[Niteshade]

A 25 point checklist:

1] Never glue parts down
2] Use heat shrink tube instead of electrical tape when possible
3] Mount the power transformer perpendicular to the output transformers
4] Use Star Grounding (only one ground contact to the chassis
5] Chokes are great for filtering, but high capacity filter caps work excellent with or without a choke
6] Use full-wave bridge rectification, never half wave
7] Always use fuses and power switches
8] Don't use undersized power transformers
9] Hummm will/can be your biggest issue. Take your time and find out where it's coming from.
10] No need to spend allot of money on parts. Look for used ones.
11] Always discharge the filter capacitors GENTLY with a resistor (500Ohm or so) before working on your amp.
12] Stick with clean, easy to follow designs
13] New to soldering? Solder clean bits of junk wire together first. Cold joints and solder blobs are not good.
14] Make sure all your components are rated OVER the minimum voltage of the power supply
15] Never leave your creation on unattended
16] Do not set tubes for excessively hot operation
17] Be careful of filament current requirements vs what the power transformer can put out
18] Do not group the power tubes close together
19] Make the preamp/driver stages far away from the power transformer
20] Don't skimp on necessary parts to build the amp safely
21] Push-Pull designs are less susceptible to hum vs single ended ones
22] No need to be fancy, build ruggedly. Steel or aluminum is better than wood.
23] Use a good quality wire, not something the melts easily
24] First timers: Use octal socket tubes. They are easier to solder to.
25] HAVE FUN!!!!

[DanTheMan]

Excellent Nightshade!

Sincerest thanks,

Dan

[JoshK]

Nice list.  A couple are arguable but overall its beneficial to adhere to.  I'd add:

26)  A weekend spent reading Morgan Jones, Building Valve Amplifiers will save 5 weekends debugging/rebuilding. 

[ghpicard]

14] Make sure all your components are rated OVER the minimum voltage of the power supply

I would change this to:

14] Make sure all your components are rated OVER the maximum voltage of the power supply.

Cathode bypass caps could be an exception but for a start, it's a fine list !

[mgalusha]

Nice. perhaps add a line for the one hand rule.

[THE_ANSWERS]

A 25 point checklist:

1] Never glue parts down
2] Use heat shrink tube instead of electrical tape when possible
3] Mount the power transformer perpendicular to the output transformers
4] Use Star Grounding (only one ground contact to the chassis
5] Chokes are great for filtering, but high capacity filter caps work excellent with or without a choke
6] Use full-wave bridge rectification, never half wave
7] Always use fuses and power switches
8] Don't use undersized power transformers
9] Hummm will/can be your biggest issue. Take your time and find out where it's coming from.
10] No need to spend allot of money on parts. Look for used ones.
11] Always discharge the filter capacitors GENTLY with a resistor (500Ohm or so) before working on your amp.
12] Stick with clean, easy to follow designs
13] New to soldering? Solder clean bits of junk wire together first. Cold joints and solder blobs are not good.
14] Make sure all your components are rated OVER the minimum voltage of the power supply
15] Never leave your creation on unattended
16] Do not set tubes for excessively hot operation
17] Be careful of filament current requirements vs what the power transformer can put out
18] Do not group the power tubes close together
19] Make the preamp/driver stages far away from the power transformer
20] Don't skimp on necessary parts to build the amp safely
21] Push-Pull designs are less susceptible to hum vs single ended ones
22] No need to be fancy, build ruggedly. Steel or aluminum is better than wood.
23] Use a good quality wire, not something the melts easily
24] First timers: Use octal socket tubes. They are easier to solder to.
25] HAVE FUN!!!!

almost all common sense,,,,,, but u forgot pick tubes that you can get and buy a bunch of them     dont know if i'd recommend used parts when you might not know if they are compromisd

[Niteshade]

 I agree with the additions and modifications to the list. It may seem like common sense, but I've seen dozens and dozens of amps built with glued down parts, no power switches, etc...


I do have to add something crucial to the list:

When using large, heavy axial lead parts, make sure they are fastened correctly. Leaving the leads too long can become a seriois problem because the component can flop around and short against something else. Try to avoid crimping the leads to 'shore' up excessive length. The crimp can become uncrimped easily. There are times when crimping is necessary- just be careful.

[JoshK]

7] Always use fuses and power switches

I like to use thermal breakers of appropriate rating.  They are essentially slow blow fuses and a switch in one.  Except that if you blow the fuse, you can reset it.  That is nice when you are debugging a trouble circuit.

I got some self lighted red rocker switch thermal breakers from mouser/digikey (cant' remember which off hand).  However, they only come in >5a values.  For smaller values, there are NTC resetable breakers (no switch, just a push button reset), I have one 1amp NTC that I got for trying out and I have a handful of Airpax 2-3a thermal breakers w/switch that I got from a surplus site.  The airpax are the most convenient for mounting, since they have a normal toggle switch mount.  The NTC mounts through the chassis, for the push reset, but iirc it was a square hole.  The lighted red rockers were a rectangular hole. 

[Niteshade]

One thing that isn't discussed much is fusing HV mains. It's difficult finding fuses in the Ma ratings. What I do is use flameproof resistors where possible in the mains and always have some kind of anode resistor installed.