erix
500+ Head-Fier
- Joined
- Jun 25, 2001
- Posts
- 835
- Likes
- 16
It's been said the enclosure is the hardest part of DIY so I built an amp without one.
I built this as a plug-n-play apparatus for experimenting with resistor values and input caps. Yes, yes, I know you've heard me bitch about input caps ad infinitum but I figured it's easy to play with different kinds in this form.
The board is 3/4" plywood, the little brackets came on my new window A/C units, the pot is a cheap 50K Alpha (with remarkably good tracking - must've slipped past the QC dept.) with an old Davies plastic knob. Switchcraft jacks round it out.
The layout is based on a layout for the META42 amp by sijosae, who I've admired for his ultra-tidy builds and super-tight layout.
I added the power supply section to his layout along with a switch and LED. The big caps are Cerafine 2200uF/16V bypassed with 1uF/63V Wima MKS2 and the C1 caps are insanely huge 1uF/400V Wima MKP10's.
For this iteration I chose resistor values from ppl's first portable pocket amp. Interestingly enough, most of the values are available in the Shack's $5 1% resistor assortment. I didn't use all the bells and whistles of his circuit (namely the capacitance multiplier, the cascode current source, and the bass boost) - just the multi-loop dual opamp (AD823 in this case) buffered by a pair of EL2001's.
And how does it sound? Abso-freaking-lutely-marvelous! I couldn't believe the power and depth of the bass - this thing can blur your vision. I don't know what it would do with ppl's bass boost circuit. The top-end is nice and clean too, the mids maybe a trifle scooped but in a good, rock-n-roll way.
ok,
erix
I built this as a plug-n-play apparatus for experimenting with resistor values and input caps. Yes, yes, I know you've heard me bitch about input caps ad infinitum but I figured it's easy to play with different kinds in this form.
The board is 3/4" plywood, the little brackets came on my new window A/C units, the pot is a cheap 50K Alpha (with remarkably good tracking - must've slipped past the QC dept.) with an old Davies plastic knob. Switchcraft jacks round it out.
The layout is based on a layout for the META42 amp by sijosae, who I've admired for his ultra-tidy builds and super-tight layout.
I added the power supply section to his layout along with a switch and LED. The big caps are Cerafine 2200uF/16V bypassed with 1uF/63V Wima MKS2 and the C1 caps are insanely huge 1uF/400V Wima MKP10's.
For this iteration I chose resistor values from ppl's first portable pocket amp. Interestingly enough, most of the values are available in the Shack's $5 1% resistor assortment. I didn't use all the bells and whistles of his circuit (namely the capacitance multiplier, the cascode current source, and the bass boost) - just the multi-loop dual opamp (AD823 in this case) buffered by a pair of EL2001's.
And how does it sound? Abso-freaking-lutely-marvelous! I couldn't believe the power and depth of the bass - this thing can blur your vision. I don't know what it would do with ppl's bass boost circuit. The top-end is nice and clean too, the mids maybe a trifle scooped but in a good, rock-n-roll way.
ok,
erix