Pumpkin preamp - ordered by Steen , official making thread

[ROVSING]

Originally posted by Magura



Oh, and what am I gonna do with the other 8 I need to practice on?

Magura

You don't need that much practice - you've got the skills Metal-Gura ...

[jacco vermeulen]

Originally posted by Zen Mod
CLICK ............... HB

[jupiterjune]

If you still want it in some sort of color, you can just strip it in a cautic soda solution, and give it another shot.

Magura--do you mean just sodium hydroxide? or is there another component?

Thanks, JJ

MPMarino--Wow, nice chasis!!! Why such thin metal though??? Yer not one of those guys who sweats over little details like "too heavy to lift?"

[Yunick]

Almost there

Waiting for mica caps for pumpkin to arrive.. Top left is cheapo reg psu for quick listening while I wait for more parts for shunty..

[Zen Mod]

Originally posted by Yunick
Almost there

Waiting for mica caps for pumpkin to arrive.. Top left is cheapo reg psu for quick listening while I wait for more parts for shunty..

[mpmarino]

Originally posted by jupiterjune


Magura--do you mean just sodium hydroxide? or is there another component?

Thanks, JJ

MPMarino--Wow, nice chasis!!! Why such thin metal though??? Yer not one of those guys who sweats over little details like "too heavy to lift?"

Sodium hydroxide (pure lye) is tough to find now. I found that the 'Zep' crystal drain opener at home depot works fine(6 bucks?). Although it leaves little black chunks on the bottom of the container. I think the crystals aren't dissolving entirely.

It already comes in at about 50lbs - with maybe 20lbs to go!!

I'm really disappointed with the way the knobs feel - too wobbly. They are large solid alu and don't feel right hanging off of a junkyard motorized pot and input selector. I'm building a bearing carriage with stainless shafts for the assembly to eliminate play and make 'er bullet proof..

[Zen Mod]

Originally posted by mpmarino



...

I'm really disappointed with the way the knobs feel - too wobbly. They are large solid alu and don't feel right hanging off of a junkyard motorized pot and input selector. I'm building a bearing carriage with stainless shafts for the assembly to eliminate play and make 'er bullet proof..

put selector and pot on back of uckin' fugly case, and make extending shafts from front plate to back;

you can drill bigger holes in front plate and put bearings as shaft guides ...... if ya're nutzzzzzzzzz ....... look at Igor's preamp thread ;

or - be smart and use messing as guides

edit:

http://www.diyaudio.com/forums/showt...28#post1340228

[mpmarino]

Originally posted by Zen Mod



put selector and pot on back of uckin' fugly case, and make extending shafts from front plate to back;

you can drill bigger holes in front plate and put bearings as shaft guides ...... if ya're nutzzzzzzzzz ....... look at Igor's preamp thread ;

or - be smart and use messing as guides

edit:

http://www.diyaudio.com/forums/showt...28#post1340228

Naahh! Already been done.




I'm using two bearings per 'axle' with thrust washers to eliminate all play

Relay set-ups for atten and select so no shafts thru da case allowed or needed..

.....gotta come up with a clutch for the atten motor. I'm still 'junkin' for parts for the boards, so no time lost



edit: What is messing (well, in a preamp!)

[jacco vermeulen]

Originally posted by mpmarino
the knobs feel - too wobbly.

Making them hollow is my preference, i enjoy big knobs (read as you please)
Shrinking a hollow body on a solid base is easy, machine the inside edge of the knob body and there's no seam in sight.
Brass can be welded, then polished and chromed =>

[jacco vermeulen]

The spots are dust, gotta love polishing if you've got a thing for chrome.
(= 2" diameter x 1.5" height)
I've tried everything from solid steel, to brass and solid aluminum.
All too hefty in the size i prefer, shaft guide or no, only ones that work well with solid knobs are the monster switches as used in the BT.