Yeah, they are large enough - those mentioned by papa is actually normal radial electrolytics. I'll add a special footprint for those before fabrication.
BA-2 versus Aleph series
Dear Mr.Pass,
Can you tell us something about the BA-2 sound compared with an Aleph (5) series poweramp?
What are the procs and cons?
😕
Thx in advance,
Johan.
Dear Mr.Pass,
Can you tell us something about the BA-2 sound compared with an Aleph (5) series poweramp?
What are the procs and cons?
😕
Thx in advance,
Johan.
Well I'm not pass and I haven't heard the beast yet, but from the schematics I would think that it is safe to say that it sounds more like a pushpull amp. 😉
You will have less 2nd harmonic distortion and more 3rd. So it will probably sound more analytic and have a better control over the bass.
You will have less 2nd harmonic distortion and more 3rd. So it will probably sound more analytic and have a better control over the bass.
Here is what I'm using on your power supply boards. They get a little bit tight as you can see...
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I think it might be possible to just add some more holes, so you can connect like you are proposing.
I have added some extra holes for the two 2sj74 option instead of the illusive 2sj109...
Another two things thing that need to be sorted out are 1) the trimpots - they should be accessible when vertically mounted (they kinda already are since they are so close to the edge) and 2) Q203 needs a little heatsinking, which there must be room for.
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In the darker corners of this forum, there is a strong passion for being able to mount the flat parts of to-92 casings together... 😱
It should give slightly better heat transfer between the dies - I would guess the timeconstant to be fairly large though. 😉
You can also use the sweet little dual inline to-92 heatsinks from the group buy but you need to lay them end to end. That way either single j109 or j74 pair fits nicely. Peter did this on the Aleph J boards.
Those heat-sinks are custom made by EUVL:
http://www.diyaudio.com/forums/showthread.php?postid=1690438#post1690438
I don't know if he has setup a shop where you can buy them, but mounting the jfet flat to flat with thermal grease and plastic strips around is a perfectly reasonable alternative solution IMHO.
....
but - if you look at Papa's UGS pics ....... jfets are all around ......
Yeah that is true, but I would bet papas soldering skills are above average here on this forum.
But if people prefer not to have the shortcut on the boards - I can remove it.
Yes, that is how I was doing it so far, but my impression was that Euvil's solution provides some heat sinking. If that is not needed than having them flat to each other is of course quite fine.
AR2,
This is a diy forum. Get some thin copper and cutout a suitable shaped heatsink and sandwich it between the two jfets on the flat side. You will have close tracking and cooling at the same time. If you come up with something you are proud of let us see it. There are no constraints placed on diy.
Tad
This is a diy forum. Get some thin copper and cutout a suitable shaped heatsink and sandwich it between the two jfets on the flat side. You will have close tracking and cooling at the same time. If you come up with something you are proud of let us see it. There are no constraints placed on diy.
Tad
I think you guys are missing my point.
If we decide to design the circuit and jFet position to the Euvil's heatsink, which has two jFets distributed in line than it is hard to do what is normally done in situations like this - attach jFets flat face to face. I would be my preference to have them face to face. I love what Euvil did with his heat sink, but if the sinking is not required, than it would not make any sense to design board right now based on it, because it is not possible for anyone just to go and buy those heatsinks. If we decide to to Euvil's rout, than my question was how or where to get those, since that is one very elegant solution. I hope this makes it clear for you.
Euvls' heatsink solution was to allow thermal matching to fit the standard 7pin 389/109 pin layout.
These are obsolete devices and there is no point in designing for an obsolete pin configuration.
These are obsolete devices and there is no point in designing for an obsolete pin configuration.
