Man, you guys dont waste any time
Power buffer
Am I right that only the single ended BA-1 can be biased without the frontend, or....?
But wasnt it in the BA-2 manual mentioned that bias curcuit had been moved to output board to ... ?
Im really confused now
And your output boards are 3pair output ?
Which means one heatsink pr channel ?
Power buffer
Am I right that only the single ended BA-1 can be biased without the frontend, or....?
But wasnt it in the BA-2 manual mentioned that bias curcuit had been moved to output board to ... ?
Im really confused now
And your output boards are 3pair output ?
Which means one heatsink pr channel ?
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Seems I have been focused on F5 and ignored BA amps that I forgot how long it has been going on
I have scimmed through both BA-1 and BA-2 and havent found any answers to my question
BA-2 tho seems to have got all the interest by now
Well, it does seem to make sense to use fewer outputs with more bias, to keep the classA output into lower impedance
So, I have the same question, will BA-2 work ok with just the bias board, as a power buffer, or will I need the input voltage gain board as well ?
And are the output boards complete mono boards, 3pair mono ?
I have scimmed through both BA-1 and BA-2 and havent found any answers to my question
BA-2 tho seems to have got all the interest by now
Well, it does seem to make sense to use fewer outputs with more bias, to keep the classA output into lower impedance
So, I have the same question, will BA-2 work ok with just the bias board, as a power buffer, or will I need the input voltage gain board as well ?
And are the output boards complete mono boards, 3pair mono ?
Hi tinitus, the final boards are very similar to those posted here: (post 108 and 110)
http://www.diyaudio.com/forums/pass-labs/150653-burning-amplifier-ba-2-a-11.html#post1989526
http://www.diyaudio.com/forums/pass-labs/150653-burning-amplifier-ba-2-a-11.html#post1989611
Each output board has 3 pairs as Nelson Pass writes in his article that most people would probably prefer to have 2 or 3 pairs.
There are 3 boards in one BA-2:
Gain Stage - input board/frontend
Bias board - This is just needed for the output
Output board - 3 complementary pairs
You can use the gain stage as a preamp if you like.
The output boards (including bias) can also be used with other gain stages.
http://www.diyaudio.com/forums/pass-labs/150653-burning-amplifier-ba-2-a-11.html#post1989526
http://www.diyaudio.com/forums/pass-labs/150653-burning-amplifier-ba-2-a-11.html#post1989611
Each output board has 3 pairs as Nelson Pass writes in his article that most people would probably prefer to have 2 or 3 pairs.
There are 3 boards in one BA-2:
Gain Stage - input board/frontend
Bias board - This is just needed for the output
Output board - 3 complementary pairs
You can use the gain stage as a preamp if you like.
The output boards (including bias) can also be used with other gain stages.
Ok
Ahh, ok, gain stage board is stereo, fore a stereo amp
Used "outboard" fore mono amps
Easy to try either this gainstage, or another, maybe even a tubepre
That sounds like fun 🙂
Hmm, and bias module will take 30Vdc rails(22volt trafo) ?
I remember 30V being mentioned as possible, but thought it was related to the Jfet input
Ahh, ok, gain stage board is stereo, fore a stereo amp
Used "outboard" fore mono amps
Easy to try either this gainstage, or another, maybe even a tubepre
That sounds like fun 🙂
Hmm, and bias module will take 30Vdc rails(22volt trafo) ?
I remember 30V being mentioned as possible, but thought it was related to the Jfet input
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Yeah, the gain stage is stereo, but you can cut it if you want to make mono blocks. The jfet on the gain stage is really what puts a limit on the supply voltage.
Nice, now I think I know what to do
But first things first, my F5, which hopefully doesnt turn into a "burning amp"
But sure is nice to have a plan 🙂
But first things first, my F5, which hopefully doesnt turn into a "burning amp"
But sure is nice to have a plan 🙂
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So to confuse things more possibly, For a stereo amp
you would need 5 boards in total:
(1) Gain Stage Board
(2) Bias Boards
(2) Output Boards
The BA-1 and BA-2 use the same Gain Stage board,
but have different Bias Boards and Output Boards
My understanding is that the most likely piece to change in future models is the Gain Stage, so once you have built up a Complementary Chassis (BA-2) or a Single Ended Chassis (BA-1), You can modify them to some future models by merely changing the Gain Board. (OR adding a second one with switching for comparison? ) This may be even easier if the Gain Board is in a separate box- especially for those few with the actual "Burning Amp" short chassis from Nelson which has little internal room.
Mark
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Correct me if I'm wrong, but doesn't BA-2 have 6 complementary pairs of output MOSFETs ( 2 output PCBs per channel) ?
If you are talking about the original chassis, given out at The Festival, some had 6 pairs per channel and others had 4 pairs. In the BA-2 article I believe Nelson says that 2-3 pairs would work well for most people, though the schematic shows the 6 pairs.
So after way too much discussion, 😉 we decided on each output board being 3 pairs in one row, and as you mention, if you want more, use 2 Output Boards per channel.
The Output boards are long and thin, so can be stacked one above the other on most heatsinks. The devices are stacked on the original chassis in two rows.
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Group Buy
Hi cviller,
It’s cold here in Minnesota; I need a larger amp to warm my room. When are you going to setup the group buy for the boards?
Thanks,
🙂
Hi cviller,
It’s cold here in Minnesota; I need a larger amp to warm my room. When are you going to setup the group buy for the boards?
Thanks,
🙂
I have ordered the boards, and they should be here by the end of january (at the latest). But for you to be able to order, we need to decide how to set up the order system and all that - it is going to be somehow through diyaudio, so this is very much up to Variac to decide how the coolest way to proceed is. 😉
Hi Mark,
when I take the bias and output boards of BA-1 or BA-2 directly without gain stage is the input balanced possible for instance for use with the balanced output of pumpkin?
Thanks for your work!
when I take the bias and output boards of BA-1 or BA-2 directly without gain stage is the input balanced possible for instance for use with the balanced output of pumpkin?
Thanks for your work!
nope ..... and yes
you still need two outputs for balanced -same as we spoke about F4 ;
in fact - if you look at first page of (this) thread , you'll see that there is no big diff to F4
Very polite Zen Mod! Du bist ein Schatz!
....the BA-2 has a push-pull design like F5, why is it so difficult😱 to get a balanced input for F5 without doubling all components?
I sent you a PM for LS.....
....the BA-2 has a push-pull design like F5, why is it so difficult😱 to get a balanced input for F5 without doubling all components?
I sent you a PM for LS.....
Very polite Zen Mod! Du bist ein Schatz!
....the BA-2 has a push-pull design like F5, why is it so difficult😱 to get a balanced input for F5 without doubling all components?
.
please - my brain is in sort of red (not Vino) now ..... can you give me a link for B2 schm
I had little mishap with my full PM inbox 🙄
feel free to use >sasica5@gmail.com<