. Bones]

Wow. To paraphrase David St.Hubbins, "The more the pedal industry stays the same, the less it changes."



I gotta say that while BCC improved one or two things over the Spark Booster, the first stage and the Vref buffer are both completely unnecessary and a waste of parts. The first stage is configured as a 2nd-order unity-gain low-pass filter tuned to 14KHz in the SB, 33KHz in the TIB. Nobody is going to hear that. The OPA2134 has FET input. A bootstrap (R5, R6 & C3 in the SB) is completely unnecessary. Using a $6 high-performance audio opamp as a Vref buffer is a joke. This is a good circuit, and can be build with two TL072s with no loss of functionality.



Looks like the SB was first to market by probably 5 years based on the dates of the online reviews. Laney's Black country Customs division is pretty shameless claiming to have "created" the TI Boost.

 

[spi]

Looks like the SB was first to market by probably 5 years based on the dates of the online reviews. Laney's Black country Customs division is pretty shameless claiming to have "created" the TI Boost.

They also jacked up the price quite a bit. A SB is $79 and a BCC is $199.

 

[KR Sound]

“Tony Iommi signature Boost pedal”

 

[Chuck D. Bones]

Is that the 4-knob SB? Or the SB-Mini?

Tony's signature on the pedal is worth at least $100

Getting a bit off-topic, but has anyone watched Guitar Star season 2?

 

[MattG]

I gotta say that while BCC improved one or two things over the Spark Booster, the first stage and the Vref buffer are both completely unnecessary and a waste of parts. The first stage is configured as a 2nd-order unity-gain low-pass filter tuned to 14KHz in the SB, 33KHz in the TIB. Nobody is going to hear that. The OPA2134 has FET input. A bootstrap (R5, R6 & C3 in the SB) is completely unnecessary. Using a $6 high-performance audio opamp as a Vref buffer is a joke. This is a good circuit, and can be build with two TL072s with no loss of functionality.

"The first stage is configured as a 2nd-order unity-gain low-pass filter" - reading other random comments about this circuit on the web, I saw that called a Sallen-Key filter. I always wondered what the purpose of it was in the SB/TIB.

IIRC, the TCE MojoMojo and Dark Matter (based on DIYSB/FSB traces) also have that filter up front. Appears to be a thing with TCE!

 

[Chuck D. Bones]

Sallen-Key is the specific config of this active filter. Sallen-Key can be 2nd-order or higher, low-pass or high-pass, etc. There are other ways of realizing an active filter, but Sallen-Key is popular because it has a low parts count and is easy to design and manufacture.

https://en.wikipedia.org/wiki/Sallen–Key_topology

 

[cdwillis]

I just breadboarded this biatch.

It's a straight-ahead slightly dirty boost, with a fair amount of extra parts. Details to come in The Boneyard.

For anyone who didn't already know, this is not an amp-in-a-box like The Wizard or Sabbra Cadabra. If you want to sound like Tony Iommi, you need to use this baby to push a Laney 100 amp 'cause that's how he does it (according to the Black Country Customs website).

Seems like a clone of the Spark booster, but parts of the Spark booster circuit look like the Xotic RC Booster. Makes me wonder if they were inspired by that or just had some of the same circuit results designing their own boost.

 

[Chuck D. Bones]

It's all pretty generic. A soft clipper into a Baxandall tone stack. The thing about the SB / TIB that makes it stand out (to me anyway) is the switchable Mid Boost in front of the clipping stage.