Modified Crack: standard + speedball combo

Costes

New member
Hi everyone!

I modified my crack in a way that allows me to listen either as the standard crack, or either as a speedballed crack, because both have their beauty :)
I really like being able to choose between both systems, just by using a switch which than activates some relays, after 5 seconds the crack than powers on via an other relay. Once the crack is on, you can no longer switch between standard or speedball, as a safety for the tubes/circuits.

I let myself go a little bit with some other circuits :) I added a VU meter, and some temperature sensing circuits to decrease the heat in my very confined space :) There is a fan that activates first in standard mode, to cool the big resistors attached to the heatsink. In speedball mode this fan only activates after a high temp is registered, because before, a fan beneath the ventilation hole of the top plate will activate.

Temperature can be monitored from the outside by a series of leds above the VU meter.

All in all, i'm very happy with the result, and the amp runs cool for hours.

Thank you bottlehead for designing such a nice sounding amp, and i had a lot of fun building it :)
PS: hope you guys don't mind i made it into such a monster  ;D

Grtz from Belgium





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This is the most complex mod I've ever seen in my life!

You must be proud of your stunning technique,

Compliments  8)
 
Wowzers the award for the Crack with the most stuffing must surely be yours.  It looks like you will need another box for chokes and film caps  ;)

I am wondering about the VU meter also what was the power requirements and where did you tap it from, why only one is it a sum of both channels or just one side?
 
Wow....the term "modified" doesn't do it justice  ;D
It looks great......and complex on the inside. The VU meter is a nice touch.
You called it a monster maybe you should name it Franken"Crack"  ;)

One of a kind build.....very nice !!


 
Hi,
Thank you for the nice reactions!

The VU meter is powered via a 12V supply. The bottlehead transformer is used only for the audio, the rest is powered via that 12V supply.
It takes its signal from both channels :)

Greets!!
 
Wow, that is quite ingenious. I love the sound of the stock Crack and am a little hesitant installing the Speedball and losing some of that tubey-goodness. Seems like you found the perfect solution...
 
I've got to admit, I was pretty speechless, hard to believe from the guy with the highest post count.

You have made a number of "new to Bottlehead" mods.  You can become a trendsetter.  I really like that you put connectors in there so you can take the circuitry off of the base.

Congratulations!
 
Thats an impressive amount of hardware you have managed to package in there.  I am curious as to what it all does, there seems to be a lot more in there then just a VU meter and Temp driver?
 
There are more circuits in there indeed, most of them either serve as logic for switching the right relay at the right time,
or control the led's brightness in the VU meter via a light sensor, or speed control of the 2 fans...

It was a bit of an experiment for using transistors for logics, delays, switching, ... :)

For a next version it would be nice to use an arduino system with touchscreen or something  :P
 
Well done. Great build mate.

Also...and I think I speak for many of us less...proficient here...Would be greatly appreciate it, if you had the time, and could post a "how-to" for the VU meter in terms of connecting one and powering it....Sort of like a newbie guide.

All the best.
 
Sure, mine is something very similar to this schematic:

http://electro-music.com/forum/phpbb-files/electronique_vumetre_002_206.gif
For powering it (usually 12V), i just added a small power supply into my build of the crack.

But you can buy a VU driver online as well  ;)

Grtz
 
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