Hoffman Amplifiers Tube Amplifier Forum

Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: passaloutre on March 19, 2024, 11:46:33 pm

Title: Existing chassis holes?
Post by: passaloutre on March 19, 2024, 11:46:33 pm
If you’ve noticed many of my recent questions, you may know where I’m going with this…

In the process of repurposing a few old radios and PA amps into guitar service, many of the existing chassis holes for tubes, cap cans, transformers are not in the ideal spots for the layouts I’m choosing.

So far I’ve just been drilling holes for new tubes, jacks, pots wherever needed and leaving the existing holes as is (trying my best to use existing holes but some just don’t make sense for the new layouts). Most of these devices were headed for the landfill, so I’m not too worried about originality, just wondering about the structural integrity, safety, shielding ramifications of leaving a bunch of holes in my chassis. I could cover them with steel, aluminum, plastic plates or plugs, but do I really need to?

I hope to secure most of these in head or combo cabs eventually, so it’s not like stray fingers could find their way in…
Title: Re: Existing chassis holes?
Post by: tubenit on March 20, 2024, 05:20:40 am
When I have converted Bogen amps, I typically will cover open holes with aluminum sheet metal. I view it as a safety issue and also that perhaps it helps with shielding.  It's easy to do.


With respect, Tubenit
Title: Re: Existing chassis holes?
Post by: dwinstonwood on March 20, 2024, 07:30:15 am
On my last build, I covered a chassis tube socket hole with a metal hole plug. On a steel chassis it could be soldered in place, I guess.

I see that AES stocks them: https://www.tubesandmore.com/products/covers-chassis-holes-nickel-plated-steel
Title: Re: Existing chassis holes?
Post by: tdvt on March 20, 2024, 08:34:45 am
I have a few recycled chassis & haven't gotten around to using them yet, but have been pondering this same issue.

I am leaning towards re-skinning the entire mounting plane (top/bottom, depending on your perspective) with a second layer for a fresh start
Title: Re: Existing chassis holes?
Post by: sluckey on March 20, 2024, 08:59:44 am
What to do with the extra holes. I think it depends on the particular chassis conversion project.
This is my holiest chassis. I just left the holes uncovered. Thankfully the tube sockets were already lined up like I wanted for my new layout.   :icon_biggrin:

https://sluckeyamps.com/RCA/RCA.htm
Title: Re: Existing chassis holes?
Post by: acheld on March 20, 2024, 10:14:01 am
I think it depends on your tolerance for risk, and the amount of control you have over the use of the amp.

If you build an amp, then sell it, you do have some degree of responsibility to provide for safe use of the amp. The degree can be argued up and down all day, but there is "some" responsibility there. 

Now, you can write disclaimers in your bill of sale til the sun goes down, but if someone's child sticks a finger where it ought not, you could have a problem.   Mind you, I'm not sayin' it's your fault that a kid sticks a finger in a live amp without proper supervision, but it can happen.

I'm ok with my re-tread (some many times) amps with big holes.  But I will control them, and they won't ever be plugged in around grandchildren.

But any amp that goes out into the wild gets the plugs or covers . . .   

Like I said at the start, it all depends on your own risk tolerance.   Everyone here is going to have a different answer, and I respect that. 
Title: Re: Existing chassis holes?
Post by: shooter on March 20, 2024, 11:00:35 am
Quote
someone's child sticks a finger where it ought not
the Darwin awards are for just such occasions  :icon_biggrin:


put some Blinky LEDS inside the chassis, using the signal to set the blinks, that will pacify  the curious
Title: Re: Existing chassis holes?
Post by: passaloutre on March 20, 2024, 11:50:28 am
Quote
someone's child sticks a finger where it ought not
the Darwin awards are for just such occasions  :icon_biggrin:


put some Blinky LEDS inside the chassis, using the signal to set the blinks, that will pacify  the curious

Sounds like a high-stakes game of Operation, which is precisely how I feel sometimes sticking my voltmeter into a live amp…
Title: Re: Existing chassis holes?
Post by: J Rindt on March 20, 2024, 01:12:14 pm
On my last build, I covered a chassis tube socket hole with a metal hole plug. On a steel chassis it could be soldered in place, I guess.

I see that AES stocks them: https://www.tubesandmore.com/products/covers-chassis-holes-nickel-plated-steel (https://www.tubesandmore.com/products/covers-chassis-holes-nickel-plated-steel)
Wow..... those are rally nice.
Talk about convenient  :smiley:
Thanks for the Link/Info
Title: Re: Existing chassis holes?
Post by: shooter on March 20, 2024, 01:41:55 pm
FWIW, you can find plugs like that at Lowes in the electrical isle and hardware isle.  save the internet, buy a local  :icon_biggrin:
Title: Re: Existing chassis holes?
Post by: J Rindt on March 20, 2024, 02:02:53 pm
FWIW, you can find plugs like that at Lowes in the electrical isle and hardware isle.  save the internet, buy a local  :icon_biggrin:
Yeah.

I am going to our local Ace Hardware later in the day.I will check what they have.
People working on amps are probably already making an order from CE anyway, so it is kind of natural i guess.
Title: Re: Existing chassis holes?
Post by: kagliostro on March 21, 2024, 02:32:18 am
To me the best way to solve the problem Is to use a thin aluminium sheet to cover the whole TOP of the old chassis and drill the new holes where required

You can use the same method also for the faceplate and backplate

It will result in a more professional looking work

Franco
Title: Re: Existing chassis holes?
Post by: Kev-W on March 21, 2024, 04:54:19 am
I have a Hammond chassis I drilled the wrong way round when I made my first micro amp, it will get a piece of 1mm ali plate pop riveted to the top when I attempt another one, but if it was to cover the odd hole it wouldn't be hard to copy the blanking plates with screws through the existing holes.
Title: Re: Existing chassis holes?
Post by: kagliostro on March 21, 2024, 08:19:12 am
With a minimum of carperter practice it will be not very difficult to do

otherway practice all new holes on the new top

Franco