Author Topic: Opening a 200s head  (Read 3461 times)

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Offline Happy Face

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Opening a 200s head
« on: August 21, 2012, 08:30:11 pm »
I vaguely remember that roadies had some trick so you did not have to remove the front grille to pull a 200s chassis.

Am I mistaken?

It's a royal pain in the buttocks if you change pre-amp tubes a lot.

Thanks.

Offline EdBass

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Re: Opening a 200s head
« Reply #1 on: August 22, 2012, 08:06:33 am »
I don't know if it's a trick, all you have to do is remove the four chassis mounting bolts from the bottom and slide the chassis out from the back.

Offline Happy Face

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Re: Opening a 200s head
« Reply #2 on: August 22, 2012, 09:15:53 am »
Thanks Ed, that's what I remembered. But on the '68 200s I just bought, that doesn't work. I have to take off the front grille too, which is a nuisance since you have to maneuver around the trannies.

I have some very faint memory of guys breaking the rivet so you could pull the face plate off instead. So I looked at it, but did not do it because putting it back on can be annoying. 

But from what you said and I remember from the other 200s, Sorado and 2000s heads I used in the day, now I'm wondering if the grille panel is not original.

Offline BassHog

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Re: Opening a 200s head
« Reply #3 on: August 23, 2012, 12:21:59 pm »
Strange, I have not seen a Sunn tube head that you couldn't just slide the chassis out from the back.
Do you have pics?
67 Sunn Solarus
70 Sunn Sceptre
71 Sunn 350B

Offline EdBass

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Re: Opening a 200s head
« Reply #4 on: August 23, 2012, 07:30:44 pm »
I've never seen that either. I don't think I smell what you're cooking; does the chassis wedge under the grill panel or is there something on the front panel physically holding the chassis in place?

Offline Happy Face

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Re: Opening a 200s head
« Reply #5 on: August 23, 2012, 08:19:01 pm »
Hi guys, thanks.

The control panel plate catches on the grille. It just won't pull out. The guy I bought it from warned me about it and he was right. 

It's not the end of the world, but I do like to fiddle with the preamp tube now & then. I just stepped it down to a 12AT7 which makes a world of difference with my Guild basses (hot passive pickups).  But in a rockin' trio, I'd probably go back to a 12AX7 or variant thereof.

I suppose I'll learn to seat the tube blind.

(In retrospect, the front panel thing must have been a different type of amp. Memories from back then can be hazy...) 

Anyway, this is a strange one-off that is not real hard to live with.

Offline loudthud

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Re: Opening a 200s head
« Reply #6 on: August 23, 2012, 08:32:23 pm »
Get yourself one of those really long #2 phillps screwdrivers. It will come in handy if you ever need to remove the grill on an old speaker cabinet. Maybe you can just leave the screws out for the grill panel on the amp and just push it out from the back when you want access to the preamp tubes.

Offline Happy Face

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Re: Opening a 200s head
« Reply #7 on: August 24, 2012, 08:17:01 am »
Thanks. A great idea. Easier than installing clips, which is what I was pondering.