Installed the speedball mod on my Crack.
Outside the f***ing solid core wire (which I hate working with) which breaks as soon as you look at it, if you don’t plan the routing ahead of time, it’s a very easy update. I desoldered some components instead of cutting leads for the install, but you don’t need to so that.
Basically it replaces both anode resistors with a constant current sources, this should increase linearity, and have some marginal effect on the gain.
Short version, well worth it, opens the treble up a fair amount, makes it sound a faster, also seems to improve the Bass control and extension.
It’s still a relatively big/full sounding amp, but more refined.
With appropriate headphone Sennheiser HD6??, or ZMF’s (and I assume the high impedance Beyers), I would rate the Crack with Speedball, up there with pretty much any tube amp I’ve heard under $1K.
How hard was this build? I am very interested to build one of these amps with my father… And get a warm up for debugging my old 1950’s Fisher tube amp to finally remove the buzz that has been longer than I have been alive.
That buzz is probably due to old caps in the system…You need to re-cap the system, very typical with old audio stuff…the issue will be trying to find the values, voltage, size to fit in the areas…sometimes this can be a real chore.
Its pretty neat to get old stuff working again, a true labor of love!
Alex
Note: The BH crack is a good first time kit…if you know how to solder its pretty staright forward…I have built several of the BH kits…all worked first time…a little patience and read the manual, measure twice cut once etc…
I think the instructions are online, they are VERY clear.
You need to be able to read and follow instructions, I actually missed one step in my initial build, but I caught it when inspecting the amp.
You need to be semi competent at soldering (wouldn’t do it as a first soldering project).
You need a meter to test voltages and resistance.
You need to understand that your dealing with high voltages when it’s plugged in.
The only other “hard” part IMO is the choice on Solid Core wire for the point to point wiring, the issue with it, is it fatigues and tends to break where it was stripped if you don’t pre-bend it to avoid the stress points. That’s more frustrating to work with than difficult, and it technically the right choice for these sort of point to point designs.
I’d expect most people with some soldering experience who can read and follow directions would end up with a working amp.
I’ve done that stuff before and in high school I got my IPC electrical manufacturing training before going to school for EE. Well versed in old school electronics as my dad introduced me to old HAMs that worked at Cedar Rapids Collins Radio head quarters. I know what I’m in for but thanks for the heads up on the caps! I always forget those can bad.
I really hope I don’t have to verify resistors still working… those are the most annoying failures to debug due to shear volume.
As far as soldering… 0203’s without binoculars since 2005.
If this is happening then your wire strippers are cutting into the solid core wire and this will happen. I use it all the time and do not have this issue…check your wire cutters…
They use solid wire because first time builders have way more issues using stranded wire…omg shorts etc…
Because of this, the old school trick I use is roll the wire over and exact knife. Plus I swear the blood before you get the scar tissue built up makes is sound better.
I use a scalpel, but that’s how I usually strip wire.
I mean it’s quite possible it’s incompetence on my part.
I can see the mutli-stranded wire argument for beginners.
Golly gee, I have been doing this stuff since I was 15 years old and I am 70 now!! and I have used knifes, scaples etc…and depending on how you do it, it can be fine but often not…get a really good pair of wire strippers and use the right guage setting and you will be good to go…
I started using scalpels instead of craft knives years ago, scalpel blades are incredibly cheap and disposable, and a decent scalpel handle is not overly expensive.
I’ve never owned a wire stripper that actually worked consistently, but I’m open to suggestions.
They really don’t go for the same goal, really amps going for different things. Also really depends on the headphones you have if the crack will be the right fit for you
Without speedball, yes, with speed ball more so.
They’re probably similar topologies, but the Crack ships with higher quality components, it’s just a better amp. And there is no real speedball equivalent for the DV.