I just read over this (while I was reading whatever somethings 🙂 )
Why would one want to cripple an F4?
Why would one want to cripple an F4?
uhm...
F4 without the input buffer?
...
huh?
F4 without the input buffer?
you'll find somewhere info from Man with Silver Beard himself , about crippled input impedance ;
[…]
I hope I'm clear enough now , so don't huh! , please
...
huh?
And the BA3 OS and F4 are essentially same circuit - the former with no input buffer (when looking only at the OS)
I didn't mean to mock anyone, sorry if it got through otherly ...
if buffers aren't needed, does it improve anything to omit them or is it just pure joy?
if buffers aren't needed, does it improve anything to omit them or is it just pure joy?
what I meant - I was joking when I titled it "Crippled" , not you mocking ..... 🙂
in cases when preceding stage is having enough Cojones (low Rout), some people find that saving two pairs of JFets for something else is welcome
and - sometimes superfluous stage is really superfluous ...... even if you can't hear it's really better without unnecessary buffer stage, it's good enough if you're sure that it isn't worse
in cases when preceding stage is having enough Cojones (low Rout), some people find that saving two pairs of JFets for something else is welcome
and - sometimes superfluous stage is really superfluous ...... even if you can't hear it's really better without unnecessary buffer stage, it's good enough if you're sure that it isn't worse
I had 4 power follower amplifiers. The F4 the only one with a buffer on input.
It edges out all other three without input buffers. Does it sound better because it has a buffered input? Maybe, maybe not. It does stage match better, so it might interface better with the preamp stage. That's the way I see it, but someone will certainly disagree.
Mostly depends on what you have to drive the output stage.
If it's plenty beefy then it might actually sound better without jfet buffers.
Designing it the way Papa did gives a guaranteed good result. Doing it the other way could be better or worse depending on the equipment driving it, which is not an ideal situation for a commercial product.
DIY is a totally different ball game.
If it's plenty beefy then it might actually sound better without jfet buffers.
Designing it the way Papa did gives a guaranteed good result. Doing it the other way could be better or worse depending on the equipment driving it, which is not an ideal situation for a commercial product.
DIY is a totally different ball game.
I would like to use my BA-3 output stage as a current buffer for some smaller amps (300B tube amp and F3 Clone). I am thinking these amps would be "plenty beefy" to run without an input buffer on the BA-3 output stage, looking for correction/confirmation. Connections would be as shown in image below. Thanks!
Attachments
The need for buffer is more along the lines of being able to drive the capacitance
of the power fets. For woofer this is not much of an issue....
of the power fets. For woofer this is not much of an issue....
Thanks for the responses, the 300B amp directly feeding the BA-3 output stage worked very well. I will try the F3 coming up, but I think I will need a preamp with gain to make that work well.
what dummy load at 300B output you did use?
I mean, it is necessary
though, think about 16 or 32R as load, connected at 8R tap
I mean, it is necessary
though, think about 16 or 32R as load, connected at 8R tap
I connected the tube amp to the mids and tweeters of my 3 way speaker and to the BA-3 output stage as shown for the right channel in the image in post 13. The mid, tweeter and passive crossover load the tube amp, but for the bass frequencies, the impedance of the high pass filter for the mid is probably quite a bit higher than optimum for my output transformer. I was thinking this was ok, but I am always happy to be educated. It sounds good, any other problem to be looking for?
put 32R as load directly at amp terminals
if you get too much bass, decrease load Ohms to 16 or 8R
if you get too much bass, decrease load Ohms to 16 or 8R