Fine.
Generally you may use a bipolar wherever you use a polarized. The inverse, however, isn't true.
Generally you may use a bipolar wherever you use a polarized. The inverse, however, isn't true.
using a Bi-polar electrolytic where a polar electrolytic is specified (see the + on the schematic at each polar capacitor) wastes space and wastes money.
There is no advantage in changing to Bi-polar.
There is no advantage in changing to Bi-polar.
It wasn't intentional. I purchased those by mistake. And they were a whopping $1.38/ea, so no big deal. It wasn't a question of whether they are better, but of whether I can safely use them in the same locations.
I've got a BA-3 front end pushing a F5 right now...sounds great. I want a little more power and I am considering the BA complementary output stage to replace the F5. Speakers are 89 db 3-ways w/a 3.2 ohm min. The BA complementary OS should do better into a low ohm load than the f5.
Seeing as how the front end has it's own regulated 24V supply I could run the output stage at any voltage I want. I don't have to worry about the Jfets turning to toast.
So what's the best option? BA output stage w/24V rails is 25 watts into 8R. How high can I go with the rail voltage on the output stage?
Seeing as how the front end has it's own regulated 24V supply I could run the output stage at any voltage I want. I don't have to worry about the Jfets turning to toast.
So what's the best option? BA output stage w/24V rails is 25 watts into 8R. How high can I go with the rail voltage on the output stage?
Hi Hikari1,
The BA complementary output stage has no voltage gain so you are still limited by the voltage
output available from the BA3 front end. The voltage swing available from
the BA3 front end at 24 volt rails will limit you to about 25W @8ohms.
For more power, you will need higher voltage rails on both the BA3 front end
and on the follower output stage.
The BA3 front end should support 50W at 32V rails. (Please see the first graph
under "Performance" here:
http://www.diyaudio.com/forums/diyaudio-com-articles/194809-burning-amplifier-ba-3-a.html )
Cheers,
Dennis
The BA complementary output stage has no voltage gain so you are still limited by the voltage
output available from the BA3 front end. The voltage swing available from
the BA3 front end at 24 volt rails will limit you to about 25W @8ohms.
For more power, you will need higher voltage rails on both the BA3 front end
and on the follower output stage.
The BA3 front end should support 50W at 32V rails. (Please see the first graph
under "Performance" here:
http://www.diyaudio.com/forums/diyaudio-com-articles/194809-burning-amplifier-ba-3-a.html )
Cheers,
Dennis
That's the same boat I'm in, some reading I did here (I think this thread) indicated the sound not as good when fed a single ended source? Otherwise, I would like to do it, and even have the matched quads of J-fets ( from old days when plentiful) to do it with. More study needed, plus 2 more 5U cases....I will finish Aleph J and F-6 1st, done on both except 2 more 4U cases.....store is out, and play money exhausted for now.
Russellc
I had the same idea, didnt think it through that its the increased voltage on the front end that is needed to increase output power.
Which brings up another thought: I did use a 1000 VA 24+24 transformer, but left the four front end electrolytic caps at 25 volts! I did use high quality panasonic 105 degree caps, and maybe their conservative rating is saving them. I may need to ask this in separate thread, but do these caps see the full 31 volts that are on my rails? I assume they do....
Russellc
Think I will just replace transformer with 18+18 I have on hand, easier for now! I hate unsoldering stuff off of circuit boards, dont think I have any 35 or 50 volt caps, so will have to order some.
Russellc
Russellc
hi everybody..
i have plan to build the single ended output stage with 12pcs of irf240 per channel.
my newbie questions are:
1. are the voltage still around 25v for one channel?
2. what is the minimum bias for this amp to be in class A
3. how many watts exactly it will produce with 12pcs irf240 per channel?
4. if i separate the 12pcs into 6+6 to make a balanced BA, is it still produce the same watts or divided by two?
thanks.
i have plan to build the single ended output stage with 12pcs of irf240 per channel.
my newbie questions are:
1. are the voltage still around 25v for one channel?
2. what is the minimum bias for this amp to be in class A
3. how many watts exactly it will produce with 12pcs irf240 per channel?
4. if i separate the 12pcs into 6+6 to make a balanced BA, is it still produce the same watts or divided by two?
thanks.
1) Yes.
2) Bias until you have heatsinks at 55C
3) 25V rails can swing approx. 45V Pk-Pk, (45*.3535)^2 /8ohm =31W (That is; Pk-Pk Volts RMS squared, divided by speaker ohms)
4) Power is multiplied by a bit less than 4
2) Bias until you have heatsinks at 55C
3) 25V rails can swing approx. 45V Pk-Pk, (45*.3535)^2 /8ohm =31W (That is; Pk-Pk Volts RMS squared, divided by speaker ohms)
4) Power is multiplied by a bit less than 4
Yes, that's what I meant. 🙂
BUT I did just realize that you said 12 pc IRF240... and that you are building the Single-Ended output stage. I didn't see that the first time. Sorry. 🙁
Ignore what I said about balanced. That's done with the Complementary output stage.
BUT I did just realize that you said 12 pc IRF240... and that you are building the Single-Ended output stage. I didn't see that the first time. Sorry. 🙁
Ignore what I said about balanced. That's done with the Complementary output stage.
Russell: Are you running the BA output stage and the ba3 preamp together? Do you have enough gain without a preamp in front of the ba3 front end?
Iam considering swapping my f5 for a ba complementary os. I love the f5 but it might be time to switch to something with more current for low z loads.
