I recently changed speakers to a 2.5 way, where 3 Accutons C173 drivers run in parallel in lower bass area. Impedance minimum slightly lower than 4 ohm, efficiency 89dB. Not being my main topic, the speakers are great.
J2 (diy attempt) is even more great, but can not deliver the volts/amperes in the bass section for my speakers.
I have the idea to build a Turbo-J2 - if that makes sense at all - but I am not an amp-circuit designer expert.
Thinking about parallel Semisouth in output.
Any idea's / suggestions on a J2-like 'simplified' schematic with parallel Semithsouth in output ?
No, I wouldn't say that. It is more like an F2 with a mu follower instead of the
CCS and a Fet buffering the input of the Mosfet and some negative feedback.
As such it has its own unique characteristic.
😎
CCS and a Fet buffering the input of the Mosfet and some negative feedback.
As such it has its own unique characteristic.
😎
I recommended ACA because after building F6, the ACA looks interesting with SS fets because it has no degeneration on the lower fet. So if you haveheard the ACA and like the sound with IRF's, the SS in lower position becomes even more interesting.
Nelson,
Is the feedback in the ACA acting as a two stage schade circuit?
Nelson,
Is the feedback in the ACA acting as a two stage schade circuit?
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After asking the same question about most of the 25W First Watt project builds, I do get the general impression that the Aleph 4 was the best choice for my less than sensitive B&W's.
All my friends preferred F5Tv2 to Aleph 60 in blind test. Just saying 🙂 I was not among them, btw.
Will J2 boards ever become available...? I purchased a whole bunch of SemiSouth devices in the hopes that they would one day.
Maybe I should just trade them with Nelson for a completed original amp and call it a day😉
Maybe I should just trade them with Nelson for a completed original amp and call it a day😉
Perhaps. The biggest issue is deciding on what will be the specified input transformer(s). (As specifying one may be inconvenient for some)I would also like to take a peek at the production version's schematic to see what everything evolved into...
That said, the Tea-Bag PCB kinda sorta fit on the UMS.
That said, the Tea-Bag PCB kinda sorta fit on the UMS.
I'd like something with more space between the outputs. The Jensen transformers in the original design would be fine.
The single biggest issue is magnetic induction - those tiny little transformers are in the same metal case as a big-honkin' toroid, which even if shielded, has magnetic flux all around. So in a perfect world, the input transformers are both on the same side of the case, and as far from the power transformer as possible - this means, most likely, a mirror set of PCB.
Now you could of course mount one 'upside down' in regards to the other, but then the output devices will be mounted low on one channel's heatsink, and high on the other. This will have effectively no difference on the heat transfer and efficiency of the heatsink, but trust me, the natives will become very restless and much gnashing of teeth will occur. They hate things that are unsymmetrical...
Anyway, more space between 2 mosfets isn't the issue for this amp, transformer mounting position is everything.
Now you could of course mount one 'upside down' in regards to the other, but then the output devices will be mounted low on one channel's heatsink, and high on the other. This will have effectively no difference on the heat transfer and efficiency of the heatsink, but trust me, the natives will become very restless and much gnashing of teeth will occur. They hate things that are unsymmetrical...
Anyway, more space between 2 mosfets isn't the issue for this amp, transformer mounting position is everything.
I don't see a problem with making boards similar to Nelson's original. I don't want daughter boards etc.
I completely agree.
I also understand why the Tea Bag boards were made that way, and think it was a great decision for his customers. A Store board needs to be accountable to the UMS and something similar to the original NP boards would be ideal.
I also understand why the Tea Bag boards were made that way, and think it was a great decision for his customers. A Store board needs to be accountable to the UMS and something similar to the original NP boards would be ideal.