Bottlehead Forum
Bottlehead Kits => Crack => Topic started by: tweedgv on November 09, 2014, 10:13:48 AM
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Hi guys
during the process of painting my crack, i have somehow managed to break the middle plastic bit, on the underside of the output tube…… i only put it back in, and then back out (which was when it broke) to see how it looked with the new paint job.
to be clear, its the centre piece of plastic, on the underside of the tube, that ensures the tube is inserted in the right position into the octal tube socket….. sort of cylindrical with a tear-drop-like shape
the plastic bit, now missing, is exposing a nipple (for want of a better word) of tube, which is obviously going to get hot, but is it going to damage the socket? and how am i going to be certain of inserting it in the right position, if the piece of plastic, or lack of, proves not to be an issue.
i'd love an excuse to buy another tube, but i'd also love, much more, to be able to plug this crack back in once the varnishing stage has been completed……. its been two days of painting (and no listening) now and cold turkey is showing absolutely no sign of improving.
as always. thanks in advance.
Gav
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That happens. The tube is most likely still functional . You can get an inexpensive replacement keyway that just slides over the pins:
https://tubedepot.com/products/octal-tube-keyway-replacement (https://tubedepot.com/products/octal-tube-keyway-replacement) $3
(https://d1sjrnpi226dnf.cloudfront.net/spree/products/large/SK-8KWY-3.jpg?1381959424)
I have also successfully epoxied it back as well. But there is a risk of it not holding over time.
The tube base usually shows the keyway orientation, so if you are careful, you can line up the tube and place correctly in the socket.
You are also more than welcome to use this as an excuse to buy another tube. I have used weaker reasoning!!
Cheers,
Geary
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As Geary says, you can still use it. Just be very careful to install it with the right pins in the rght socket holes. I usually put a mark on the tube base in line with the notch on the center pin hole.
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thats good news, thanks Geary
the RCA Electron tube came with the crack…. if i was to accidentally insert it incorrectly, would it damage anything??
also, on the subject of replacement tubes, there are some tung sol 5998 tubes on ebay, NOS form Turkey, how am i to trust a seller??? they are said to have been tested (amplitrex??), but to my untrained eye, they look in way to good condition……
this tube stuff is a minefield……
thanks again
Gav
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I'm sure the RCA writing was pointing to the front, but is there a more certain way i can tell of the direction it should be inserted?
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http://www.ebay.co.uk/itm/MATCHED-PAIR-TUNG-SOL-5998-421A-TESTER-AMPLITREX-AT1000-PERFECT-NOS-TUBES-/161469166629?pt=Vintage_Electronics_R2&hash=item25984ff425
what would the general verdict be on these tung Sol's?
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As Geary says, you can still use it. Just be very careful to install it with the right pins in the rght socket holes. I usually put a mark on the tube base in line with the notch on the center pin hole.
That is exactly what I have done. You don't take the tubes out often so just be careful and get the full life out of your tube.
The heater is from pin 7 to pin 8. So start measuring resistance between adjacent tube pins. when you find two that are low, maybe under an ohm, you have found pins 7 and 8. Put the mark one slot over and you are in business.
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http://www.ebay.co.uk/itm/MATCHED-PAIR-TUNG-SOL-5998-421A-TESTER-AMPLITREX-AT1000-PERFECT-NOS-TUBES-/161469166629?pt=Vintage_Electronics_R2&hash=item25984ff425
what would the general verdict be on these tung Sol's?
Way way over priced, dont even think about it. I picked up two 5998's recently for under $100, and that was expensive in my book. There is an abundance of nice tubes that will work in the Crack for ~$20 so no need to spend silly money on anything. Have a read of the Crack tube rolling threads here and on Head-fi, i'm sure Crack owners will chime in and give you some good recommendations.
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I'm sure the RCA writing was pointing to the front, but is there a more certain way i can tell of the direction it should be inserted?
All you ever wanted to know, plus some!
http://www.thetubestore.com/Resources/Matching-and-other-tube-info/Guide-Key-Fix (http://www.thetubestore.com/Resources/Matching-and-other-tube-info/Guide-Key-Fix)
Cheers,
Geary