Burning Amplifier BA-1

[Nelson Pass]

25 watts per channel seems low if the amps are dissipating 300 watts per stereo channel and the output stage is drawing 3.5A at 50V. Where are the missing 100 watts?

They are pure heat. This is a Burning Amp.

You will get a lot more efficiency out of BA#2, which is push-pull
instead of single-ended/constant current source.

If you want more efficiency out of the all-N channel output stages,
we will expect to be doubling the efficiency in a later version.

😎

 

[Variac]

One of the reasons the board area is pretty tight is that the shorter chassis is very congested inside compared to t he longer one. - Mainly due to fitting in 4 supply capacitors...

I'm not sure if there ARE any short chassis with all 240 output devices..

Nelson states that with Elna Silmic 10uF radial caps it sounds great- now those would be easy to fit!! What other radial caps are there that people might consider?, and what are their lead spacing and size?

 

[Variac]

This would be a great design for those that have gotten irf250 mosfets from Nelson over the years at Burning Amp. You would only need 4 or 6 per channel as each 250 is pretty much two 240's in one can...

 

[eyoung]

I am waiting with much excitement and anxiety.

That would be a bump, I Think...

keep me in the loop.

Elwood.

 

[CfM]

What other radial caps are there that people might consider?, and what are their lead spacing and size?

Wima MKP10 - lead spacing 37,5 mm - width 20 mm
... would be my consideration.
But I could also go with axial caps as you proposed if this is the common agreement.


Chris

 

[Variac]

Clearly cviller intends for it to work with a lot of caps. I think having your suggestion as an option is a good idea.

 

[cviller]

I'm quite sure I have left space for 37.5 pin distance - if not it's a mistake. 😉

 

[Variac]

He's worried about the width too..

 

[Variac]

WE HAVE CORRECTED THE ARTICLE

Now its Rev. 1.0 as suggested

Please check it out........🙄

Thanks for your patience

 

[Eric Weitzman]

If you want more efficiency out of the all-N channel output stages,
we will expect to be doubling the efficiency in a later version.

😎

By turning it into an A5? 😉

- Eric

 

[audiojoy]

sorry got a bit lost in this thread are you still designing the boards or are they ready for purchase,will the power supply boards also be available??

 

[Nelson Pass]

By turning it into an A5?

That would lack novelty.

😎

 

[Variac]

The boards are in the final stages of design. Cviller has posted them so that he can get feedback from other members.They will be produced by diyAudio as a fundraiser. There won't be any power supply boards in this buy. The main purpose of power supply boards is to connect a bunch of "snap-in" caps, and allow use of discrete diodes rather than diode bridge blocks. They really aren't necessary for the people with the chassis, which have large "computer grade" caps and bridge rectifiers installed. BUT many other power supply boards will work. The ones produced for First Watt amp clones such as the F5 will work, possibly with some modifications.

Cviller has some, as does Peter at Audio Sector. The main purpose of power supply boards is to connect a bunch of "snap-in" caps, and allow use of discrete diodes rather than diode bridge blocks..

 

[Variac]

Nelson, look here!

I tend to use these diode bridges because they don't require a board so are easy to wire up, yet are properly exotic..

http://www.partsconnexion.com/PDF/l359.pdf

Nelson, I assume they will work even though they are rated at 27A instead of 35A as you spec?

$20 ea. though....

 

[Zen Mod]

Re: Nelson, look here!

....
$20 ea. though....

there is no Graetz for our purposes worth 20 greenies ........

look at my sig

 

[Variac]

Well.... back to the board- It needs a connection for an LED and a resisitor for the LED... (IMHO)

 

[Variac]

Hey Papa!+ (other zenlike members)
Could I use the BA1 front end as a preamp to use with my F4's? (without the biasing stuff)
I guess not near enough gain for full output, but what kind of output voltage are we talking about? Prob needs a regulated supply ?

 

[massimo]

I post again here what I wrote few days ago on "Aleph J schematic" thread:

I think that some of the new features intruduced in the BA1 front end schematic colud be applied in the Aleph J too.
I'm referring to the RC filter (R210 + C205 and R211 + C206 on BA1) useful to isolate and clean the PS a bit and to drop a Volt or so to keep the input fets well within their safe voltage range and to the CCS made by a 2SK170 instead of the ZTX550 (Q2 on A-J) plus the (noisy) zener, capacitor (C4) and dropping resistor (R5).
Also R7 could be replaced by a pot as in BA1.
Can we get rid of the IN- coupling cap (C1)?

 

[Zen Mod]

Hey Papa!+ (other zenlike members)
Could I use the BA1 front end as a preamp to use with my F4's?
I guess not near enough gain for full output, but what kind of output voltage are we talking about? Prob needs a regulated supply ?

D+ for pos input of balanced F4
D- for neg input of balanced F4

not full blast , but near enough

isn't easier to make XCCSwhatevercascoded BOSOZ , with altered gain ?
make it with altered positive PSU , and it will drive even bridgedbalancedparalleled F44 .......

ya Kwayzee Mod .......

 

[Zen Mod]

I post again here what I wrote few days ago on "Aleph J schematic" thread:

I think that some of the new features.....

re-read answers in AJ thread

both biasing and modulation of output mosfets ,via input LTP , is referenced to neg supply ;

you can't alter any voltage level there without too much fuss .

improving CCS for input LTP is another issue - do what you think is best

look at Babelfish J schematic ;everything is boiled water ......

http://tiny.pl/zfgp