Black Hole (Sunn Model T Preamp)

[Kroars]

Hey all, hope everyone is doing ok out there!

Another build from me, this one is the Black Hole from Benoit over at Coda Effects.

It's great for adding a gritty overdrive, or dialling all the knobs gets you into compressed, bass laden, doom sludge! No idea how it compares to the original preamp sound of the amp but am digging what it does.

This was one was reverse etched, painted black, then sprayed with some cool 'hologram' glitter I found and thought would try, looks pretty cool I have to say!

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Looks great! Curious, did you take voltage measurements on you SMD’s when trimming or just by ear?

 

[twebb6778]

The one I build sounded phenomenally good without any adjustments, bias trimpots all set to noon, but just got even better when I set them to 4.5v (ish). It's a fantastic circuit, and I think you'd have to try pretty hard to make it sound bad.

 

[shaunos]

Been creeping on this same post for months now taking notes on how to nail this sick etch

 

[benny_profane]

Looks great! Curious, did you take voltage measurements on you SMD’s when trimming or just by ear?

Everything you wanted to know and more about JFET tube emulation:

A closer look at the Fetzer Valve

 

[Hexjibber]

Looks great! Curious, did you take voltage measurements on you SMD’s when trimming or just by ear?

Cheers! I just did it by ear tbh, but I might open it up and revisit using voltage measurements

 

[Hexjibber]

The one I build sounded phenomenally good without any adjustments, bias trimpots all set to noon, but just got even better when I set them to 4.5v (ish). It's a fantastic circuit, and I think you'd have to try pretty hard to make it sound bad.

I find with mine I have to basically have both gain pots set high-ish and volume set to max to get a decent level out of it, trimmers are fully wound also. I'm always wary of the success of a build when I have to do stuff like that, did you find the same? I've read other reports of this circuit being really loud. It sounds pretty good but just not what I was expecting I suppose, also read elsewhere that boosting it with an OD can really bring it to life.

I do have a slight caveat of only having tried mine through a load box DI into an interface with IRs and headphones, some other pedals that seemed low on output this way actually ended up being a lot louder when I had chance to use the amp normally at a practice. Using a Fender Twin Reverb.

 

[Hexjibber]

Been creeping on this same post for months now taking notes on how to nail this sick etch

Let me know if I can help or give any tips, been doing these sorts of etches for a while now so know my way around it. Also have an etching tutorial in my sig that I know has helped people in the past, its for a 'normal' etch but the process itself isn't all that different, mainly just how you do the artwork and sanding the paint off the raised areas.

 

[shaunos]

Let me know if I can help or give any tips, been doing these sorts of etches for a while now so know my way around it. Also have an etching tutorial in my sig that I know has helped people in the past, its for a 'normal' etch but the process itself isn't all that different, mainly just how you do the artwork and sanding the paint off the raised areas.

Thanks! I think I stumbled upon your posts on reddit, too and I recognize the little guide! I have read it a bunch and bought all the materials and will dive into some etching soon!

 

[twebb6778]

I find with mine I have to basically have both gain pots set high-ish and volume set to max to get a decent level out of it, trimmers are fully wound also. I'm always wary of the success of a build when I have to do stuff like that, did you find the same?

I've tried mine through my Fender Hot Rod Deville 410, and it's VERY loud. It sounds great alone, but absolutely glorious with the boost.

Could just be variance in the J201. After all, that's what the trimmers are there for.

 

[Kroars]

I find with mine I have to basically have both gain pots set high-ish and volume set to max to get a decent level out of it, trimmers are fully wound also. I'm always wary of the success of a build when I have to do stuff like that, did you find the same? I've read other reports of this circuit being really loud. It sounds pretty good but just not what I was expecting I suppose, also read elsewhere that boosting it with an OD can really bring it to life.

I do have a slight caveat of only having tried mine through a load box DI into an interface with IRs and headphones, some other pedals that seemed low on output this way actually ended up being a lot louder when I had chance to use the amp normally at a practice. Using a Fender Twin Reverb.

I’m with you 100% that’s why I was curious

 

[Kroars]

I’m with you 100% that’s why I was curious

Thanks!!

