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Hoffman Amps Forum image Author Topic: Tube Shields  (Read 3045 times)

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Offline TIMBO

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Tube Shields
« on: April 15, 2015, 03:29:28 am »
Hi guys, bought some 9 pin sockets that take a tube shield.
Can anyone give me a quick answer to their best use. Thanks

Offline sluckey

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Re: Tube Shields
« Reply #1 on: April 15, 2015, 06:41:25 am »
I like tube shields on all little tubes that are in the signal path (except power tubes such as EL84, 6GW8, etc.). Especially on preamp tubes. No real benefit using them on a tremolo oscillator although I do.
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Offline Fresh_Start

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Re: Tube Shields
« Reply #2 on: April 15, 2015, 06:55:58 am »
Any amp where the preamp tubes are upside down. Maybe even sideways.

My Blues Jr. has a retainer for the EL-84 power tubes, although you can't use those shields on power tubes as Sluckey says.

Chip
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Offline eleventeen

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Re: Tube Shields
« Reply #3 on: April 15, 2015, 11:09:58 am »
I believe tube shields are more for retention than shielding, certainly when the tubes are hung upside down. You probably ought not use them on EL84's!

Offline TIMBO

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Re: Tube Shields
« Reply #4 on: April 15, 2015, 02:05:17 pm »
Thanks guys, Its just that I noticed on datasheets it had mentioned the shields. http://pdf1.alldatasheet.com/datasheet-pdf/view/121279/GEC/12AX7.html

Offline kagliostro

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Re: Tube Shields
« Reply #5 on: April 15, 2015, 02:56:00 pm »
There were some shield, used in military equipment (if I remember well sometime Sluckey uses this kind of shield)

whose purpose was heat dissipation

something like this



the inside has a particular configuration that increases heat dissipation, you can see it here




K
« Last Edit: April 15, 2015, 03:13:35 pm by kagliostro »
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Offline HotBluePlates

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Re: Tube Shields
« Reply #6 on: April 16, 2015, 05:42:36 pm »
Thanks guys, Its just that I noticed on datasheets it had mentioned the shields. http://pdf1.alldatasheet.com/datasheet-pdf/view/121279/GEC/12AX7.html

That's only in reference to the amount of input capacitance (more with the shield).

I've never heard a difference with/without the shield, but only tried using them on lower-gain Fender-style amps.

Offline jojokeo

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Re: Tube Shields
« Reply #7 on: April 17, 2015, 12:35:49 am »
That's only in reference to the amount of input capacitance (more with the shield).

I've never heard a difference with/without the shield, but only tried using them on lower-gain Fender-style amps.
This must be where Gerald Weber gets his ideas about not using tube shields in his books because he thinks they rob tone due to the increased capacitances.
To steal ideas from one person is plagiarism. To steal from many is research.

Offline Willabe

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Re: Tube Shields
« Reply #8 on: April 17, 2015, 01:31:27 am »
It was from Ken Fisher in the 'The Train wreck pages' in Groove Tubes books and/or from Vintage Guitar Magazine.


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