Hammerhead project I started yesterday

[homefire]

Got this from the INFO section of Geotech.

http://www.geotech1.com/cgi-bin/page...oils/index.dat


XL500 7"149.5uH1.2------XL500 12.5"140.8uH0.746

[Carl-NC]

What damping value resistor will I use ,do I just change the R11 to use these coils or is there more to be changed.
can I use an external pot for R11 for when I use different different coils or is this not a good idea.

I also used a 12" XL500 for one of my HH units. Don't recall what damping R value I used, and I'm 3000 miles away from it at the moment. I don't recommend using a pot other than to determine a fixed value to use... continuously spiking 200v on the pot wiper isn't a Good Idea.

- Carl

[Micheal]

Hi guys...I had a look the info homefire and it says XL500 12.5"140.8uH0.746

I dont know how to work out the 140.8 uHO value but I have measured the ohms on my 33cm coil and it is 1.2 ohms and the small 7''coil is 1.2 ohms aswell.

homefire do you know what damping resistor value is in the xl 500 maybe It will work in this project( is there some kind of formula for working out the damping resistor value)...what do you think Carl

[homefire]

Again it's time for a a Scope!


Do the Pot thing and just run it long enough to see what works best starting at known value.

[Micheal]

Ok that sounds pretty straight forward .But what is it that I will be looking for (I know the scope would be really good).
I have used a 1M external pot which is in the instructions anyway and see what resistance value gives best results.\
The one thing I want is to be able to simply turn the vco on or off with a switch.I had read it somewhere so Im looking for it at the moment.

I have been reading basically everything about the hammerhead 1 in the forum ...this project is so far going as planned(very educational)I hope it works when I fire it up tommorrow

[Micheal]

I finished it off today and the result was when I applied the power and switched it on...three little pops and some smoke DAMmmm....

The instructions need to be more clear with this project


I think more tinkering to do now

[Molzar]

Sounds like you blew up (pops and smoke) some of the electrolitic capacitors. Either you didn't use the the proper voltage rating or the polarity was reversed on the caps.

The instruction for this project are pretty good, and you can ask questions of the writer! Most project don't have that kind of support.

This is not an easy project and can be confusing because of the all the options.

Never does a project go flawlessly. Be patient, you'll get it to work, many other have with good success.

Nice looking pcb by the way. Get a scope.....

Molzar

[Carl-NC]

Also why I recommend building the board in stages... first the supply circuit, then test it... and so on.

[Micheal]

Sorry if I sounded nasty in any way...Im only new to this but I find it really fascinating and I really keen to make one ..I think my knowledge is limited I am learning quickly....the problem is that for a newby like me the hammerhead has a lot of variables especially the Pots there are I think 11 pots to fiddle with and this makes it very hard ...and some part numbers need to be more specific so we can buy the right parts and not wonder if the little letter change in the part number is going to ruin the project.
Whereas a complete parts placementt diagram with less variables to build is no problem coz I recently I built a theremin and it worked first go....

I checked all polarities and everything else about 10 times before I started it up...But i must say the diagram and parts list need to be more precise and shouldnt be left to question and that it will be a simple build.

I like the hammerhead and I have the pcb but I have removed everything off it and I will start from fresh again ...but more concrete parts diagram is a must for somebody like me...If there is one please place it here so us newbies can get started ...An intrsuctions with less pots to tune would be great...Thanks guys

[rajesh]

hh

hi Micheal pot is not a problem actually you mide to read c15 v article 10 time all pot will be in center point after chek.......rajesh

[angelo01]

Hammerhead PCB

Nice PCB...

Can you teach me how to do it?



Many thanks

[MetalTracker]

Hello,
I have got maybe a silly question. I started to build a HH smt version and I saw two R17 and two R19 in the parts list /opt.1/.
One 1M value and the other 100k value. Which is the correct?
Thanks for the help!
MetalTracker

[DreamOfMirrors]

I think the correct values are 100k for R17 and R19 as Option 1 schematic PDF says.

[parun14]

I need to started too!!!!!

[Agraz]

where I connect a meter to the hammerhead?