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Crack;Bottlehead OTL - Page 210

post #3136 of 5990
I had my Crack on the top of my cabinet next to my Squeezebox and the interference was bad. I had to move it about 4' away to get rid of it.
post #3137 of 5990
Quote:
Originally Posted by amcananey View Post

I would say: don't bother.

I do NOT have any problems with noise from my router (or any other source), but I have 4 of those adapters from 3 different manufacturers and all of them induce intolerable noise with 6SN7s. You can avoid the issue by building a separate power supply for the input tube, but all I can say is: it's not worth it. The Crack sounds great with 12AU7s, so why chase other tubes that are highly unlikely to be an improvement?

An easier option would be to try changing your router.

 

if you have the speedball its a plug and play affair to change tubes. 

post #3138 of 5990
In theory, it's a plug and play affair even without the Speedball. As I understand it, the 6SN7 is just a 12AU7 in a different package. It isn't a near-equivalent, it IS equivalent.

In any case, I have the Speedball installed. And I have tried 4 different adapters and probably 15+ different 6SN7s. The noise was intolerable with all of them.

According to Bottlehead, the way to avoid this is by installing a separate 6.3V DC power supply for the input tube. But that is way too much effort, given that the Crack already sounds phenomenal with the 12AU7. Besides, I am done modding my Crack.
post #3139 of 5990

HolyCheese, you could try changing the 12au7 for another 12au7. I don't think the 6SN7 is more RFI tolerant than the 12au7.

post #3140 of 5990

Well I wasn't talkig about the 6SN7's actually.

I have some PCC189's and 6H23N rocket logos laying here and hoped they might fit.

 

It's true that someone from Bottlehead is active here right? Is a faulty tube covered by warranty? Or should I go on ebay and buy another one.

 

Atleast i'm Lucky it still works as longs as I shield it somehow. :)

post #3141 of 5990

Some one from Bottlehead is active here. Me. But I don't know what various participants usernames are. The best way to get a new tube is to contact us via email - replacementparts@bottlehead.com, or by phone 206-451-4275. That way you can tell us who you really are and we can be sure we know your address. We really can't do much about our mid 20th century tubes being hammered by RFI generated by 21st century devices that are supposed to be FCC regulated. Tube shields may or may not help much. Distance between pieces of gear is the best and cheapest way to reduce the problem. However if a tube is making noise on it's own - humming or hissing or crackling, we will happily send you a replacement. If it only makes noise when you tap on it, try not tapping on it. That seems to be a reliable solution.

 

Lots of posts this weekend. Some responses -

 

Re rust on bell end - Interesting that the unfinished bell end seems to surprise builders, but they readily accept that the wood and chassis panels have no finish. The kit is intended to be finished by the builder.

 

Re planar headphones - doesn't matter that they are planar, an impedance mismatch is an impedance mismatch and bass from Crack will be flabby with low impedance cans. Use high impedance headphones with the Crack and bass will be nice and tight. We make two other amps that are designed to work with low impedance and planar headphones. Bet you never heard me say any of that before... 

post #3142 of 5990
Quote:
Originally Posted by Doc B. View Post

Re rust on bell end - Interesting that the unfinished bell end seems to surprise builders, but they readily accept that the wood and chassis panels have no finish. The kit is intended to be finished by the builder.

 



Doc,

I'm a big fan of your products, own 4 of them, and regularly recommend them quite loudly here.

But I do find the issue of the bell end frustrating. When I see a couple of unfinished wooden blocks in the package, with instructions on how to glue them together, it is obvious to me that they need to be glued together. And it is also fairly clear that if I want the wood case painted or stained, that I have to do that. Moreover, given the way the case works, I can build the Crack and get it working first, then easily finish the case later.

It was NOT clear to me, however, that the bell end needed to be treated to prevent rust. There is nothing about the bell end that clearly indicates to the lay person that it needs to be finished. It doesn't seem unreasonable that this should be mentioned in the directions (not just mentioning that users CAN paint the bell end -- I mean mentioning that users SHOULD paint the bell end to avoid rust). Especially since (unlike the wood case) it is much harder to do once the Crack is fully assembled (not impossible, just harder, with an increased risk of painting/spraying stuff you don't want painted/sprayed).