I find with mine I have to basically have both gain pots set high-ish and volume set to max to get a decent level out of it, trimmers are fully wound also. I'm always wary of the success of a build when I have to do stuff like that, did you find the same? I've read other reports of this circuit being really loud. It sounds pretty good but just not what I was expecting I suppose, also read elsewhere that boosting it with an OD can really bring it to life.

I do have a slight caveat of only having tried mine through a load box DI into an interface with IRs and headphones, some other pedals that seemed low on output this way actually ended up being a lot louder when I had chance to use the amp normally at a practice. Using a Fender Twin Reverb.

I put my Black Hole in front of PedalPCB’s op amp fuzz (Dream Fuzz) and it sounds fucking amazing. Super sludgy doom. You’re right though, I’m not a fan of the pedal by itself. I’m excited to pair it up with some others.

 

[benny_profane]

I find with mine I have to basically have both gain pots set high-ish and volume set to max to get a decent level out of it, trimmers are fully wound also. I'm always wary of the success of a build when I have to do stuff like that, did you find the same? I've read other reports of this circuit being really loud. It sounds pretty good but just not what I was expecting I suppose, also read elsewhere that boosting it with an OD can really bring it to life.

I do have a slight caveat of only having tried mine through a load box DI into an interface with IRs and headphones, some other pedals that seemed low on output this way actually ended up being a lot louder when I had chance to use the amp normally at a practice. Using a Fender Twin Reverb.

I'm not terribly familiar with the load box setup, but you shouldn't have to max everything out to get a decent output. Note that JFETs don't necessarily bias the same way as an op amp (i.e., Vref=(1/2)Vc). Did you follow the biasing procedure in the build doc? Depending on device type, a JFET can sometimes bias a little low. Check out the ROG article I linked above for a really in-depth discussion about JFETs in amp topologies.

EDIT: My understanding is that this circuit is meant to either go in an effects loop or near the end of chain (i.e., where an amp preamp would be). So, before modulation/time effects but after gain stages.

 

[Dan0h]

I've tried mine through my Fender Hot Rod Deville 410, and it's VERY loud. It sounds great alone, but absolutely glorious with the boost.

Could just be variance in the J201. After all, that's what the trimmers are there for.

Better to show up late to the party than not at all... I just finished my Black Hole today and came here looking for Bias info as the Coda Instructions just say set by ear, which I have to say most of the twist on all four trims sounds cool. Glad to see a 4.5ish suggestion which I will try. This thing is pretty damn huge sounding in my amp.

 

[Chuck D. Bones]

Looks good! Interesting knob arrangement.

 

[BeeSharp]

Wow, that enclosure looks great. I've got to give that a try. I built one of these for a local guitar player and made one for myself too.

 

[Dan0h]

Wow, that enclosure looks great. I've got to give that a try. I built one of these for a local guitar player and made one for myself too.

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Ironically for my second one, building this upcoming weekend, I have those red aluminum knobs like yours.

 

[BeeSharp]

Ironically for my second one, building this upcoming weekend, I have those red aluminum knobs like yours.

I got those at Small Bear, I got another set from love my switches. I prefer the slightly larger ones in this size from SB.

 

[Dan0h]

I got those at Small Bear, I got another set from love my switches. I prefer the slightly larger ones in this size from SB.

Nice. I ordered 3 small and 3 large, the 20mm ones, with the same red switch nut as yours. Going to use a black gorva enclosure putting the knobs to the left and the FS to the right.

 

[Fuzzonaut]

I made one of those a while ago, love it.
I put the boost on the outside, it's always on. And a big enclosure, just because.



Currently, I'm working on a two-in-one: Life Pedal (without the boost) --> Black Hole (as above, but with the boost on a foot switch).
Might doom, I hope.

 

[Dan0h]

I made one of those a while ago, love it.
I put the boost on the outside, it's always on. And a big enclosure, just because.

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Currently, I'm working on a two-in-one: Life Pedal (without the boost) --> Black Hole (as above, but with the boost on a foot switch).
Might doom, I hope.

This rules!