Valve King 112 (or others) - magnetic fields in combos?

This forum is for talking about all kinds of Peavey guitar amplifiers.
Post Reply
User avatar
Sloclone100
New Member
Posts: 2
Joined: Sun May 28, 2017 1:59 am

Valve King 112 (or others) - magnetic fields in combos?

Post by Sloclone100 » Sat Jun 24, 2017 4:25 pm

This may seem like a simple question but here goes:

Does the magnet of the speaker have any effect on the power, or preamp, tubes? I'm guessing not since the attraction of electrons is so great they would not be affected by magnetic fields. But, I have never seen this question asked before so I thought I try to see what some amp enthusiasts think. I know there are a lot of people against combos in particular, for other reasons, but I just wanted to throw this out there.

Since I have changed to KT66s' I do not want to mutilate the cage and I wonder if the cage's purpose has to do with the proximity to the speakers massive magnet. Since I do not normally see cages, I decided to run it without it if I ever go back to 6L6 style tubes.

One more thing. Is it redundant to have bias points if I use a Bias King to check current instead of voltage? I know just the slightest offset in ohms on the resistors can have a dramatic change in your readings, which is why I only use Dale 1 ohm resistors.

Thanks in advance!

User avatar
Enzo
Member
Posts: 9535
Joined: Fri Sep 12, 2008 10:24 pm
Location: Lansing, Michigan

Re: Valve King 112 (or others) - magnetic fields in combos?

Post by Enzo » Sat Jun 24, 2017 4:31 pm

They been making combos with speaker magnets right next to the tubes for what 75-80 years now? I won't start to worry about it now.

The cages are there to protect the tubes. You toss your tube screamer in there or maybe a spare cord or two with that metal plug on the end, and CRACK, your tube is broken. Won't happen with a cage.

Some amps have little shields on each preamp tube. These are to keep out hum, not magnetic fields.

User avatar
Sloclone100
New Member
Posts: 2
Joined: Sun May 28, 2017 1:59 am

Re: Valve King 112 (or others) - magnetic fields in combos?

Post by Sloclone100 » Sat Jun 24, 2017 4:38 pm

Thanks Enzo. I have been following your posts for some time now. 8) I respect your knowledge and it completely makes sense.

-Dave

dalrymple
Member
Posts: 2739
Joined: Mon Sep 15, 2008 8:12 pm

Re: Valve King 112 (or others) - magnetic fields in combos?

Post by dalrymple » Sat Jun 24, 2017 7:05 pm

You can get a pair of KT66's in there without mutilating the cage. Just a little bending allows it to accommodate the Tung-sol KT66's. No other mods needed.

Like Enzo mentioned, it protects the glass. Put it back in or you might have an expensive accident with a plug or something slapping yer bottles.
Dalrymple

Post Reply