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June 17, 2019, 08:07:55 pm

Recent Posts

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1
Crack / Re: Tube Rolling w/Crack
« Last post by Jamwagon on Today at 03:07:05 pm »
Those are the real deal.

Well that's good to know. Thanks for weighing in PB. I gave it a once over when I got home and it seems legit. My mind is at ease.

Here is the actual website in case anyone is interested
http://tubes.tw/shop/index.php?cPath=22_27&sort=3a&filter_id=14
They have a boat load of different 12AU7 brands and date codes. Not sure how much shipping costs from their web store, but prices seem to be cheaper than their eBay store.
The exact one I purchased from eBay is listed for $48

The picture I attached I found on Google. Apparently it lives somewhere on their site. Shows the differences between the CV4003 through the years. Very interesting.

Note this is the same seller that lists the French Thomson CSF 6080WA that was linked to a couple of pages back. They have a HUGE stock of those.
http://tubes.tw/shop/product_info.php?products_id=1279
Definitely worth checking out at those prices. I will probably grab one myself at some point.

Sorry for the lengthy post. I hope someone finds it useful one day!
2
Crack / Re: LED out troubleshooting help
« Last post by aphays on Today at 01:18:49 pm »
Will do. Thanks man. This definitely helps clarify things.
4
Crack / Re: LED out troubleshooting help
« Last post by Paul Birkeland on Today at 01:04:05 pm »
No dice - reheated 2L, problem still persists. Just out of curiosity, could this condition occur due to a bad component?
This is exceptionally unlikely.

I realize that a bad solder is much more likely, but is it possible that one of the resistors or capacitors was damaged by a short due to a bad connection early on that is now fixed?
No, this would give a completely different set of problems.
The first bad solder I found was at 20U, and I found it becuase I saw it spark. Could that have damaged either the resistors or the capicitor that are connected there?
No.

I'm sorry to say but when you tap on the chassis and that restores operation, that means you have a joint that isn't well connected.  We recommend poking around with a wooden chopstick to determine where this joint is so you can effect repairs.  I don't mean to sound like a broken record, but when I'm finished with a build, I will knock on it really hard to see if and LEDs shut off as a way to test that the joints are secure.  You have a loose wire, or a bad solder joint, or a broken wire somewhere in your amp. 

A shorted capacitor will cause billowing smoke and terrible stench from your amplifier.  You do not have that. 

A shorted resistor will either raise the B+ a little if it's one of the 270 ohm resistors, burn the 270 ohm resistors up entirely if the 270K shorts, red plate and draw the B+ down if one of the 3K resistors shorts, or leave high voltage at terminals 1/5 with the LEDs lit if one of the 22.1K resistors shorts.

Keep poking around with the chopstick at everything that has a solder joint.
5
Crack / Testimony to Crack's sturdiness
« Last post by borism on Today at 12:41:55 pm »
I built a Crack/speedball for my son a couple of years ago. He recently moved from the east coast to the midwest and upon arrival put the crack back into his system. He then noticed it wasn't working even though at least the small tube was glowing by his report.

After some back and forth he asked if the big tube had to be placed in its socket in a particular way. We discovered that he had forced the tube - a Russian 6N13S into the socket the wrong way.

When he corrected the error and placed the same tube correctly - the Crack was back playing music. :)
6
Crack / Re: Tube Rolling w/Crack
« Last post by oguinn on Today at 12:15:30 pm »
Not saying those are genuine because I also don't know, but I've gotten some pretty clean NOS tube boxes. Maybe I've been had, too?

Off topic: I picked up the adapter to use a 6SN7 tube and a NOS Sovtek 6H8C and rolled that in today. Sounds pretty good! Not sure that it sounds appreciably better than the Motorola 12AU7 it replaced, but it's nice to know it works and gives me more rolling options.
7
Headphones / Re: Perfect headphone / Bottlehead pairings
« Last post by pendergast on Today at 12:11:27 pm »
I received a pair of HD 6XX and I really like them with the CRACK, with speedball upgrade and that IBM tube (and a . I find the HD 6XX  to be rather delicate in the highs; detailed but with a silky finish, like a caress on some satin nightgown and haflway through the bottle of Chablis.

Your experience may vary.
8
Crack / Re: LED out troubleshooting help
« Last post by aphays on Today at 10:38:10 am »
No dice - reheated 2L, problem still persists. Just out of curiosity, could this condition occur due to a bad component? I realize that a bad solder is much more likely, but is it possible that one of the resistors or capacitors was damaged by a short due to a bad connection early on that is now fixed? The first bad solder I found was at 20U, and I found it becuase I saw it spark. Could that have damaged either the resistors or the capicitor that are connected there?
9
I'm not sure that Blue Jeans Cable is correct with their base assumption in that article, that twisted pair only rejects hum on a balanced setup.

Looking around, twisted pair seems to be part of the original telephone circuit patent, by Alexander Graham bell, in which he explains how it works.

Regards, Rob
10
Crack / Re: Tube Rolling w/Crack
« Last post by Jamwagon on Today at 10:17:24 am »
So I read something on the forums in passing about Chinese fakes. It got me a little paranoid about a Mullard cv4003 I picked up from eBay a couple months back from a seller in Taiwan that has quite a large stock of these claimed NOS Mullard M8136 tubes. I picked one up thinking I got a great deal and noted how remarkable the packaging was for an older tube. Here is the listing: https://www.ebay.com/itm/Mullard-ECC802S-M8136-12AU7WA-ECC82-box-plate-small-shield-UK-made-TUBE-VALVE/173814424654
Can anyone with more experience in these matters offer up their take on this? Do you think I've been had? I can upload more detailed pics of the tube and packaging if anyone asks.
Just seems a little too clean now that I think about it.
Thanks
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