DEMO EffectsLayouts EF120 Overdrive (Dunwich Amps DA120) ‘Matamp GT120 in a box’

[owlexifry]

Build Rating

4.00 star(s)

doesn’t seem many have built this one, and of those that have, it seems most have reported less than favourable experiences with it.
well that isn’t the case for me.
i reckon this thing sounds fantastic and does exactly what it’s supposed to.



i’ve read the discussions on a thread regarding the depth / FAC control being a bit whack on the GCI Apostle, similar to this design, with the cap selections positioned in parallel with a fixed cap, instead of in series, as orange OR120 schematics would designate.
this does result in different/perhaps undesirable low end trim behaviour, but i wouldn’t suggest that the result in this particular circuit/PCB is entirely redundant.
it also has different cap values to the GCI Apostle.

FAC/Depth cap values available are:
1n (fixed, in parallel with):
- (nothing)
- 2n2
- 4n7
- 10n
- 22n
- 100n

1n is a bit clanky, but not useless.
1n+2n2 noticeably thickens up.
1n+4n7 slightly thicker.
1n+10n sounds quite nice and balanced.
1n+22n same (not much difference from 10n)
1n+100n is thicc and wooly. burly setting.
the significance of difference in tones does depends on gain/drive settings.


- boost control is an odd one.
it’s like a weird sorta mids / sorta presence boost that goes bonkers at really high settings. it’s cooked, but in a good way.

- gain control works great.
- drive control doesn’t seem to do much until 11/12 o’clock, but does what it needs to from there.

i think this is a wonderful distortion. a win for the mighty MOSFET.
it can be sensible and crunchy, crisp and articulate with a bridge pickup for rock tones if you want it to, and then goes absolutely fat, oversaturated and blown-out for doom tones. the gain+drive controls can set this just right.
tones of gain available.

in this demo i selected the electrovibe to be a boost (vibe mode, intensity on zero).
it’s a mad fat boost in vibe mode. (in chorus mode its a bit more mid focused).
- FAC set to 1n+10n.

weird story time:
i have to report the strangest experience ive ever had with a PCB and i’m still not sure if it was just me being a twit, or a bad PCB:
- when i first started testing, the LED blew out.
- double checked everything, no shorts, had a 22K in the CLR position for a waterclear LED.
- removed the LED, dry fitted another one. same thing, blew out. lol.
- removed the 22K from the CLR position.
guess what:
- from the 1N5817, that feeds the CLR, i was getting continuity to both sides of the CLR. wtf.
so the CLR position on the PCB doing jack shit. or i did something wrong, but i have no idea what or which.
anyway, so i just snuck in a 22K inline with the LED anode and inserted the LED as per normal, and all sorted, operating as normal.
so strange

 

[Einzeln]

You might like the Mofeta(model T)

 

[owlexifry]

You might like the Mofeta(model T)

i did like that one. i breadboarded it, and then i liked it even more after i modified it for super lead/plexi inspired tones (final build report pending). an excellent JFET distortion.

 

[Einzeln]

Yeah. Now I remember. You made a demo.

 

[comradehoser]

Hm! Well, maybe for me it might be comparison bias since I built the Apostle and Monarch first.

Maybe you've a better touch with circuits than me, since my Figment preamp doesn't sound half as interesting as yours.

Maybe it's Maybelline.

 

[Hal Harvey]

Beautiful. Lead dress is a great example of “how it should be done”.

I built all the other Effects Layouts Dunwich PCBs except for this one because I was planning on building the actual amp. I may end up building this one too because a) your demo of it sounds fucking great, and b) really it’s own (non-redundant) thing.

 

[VanWhy]

Nice build. I have this one just about ready to go so it's cool to see and hear your demo. I personally love MOSFETS for my rig. Good stuff dude.

 

[owlexifry]

Figment preamp doesn't sound half as interesting as yours.

it might just be a matter of difference in the selection of JFETs (maybe?)
but what really does make a difference is how the collector trimpots are dialed in. i find these significantly alter the amount of overdrive generated at each stage.

Beautiful. Lead dress is a great example of “how it should be done”.

ay thanks! good ol’ solid core makes it easier.

