my latest amplifer

[Easyamp]

I thought I'd share my latest almost finnished amp with all.

It's basicly a p3a front-end with constant current instead of the boot strap and then into a tip122 quasi output but at a lower voltage so I could use 2n390X throught out.

It was made with parts on hand so some values are less then optimum like the 33p cap in the front-end should of been larger.

[Easyamp]

Here's the shcematic.

[millwood]

it looks good.

one observation: since you alread have the ccs there, why don't you just add one transistor so that the input stage also has a ccs?

[Easyamp]

Good point, I don't know.

I have the student version of pspice so 10 bjt or less but I could of done the front end seperate from the rest to work out genral values and soft analisys.

I think I'll revise.

Thanks

[Workhorse]

u can use Circuitmaker Student edition for 50 device limitation

[millwood]

by the way, what does R18 (220ohm) do for you?

[Easyamp]

by the way, what does R18 (220ohm) do for you?

I only had a 500 ohm pot on hand and this would not work. So I added the 220 ohm r to get me into the 500~700 ohm range which would get me a fair amount of offset control and get the A class vas to work properly.

[millwood]

but isn't it shorted by the wiper? maybe you wanted to put it above the trimmer, depending on the desired value of the resistor / trimmer combination.

[Easyamp]

r18 is on the otherside of the trimmer, it's just a typo I made recreating the circuit in eagle to post online.

[Easyamp]

Here's the reivsed.

I like to to keep simple things simple, but Millwood if your reading, do you think by using a shared ccs in the df stage I will be introducing more noise by the flucutuations caused by the vas, than I can wrinkle out by the increased gain of the new df's ccs vs negative feedback?

I have one made already, I'll make another with the revisions and see which looks good.