I have a stack of BC parts and Toshiba 2sc2240 devices. I don't know why but I've lost interest in bipolars (must be Nelson's influence). Bad Papa. Hahahaha
If I take it to 50mA is it still a waste of a good part?
2picoDumbs
Have you sorted them out for hFe? I could use a matched set of 20 and would be willing to trade, pm me.
juma
What is so terrible about the irf9610 in the Aleph-X? If you use a cap multiplier on a CLC power supply with cancelling coils, they aren't noisy, they source current like crazy and they are more durable and stable than the BC parts. Yes, their Ciss is higher but do you really need more than 80kHz bandwidth? From my understanding, more bandwidth invites more RF and line noise headaches in addition to stability issues. Please correct me if i am misguided about my notions because I am not an experienced builder.
Have you sorted them out for hFe? I could use a matched set of 20 and would be willing to trade, pm me.
juma
What is so terrible about the irf9610 in the Aleph-X? If you use a cap multiplier on a CLC power supply with cancelling coils, they aren't noisy, they source current like crazy and they are more durable and stable than the BC parts. Yes, their Ciss is higher but do you really need more than 80kHz bandwidth? From my understanding, more bandwidth invites more RF and line noise headaches in addition to stability issues. Please correct me if i am misguided about my notions because I am not an experienced builder.
Give me 2 weeks to find them. I'll have a quick look tonight, I might get lucky.
Or a hunderd, or 2sj18 at 0.5A (just take care of biasing)... Such ideas are dime a dozen...
.. All true, but it still doesn't change a fact that it sounds muddy and grainy (less so in X than in standard Aleph). Although, many are interpreting that as sweet and full of micro detail and that's OK too ...
I tend to agree with your original comment but can BC560 drive 6 pairs of IRFP240
SOME HELP NEEDED
ZEN, first of all: thanks for your attention.
I understood your point of view about my question.
I took some time studying the zen amplifier till variation 4 and the NP patent 5710522 about the active current source ( your advice! Thanks again..). I can tell that i understood then ( so i think...).
But i need some help with another question:
I need to use two switching power supply to make a +/-V. I want to better the original filtration from these PSU and i do not know how would it be the right way to do this.
I drew two options and i would like you all to help me pointing which one is the right or best way to do it.
I thank you all that should take some time in helping me.
ZEN, first of all: thanks for your attention.
I understood your point of view about my question.
I took some time studying the zen amplifier till variation 4 and the NP patent 5710522 about the active current source ( your advice! Thanks again..). I can tell that i understood then ( so i think...).
But i need some help with another question:
I need to use two switching power supply to make a +/-V. I want to better the original filtration from these PSU and i do not know how would it be the right way to do this.
I drew two options and i would like you all to help me pointing which one is the right or best way to do it.
I thank you all that should take some time in helping me.
Attachments
too bad matched 2SJ313s are not really available. kind of expensive to buy up a lot and match a few to be used. other than that I might be willing to try that change in my Aleph30.
maybe Papa could release a small batch through the store? (after all it's only fair after he stirred the pot, right?
)
maybe Papa could release a small batch through the store? (after all it's only fair after he stirred the pot, right?
)
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BD sell them for $7.65 each B+D Enterprises - Search results for: '2sj313'
But if you don't want to buy a stack of them I could send you 2 matched pairs for $30 plus shipping
But if you don't want to buy a stack of them I could send you 2 matched pairs for $30 plus shipping
Zen Mod uses this for
babefish to replace the infamous J74, see http://www.diyaudio.com/forums/pass-labs/273318-about-possible-babelfish-j-interest.html. I ask ZM whether I could use these to replace the 2J74, the answer was yes, see posts 56-59.
The Rochester Electronic price is still very affordable. I bought 100 along with some other hard to find jfet as well. I intend to modify a A30 PCB to it into an AJ with these. If it is good for ZM, it is good enough to me
babefish to replace the infamous J74, see http://www.diyaudio.com/forums/pass-labs/273318-about-possible-babelfish-j-interest.html. I ask ZM whether I could use these to replace the 2J74, the answer was yes, see posts 56-59.
The Rochester Electronic price is still very affordable. I bought 100 along with some other hard to find jfet as well. I intend to modify a A30 PCB to it into an AJ with these. If it is good for ZM, it is good enough to me
Oh, I build last days an Aleph 30 and first impression was bad….
)
On the bench I saw that the current for the three pairs was very high, 1A for one pair, 3A for one channel.
The PSU was too weak for this current and the voltage had dropped to +/-21V instead of +/-25V.
I had to bring down the resistor that regulates the bias from 47k to around 32k. In this way the current for one pair was now 0.6A and for one channel around 1.8A.
Also I had a small mismatch in the Aleph current source
I had to change the 820R to 970R to get the 50% contribution.
Now the amp sings as I am used to, hearing Nelson amps.
One more star on my Pass amps heaven!
But only with the IRF9610 in the frontend, the sound with the J313 was for my ears too thin and much less involving and less dynamic.
Possibly the I had to rearrange the Aleph CCS again or the something like this or play with the feedback, because the j313 seem to have a bit less transconductance.
But why should I do this…..,
I like the old Mosfet sound really really …….
))
)On the bench I saw that the current for the three pairs was very high, 1A for one pair, 3A for one channel.
The PSU was too weak for this current and the voltage had dropped to +/-21V instead of +/-25V.
I had to bring down the resistor that regulates the bias from 47k to around 32k. In this way the current for one pair was now 0.6A and for one channel around 1.8A.
Also I had a small mismatch in the Aleph current source
I had to change the 820R to 970R to get the 50% contribution.
Now the amp sings as I am used to, hearing Nelson amps.
One more star on my Pass amps heaven!
But only with the IRF9610 in the frontend, the sound with the J313 was for my ears too thin and much less involving and less dynamic.
Possibly the I had to rearrange the Aleph CCS again or the something like this or play with the feedback, because the j313 seem to have a bit less transconductance.
But why should I do this…..,
I like the old Mosfet sound really really …….
))
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Dear Gerd. I knew about your reputation and the effort you did and do all the time with this kind of circuits. In your experience, Could you establish a score to the list of the amps you listen?
The reloaded A30? Does is better to your hears better or not to the rest of amps? Best Regards and thanks for your comments.
The reloaded A30? Does is better to your hears better or not to the rest of amps? Best Regards and thanks for your comments.
I had my Aleph30 biased to 0.7A per fet (pair), PS rails at 25.5V and drove it of course balanced from Oppo-105. after I added AlephP as a preamp (and maybe because the Elna cap broke in at the same time), the bass showed up and it started sounding really good.
I listened to it to for about a year only on my Elsinores and then converted it to BA-3b monoblock (and made another one of those of course). those are kick *** amps so there is no going back. but I thought of "reloading" Aleph30 with matched 2SJ313s (if somebody was to sell them without sk2013s?) and to give the amp away as a gift to family.
now I am having second thoughts about the conversion after Generg's comment. maybe I should wait for another opinion? not that I am in a rush. the cards are sitting fully assembled and waiting for better days.
I listened to it to for about a year only on my Elsinores and then converted it to BA-3b monoblock (and made another one of those of course). those are kick *** amps so there is no going back. but I thought of "reloading" Aleph30 with matched 2SJ313s (if somebody was to sell them without sk2013s?) and to give the amp away as a gift to family.
now I am having second thoughts about the conversion after Generg's comment. maybe I should wait for another opinion? not that I am in a rush. the cards are sitting fully assembled and waiting for better days.