Darkvoice 336 + 336i Tuberolling [ tubes ] - Page 50

Fitz Modded my 336i

I just Fitz-modded my DV. Took me 10 minutes and hum-be-gone.

Niiiiice.

When did yours start humming? Mine doesn't hum. Is changing all these tubes causing the hum?

My theory on this..



NOS and tubes that haven't been used for MANY years, usually have some sort of "noise" when you first turn them on. (on new 336i's)

I also believe that the more "burn-in" your components in the 336i get, the less likely the chance of any "noise".



For instance, I've probably swapped different tubes in my amp numerous times, and not once did one of them have any "noise". I had "noise" in some tubes at the beginning, but now, my amp has about 1,000+ hours, and I've yet to encounter the problem. I've had everything from NOS, to tubes not used in 20 years, to used tubes, and everything in between.

It's been about 4 months since I last came across a tube with some irregular "noise". So I am starting to wonder if all the burn-in on my amp has something to do with me not hearing the "noise" anymore.





-Nick

Tube rolling won't cause anything to hum. If your's is quiet, be happy and let it be.

Some tubes will hum in my unit and some are dead quiet. The current pair that I'm running had considerable hum, and burn-in time, pink noise, white noise, and freq runs weren't doing the normal trick of eradicating it. I'd be damned if my favorite combo wasn't going to be quiet, so out came the soldering iron.

Now the SOB is dead quiet with no deficit to the quality.

I am happy with mine, I'll admit. However, as to the Decware MLB, one of Steve's articles suggested that swapping a lot of tubes in that could cause it to develop hum. Hmmmmm.

To some extent, I believe this to be true. Everything audio-related, IMO, always sounds better with some time on it. In this case, by putting some caps across the cathodes of the preamp tube, you essentially filter any AC that's coming across.

Heheh, that was the exact same reason why I modded mine in the first place. Glad it worked out for ya.

Hey,

Stores are open again tomorrow so ill go into town and see if I can grab a 6080 WC tube somewhere for the rear, if not ill fall back on the internet stores/headfi people;p.

*edit
Seems all audio stores I can go to are closed on monday ;(.

Thanks again, bud. I split the difference between 100 and 300 and went with 220uF. Put an o-scope on the leads before and after and saw the 60 cycles take a hike!

Chris-

Can you possibly post some pics of the mod, or at least explain in detail exactly where to place those caps? Also, did you use electrolytic/paper/foil type and what is the voltage rating on them (caps).

THANKS!

Info PM'd

Thank you...

OK. I got the necessary caps to do the 'Fitz Mod'. $3.00 out the door from Radio Shack.

Think I might also order a 5998. Nick has made me very curious about those...

Hey Nick-

I just went back and looked at the pics of your bad boy to compare them with my Sylvania 6SN7GTB. Mine looks like a cross between the two you illustrated. Whereas the two shown in your post have 3+3 holes and 2+2 holes. Mine has 3+2 holes (3 left, 2 right). It doesn't appear to be a bad boy or a good boy. Perhaps its a Good 'Ol Boy. Do you know anything about this particular tube? Oh yeh, it has a chrome top, but only over the dome. The chrome doesn't extend down the sides like some I have seen. THANKS!

Is it a "chrome dome"



or "chrome top"





Also, if you can, include a picture of your plates.



-Nick