Leaving aesthetic matters up to customers without comment is one thing, but I do think that functional matters should by explicitly discussed. To be clear: I'm not saying that Bottlehead should finish the bell end for me. I'm saying that you should alert customers that they need to finish the bell end themselves in order to avoid rust.

Best regards,
Adam
post #3143 of 5990

I used gun bluing on my end bell. I buffed the corners to give it that "antique" look. Bluing is a form of oxidation that will prevent the formation of rust, so those of you that are looking to treat the metal without painting it look into a bluing kit. They're fairly cheap and the bluing is easy to apply.

post #3144 of 5990
Quote:
Originally Posted by Tequilasunriser View Post
 

I used gun bluing on my end bell. I buffed the corners to give it that "antique" look. Bluing is a form of oxidation that will prevent the formation of rust, so those of you that are looking to treat the metal without painting it look into a bluing kit. They're fairly cheap and the bluing is easy to apply.

 

Are you sure about that?   I have a Birchwood Gun Blue kit on order but i read it wont stop oxidation so its advised to clear lacquer the finish afterwards.  Either way i figured it would be a more interesting finish that plain paint, that said paint is my backup plan incase it all goes horribly wrong.

 

@amcananey, its mild steel of course its going to oxidize with moisture, they paint cars for that very reason.  It might take months, it might take years, it all depends on your climate and humidity.

post #3145 of 5990
Quote:
Originally Posted by mcandmar View Post
 

 

Are you sure about that?   I have a Birchwood Gun Blue kit on order but i read it wont stop oxidation so its advised to clear lacquer the finish afterwards.  Either way i figured it would be a more interesting finish that plain paint, that said paint is my backup plan incase it all goes horribly wrong.

 

@amcananey, its mild steel of course its going to oxidize with moisture, they paint cars for that very reason.  It might take months, it might take years, it all depends on your climate and humidity.

Well, any hole or even a microscopic area where bare metal is exposed can cause the formation of rust. Just like a car that has a razor thin scratch in its paint; it is still subject to getting rust. I have an antique shotgun that was factory blued but is now developing a few pitted areas of rust, but that's expected over time if the bluing isn't maintained much like a car's paint. I applied the bluing about 2 years ago, and to this date there's no rust, but if it's not maintained then I would imagine rust could form down the line...

 

The idea is that rust is less likely to form because one form of oxidation is being substituted with another.

post #3146 of 5990

Bluing looks great, but does not prevent rust. Ask any gun owner. We suggest shooting the bluing with clear coat.

 

Adam - I will take your suggestion under consideration. Are your bell ends rusting?

 

It is really easy to paint a bell end that is installed. Simply cut a rectangular hole the size of the bell end in a piece of cardboard. The cardboard should be bigger than the top of the amp so it protects it from overspray. Place the cardboard over the amp with just the bell protruding through and shoot your favorite spray. We have done many bell ends here with this method, in fact we have a carboard mask we keep in a cabinet specifically for the purpose.

post #3147 of 5990
Can I use a regular spray paint can to do the bell end job?
post #3148 of 5990

Yes.

 

Oil based paint is way, way, way better than the acrylic stuff.

post #3149 of 5990
"@amcananey, its mild steel of course its going to oxidize with moisture, they paint cars for that very reason. "

That's great...as long as you know that it is "mild steel". And how exactly am I supposed to know that? I wouldn't know steel from any other metal. I know the chassis is aluminum, and I know aluminum doesn't rust. Beyond that I don't have a clue.
post #3150 of 5990
Quote:
Originally Posted by Doc B. View Post

Bluing looks great, but does not prevent rust. Ask any gun owner. We suggest shooting the bluing with clear coat.

Adam - I will take your suggestion under consideration. Are your bell ends rusting?

It is really easy to paint a bell end that is installed. Simply cut a rectangular hole the size of the bell end in a piece of cardboard. The cardboard should be bigger than the top of the amp so it protects it from overspray. Place the cardboard over the amp with just the bell protruding through and shoot your favorite spray. We have done many bell ends here with this method, in fact we have a carboard mask we keep in a cabinet specifically for the purpose.
Thanks, Doc. I've since become aware of that solution.
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