Burning Amp BA-3b (Balanced)

[escucalin]

Not seeing them on Spencer's page...am I missing them, or do I just need to contact and inquire?

Thanks,

Russellc

i've made my fill for the ba3 a few months ago.... maybe he still sources them

 

[escucalin]

Bahhhh

You guys making me itching to get those 2sk2013 again... Must resistttt

resist resist... this itch costs kids trough college

 

[escucalin]

when you have BA3 Balanced amp , you can drive it with SE source , as any (proper) balanced amp, or amp having balanced input - just short pins 1 and 3 of XLR input , while using RCA jack

in other words- short neg. input of amp to GND

ofcourse that will make one channel silent ... thats why i asked about bridging ... with a simple alteration in input topology a balanced channel can be driven by a se source much more effective and now wasting the silent channel's bias and capability.

of course that you need pretty much same voltage envelope on input , as in case with balanced

FE of amp itself is doing SE-Bal conversion

let me understand that right: If we drive two Ba3 amplifier channels bridged feed by an unbalanced source; there is no extra swing hence no extra power?


->

 

[Zen Mod]

as I wrote : when you have BA3 Balanced amp.....

I was under impression that you were asking how to fed SE signal to one channel of balanced amp, not asking how to properly bridge two channels of BA3 SE

 

[AnthonyA]

 

[wengtech]

repost sorry

======================
hello,
can we make this ba3 preamp into an amplifier using 2sk1058 2sj162 device
simply by changing the value of some parts and increase the bias current?
biased at 1.2A 25v 30watt, device Pd rated max 100watt.
🙄

please advice.
======================

sorry for repost, i've posted at wrong thread before.😀

thanks 6L6.

 

[Zen Mod]

and 6L6 did answer there ....... yes , you can

🙂

 

[wengtech]

hello ZM,
any adjustment needed?
or just build like that?

can it deliver 25watt output power into 8ohm spk, just like F5 amp does?

🙄

 

[Zen Mod]

I wouldn't make it without overall NFB , but that's your choice

simple F5 is delivering 25W , bridged ...... theoretically 4 times more , practically at least 3times

not trying to be precise too much

 

[wengtech]

I wouldn't make it without overall NFB , but that's your choice

if we put nfb then it will become 100% F5 amplifier😀

isn't that BA3 is about no feedback amplifier?😕

thanks.

 

[Zen Mod]

horses for sources...... for courses

BA3 is having source follower (common drain , even if dummy ZM is always confused with that "common something") OS , which alone is having pretty low Rout

what you're proposing is having common source arrangement of output mosfets ,so wimpier ....... and always needing help of NFB to lower resulting Rout

if you want to mimic lousy made toob gadgets , just make lousy made toob gadget

no need to mimic it with sand , bashing how you made something new

though , your pleasure is always your own first , so don't let anyone spoiling it .....

 

[wengtech]

ok, i see.
maybe i should try to build and hear it my self
it's worth to try for me, at least for learning😀

btw Q3 Q4 are reversed from previous schematic,
the BA3 output Q3 should be Pch, and Q4 should be Nch.

and also i attached another schematic, i think it might be entertaining too,
maybe can call it folded ba3 or flipped output ba3?
or maybe don't have related with ba3 at all?😕 no offend please😉
i'm only a noob with very little experience..😀
and i don't know yet whether it will work or not as an amplifier..😀

please some advice.
thanks.

 

[Zen Mod]

left sch is sorta OK, you can even toss source resistors of outputs , consiodering that laterals are having nice TempCo , starting from 100mA of Iq

right schematic (that folded one) ...... no workie ....... at least my 2 cells can't fold it enough to see it working

🙂

 

[wengtech]

left sch is sorta OK, you can even toss source resistors of outputs , consiodering that laterals are having nice TempCo , starting from 100mA of Iq

eliminate source resistor, I see...
but I think it will be easier to look at bias if resistors are there.

right schematic (that folded one) ...... no workie ....... at least my 2 cells can't fold it enough to see it working

🙂

Is it because of that lateral mosfet? (wrong bias circuit)
Will it working if using 2sk2013 2sj313 or irfp9240 irfp 240 devices?

Thanks.

 

[Zen Mod]

no Bubba

which way you think to squeeze normal Iq for stage like that?

it is late/early in my neck of wood , but I can't see that possible with these resistor values

not even counting that you can't modulate output mosfets via source ....... I mean , you can , but for that you need complete amp modulating output mosfets

 

[AnthonyA]

Zenmod

Is it possible that become a preamp? Say with a F5 topology?

Any advantage VS 2013 313?

 

[Zen Mod]

it is "F5" topology

no advantage , for preamp duties , using bigger parts than 2013/313

 

[AnthonyA]

So the only spooky ones is still korg and sit right? For preamplifier? How bout lu1014?

 

[Zen Mod]

depends what you mean with Spooky 🙂

with amps , SITs are Spooky (SIT 1, SIT 2, SIT 3, amp you posted about .....)

with preamps , Spooky for me is Iron Pumpkin

though , completely different Spookiness than with amps

so , maybe Mr. Rothacher's Sony VFet preamp ........ can't remember its name now ......

 

[AnthonyA]

Luminaria MR design

No kidding?iron pumpkinz. What sort of spookiness u mean this preamp.