I want to make sure I'm using proper component type and implementation.

[SoulFetish]

(I posted a similar question on AX84, so I apologize for double dipping on this one. But I'm anxious to finish this up and but some holes in my chassis).

First I want to make sure I use the appropriate fuses on my secondary power supplies. I just read a good article on Sound.Westhost here:
Circuit Protection
After giving that a quick read, along with articles written by Merlin, RG, and others I have pretty solid understanding on why fusing is placed where it is in a circuit. I'm learning more about where faults commonly occur and what can be done about protecting against them. The issues I'm running into are finding the real estate inside my chassis to accommodate 4, socket-able fuses and what kind of fuse makes the most sense. A couple of ideas I had were to either use inline fuse holders on the secondary leads (this seems like it would end up being a bit clumsy and awkward trying to put them in at this point of the design), and the other was possibly mounding a full enclosed fuse block outside the chassis adjacent to the power transformer secured to the chassis. Here's what worries me with that; I don't like the idea that high voltages will be present outside the confinement of the chassis. I would be worried in the event that the cover ever got lost, a unwitting musician would just leave it exposed. I've seen people lift the earth off their amps and wrap tin foil around fuses to "fix" them, so I'm not going to put them outside the chassis. I will check the unloaded RMS voltages to be sure, but according to this schematic of the power supply could someone recommend a fuse type designed for this use. What do you all do for your builds?

A couple of other questions real quick...

- Is there any reason not to use Pemnuts on the inside of the chassis for mounting the transformers?

- Also, Count someone recommend a UF recovery diode bridge in an inline rail package?
Its for a ±150V supply(300V total) under 100mA. I could alternatively use a WOG package as well.

[J M Fahey]

4 of these in 20mm length inside the chassis takes little real space.


Pemnuts? heavy transformers?
I'd only trust them if mounted on the opposite side of the transformer, so they'd have to go through metal to be pulled.

Now if on the same side, they're held only by friction.

Might do to hold a PCB , reverb tank, etc; but not transformers; the first time stage hands, Mail or any handler drops your amp you have a wrecking ball inside the amp.

UF diodes? Hope you don't believe the myth that they work magic at 50/60 Hz mains frequencies.

[nosaj]

(I posted a similar question on AX84, so I apologize for double dipping on this one. But I'm anxious to finish this up and but some holes in my chassis).

First I want to make sure I use the appropriate fuses on my secondary power supplies. I just read a good article on Sound.Westhost here:
Circuit Protection
After giving that a quick read, along with articles written by Merlin, RG, and others I have pretty solid understanding on why fusing is placed where it is in a circuit. I'm learning more about where faults commonly occur and what can be done about protecting against them. The issues I'm running into are finding the real estate inside my chassis to accommodate 4, socket-able fuses and what kind of fuse makes the most sense. A couple of ideas I had were to either use inline fuse holders on the secondary leads (this seems like it would end up being a bit clumsy and awkward trying to put them in at this point of the design), and the other was possibly mounding a full enclosed fuse block outside the chassis adjacent to the power transformer secured to the chassis. Here's what worries me with that; I don't like the idea that high voltages will be present outside the confinement of the chassis. I would be worried in the event that the cover ever got lost, a unwitting musician would just leave it exposed. I've seen people lift the earth off their amps and wrap tin foil around fuses to "fix" them, so I'm not going to put them outside the chassis. I will check the unloaded RMS voltages to be sure, but according to this schematic of the power supply could someone recommend a fuse type designed for this use. What do you all do for your builds?

A couple of other questions real quick...

- Is there any reason not to use Pemnuts on the inside of the chassis for mounting the transformers?

- Also, Count someone recommend a UF recovery diode bridge in an inline rail package?
Its for a ±150V supply(300V total) under 100mA. I could alternatively use a WOG package as well.

If your really out of space dogbox it on the other side.

nosaj

[SoulFetish]

4 of these in 20mm length inside the chassis takes little real space.


UF diodes? Hope you don't believe the myth that they work magic at 50/60 Hz mains frequencies.

**Well, as a rule of thumb, I'll believe anything if it gets me laid. Having said that, there is overwhelming evidence to suggest that making a compelling argument for one semiconductor over another has never (and I stress this) EVER gotten anyone laid in the history of earth.

Of course I don't believe the myth that they work magic at 50/60 Hz, that's crazy. It's 100/120 Hz where all the magic happens.

[SoulFetish]

I realized I never posted the schematic of the power supply. Here is the PS schematic and a illustration of how I would install the pemnuts:

[SoulFetish]

After thinking about this and researching every type of fuse holder/block I could find, I drew up this configuration. It pretty much achieves my goals for routing power supply wiring, protecting my circuit, easily sourced component replacement, easy fabrication(and kept to a minimum) and safe. Because it uses available space within the enclosure very efficiently it leaves horizontal board space for other components. I think I'm going to mount the fuse holders like this(or a variation of this):

[Enzo]

You seem locked into the panel mount holders intended for external access. Most of the secondary fuses usually fail when something is wrong, so you have to pull the chassis anyway. The simple clips like Juan posted come in four-sets as well as singles. And would mount on the inside chassis wall like your bracket. And ther is no way to lose a fuse cap with the clips. Remember, inside the amp, exposed fuses are no less safe than all the other parts with voltage on them that are exposed.

[SoulFetish]

The simple clips like Juan posted come in four-sets as well as singles. And would mount on the inside chassis wall like your bracket. And ther is no way to lose a fuse cap with the clips.

Great point about the caps. No, wait... all good points. That makes more sense and I don't have to install an L-bracket. I'm so close to being done with this thing. I've been staring at it for so long that I'm missing obvious things. Thanks.

[SoulFetish]

Juan, by the way, thanks for posting the info originally earlier and giving me a quick reply. I appreciate the feedback, dude.