Crack static

[bmurph7]

I completed my Crack a few months ago, and have been enjoying it since.  A couple of months ago, after about listening for 15 or 20 min. I experienced a squeeking noise that would last a couple of seconds and then go away.  Since that time, it has become static instead of a squeek, and lasts up to 10 minutes or so and then goes away and the amp is again noise free for the rest of my listening session no matter how long.  I have cleaned all my interconnects with DeOxit, and nothing changed.  Could it be a bad tube?  As I said, once it goes away, the amp is again quiet, but it seems to be lasting longer as time goes on.
Any advice and opinions would be appreciated.

[Doc B.]

Yup, probably a tube.

[bmurph7]

Thanks Doc

I'm new to diy, but having a great time.  Love the amp! Thanks for that, and all the help.

Brent

[Grainger49]

Brent,

Usually the stock tubes are good and last a long, long time.  I played my Sovtek 2A3s till they were pretty flat!  I rolled 12AT7s till I couldn't think, then changed the drivers in my Paramour amp. 

Every so often over the last 10 years I turn on the system, all tubes, and think "something is wrong."  I go through the system changing to new tubes.  When I find the one that was getting old I put the others back and save my stock for when the preamp and phono stage needs a new tube. 

Collect a few, they are always good just for a sanity check when troubleshooting.  That should be maybe once a year.

[bmurph7]

Thanks Grainger

As I said, I'm new to this, so I have no spare tubes, but I'm looking forward to getting a few.  The day after my post, the static went away and has not returned.  I'm assuming this happens with tubes occasionally as they burn in?  Even so I'll get others.  I'm reading the posts to try and decide what to get.  My budget is limited, but next month I'm ordering the Speedball.  Really looking forward to upgrading and rolling.  The amp sounds great now, so I'm interested in how much better it could sound.

Thanks

Brent

[Grainger49]

There is a good but loooong thread in the Crack folder about tube rolling.  You will find a wealth of knowledge there.

[bmurph7]

Thanks Grainger

I've been reading that and other threads, and I'm learning but with no electrical background its been slow. Also using Wickipedia for definitions, but some things I still can't find. Like what is aC-R-C-R-C filter? Can't find that yet.  Also a Choke, and what is an iron upgrade?  Doc suggested a text book from a trade school, so I'm also looking for that.  Its' all great fun though.  I couldn't even solder when I got my Crack, and although I'm no expert, I do well enough now to put together a kit.

Thanks again for all the help.Brent

[Grainger49]

It stands for Capacitor, Resistor etc.  In the case of putting a choke in it reads CLC with the L being the inductor. 

An iron upgrade is buying better transformer for an amplifier.  Putting a choke in the power supply in the place of a resistor in a CRC filter is also an iron upgrade.  There are several other places to try a choke depending on the design.

[bmurph7]

Thanks Grainger


I just downloaded some basic manuals that were recommended for a basic education.  Thanks for answering my questions.  I love music and good sound, and it's really fun learning how it is reproduced.

Again, Thanks for the help

Brent

[BNAL]

The power supply is a great place to start when improving sound quality. I have experienced the greatest improvement by making changes to the power supply. If you look at upgrades offered for the Bottlehead kits they for the most part focus on the power supply.

My Crack uses a CLCLC configuration. I replaced the resistors in my power supply with chokes. I f3el 8t made a nice improvement, but feel the speedball was a greater improvement.