Tube Rolling w/Crack

Lately one of my RCA 6AS7G's with a old 5963 Sylvania have been magical to me at a very low cost compared to the RARE NOS stuff.

The bugle boy is in the same great class to me, I got it for $32 in a eBay auction which I never seem to win, too cheap here this is the most I have ever spent on a 12AU7 type tube!!

But I was a sucker for that Amperex!!! Ha!

The NOS Sylvania 5963 was $7.50!

Alex
 
I've got about 25 hours on my Crack and Crackphones now. Initially there was a very slight low level 'ring' in the left channel, for lack of a better term. Last night I swapped out the 6080 (at least I think that's the tube, there are no markings on it whatsoever) that came with the kit for a Winged 'C' 6H13C I got from the tubestore. The amp is now dead quiet and I am blown away by how good this thing sounds. I've got the boards all soldered up for the Speedball but I'm going to try and put 100 - 150 hours on the Crack stock before I install it. I may not make it that far though.
 
One very important observation I made was after the speedball was any of the tubes I had that was noisy or had small idiosynchroncies all became quiet, normal , no ringing, no buzzing, no small noises etch... it seems to make things more stable for all kinds of tubes supported but the crack design.

To me this is incredible, I had a 6AS7G that was very finicky and now its a solid performer!

Great upgrade for tubes for me!

Alex
 
Well, I got my first tube! A RCA 6AS7G vacuum tube - top getter - black

I got it from Leeds on etsy for $18 shipped. I had a slight channel imbalance with my first tube, and that is gone with this new tube.

I do notice that the tube is extremely sensitive to vibration. The amp sits on my desk, and if I tap my desk, I can hear some distortion through my headphones.  I put some DiversiTech 3" square HVAC vibration isolators under the crack, and it really helped. Note, these isolators come in 2, 3, and 4 in sizes, are really inexpensive, and are great. At any rate, is it common for tubes to be ultra sensitive to vibrations?
 
Allan,

When I first started listening to the crack I had many sensitivity issues....I could lightly tap on the table near or on the sides of the crack or top plate and hear the knocks or pings from this light tapping.

I had a few 6AS7G tubes that seemed very sensitive as well to any slight bumps of the amp or table....

Some after several minutes of warm up (30 or so) seemed to "mellow" out and not be as sensitive....I chalked it up to vacuum tubes etc.

However lately after installing the speedball update all these tubes now seem not sensitive at all.....I am listening now and can hit the table hard or tap the crack wood panels with absolutely no impact on the sound at all.

I also just found a cold joint in the signal tube and reflowed that and this may have been a part of all this as well.

So you might want to check or reflow the tube socket pins on both tubes to make sure your not getting any impact from a bad or marginal solder junction.

Especially if more than one tube is acting this way.

Alex
 
adydula said:
Allan,

When I first started listening to the crack I had many sensitivity issues....I could lightly tap on the table near or on the sides of the crack or top plate and hear the knocks or pings from this light tapping.

I had a few 6AS7G tubes that seemed very sensitive as well to any slight bumps of the amp or table....

Some after several minutes of warm up (30 or so) seemed to "mellow" out and not be as sensitive....I chalked it up to vacuum tubes etc.

However lately after installing the speedball update all these tubes now seem not sensitive at all.....I am listening now and can hit the table hard or tap the crack wood panels with absolutely no impact on the sound at all.

I also just found a cold joint in the signal tube and reflowed that and this may have been a part of all this as well.

So you might want to check or reflow the tube socket pins on both tubes to make sure your not getting any impact from a bad or marginal solder junction.

Especially if more than one tube is acting this way.

Alex
Click to expand...

Thanks.  I re flowed all the joints when I completed the crack, but I'll look closely when I install the speedball. I've been procrastinating the speedball, so I need to off my duff and get 'er done!
 
It was a strange problem with me having the amp work solid for a few weeks, it looked like the LED diode going into pin 8 of the 12AU7 socket must have been a cold or fractured joint from the outside it looked nice ands shiny... but when wiggling it the popping or cracking sound became very reproduceable...as well as rocking the tube in its socket causing the joint to flex and if not soldered well caused this intermittent and who knows what else....

The speedball to me really made the crack another level higher than the original base and much more noticeable than swapping out tubes!!

Alex
 
Hi 12AU7 rollers,

do you guys know anything about the B329 valve ?  I'm pretty sure it's just a rarely seen British valve code used for a 12AU7.  There's hardly any information about it.  I think they may have all been made by Mullard (and perhaps Brimar) and were specially selected tubes possibly only for re-sale by Marconi.

Anyway, just wondered if anyone had use one or had any thoughts.  I love the 12AU7s - surely must be one of the most diverse tube-types there ever was.


Jeb.
 
Thanks Paul. 

Another question - Do you know what is meant by a "toast" plate ? Is it just another term for a box plate like you see on something like the mullard cv4003 or is it some other shape?
 
Any recommendations for a good 12au7/ecc82 tube to go with my Mullard 6080 in the Bottlehead Crack+Speedball+HD650?

E5KfiOk.jpg
 
I have a 9 pin socket saver if i cut pin 5 and solder a jumper wire from pin 9 to pin 5 will this work for 6CG7 for the CRACK?
I noticed that the 6CG7 pin 9 is N/C that is why i thought about jumping pin 9 to pin 5 socket saver(Pin 5 is cut so it's not plug in to the crack's pin 5 socket).


Thanks!
 
i luvmusic 2 said:
I have a 9 pin socket saver
Click to expand...
Socket savers tend to have fatter pins to fit into loose, worn sockets.  If you put one into a fresh socket, you are going to stretch out the contacts a bit.

Pin 9 on the 6CG7 often time needs to be grounded, as there's sometimes a shield between the triodes. 

See other posts on the forum about various tube adapters, and the relatively low level of satisfaction when using them.

-PB

(If you want to use the 6CG7, just rewire the amp to do so)
 
Caucasian Blackplate said:
Socket savers tend to have fatter pins to fit into loose, worn sockets.  If you put one into a fresh socket, you are going to stretch out the contacts a bit.

Pin 9 on the 6CG7 often time needs to be grounded, as there's sometimes a shield between the triodes. 

See other posts on the forum about various tube adapters, and the relatively low level of satisfaction when using them.

-PB

(If you want to use the 6CG7, just rewire the amp to do so)
Click to expand...

I will look into it.

Thanks Again!
 
Hi i'm running a newly received 5-10hrs tung sol 6as7g and well it definitly fills out the lower mid range and upper bass very nicely but the mid to lower bass just seems to let go its just to over the top, not natural. Im running sppedball but on the big bass notes seems to let go.  I wonder if others have thought tha same? Im wondering if there is an alternative out there that gives more than the 6080 but more refined holds back a bit over the 6as7g sort of in the middle?
Thoughts?
 
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