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Crack;Bottlehead OTL - Page 232

post #3466 of 5570
Quote:
Originally Posted by mordicai View Post
 

Started my Speedball today and need to buy a stronger magnifier.  I feel like I'm a brain surgeon.  The next level in miniaturized electronic's is going to be a blast to build. By the way, I'm 73 with only vision in one eye. If I can do it, you can.

 

I know that feeling and I am 45! and just managed with my old magnifier on the speedball build. The week before Christmas I found a 2.5x magnifying glass with 2 LED lighting modes for £4.99 at my local Lidl store. I  was expecting it to be a cheap plastic affair but was quiet surprised at the quality machined aluminium construction, it has a nice weight to it. It also came with a zipper case and 2AA batteries included and a 5 year warranty . I wonder how they make and ship things like this for the money and why some plastic fantastic products cost so much.

 

ZC

 

ZC

 

ZC

 
I was so surprised at the quality I googled it and found a little review.

Edited by JamieMcC - 1/5/14 at 9:45am
post #3467 of 5570
That is really cool!
Quote:
Originally Posted by JamieMcC View Post

I know that feeling and I am 45! and just managed with my old magnifier on the speedball build. The week before Christmas I found a 2.5x magnifying glass with 2 LED lighting modes for £4.99 at my local Lidl store. I  was expecting it to be a cheap plastic affair but was quiet surprised at the quality machined aluminium construction, it has a nice weight to it. It also came with a zipper case and 2AA batteries included and a 5 year warranty . I wonder how they make and ship things like this for the money and why some plastic fantastic products cost so much.

ZC

 
ZC

 
ZC

 
I was so surprised at the quality I googled it and found a little review.

 
http://www.candlepowerforums.com/vb/showthread.php?145561-LIDL-Magnifying-Glass-with-LED-Lighting
post #3468 of 5570

I think I may have a defective tube on my hands...  I cleaned the pins with steel wool and contact cleaner and I still get the same crackling.

 

More than anything, I want to ensure that my amp isn't frying tubes for some reason :eek:.

 

Is that a possibility, or am I just crazy?

post #3469 of 5570
Quote:
Originally Posted by bigfatpaulie View Post
 

I think I may have a defective tube on my hands...  I cleaned the pins with steel wool and contact cleaner and I still get the same crackling.

 

More than anything, I want to ensure that my amp isn't frying tubes for some reason :eek:.

 

Is that a possibility, or am I just crazy?


I'd let the amp run for a few days to cook the tubes in a bit.  A very common source of crackling is a flaky solder joint. 

post #3470 of 5570
Quote:
Originally Posted by bigfatpaulie View Post
 

I think I may have a defective tube on my hands...  I cleaned the pins with steel wool and contact cleaner and I still get the same crackling.

 

More than anything, I want to ensure that my amp isn't frying tubes for some reason :eek:.

 

Is that a possibility, or am I just crazy?

 

Well, there surely could be something going on with the tube. Odd behavior from a vacuum tube is a sign that the tube is at end-of-life. There is no simple way to describe what could go wrong, because there are lots of ways they can fail.

 

I would highly suggest trying other tubes. My favorite 12AU7's are d-getter Mullards, but you might spend $100 for one of them on ebay. If you're on a budget and/or just want something else to check it out with, I suggest an old American made tube, particularly the long black plate variety. But honestly, any old American made tube will sound awesome compared to the stuff made today.

post #3471 of 5570
It's not always a sign that tube is at the end of it's life. Tubes that have been in storage can lose a bit of vacuum, and the cathode could need some heating time to reform. Running them for a while can activate the getter and improve the cathode emission. If it's just making a little crackling or rumbling noise it won't hurt anything and it's worth cooking it for a while before you write it off. If it's making loud cracking and arcing over inside it does need to be tossed.
post #3472 of 5570

Interesting...  I tend to leave my amp on...  Too long (I forget :blink:).  Thank you everyone for the advice.

 

I cleaned the pins and that *seems* to have fixed the problem.

 

I really love this amp though.  I ordered a RCA 6AS7G black plate to go with my ECC82 :bigsmile_face:.  Thanks for a great amp, Doc!

post #3473 of 5570

I use the RCA 6AS7G and I love it.  I'm also using a RCA clear top 12AU7 and that seems to be working out well.

post #3474 of 5570
Quote:
Originally Posted by Dark Helmet View Post
 

I use the RCA 6AS7G and I love it.  I'm also using a RCA clear top 12AU7 and that seems to be working out well.

 

The RCA clear top pairs really nicely with the smoothness of the 6AS7G tubes.

post #3475 of 5570

Thought I'd let everyone know that I've just listed my Crack w Speedball for sale :eek: and a bunch of tubes too, including the ever popular GEC 6AS7 straight brown base for about $70 less than I could find on eBay!

 

http://www.head-fi.org/t/698768/melbourne-bottlehead-crack-speedball

 

http://www.head-fi.org/t/698771/various-6080-and-12au7-tubes-and-equivalents

post #3476 of 5570
Quote:
Originally Posted by bigfatpaulie View Post
 

I think I may have a defective tube on my hands...  I cleaned the pins with steel wool and contact cleaner and I still get the same crackling.

 

More than anything, I want to ensure that my amp isn't frying tubes for some reason :eek:.

 

Is that a possibility, or am I just crazy?


This can also be a funky solder joint.  If you have crackling in both channels, I would start with the power supply. 

post #3477 of 5570
Quote:
Originally Posted by Loquah View Post
 

Thought I'd let everyone know that I've just listed my Crack w Speedball for sale :eek: and a bunch of tubes too, including the ever popular GEC 6AS7 straight brown base for about $70 less than I could find on eBay!

 

http://www.head-fi.org/t/698768/melbourne-bottlehead-crack-speedball

 

http://www.head-fi.org/t/698771/various-6080-and-12au7-tubes-and-equivalents

 

The Mainline is forcing you to retire your Crack?

post #3478 of 5570
Quote:
Originally Posted by audiowize View Post
 


This can also be a funky solder joint.  If you have crackling in both channels, I would start with the power supply. 

 

Thanks.

 

It's just the right channel.  It is much better now since I cleaned the pins on the tube.  Oddly enough, it still happens when I leave the amp for several hours.

post #3479 of 5570
post #3480 of 5570
Quote:
Originally Posted by bigfatpaulie View Post
 

 

The Mainline is forcing you to retire your Crack?

 

At this rate he's probably going to recycle those funds into building their monoblocks...

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