Crack Addiction - updates?

[jrebman]

Regarding the C4S upgrades, if you had to choose one would it be the voltage amp tube or the cathode follower?  Which one makes the most difference?

Thanks,

Jim

 

[Paul Joppa]

Regarding the C4S upgrades, if you had to choose one would it be the voltage amp tube or the cathode follower?  Which one makes the most difference?

Until someone does the experiment, all we can do is guess.

Normally, I'd say the cathode follower, but that's based on experience with preamps where the load impedance is high. Since the Crack has a low-impedance (headphone) load, the C4S won't increase the net load impedance very much at all. So I'd guess the voltage amp stage C4S will have the greater effect.

But what you hear does not always correspond to your theories, so I'd rather withhold judgment until we have some actual experience.

 

[jrebman]

Paul,

Thanks.  Guess we'll just have to wait though I wonder how many folks would try one without the other.

I'm trying to keep things running  as cool as possible, and if the CF CCS isn't a huge improvement over the VA alone, then I may just skip it.

-- Jim

 

[Doc B]

In the first example I built I think the VA load had a little more impact than the CF load, but using both sounded best. As for heat, whether it's cathode and plate resistors or active loads there will be more or less the same amount of heat under the hood. Going from one to the other doesn't really increase the current draw enough to make a big difference, not like adding a shunt regulator with a bunch of additional current draw and increased B+ might.

 

[ironbut]

Thanks, Paul.  How much room is there in the corner by the volume pot?  Enough to get one of the TKDs in there -- maybe with a little creative metalwork on the top plate?

-- Jim

I put one of the conductive plastic TKD's in mine and with just a little time with a rat tail file, it fit the stock hole no problem. Unfortunately, the pot that I used was from an old project of mine and it was history so I need to order another one. Be advised, the length of the shaft is much longer but with the application of some spacers on the bottom, the knob sits just a little higher than it did originally.

 

[jrebman]

Doc,

Thanks, and as long as the heat is roughly the same, no need to worry here.

Steve,  Thanks, I did some fiddling with this yesterday and came to the same conclusion -- that I could either drill or file out the existing hole and then file a notch for the index tab.  I'd also cut the shaft down a bit and use a nice quilted maple knob I have, or leave it as-is and use one of the big audio note gold knobs I also have.

-- Jim