[Wooderson]

Quote:

Originally posted by BPRJam ... imagine it gives you that professional feel to press the button, and hear those relays snap. What did you think of the Velleman kit? Which transformer did you use, and where did you get it?

It does have the feel you talk about. The switch is very well made... feels very solid and has a very nice action to it. With all that it's hard to believe that the contacts are so poorly rated.

I don't have a lot of experience with the Velleman compared to much of anything else. My guess is that it should be considered the first step up from an Elpac wall wart. The kit was very easy to put together... easy to dial-in the desired voltage too. My only complaint is that it does not look nearly as "pretty" as the TEPS or Mark's "1/2-a-PS1" supply (does it have a name?). I used an Amveco/Talema 22x22 with the secondaries wired in parallel. Digikey part #TE62055-ND. I have mine putting out 25V (The working voltage of my C1's).

Had something like the TEPS been around when I was doing this I likely would have built that instead. Hey, it at least would have given me some needed experience with etching

Nisbeth and jboehle: I like the clear-top idea! That should be cool to see.

 

[Voodoochile]

Quote:

Originally posted by Wooderson My only complaint is that it does not look nearly as "pretty" as the TEPS or Mark's "1/2-a-PS1" supply (does it have a name?).

erix dubbed it a 'PSzero.5'
That works for me.

No one will vandalize your power switch either, Wooderson!

 

[Grelkman]

No way that's only your second project, Wooderson.

Congrats!

 

[Edwood]

Quote:

Originally posted by Voodoochile No one will vandalize your power switch either, Wooderson!

Most vandals will run away from the sight og the "vandal resistant" switch.

And if they don't the power switch will be the only thing left unscathed in the smoldering pile of PPA remains.

Seriously, though. As tough a switch that it is, it will still get scratched. It's a pretty stiff switch, unless that PPA weighs alot, you would have to hold onto the PPA while you press the button.

-Ed

 

[Dan the audioman]

WOW!!!!!! That is one of the pimpest amps i have ever seen!!

HATS OFF TO WOODERSON!!!

Beautiful man, simply beautiful.

 

[Pars]

Wooderson,

That is one nice looking amp! Congrats!

A question for you:

The Par Metals case... I am going to build a Gilmore, but need a case about this size. From perusing their website, it appears that the standard finishes, if you pick anodized, leave most of the case painted (yechh!). Looking at yours, it appears to be a natural or naodized aluminum... or is this the alodined finish?

That switch is awesome. Thanks for sharing the diyAudio thread and related info on it... I may just have to do one of these on mine when I get around to it.

Happy listening!

Chris

 

[Voodoochile]

If you ask them specifically to anodize the entire chassis, they will do it as an upcharge. This is a great idea, because their painting skills leave a bit to be desired. But other than that, they make a really nice (and sturdy) chassis.

Edwood- I did not realize that the Bulgin had a high actuation pressure- makes sense though. I had always *assumed* it was more like one of those capacitance switches for some unknown reason.
It sure is snazzy looking though.

A smouldering pile of aluminum slag... with the 'eye' still glowing faintly... reminiscent of the governor of california.

 

[Wooderson]

Quote:

Looking at yours, it appears to be a natural or naodized aluminum... or is this the alodined finish?

This is the clear alodine finish. I noticed they like to paint the main body of the case for the other finishes too. I didn't know they would anodize the whole thing. Thats good to know.


Quote:

It's a pretty stiff switch, unless that PPA weighs alot, you would have to hold onto the PPA while you press the button.

Yeah... it could have a little less tension for this particular application, but I haven't yet felt that it is too stiff. It's got to be similar to (or easier than) some of the rocker-type switches out there.

Quote:

A smouldering pile of aluminum slag... with the 'eye' still glowing faintly... reminiscent of the governor of california.

Oh man... what a visual! Now I'm going to have to unplug it at night so I can sleep!

A little off topic: Anyone tried or considered using a bi-stable impulse relay to switch power off and on with a momentary switch? From what I understand (sometimes very little!) it could be made to accomplish the same thing this circuit does.

 

[arteitle]

Quote:

A little off topic: Anyone tried or considered using a bi-stable impulse relay to switch power off and on with a momentary switch? From what I understand (sometimes very little!) it could be made to accomplish the same thing this circuit does.

Since seeing that great Bulgin switch, I've been thinking about the simplest way to do this. It occurred to me that maybe a two-coil DPDT latching relay could be used, with one of the two SPDT switches it contains used to control whether the pushbutton energizes the set or reset coil of the relay, but then I realized that this setup would just oscillate as long as you held down the pushbutton. Perhaps a capacitor could be charged while the pushbutton is disengaged, so that it delivers a pulse instead of DC, something like in the CMOS inverter/latch schematic posted earlier.

(edit: Maybe something like this, adjusting R and C as appropriate: )

A Google search also turned up this interesting design, using just a pair of standard relays and a pushbutton: relay toggle

Aaron T.

 

[guzzler]

the other option i was thinking about last night, is to use a circuit like the one mentioned in the LM317 datasheet, ie the TTL switched one. Doing it that way means you don't need the relay at all, you cut way down on the part count, using an LDO regulator for a flip-flop chip run from the unregulated output of the bridge, not too hard at all and for maybe a £1 in cost instead of the £16 that a digital control system is going to cost (thats including the switch though at £6, so £10 for the electronics: relay, transformer, flip flop etc)

just a thought...

g

 

[arteitle]

Even simpler yet, National has a part called LM2941, an adjustable 1A regulator like the LM317, with the addition of an ON/OFF control pin. When the pin is grounded, the regulator is on; when it's high, the regulator is off. Essentially it acts as an inverter, so with just one additional inverter gate (admittedly hard to come by alone, as they're usually six to a chip), a capacitor, and a few resistors, one could implement the flip-flop shown earlier.

Aaron T.