Use regulated PSU from thread:
http://www.diyaudio.com/forums/solid-state/173462-studio-reference-amplifier-2.html
AX11 finalized
Hi,
today I finished to build my AX11. At the start I have got a case and trafo and I thought about small, but very good amplifier. I decided to build AX11.
I never made so stuffed construction. But the result is here.
I used transistors: BC456, MJE 350 instead of MPSA92, MJE 340/350 instead of BC639/640, 2SC4793/2SA1837 instead of BD139/140 and 2SC5200/2SA1943.
I had some problems with stabilizing BIAS.
Controlling of AX11 ensures PIC16F84 (ON/OFF, LEDS, Relais), but small quiet fan to cool is driving by thermistor and two transistors (I didn't use PWM from PIC).
The sound is perfect!!!
Some pictures
Hi,
today I finished to build my AX11. At the start I have got a case and trafo and I thought about small, but very good amplifier. I decided to build AX11.
I never made so stuffed construction. But the result is here.
I used transistors: BC456, MJE 350 instead of MPSA92, MJE 340/350 instead of BC639/640, 2SC4793/2SA1837 instead of BD139/140 and 2SC5200/2SA1943.
I had some problems with stabilizing BIAS.
Controlling of AX11 ensures PIC16F84 (ON/OFF, LEDS, Relais), but small quiet fan to cool is driving by thermistor and two transistors (I didn't use PWM from PIC).
The sound is perfect!!!
Some pictures
A lot of thought went into packaging that lot. Superb.
Have another look at the way the fan cools the three heatsinks.
Have another look at using twisted pairs for the Flow and Return of every cable.
Have another look at the way the fan cools the three heatsinks.
Have another look at using twisted pairs for the Flow and Return of every cable.
It's my own version of pcb, designed in Sprint-Layout. On the board are also components of speaker protection.
And by the way, the second step will be construction of processor controlled preamplifier. I can use the same case but with half height then my AX11 (only 40mm). It will be communicate with processor in AX11 (function master/slave only). I'm thinking about Wolfsons WM8816 or PGA2311 as volume control, four inputs (switching by signal relais). Or maybe I use Sanyo LC7537, obsolete but in my possession.
I try to upload PCB of my AX11 in pdf. There are some "specialities" - I used TO‐220 Power Resistor (35W) in place 0.22R, I had a lot of special metal resistors 100R, 20k, so I used it (f.ex. 200R - twice 100R in serial).
Speaker protection circuit
There is speaker protection circuit. I isn't my own project, I only used this idea in my solution. Primary it was construction set which produced CZ firm EZK.
There is speaker protection circuit. I isn't my own project, I only used this idea in my solution. Primary it was construction set which produced CZ firm EZK.
