Tube Rolling w/Crack

[AllanMarcus]

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

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!

[adydula]

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

[Jeb Jeb]

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.

[Paul Birkeland]

do you guys know anything about the B329 valve ? 

It's indeed just a 12AU7.  It looks like potentially it was an early Marconi 12AU7.

[Jeb 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?

[Paul Birkeland]

Thanks Paul. 

Another question - Do you know what is meant by a "toast" plate ?

I've only seem that reference made for getter shapes.

[Jeb Jeb]

Hmmm cool - yes, visually that makes more sense for a squareish getter shape.

thanks for your help!

[bocosb]

Any recommendations for a good 12au7/ecc82 tube to go with my Mullard 6080 in the Bottlehead Crack+Speedball+HD650?

(https://forum.bottlehead.com/proxy.php?request=http%3A%2F%2Fi.imgur.com%2FE5KfiOk.jpg&hash=45c4cd683721b2b8cbb63ef21732d7ac593e8ecf)

[i luvmusic 2]

Anyone here tried 6211 on their stock crack/will it work?

[Paul Birkeland]

Anyone here tried 6211 on their stock crack/will it work?

It will not work in the stock Crack.  It will work poorly in a modified Crack, as it has much more gain than the 12AU7.

[i luvmusic 2]

It will not work in the stock Crack.  It will work poorly in a modified Crack, as it has much more gain than the 12AU7.

Thanks!

[i luvmusic 2]

 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!

[Paul Birkeland]

I have a 9 pin socket saver

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)

[i luvmusic 2]

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)

I will look into it.

Thanks Again!

[netosullivc]

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?