Modded Crack - add bypass cap, choke and Cree diodes

[tim273]

Makes sense, I was wondering that too.  Maybe in time they'll come down in price and then might be worth it.

[Paul Birkeland]

By the time that happens, there will be another generation or two of Schottky diodes to replace them.

[tim273]

That is very true!

[tim273]

One more dumb question, if I were able to somehow make room, could I replace both 270/5w PS resisters with two C-7X chokes?  Seems like it would be an even better solution based on the research I've done and would remove even more ripple.  Or would this be one of those diminishing returns kind of thing?

[Paul Birkeland]

How much ripple do you hear now?

[tim273]

I suppose not to much, it's dead quiet, just more of a curiosity.

[tim273]

So instead of adding these upgrades to my existing build, I created a new build and incorporated them in.  I pretty much followed the original couple of posts, 1uf Clarity Cap on the last PS cap, added the choke and used the Cree diodes.  I also added film capacitors.  After I did the resistance checks, I was a bit nervous powering it up the first time, so I said a prayer and turned it on and no smoke!  I did the voltage checks and they all were within range.  Whew!

Anyway, I've been using it for a few days now and it sounds great!  It's almost like having the Crack with Speedball, even though there's no speedball.  I've got it pared up with my 600 ohm Beyerdynamic DT770 Pros (well more like 550 ohms), but the bass is very good, deep, tight and controlled.  The film caps add a smoothness that electrolytic ones don't have.

Anyway, it's a worthwhile upgrade.  I went with the Mundorf capacitors, but I'm not sure the sound is $120 better.  If I were to do it again, I would probably choose cheaper film caps, maybe the Dayton Audio ones, but that's just my opinion.

I'm planning on adding the speedball over the holiday weekend, so I'll post some pictures once that is done.

[tim273]

Ok, changed my mind, here's some initial pictures.

[ALL212]

Nice build!  Got all the stuff inside the box.   

[tim273]

Thanks!  Yeah, I followed the great instructions on this post!

[tim273]

So I've been listening to this mod for a few weeks now and I will say I agree that it's "all about dat bass."  I have a pair of modded 600 Ohm DT770 Pro's and the bass is deep and tight, but I really hear the sub-bass.  In addition I do hear more detail, but I really notice the bass response.  So great mod over all!

[larcenasb]

Hi,

I'm just trying to gather safety info about handling capacitors. I know electrolytics can be dangerous when charged and that you should only handle the body of the capacitor unless you know for sure it's discharged. But what about film caps? Do they need to be discharged too before handling freely? If so, will an insulated screwdriver across both terminals (like with an electrolytic) be advisable? Thanks and pardon my ignorance.

[Doc B.]

Don't use a screwdriver. Use a 10K ohm resistor. A screwdriver will spark on a cap with a lot of charge. Film caps of higher values should get the same treatment.

[larcenasb]

Thanks, Doc!

So, should I hold the resistor with insulated pliers, the cap by the body, and then join the leads? Like the attached crude picture?

"Film caps of higher values" ... How high? For example, what about the Crack's 100uF film output caps, or a power supply film bypass cap (2.2uF or less)? Thanks so much again, Doc, and I hope you and Queen Eileen are doing well during this rough time.

[Paul Birkeland]

If you get a 10W resistor for discharging caps, you can use an insulated pair of pliers to hold the body of the resistor to discharge things.  You don't want to do that with a small metal film resistor, as you'd likely crunch through the outer coating of the resistor by grabbing it with the pliers.