I built all the other Effects Layouts Dunwich PCBs except for this one because I was planning on building the actual amp. I may end up building this one too because a) your demo of it sounds fucking great, and b) really it’s own (non-redundant) thing.

the actual amp would be amazing! those kits were tempting.

it’s certainly got a nice satisfying grind going on. i haven’t tried it with anything beyond 9V supply yet, but i’m glad the demo could be inspiring enough!

Nice build. I have this one just about ready to go so it's cool to see and hear your demo. I personally love MOSFETS for my rig. Good stuff dude.

cheers!
get keen it’s a winner
which MOSFET circuits are you digging? i’m not very familiar with many

 

[jwin615]

Nice!
I have 2 boards populated for this, minus pots.
Kinda makes me worry about my F-in with the fact cap values. We'll see.
It's to early to think on a Saturday but maybe your led issue is a wiring issue?

Lug 2 is input tip(unpopulated)
Lug 1 is circuit input.
Wait, no. Your wiring looks fine.
I'll check my boards and see if they exhibit the same behavior
Thanks for including this info in your report. I sure as hell don't want to unmount these beasts just to chase led issues!

 

[owlexifry]

Nice!
I have 2 boards populated for this, minus pots.
Kinda makes me worry about my F-in with the fact cap values.

FAC cap values?
yeah i guess a few substitutions might be worthwhile. especially if you have x2 boards to compare with

I'll check my boards and see if they exhibit the same behavior
Thanks for including this info in your report. I sure as hell don't want to unmount these beasts just to chase led issues!

let me know how you go, i’m gonna laugh if im the only one that has this issue

 

[Paradox916]

Stony AF!

 

[comradehoser]

but what really does make a difference is how the collector trimpots are dialed in.

That's the one. I went back and returned retuned by ear. Made a really big difference. Even got a nice clean for the first 1/32nd of the gain pot rotation. And finding the right setting on my Palisades/Stockade for the tite chuggs. Now I've got owlexifry squealies and excellent modern metal tones going on. So. Freaking. Loud. Holy. Loudest pedal I have, hands down.

For the EF120 I think I'll have to do an EF120/Viceroy/Apostle showdown if I can figure out how to post video and/or audio. Could also be a rig combo effect. I've noticed pretty much everything sounds pretty great through what it is you have going on.

 

[owlexifry]

That's the one. I went back and returned by ear. Made a really big difference.

heck yes!

Even got a nice clean for the first 1/32nd of the gain pot rotation.

this right here.
i might be full of shit here, but IME when dialling JFETs for a distortion circuit, I've always felt that it should be possible (and perhaps necessary) to have a relatively nice 'clean' early on in the gain range.
just like a real amp would. (i.e. MIG50, JCM800 etc.)

perhaps this ensures adequate headroom for particular gain stages, im not sure.

finding the right setting on my Palisades/Stockade for the tite chuggs. Now I've got owlexifry squealies and excellent modern metal tones going on. So. Freaking. Loud. Holy. Loudest pedal I have, hands down.

haha yep it is shockingly loud.

For the EF120 I think I'll have to do an EF120/Viceroy/Apostle showdown if I can figure out how to post video and/or audio.

i've found soundcloud is pretty good for sharing audio.

Could also be a rig combo effect. I've noticed pretty much everything sounds pretty great through what it is you have going on.

thanks! in these demos it's just GTR > [pedal(s)] > amp > speaker cabinet.

it also probably helps when i record a demo video, the audio is being captured with an SM57 & scarlett 2i2 preamp into an iphone adaptor. i don't edit anything, it's all raw, but at least the audio isn't coming from an iphone mic.

 

[comradehoser]

when dialling JFETs for a distortion circuit, I've always felt that it should be possible (and perhaps necessary) to have a relatively nice 'clean' early on in the gain range.
just like a real amp would. (i.e. MIG50, JCM800 etc.)

I think it indicates you have the preamp dialed in correctly, for sure, if it's a preamp. Some other circuits, though, it's hard to get to, if not impossible, since it seems like they're designed dirty.