Pumpkin preamp - ordered by Steen , official making thread

For tapping aluminum there are some tricks. Using a pillar drill or drill press as I know them is certainly helpful. If you are specifically talking about drilling heatsinks, I have often had the problem of the drill location coming out the other side partially on a sink fin. This will cause the bit to bend away from the fin and snap.

I use WD-40 as a lubricant when I don't have magic tap aluminum at hand. That stuff works better than anything else I have tried. It reduces broken drills and taps considerably. So, the trick is to mark the hole location as needed and start the hole dry. This will allow you to accurately locate the drill point on the mark. Once there is a small divet started, add you lubricant and begin drilling. With a pillar drill and a small bit, be very careful not to apply too much pressure. So drill down a bit and then lift the bit up and out of the hole. What you want to see is the aluminum in the flutes of the bit spin free as the bit comes out of the hole or as you plunge back into the hole, the aluminum should ride up the flutes and fall away. If you see that the material in the flutes is not clearing, you should stop and use a pick to get it out. When you break a bit 90% of the time it is caused by the material loading in the flutes and binding in the hole. Don't allow the material to load up in the flutes. Depending on the depth of the hole, put a drop of oil in the hole midway through the hole. You can tell if you need more oil if the flutes are not ejecting the chips well.

Tapping follows the same rules. Keep the chips out of the hole and you shouldn't have an issue.
 
jacco vermeulen said:
Dans cette taille, la crème brulée.

Only similar legged types that fit "a kit complet" are the TQ2/EA2, an Omron G6H.
(Flat's setup is very nice, not picky about a certain voltage type)

Je suis ton homme!
(I would prefer 12V relays as it is then easier to go down to 9v without to much dissipation in reg.)
manu
 
What gain setting are you guys using to drive F4 amp? My Xbosoz has a gain of 13 db with stock feedback resisters and my volume is at 3/4 for normal listening on F4. Chocky's documentation states 4.7 - 15X gain depending on R5,R6. I am not sure how that related to 13db gain. If I up gain to 15x with 150k it states to lower C1,C2 mica to maintain same R/C ratio, however the internet calculator I was using increased it (lame engineering skills). Another curious question why is a Ei transformer preferred for this application ( I defer to previous excuse).

Thanks
Bill
 
wirewiggler said:
What gain setting are you guys using to drive F4 amp? My Xbosoz has a gain of 13 db with stock feedback resisters and my volume is at 3/4 for normal listening on F4. Chocky's documentation states 4.7 - 15X gain depending on R5,R6. I am not sure how that related to 13db gain. If I up gain to 15x with 150k it states to lower C1,C2 mica to maintain same R/C ratio, however the internet calculator I was using increased it (lame engineering skills). Another curious question why is a Ei transformer preferred for this application ( I defer to previous excuse).

Thanks
Bill


EI xformer just let less junk from mains in PSU


gain ........... it's not so critical
just put whatever you have of resistors there , and difference in volume pot position will be ........ 10 degs .....
 
es44 said:
Drillsize for metric thread. Ofcourse Danish is easy to understand 😀
MM thread = (gevind)

"Gevindbor" = drillsize

"Stigning i mm" = x MM pr. "wrinkle"

"Max. indvendig diam. mm." = absolutely max drillsize


thanks es44 thats exactly what I couldn't find....

also thanks choky but my feeble little excuse for a brain has now gone metric cos its harder to find imperial drills in funny sizes in these parts nowadays

Ed
 
sorry for barging in, but here are a few more tips for drilling and tapping:

1) use a sharpie to put a little mark on your drill bit to show when you have hit the right depth -- that way you won't drill through

2) I like to use a drill chuck (sans drill) to hold the tap bits. This forces you to turn circles with the tap, rather than pushing on it like you can do with a T-handle. (hey, vector math is useful for something!) The chuck will also slip a bit if you hit a rock, it has saved me more than one tap

3) use a sharpened nail set to punch a little divit in the AL to keep the drill bit from swimming when starting a hole.

good luck, JJ
 
Thanks Master,
I will swimm some 100 OT post back and give a look at maître jacques blured thumbnail😀

(BTW : I am worrying a little bit because Jaccos last pic had normal size and was sharp... What happens to him? 😀 Nothing wrong I hope...)

But in order to make my life as easier as possible, I will probably stay by this tie wrap method, technicolor or not...

:rofl:

(Je suis méchant, moi non plus?)