Someone asked me for 2Sk3497 matched pairs.
We have a few hundreds left, but we'll only offer them as matched quads together with 2SJ618, which we have in equal numbers.
So for this build, you'll have to use IRFPs I am afraid :
FirstWatt J2
Patrick
We have a few hundreds left, but we'll only offer them as matched quads together with 2SJ618, which we have in equal numbers.
So for this build, you'll have to use IRFPs I am afraid :
FirstWatt J2
Patrick
could the IRFP054 or the FQA32N20C replace the 2SK3497 with similar performance?
High Yfs and Cin maybe not as linear as 2SK3497
High Yfs and Cin maybe not as linear as 2SK3497
The answer you can find out for yourself by either simulation or proto build, or both.
I have only built with 2SK3497. So that is what I have to share.
Cheers,
Patrick
I have only built with 2SK3497. So that is what I have to share.
Cheers,
Patrick
I would like to speak for myself and all others who were fortunate to have acquired a pair of gift Semisouth jfets but are still new to all of this.
I feel there is a disconnect here from what the expectations are in this thread and from EUVL. While I appreciate the time and effort made to make what is no doubt a great circuit my skills are lacking to take it the rest of the way.
I personally have built 4 Pass DIY amps and am confident in my assembly and setup skills. I can recognize different blocks of the circuit. I understand what it means to adjust bias, offset etc.
Where my skills are lacking is in the understanding of how certain changes in values affect the choice of parts, namely this upper FET which is just as or more unobtainable that the Semisouth.
I don't think I'm alone in the desire for certain values on this circuit and PCB which will allow the construction of a working facsimile to what was originally presented in 2019.
Patrick, it seems your suggestions are just build. I will have to take your tough love, burn things up and learn the hard way. Maybe that will prepare me to take on one of your X builds in a few years time. Otherwise I and many others are eager to build and have the basic skills, we just require a little more of a helping hand to see this through.
I thank the generous person who offers up the insight I know I and lots of others are looking for with respect to bringing this amp to life with our new precious silicon that we are very concerned about using properly and avoiding any catastrophe.
I feel there is a disconnect here from what the expectations are in this thread and from EUVL. While I appreciate the time and effort made to make what is no doubt a great circuit my skills are lacking to take it the rest of the way.
I personally have built 4 Pass DIY amps and am confident in my assembly and setup skills. I can recognize different blocks of the circuit. I understand what it means to adjust bias, offset etc.
Where my skills are lacking is in the understanding of how certain changes in values affect the choice of parts, namely this upper FET which is just as or more unobtainable that the Semisouth.
I don't think I'm alone in the desire for certain values on this circuit and PCB which will allow the construction of a working facsimile to what was originally presented in 2019.
Patrick, it seems your suggestions are just build. I will have to take your tough love, burn things up and learn the hard way. Maybe that will prepare me to take on one of your X builds in a few years time. Otherwise I and many others are eager to build and have the basic skills, we just require a little more of a helping hand to see this through.
I thank the generous person who offers up the insight I know I and lots of others are looking for with respect to bringing this amp to life with our new precious silicon that we are very concerned about using properly and avoiding any catastrophe.
exactly my intent too, get the best possible amp with a pair of Semisouth that Papa offered us graciously.
That is why I ask so many questions before building
what is a current production mosfet that can perform near as the unobtainium 2SK3497?
Is the J2 mu follower better than the modulated CCS of aleph J ?
maybe try the DC coupled F8 topology instead of J2 ?
That is why I ask so many questions before building
what is a current production mosfet that can perform near as the unobtainium 2SK3497?
Is the J2 mu follower better than the modulated CCS of aleph J ?
maybe try the DC coupled F8 topology instead of J2 ?
I just imported four 2SK3497 from
株式会社若松通商 / 2SK3497
You will need to use a Japan shopping/shipping service, I used fromjapan.co.jp and that went smoothly.
The devices are unmatched. On that note, can anyone tell me at what operating point should I measure them?
株式会社若松通商 / 2SK3497
You will need to use a Japan shopping/shipping service, I used fromjapan.co.jp and that went smoothly.
The devices are unmatched. On that note, can anyone tell me at what operating point should I measure them?
Let me repeat one last time.
I have only built with 2SK3497.
So I can only tell you from that experience that they work without problems.
I have not built with any other MOSFETs.
So I cannot give you an answer what will work or what not.
There are other people around who have built the same with IRF FETs.
So maybe they can share their experience.
And of course I am sure Nelson has tried many combinations.
He is the only one who could give you authoritive answers.
Cheers,
Patrick
I have only built with 2SK3497.
So I can only tell you from that experience that they work without problems.
I have not built with any other MOSFETs.
So I cannot give you an answer what will work or what not.
There are other people around who have built the same with IRF FETs.
So maybe they can share their experience.
And of course I am sure Nelson has tried many combinations.
He is the only one who could give you authoritive answers.
Cheers,
Patrick
Its also worth looking at ZM's babelfish J2, where he used the IRF150 in the current source position. I've built that circuit with SJEP on bottom, and its fantastic.
Thanks a lot for all these informations and patience,
one last question, in the J2 bias is done with an optocoupler, in Aleph J with a BJT.
since no galvanic isolation is needed (emitter of transitor and cathode of led are connected together)
could a BJT be used in the J2 to replace the optocoupler?
one last question, in the J2 bias is done with an optocoupler, in Aleph J with a BJT.
since no galvanic isolation is needed (emitter of transitor and cathode of led are connected together)
could a BJT be used in the J2 to replace the optocoupler?
Now this is a beautyfull chassis. I like the construction. Selfmade? Where can i order this?
Seems this is a moving target - new link now.
But look, 340 mm wide. The original black ML-2 chassis is 19" wide. So engraved or no, it is not an exact copy of the original. But still fully usable as a chassis for some amp of course. If so, I would have purchased a l"no logo" version.
/RK
The original ML2 looks like this (attached on the left).
I don't think you can call the one I bought a carbon copy, despite whatever has been engraved on the front plate or not.
It is a pity that they have still left the engraving on at ebay offers (under the same description but different addresses).
But you can find a lot of nice chassis on offer from WeiLiang :
Power amplifier case - Shop Cheap Power amplifier case from China Power amplifier case Suppliers at weiliang audio Official Store on Aliexpress.com - amplifier case,aluminum amplifier case,breeze audio aluminum,amplifier chassis,breeze audio,aluminium chassis
including 480x500x215mm ones :
Brise audio 50W ClassA verstarker aluminium chassis/fall BZ4822A|aluminium chassis|breeze audioaluminum chassis case - AliExpress
Postage is unfortunately a big chunk of the total price.
Patrick
.
I don't think you can call the one I bought a carbon copy, despite whatever has been engraved on the front plate or not.
It is a pity that they have still left the engraving on at ebay offers (under the same description but different addresses).
But you can find a lot of nice chassis on offer from WeiLiang :
Power amplifier case - Shop Cheap Power amplifier case from China Power amplifier case Suppliers at weiliang audio Official Store on Aliexpress.com - amplifier case,aluminum amplifier case,breeze audio aluminum,amplifier chassis,breeze audio,aluminium chassis
including 480x500x215mm ones :
Brise audio 50W ClassA verstarker aluminium chassis/fall BZ4822A|aluminium chassis|breeze audioaluminum chassis case - AliExpress
Postage is unfortunately a big chunk of the total price.
Patrick
.
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