First little amp project

anickode · 18th March 2010, 01:51 AM

My first amp project: A small 386 IC based battery powered guitar amp. All the components were either scavenged or picked up at radio shack. Total cost was around 15 bucks. The enclosure is a .50cal ammo can, 4 1/2" 8 ohm full range speakers in series. Powered at 12v by 8 AA batteries. I was a little frustrated that I couldnt find a 5k pot with a short stem

but it's not hard to shorten the stem and epoxy a knob on.

It sounds OK... has volume and drive adjustment, and will get everything from clean to super overdrive.

Jarno · 18th March 2010, 01:15 PM

Looks like it means business!
Those potstems are meant to be cut to size I think, you can just put a knob on there with a set screw to fasten it. If you want to be extra careful, file a flat spot where you put the set screw (i never do).
Measure the stem before ordering knobs, it's usually either 1/4" or 6mm, although there are some other diameters as well (4mm for instance).

Nigel Goodwin · 18th March 2010, 02:56 PM

Quote:

Originally Posted by Jarno

Looks like it means business!
Those potstems are meant to be cut to size I think, you can just put a knob on there with a set screw to fasten it. If you want to be extra careful, file a flat spot where you put the set screw (i never do).
Measure the stem before ordering knobs, it's usually either 1/4" or 6mm, although there are some other diameters as well (4mm for instance).

It's best to cut the shafts BEFORE you fit the pots, so you don't strain them. I've always cut plastic shafts with side cutters, and obviously metal ones with a hacksaw.

Likewise I never file flats on the shaft either - pots normally have either a flat all the way down, or no flat at all.

anickode · 18th March 2010, 07:24 PM

I'm just planning on cutting it with a small abrasive wheel, so it shouldn't put much strain on the pot when I trim it.

Minion · 18th March 2010, 11:55 PM

I get those crappy pots at Rat shack when I am desperate , I usually just cut the shaft down to size with my Dremmel and use a knob with a screw inset ...... cool looking amp though .....

Cheers

Jarno · 19th March 2010, 08:23 AM

I would use the paper masking tape (blue in the US, pale yellow overhere) to make sure nothing can make it's way into the pot (even though the fit of shaft and bearing is pretty tight, and filled with grease).

anickode · 19th March 2010, 10:50 PM

Hmm, that's a good suggestion. I've got some knobs to put on there too, which will help keep the pots protected as well. ^_^

18th March 2010, 01:51 AM	#1
anickode diyAudio Member Join Date: Mar 2010	First little amp project My first amp project: A small 386 IC based battery powered guitar amp. All the components were either scavenged or picked up at radio shack. Total cost was around 15 bucks. The enclosure is a .50cal ammo can, 4 1/2" 8 ohm full range speakers in series. Powered at 12v by 8 AA batteries. I was a little frustrated that I couldnt find a 5k pot with a short stem but it's not hard to shorten the stem and epoxy a knob on. It sounds OK... has volume and drive adjustment, and will get everything from clean to super overdrive.

18th March 2010, 01:15 PM	#2
Jarno diyAudio Member Join Date: Sep 2002 Location: Rosmalen, The Netherlands	Looks like it means business! Those potstems are meant to be cut to size I think, you can just put a knob on there with a set screw to fasten it. If you want to be extra careful, file a flat spot where you put the set screw (i never do). Measure the stem before ordering knobs, it's usually either 1/4" or 6mm, although there are some other diameters as well (4mm for instance). __________________ Oemptempa petoempetapap

19th March 2010, 08:23 AM	#6
Jarno diyAudio Member Join Date: Sep 2002 Location: Rosmalen, The Netherlands	I would use the paper masking tape (blue in the US, pale yellow overhere) to make sure nothing can make it's way into the pot (even though the fit of shaft and bearing is pretty tight, and filled with grease). __________________ Oemptempa petoempetapap

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18th March 2010, 07:24 PM	#4
anickode diyAudio Member Join Date: Mar 2010	I'm just planning on cutting it with a small abrasive wheel, so it shouldn't put much strain on the pot when I trim it.

18th March 2010, 11:55 PM	#5
Minion diyAudio Member Join Date: May 2006	I get those crappy pots at Rat shack when I am desperate , I usually just cut the shaft down to size with my Dremmel and use a knob with a screw inset ...... cool looking amp though ..... Cheers

19th March 2010, 10:50 PM	#7
anickode diyAudio Member Join Date: Mar 2010	Hmm, that's a good suggestion. I've got some knobs to put on there too, which will help keep the pots protected as well. ^_^

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