Burning Amplifier BA-1

[Zen Mod]

please - be patient

I had few brainstorming days with some other things ;
today I drew my own first ever pcb with Eagle ........ in fact - first with any prog

my head is bigger than Eiffel Tower .....

[generg]

dear zen Mod,

I knew you are working hard, I suppose it is interesting and fascinating for you!

Go on!!

I have all time!

[generg]

the power of Monsieur Eiffel is with you..................

[generg]

hi cviller, hi Variac,

I suppose there is another small problem with the frontstage board of BA-1 and BA-2.

In the manual of BA-2 Nelson mentions the possibility to use an Elma Silmic for C203 and advises ".... in which case you want to orient the + polarity pointed to the left, toward the R215."

This only true for BA-2!

For BA-1 you have to change polarity vice versa!

But on the frontstage board the polarity is marked only for the BA-2 case.

BA-1 users might have problems when using electrolytic capacitors!

Am I right?

best regards
and I hope you have the same fine summer weather we have here now

[generg]

...... I know it is holiday time,
Nevertheless is there anybody outside there who can help me with my problem what to do with the two biasing branches of BA.-1 when I omit the coupling cap ( see posting 158 ).
Should I keep the negative branch and the positive branch is done by the front stage?

[Zen Mod]

generg - please put here exact output stage you want to use ;

pictures are small enough , so don't hesitate to post them ;

my problem is that I'm often mixed in few threads , so it's sometimes mess in my head while trying to keep up with several different heads ......

[generg]

Oh thanks Zen Mod,

The best is I give you the BA-1 link. Nelson mentions on page 5 : Strictly speaking you do not have to use this capacitor, but it does make adjustment and long term DC stability very easy to achieve.
I want to omit the coupling cap do you understand his words right I have to keep the negative branch and the positive part is taken over by the front stage?

Burning Amplifier BA-1

[generg]

Originally Posted by Zen Mod

generg - please put here exact output stage you want to use ;

pictures are small enough , so don't hesitate to post them ;

my problem is that I'm often mixed in few threads , so it's sometimes mess in my head while trying to keep up with several different heads ......

..... You must have at least 15 heads!

[Zen Mod]

Originally Posted by generg

Oh thanks Zen Mod,

The best is I give you the BA-1 link. Nelson mentions on page 5 : Strictly speaking you do not have to use this capacitor, but it does make adjustment and long term DC stability very easy to achieve.
I want to omit the coupling cap do you understand his words right I have to keep the negative branch and the positive part is taken over by the front stage?

Burning Amplifier BA-1

OK - I'm digging it , but just half

you want BA1 output stage , connected to BA1 input stage , but DC coupled ?

or what ?

just let me know , and I'll do the pictures

edit :

I digg it 100%

pics later

[Zen Mod]

there is certainly more than one way for skinnin' the Cat , and there must be certainly more elegant ones ........

this one is rofl solution , only one which I'm capable to rethink in this moment

anyway - concept is here , and I think that price for avoiding one cap is pretty high ....... going DC all the way is pretty much complicated if you are keen to use universal input stage ... and you see exactly that

DC offset on output will be issue , and you must find how much

maybe is best to use 47(50)R pot in place of 39R