Hello everyone. I was wonder if I were to build a BA-3 preamp with 32V rails, Do I have to increase the voltage rating on the 1000uF capacitors (C1 and C2)?
I just happen to have everything I need for a 32 volt PSU right here in front of me, so it would be easy to continue with it.
I think with 32 V rails you're to the point where you need to parallel JFETs and change some other values .
Look at Post 1034 of the BA-3 as Preamp thread where Salas did a simulation of 35V rails (and 30dB gain).
Well, I was looking at the BA-3 amplifier article and Nelson runs it at 32V for his performance tests. Maybe it's OK. Hopefully some experts will chime in.
It's not going to hurt anything to run it at 32v. Yes, you should uprate and have 35v caps on the board even though they don't see the full voltage in operation, I'm not sure what happen at start-up...
That said, if you are not running a follower output stage, it's complete and utter overkill. You'll never use the voltage swing and be running your Jfets near or at the limits.
That said, if you are not running a follower output stage, it's complete and utter overkill. You'll never use the voltage swing and be running your Jfets near or at the limits.
Thank you for your replies and information. Much appreciated. I will drop the voltage down to 24V
I'm all for using the parts you have on hand - there's a small victory in every part used and not remaining in a drawer, coffee can or other more official organizational method... But in this case lower voltage is likely best.
I apologize, I meant the much smaller C3 that appears near the large C3.
Is that for a bypass cap?
It's in case you want to use an electrolytic instead. You can use either or both but make sure you have a cap on the output.
another that points
Hi
I have a buffer B1 for a monophonic f5T amp . I'm fine with the combination but I would like some gain in preamplificador, ¿ as would combine the BA-3 with F5T?
I think I'll try . I have a pair of 2sj4 8.2 idss and a pair of 2sk170 of 9.22 idss , can be worth ?.
It is very difficult to find toshiba mosfet . I think I'll try to fairchild . In mouser they sell at a good price . I wondered whether to buy a few and try to match them . Is there any guidance for measuring and match the mosfet ?.
Thank you very much!
Hi
I have a buffer B1 for a monophonic f5T amp . I'm fine with the combination but I would like some gain in preamplificador, ¿ as would combine the BA-3 with F5T?
I think I'll try . I have a pair of 2sj4 8.2 idss and a pair of 2sk170 of 9.22 idss , can be worth ?.
It is very difficult to find toshiba mosfet . I think I'll try to fairchild . In mouser they sell at a good price . I wondered whether to buy a few and try to match them . Is there any guidance for measuring and match the mosfet ?.
Thank you very much!
Hi,
Could this be a good solution to use "behind" a passive preamp?
I mean between the DCB1 and a power amp? (Ovation NX)
Looks like it would be! The combination I have lacks gain...... Also I drive two subs on the same output as the NX....
Thanks
Could this be a good solution to use "behind" a passive preamp?
I mean between the DCB1 and a power amp? (Ovation NX)
Looks like it would be! The combination I have lacks gain...... Also I drive two subs on the same output as the NX....
Thanks
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You can use those jfets if you use p3 to match the output and harmonics...you will need a scope or software to do this.
The outputs don't need to be matched, but if you want to match them there is a good article on mosfet matching on the pass diy site.
You won't need the b1 in front of the ba3. The ba3 will buffer the signal and supply a low output impedence. Just a volume pot in front of the ba3 is all you need.
I am using a BA3FE to power a crippled F4 running at +-32V rails.
Do I need to run the BA3F3 also at +-32V to be able to drive the F4 to clipping (not that I will ever listen that loud)?
Or can I run it at a lower voltage?
Do I need to run the BA3F3 also at +-32V to be able to drive the F4 to clipping (not that I will ever listen that loud)?
Or can I run it at a lower voltage?
same or even better - higher voltage , to have full tilt needed for OS
JFets are hopefully cascoded
JFets are hopefully cascoded