Burning Amp BA-3

[wintermute]

Hi Guys, I need to get some 2sk2013/2sj313's for my BA3 boards before they become unobtainium.

if I can specify the current for matching, what is a desirable current? I've searched the thread but haven't seen any recommendations. I already have the 70/74's matched at 10mA as per Nelsons artcile.

Is the figure for the mosfets less important? should I just ask for two matched pairs that are close together and not worry too much about the absolute value?

Tony.

 

[Zen Mod]

..... should I just ask for two matched pairs that are close together and not worry too much about the absolute value?

Tony.

yes

grab them while you can

 

[wintermute]

Thanks Zen Mod!

Tony.

 

[AndrewT]

Buy random selected mosFETs.
What about considering Fairchild alternatives?

 

[wintermute]

I figured if I can get the toshibas then I should. Could just be a case of because Nelson used them everyone assumes that they are best, but I figure if they are what Nelson specced then I can't really go wrong

It will probably be quite a while before I actually build it, but I want to secure the parts whilst I still can

Tony.

 

[Zen Mod]

there are some possibly better alternatives , but even more unobtanium

2SK213/2SJ76
2SK214/2SJ77

for instance

 

[tinitus]

wonder how a BA3 would sound without the frontend, driving an 110db compression driver
shoot, too much whiskey, sorry

 

[Zen Mod]

will it drive F4 ?

 

[tinitus]

hey, dont forget it gets some drive powr from whatever drives whatevr basses have to be driven

 

[tinitus]

ups, sorry to hear you are drunk too

 

[noSmoking]

ups, sorry to hear you are drunk too

well I maybe if the wiskey is a good brand that driver may sound very well,but some old rot gut cheap stuff might upset the bias and it'll run lousy ,lol.NO I've been drinking some BEER and good Texas wine.......yeehaw!!!! And I cooked about ten Chickens and there almost gone,lol.
HAPPY 4TH of JULY!!!!!!!!!!!!!!!!!

 

[Nikitas]

Hi all!

Somebody in a previous post has asked about mixing and matching ba3 with f5. Has anyone tried that?

If someone (me) tried to use ba3 as a unity gain buffer would the adjustment of the gain resistors ratio suffice or other adjustments have to be made?

What about the input of the ba3 in the above case?

 

[Zen Mod]

example of redundancy

why you would to do that ?

no matter how stage good is , it's always better if you can go without it

 

[Nikitas]

hm? I guess you are talking about ba3+f5?

I was just thinking about it, that's all.

But using ba3 as a unity gain buffer I'm serious about if it can be done and how.

 

[Zen Mod]

just keep decreasing R13 , 'till you are satisfied with gain

 

[Nikitas]

Thanks Zen!

Do you think the combo of ba3 as a buffer and f5 is a good match?

Do I have to change anything at the input of ba3?

 

[Zen Mod]

well - I already told you - if you can go without it ...............

no need to change anything on input

read my comment in Papa's BA3 article - with proper parts nomenclature , and everything will be clear

http://www.diyaudio.com/forums/diyaudio-com-articles/194809-burning-amplifier-ba-3-a.html

 

[Nikitas]

:/ Let's see......

 

[neoinc]

My new BA3 powered up well. The bias has been set as per schematic. Can't wait to mount the crippled F4 transistors and put the system to sing.

 

[Ryssen]

If I build the version with 6 transistors/channel will a 600VA trafo be enough for 2 channels?