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Author Topic: Close off the back of a tube amp?  (Read 5313 times)

Mattxorz

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Close off the back of a tube amp?
« on: October 14, 2011, 05:01:35 PM »
How bad of an idea would it be to close off the back of a tube combo amp? In sealing it, the amp could not vent... Should I even bother? Specifically, I'm talking about a Peavey Valveking 212 combo.
http://kensprosounds.com/shop/images/PeaveyValveking212_01.jpg
Here's a picture of the back.

techno-rachit

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Re: Close off the back of a tube amp?
« Reply #1 on: October 15, 2011, 10:45:48 PM »
I do not think that it is ideal to close the back of this amp. You can already see that the metal cover on the tubes is giving them protection as well as ventilation. I have not made any tube amp yet, but whatever tube amp i have seen, the tubes have always been visible to me!  :D
So i would suggest not to cover the whole back.
Instead, you could partially cover the amp....i mean only till the level below the tubes are located.

Cheers.

Mattxorz

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Re: Close off the back of a tube amp?
« Reply #2 on: October 15, 2011, 11:49:22 PM »
It's not a protection thing- it's a speaker response thing that makes me want to do it. I got some Celestion V30's to put in, and they just don't sound right to me without a closed back cab. I may end up converting this amp into just a head, and build my own cab for the speakers, but if I can keep it a combo without screwing myself, I'd like to.

techno-rachit

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Re: Close off the back of a tube amp?
« Reply #3 on: October 16, 2011, 07:50:30 AM »
I don't know how the amp will sound after closing the cabinet from behind as well as how it will affect the functioning of the tubes...You better go with the Head-Cabinet Idea as it will at least keep your tubes vented.

Mattxorz

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Re: Close off the back of a tube amp?
« Reply #4 on: October 16, 2011, 11:10:44 PM »
Yea, seems that way.

joecool85

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Re: Close off the back of a tube amp?
« Reply #5 on: October 17, 2011, 02:15:15 PM »
I'd be a little concerned about heat from the tubes causing issues as I've never seen a closed back tube amp.  That said, I'm no tube guru so I could be wrong.
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RubberSalt

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Re: Close off the back of a tube amp?
« Reply #6 on: November 01, 2011, 04:17:33 PM »
Why not relocate the tubes? Or even go as far as sectioning off the tubes and having an ultra quiet computer fan for ventalation ?

Or section off the tubes and port the amp with the tubes in the port?

guitarpicker7

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Re: Close off the back of a tube amp?
« Reply #7 on: November 02, 2011, 06:10:07 PM »
Not a good idea... those open back cabinets are designed as modified infinite baffle enclosures (infinite baffle blocks the rear sound wave from mixing with the front sound waves, causing cancellation at various frequencies- a TRUE infinite baffle is (duh) huge, so a smaller version with folded sides is usually adequate to prevent mixing of the front and rear sound waves.

On the other hand, you can run the amp output thru a closed, or properly ported, cabinet. A 12 or 2x12 or 4x 12 with the proper impedance can make a big difference in sound.

Seimic Audio has some good stuff!

rock on