Let me present my, pretty much, finished (for now) Crack:
IRONCLAD
-or
Brass Shithouse, alternatively.
Mods:SpeedballOutput Caps:
Mundorft MKP, 100uF 250VChoke:
Hammond 157MPot:
TKD 2CP-601Power Bypass Cap:
JB JFX, 2.2uF 250VCosmetics:Polycoat for base
Clearcoat for transformer bell
Knob: Elma Marconi Classic British Wing Knob from HifiCollective
Brass corners: Heart of Brass Etsy store
Pictured tubes:
Mullard 6080
Mullard 12AU7
-just because they fit the IRONCLAD (capital letters required) theme
Before I move on to some more detailed descriptions of the mods, let me just make it absolutely clear that I am an awful audiophile.
I have almost no frame of reference, my experience with amps is limited to once owning an APPJ "something" and still owning a couple of broken down old Tandberg receivers (next project: restoring them!).
To be completely honest, I just did all this for the fun of building.
And to be even more honest, I thought the Crack sounded wonderful without mods, and after mods it ...errr still sounds wonderful. But I can't for the life of me tell what's different.
But I did find the bass more punchy and clear after the Speedball, so that's nice.
Speedball:Not much to say, order the kit and stuff it in.
Audible difference:
Nicer bass.Choke:I debated wether to suspend the choke from the top plate or mount it in the base.
In the end I decided to screw it to the inside wall of the base, where I think it fit rather nicely.
I might stuff in another choke just to adhere to the IRONCLAD theme...nah.
Audible difference:
Not that I could hear. My Crack was dead quiet before and is still dead quiet.Power bypass:The small film cap was cheap so I figured "why not".
Bypassed the last cap in the PSU.
Audible difference:
Nah.Pot:There was a slight, expected, imbalance at lower levels with the stock pot.
So I figured, "why not".
Went for a TKP pot just because lot's of people go for the Alps.
The stock pot was just as smooth as the TKP, I find the TKP takes a little more force to rotate.
The TKP fits in the plate hole, so no need for filing.
But the “locking tap†makes the pot’s terminals face away from the nine pin socket and it’s considerably smaller than the stock pot, so you might have to choose between running longer wires to and from the pot or figure out how to mount the TKP facing another way.
I ended up putting an extra nut on the pot, so the locking tap didn’t reach the plate. But the pot is still a little small, so my wiring to and from the pot is a mess, gonna fix it up some day.
Audible difference:
better channel balance at lower volume levels.Output caps:These are probably my favourite.
Not because of the sound, just because I like the look of them.
But soldering the fat leads with a 15W iron was an enormous pain in the ass; took ages to heat up.
They’re suspended below the top plate by metal mounting clamps. I quite like the clamps as they’ll let me swap caps quite easily if needed and they look sturdy.
Audible difference:
sorry, can’t hear it.Brass corner pieces:I wanted some square, metal feet for my Crack.
It was pretty much impossible to find exactly what I pictured so I landed on these metal corner guards that I mounted like legs.
While I quite like the look, the Crack has gone from an intriguing oddity on my desk to a brutal and ostentatious behemoth.
Audible difference:
by far the largest sonic improvement of any modification.Conclusion:As I’ve said, I have a poor frame of reference and a poor audiophile ear.
So when I say that I can’t hear an improvement in the sound of my Crack, it’s just that:
I can’t hear it, not saying it’s not there.
Besides, by the time I’ve actually installed a mod, I’ve forgotten what the damn thing sounded like before!
I had a stock Crack about three months before I started modding it.
I’m still not quite done with the Crack. I’m going to put in some new wires to and from the pot, reflow a couple solder joints and I’ve also got two bypasses for the output caps lying around. But after that I’m probably done.
As for the whole IRONCLAD thing, I’m well aware it’s just a pretty ordinarily modded Crack with tacky tat screwed on. But it’s
mine. IRONCLAD!
The only mod I can recommend is the Speedball.
The other stuff I just did for the fun of tinkering, and if you like that sort of thing: go for it!
Just don’t expect to have your mind blown.
To finish up, I love this thing.
The sense of ownership and accomplishment after building and modifying the Crack is both intimate and rewarding. I can heartily recommend getting a Crack to anyone, both the stock Crack and the Speedball are easy builds thanks to exemplary manuals.
Bottlehead have created a beautiful kit and a wonderful forum that attracts helpful and friendly people. And I’m glad to be a tiny part of it.
EDIT: If any other toob noobs like me want some more info on how to do any of these mods, just ask
