BA-3 Amplifier illustrated build guide

Member
Joined 2003
Paid Member
yes , you can

but then you must remember for all times that there is some DC on output RCA

if you're making integrated with MoFo , then it's no brainer

though - in case of stand-alone pre , you can make two sets of RCA outputs , visible named as DC coupled and AC coupled

Wondering about this, can the two outputs, one AC one DC just be wired off the same output pads of boards? One wire set to RCA, one wire set to caps, then on to other RCA? Or should there be something, resistors, etc to isolate them?

Russellc
 
I have been working to increase the gain of my BA-3 board

At the suggestion of the gentlemen on this thread...

To get more gain out of my BA-3 board, I increased r13 in steps. I saw that gain did go up. Where for one volt rms of input, I was getting 9 volts rms of output...With a higher ohm r13 of around 500 ohms, I could get 18 volts rms of output from one volt rms of input. No clipping observed on my scope at 1 volt input.

However, I could see on my scope that upon raising the input voltage to 1.5 volts or so, the output would clip.

It seemed that I could get more output swing with out clipping by raising the bias of the MOSfets. But I could only do this to a point. I then blew out a mosfet when I was at 3volts dc across the bias resisters.

So is there a way I can get rid of the clipping when input voltage is raised to say 2 volts.

This has been a great and instructive project...Haven't started the MOFO yet.
 
Official Court Jester
Joined 2003
Paid Member
do not use force , use a bigger hammer

increase gain (R13) , not input voltage

2Vrms , when everything is OK, is on the verge of clipping (of everything) , but with 510R for R13 , that's output swing of nearly 70Vpp , if you're using +/-36V rails

so ,make your mind - whatever you need , you need to optimize stage , not forcing it on input

though , connecting 115Vac directly from mains to input could induce some interesting things , even if not for long

:clown:
 
Thanks Zen Mod ,yes I am of a natural cautious ,at this moment I listen to the little Mofo +BOZ=not bad like listening but the Zen 9 is superior,the criticism is very valid because the Boz does not have enough gain and has an impedence can-be too high,Iyearn to achieve the BA-3 fronted .