sneak peek

[Rabbitz]

For those wondering why people fear valve gear - it is quite simple:

The grid voltages for a valve typically run at levels around 600 V. However, they can run MUCH higher depending on amp design and purpose - 3000 V is not very unusual.

Some designs have enormous capacitors - think it of a big-arse battery that will discharge that 600 to 3000 V charge very quickly at surprisingly high current. Capacitors can hold lethal charges for very long periods, thus keeping it very dangerous for those sticking fingers into a chassis even one that is unplugged...

[DrNomis_44]

It's a nice idea, but it's been floated before.
Ads and the team are very conscious of the safety and quality of their products - one problem with DIY amps is that if you do it wrong the consequences can be pretty big - hence nice economical complete amps vs DIY.

Doc's suggestion of lamington amps is a good one, and reports of them are good

Definitely, when building a valve type guitar amp the danger of getting an electric shock from one is very real, there is very little margin for error, and all it takes is for electrical current to pass from one hand across your chest to your other hand to cause your heart to go into fibrillation (the heart stops beating normally), which will have fatal consequences if you don't know what you're doing, I've been pretty lucky so far but I wouldn't tempt fate.


To safely work on a valve amplifier you need to follow correct electrical-safety procedures.


When I did an Electrical Testing & Tagging course to get my Electrical Testing & Tagging card, we were taught that as little as around 100mA, or .1 of an amp, is enough to cause heart Fibrillation, the current levels in a valve guitar amp can easily exceed this due to the HT supply filter caps (typically around 100uF or so in value) storing electrical charge, it's not the voltage that kills, it's the current.

https://engineering.dartmouth.edu/sa...alCurrent.html


And considering that the average Australian household 240V AC power socket is capable of supplying up to something like 15 Amps , they can be instantly lethal.

[Guvna19]

It's a nice idea, but it's been floated before.
Ads and the team are very conscious of the safety and quality of their products - one problem with DIY amps is that if you do it wrong the consequences can be pretty big - hence nice economical complete amps vs DIY.

Doc's suggestion of lamington amps is a good one, and reports of them are good

Wise advice , and all points taken. I hearby retract the DIY amp suggestion in the name of Safety

[dave.king1]

Amen, Reverend King! Testify!

Let me see, brass compass across live 240v in the music room at high school, yeah fingers did go across it first.

Then some years later found out how much kick 385v on the anode cap of my AC30 clone had.

Then later again dropped a ring spanner across 50v DC, main bus bars carrying about 3.5K amps from memory, the spanner simply disappeared in a bright flash into an alternate universe

[DrNomis_44]

Had a pretty shocking experience when my hand touched two pins of the power plug of a three-phase arc welder, I was in the process of replacing said plug with a new one and forgot to discharge the two dirty great big capacitors lurking in the back of the three-phase arc welder, did I jump?.....yes.

The three-phase arc welder I was working on was designed to run on three-phase 415V AC, no wonder I suddenly jumped and dropped the power plug.

[FrankenWashie]

Let me see, brass compass across live 240v in the music room at high school, yeah fingers did go across it first.

Then some years later found out how much kick 385v on the anode cap of my AC30 clone had.

Then later again dropped a ring spanner across 50v DC, main bus bars carrying about 3.5K amps from memory, the spanner simply disappeared in a bright flash into an alternate universe

Yep, walked in on my brother changing over a single GPO to a dual plug GPO in his room way back when. Coversation went like this:

Me: WTF are you doing?!?!
Him: it was cracked and I want the extra plug
Me: you are not a qualified electrician
Him: It's okay, I've switched it off....(shows me the outlet switch in the off position)
Me: did you at least pull the Fuse or switch off the main switch?
Him: ????? Urrrrrr???
Me: ............ I'm just going to the fuse box, I'll come back in a minute to slap the stupid off you.

[DrNomis_44]

Yep, walked in on my brother changing over a single GPO to a dual plug GPO in his room way back when. Coversation went like this:

Me: WTF are you doing?!?!
Him: it was cracked and I want the extra plug
Me: you are not a qualified electrician
Him: It's okay, I've switched it off....(shows me the outlet switch in the off position)
Me: did you at least pull the Fuse or switch off the main switch?
Him: ????? Urrrrrr???
Me: ............ I'm just going to the fuse box, I'll come back in a minute to slap the stupid off you.

Geez, your brother should be grateful to you for saving his life.

[FrankenWashie]

He just didn't get that what he was trying to was dangerous, most people don't realise exactly how dangerous many things around the house are. He'd figured that because he'd turned it off that it was safe to work on.

[stan]

wow Franken - it's takes a lot of slapping to remove stupid, you must have been busy...

[FrankenWashie]

wow Franken - it's takes a lot of slapping to remove stupid, you must have been busy...

I've been trying to slap some sense into my older brother since i was about 5. Coming up to 37 years worth and i think i've finally made a breakthrough! Persistence is the key.