300mA CCS able depletion mode device will do. It will be a slower type though (more capacitive)
Always allow at least extra 5V across when there is a MOSFET CCS in the way. Thus you should not use more than +/- 20V for the BA-3FE with +/- 25V raw DC available and that reg. Lower rails just means lower input signal ceiling before clip when gain is the same. About 20% less swing allowance in this 20V instead of 24V rails case.
I didn't, but I do now. I bought an old (I mean really old) HP331a distortion analyzer cheap on eBay. But once again I don't know how to work my test equipment LOL. I can null out the fundamental frequency, and get a THD measurement, but my output on the scope sure doesn't look like 6L6's. it doesn't change with P3 adjustment either. Been reading the manual and watching an excellent video on how to use the analyzer, but haven't figured out what i'm doing wrong yet.
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BA3FE preamp use to drive F4
Hallo Friends.
I have registered there are 3 threads around use BA3FE as preamp.
Thats a FE like F5 and has enough/to much? gain to drive the F4- any guys
have done it, i have read.
But i have not registered for me- have i to change any part in value?
6L6- Jim gives advise to higher the pots to 1k by using FQP3 Fet, its clear.
It would be very nice and helpful, if someone can give a little support to me, so that i not have to search along 3 threats to find details.
You can also PM to me directly.
Great Ideas here, fun to read.
Thank you my Aleph J is in progress to finish.
Regards Bangla H 50+
Hallo Friends.
I have registered there are 3 threads around use BA3FE as preamp.
Thats a FE like F5 and has enough/to much? gain to drive the F4- any guys
have done it, i have read.
But i have not registered for me- have i to change any part in value?
6L6- Jim gives advise to higher the pots to 1k by using FQP3 Fet, its clear.
It would be very nice and helpful, if someone can give a little support to me, so that i not have to search along 3 threats to find details.
You can also PM to me directly.
Great Ideas here, fun to read.
Thank you my Aleph J is in progress to finish.
Regards Bangla H 50+
No parts change necessary to drive f4. 1k pots are if you choose to use Fairchild mosfets instead of toshiba. 1k pots will work with the toshiba mosfets as well but will have less adjustment range. It does not effect gain...
Ba3 has about 20db of gain, I use it to drive an f5 which has 15 db of gain. Is it enough for an f4? That depends on your speakers.
Ba3 has about 20db of gain, I use it to drive an f5 which has 15 db of gain. Is it enough for an f4? That depends on your speakers.
BA3FE driv F4
Hallo Hikari1.
Thank you for quick and short feedback.
It is very nice to read only pot to 1k change.
I have followed last 20 sites and more your discussion about the given output
gain from BA3 to overshoot/Clip the F5.
Yes, my experience, without any measuring equipment, in home listening is
that you have to give more volume on pot evens out gain differences.
The modern Flat TV are big s.....t, because mostly you only could use headphone for signal out to couple your diy stuff.
Yesterday i have ordered two BA3FE boards in diy Audiostore.
Now i have to pick parts- FQP Driver.
A bit more reading here and if i be successful give reply.
Regards Bangla.
Hallo Hikari1.
Thank you for quick and short feedback.
It is very nice to read only pot to 1k change.
I have followed last 20 sites and more your discussion about the given output
gain from BA3 to overshoot/Clip the F5.
Yes, my experience, without any measuring equipment, in home listening is
that you have to give more volume on pot evens out gain differences.
The modern Flat TV are big s.....t, because mostly you only could use headphone for signal out to couple your diy stuff.
Yesterday i have ordered two BA3FE boards in diy Audiostore.
Now i have to pick parts- FQP Driver.
A bit more reading here and if i be successful give reply.
Regards Bangla.
reread up from page 40
Hallo Friends.
I have taken some hours to read along up to page 40 here and can now answer
my question by me self.
Hikari, Marra, schoom- very extraordinary build with extra ripple eater!- called
shaun by marra
Yes, thanks 6L6 and ZM not to forget AndrewT you can find all you need here.
My store boards are received yesterday now picking Parts.
Thanks to all given/sharing experiences.
Regards Bangla.
Hallo Friends.
I have taken some hours to read along up to page 40 here and can now answer
my question by me self.
Hikari, Marra, schoom- very extraordinary build with extra ripple eater!- called
shaun by marra
Yes, thanks 6L6 and ZM not to forget AndrewT you can find all you need here.
My store boards are received yesterday now picking Parts.
Thanks to all given/sharing experiences.
Regards Bangla.
BA3 FE ,set to 6- 9db of gain will suffice
-say that you don't go bellow 24Vdc rails (so , after the reg)
-I'm not familiar with Store reg , but I believe that I noted it is of series type ; whatever , it needs at least 6V of headroom ( input/output difference) , considering possible 10% sag of mains voltage ....... which means 30Vdc
you'll get that , somewhat depending of xformer size ( power capability , which measn regulation factor ) with proper xformer with dual 24Vac secondaries ( or 48Vac center tapped)
if you end up with less than 30Vdc at reg inputs , just set output to little lesser than 24V ........ say 23 or 22V5
-say that you don't go bellow 24Vdc rails (so , after the reg)
-I'm not familiar with Store reg , but I believe that I noted it is of series type ; whatever , it needs at least 6V of headroom ( input/output difference) , considering possible 10% sag of mains voltage ....... which means 30Vdc
you'll get that , somewhat depending of xformer size ( power capability , which measn regulation factor ) with proper xformer with dual 24Vac secondaries ( or 48Vac center tapped)
if you end up with less than 30Vdc at reg inputs , just set output to little lesser than 24V ........ say 23 or 22V5
It depends on your needs and power supply choice. The circuit can accept up to 32V safely according to Nelson,If you have a "regular" power amp with some voltage gain then 24VDC is enough and will keep everything cooler. IF you have a BA3/F4 sort of power amp with higher psu rails then you might need the extra voltage in your preamp as well.
Regarding VA, the circuit draws about 50mA per channel so 100mA total at the recommended bias currents.
If you build a shunt psu like some shown around here then you'll need a bigger transformer, but for a "regular" IC based linear PSU then 15-20 VA is more than enough.
For example I am building my BA3 pre with the salas SSLV shunt PSU which will draw almost 0.7 AMP at 32VDC so that's 22.4VA. I am using an 100VA as it wasn't much more expensive than a smaller 60VA one and I might use the spare current capability in the future.
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OK , I'm always for overkill , but 0A7 for programmed current for shunt per rail is ridiculous , with BA3 FE as load
as for shunt programmed current , there is simply no need for more than twice or trice of load current
remember , benefits of shunt reg aren't in wasting heat and power , but in dynamic nature of it
as for shunt programmed current , there is simply no need for more than twice or trice of load current
remember , benefits of shunt reg aren't in wasting heat and power , but in dynamic nature of it
