# Black Hole (Sunn Model T Preamp)



## Hexjibber

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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## Nostradoomus

That looks awesome dude!

So you didn’t negative out the colours? Cool


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## Hexjibber

Nostradoomus said:


> That looks awesome dude!
> 
> So you didn’t negative out the colours? Cool



Thanks! Yeah exactly that, you just have to do your design the opposite way round when doing the artwork and as long as you spray the box a dark-ish colour it can really pop! I've also done some where I haven't painted the whole box and they can also look cool, like this one..


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## Nostradoomus

That’s awesome! Makes it look like a faceplate. My local paper supply company phased out the super light glossy cardstock I was using, what do you use? The thick stuff just clogs in my bottom feed printer.


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## Hexjibber

Nostradoomus said:


> That’s awesome! Makes it look like a faceplate. My local paper supply company phased out the super light glossy cardstock I was using, what do you use? The thick stuff just clogs in my bottom feed printer.



I use this one, it's not super thick.. I think? I'm not sure they make this any more, unless they've just updated the packaging or something. I bought a job lot of packs a few years ago but will have to source something else eventually. I have seen this one pop up on eBay from time to time though.


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## Nostradoomus

Yeah that’s around 65lb paper, I think the stuff I used was about the same. ‘Twas nice while it lasted haha


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## Chuck D. Bones

Just beautiful!


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## twebb6778

Looks great! I've got one of these on the way too!


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## Mourguitars

Awesome build !

A lot of you guys are taking these enclosures to a whole different level ...man they look awesome , again nice looking build 

Mike


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## Hexjibber

Thanks guys!


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## Barry

Those look fantastic, you’ve really got that etching process refined


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## HamishR

Just awesome.


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## MightySmallElectrons

I’m slow...let me see if I got this? You etch the part that is now black, paint the whole enclosure and then sand off the paint from the high parts (design and lettering)?


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## Nostradoomus

Yeah


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## Nostradoomus

Yeah that works pretty good, thanks Hex!

Guess the clone! Hurr durr!


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## Hexjibber

MightySmallElectrons said:


> I’m slow...let me see if I got this? You etch the part that is now black, paint the whole enclosure and then sand off the paint from the high parts (design and lettering)?



Yeah that’s it exactly


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## Hexjibber

Nostradoomus said:


> Yeah that works pretty good, thanks Hex!
> 
> Guess the clone! Hurr durr!
> 
> View attachment 3837



That looks awesome! Look forward to seeing the painted result, would like to know if it’s worth building also as am curious!

I find sometimes it can be hard to get a good transfer doing a reverse etch as there is less ink in contact with the enclosure. I usually have to carefully lift up the paper starting at one corner and if some parts haven’t adhered I put it back down again and re-iron. It normally happens near the edges if anywhere. As a general rule the more the design ‘fills’ the face of the enclosure, the easier the transfer can be.

Almost finished my next build, report coming soon!


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## Nostradoomus

I always just cross my fingers and hope...maybe an extra minute with the iron if I don’t feel confident. I always sink mine into water to cool it down so there’s no re-ironing happening after that haha.

This one is a commission to make a V2 Life Pedal clone w/exp pedal. I’ll try to do a demo when I’m finished...it’s definitely worth building if you like Rats.


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## Nostradoomus

Not bad for a first go at it!


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## Chuck D. Bones

Looking good!


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## Kroars

Hexjibber said:


> 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!
> 
> View attachment 3715
> View attachment 3716
> View attachment 3717
> View attachment 3718


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


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## 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.


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## shaunos

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


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## benny_profane

Kroars said:


> 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


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## Hexjibber

Kroars said:


> 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


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## Hexjibber

twebb6778 said:


> 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.


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## Hexjibber

shaunos said:


> 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.


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## shaunos

Hexjibber said:


> 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!


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## twebb6778

Hexjibber said:


> 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.


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## Kroars

Hexjibber said:


> 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


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## Kroars

Kroars said:


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


Thanks!!


Hexjibber said:


> 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.


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## benny_profane

Hexjibber said:


> 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.


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## Dan0h

twebb6778 said:


> 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.


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## Chuck D. Bones

Looks good!  Interesting knob arrangement.


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## 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.


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## Dan0h

BeeSharp said:


> 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.
> 
> View attachment 7628View attachment 7629


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


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## BeeSharp

Dan0h said:


> 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.


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## Dan0h

BeeSharp said:


> 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.


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## 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.


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## Dan0h

Fuzzonaut said:


> 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.
> 
> View attachment 7634
> 
> 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!


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