Hello everyone,
And a happy new year to all of you!
I've been reading my eyes out, trying to aviod bothering fed up DIY-experts with asking silly questions. It seems though, I'm going to have to do it anyway.
My starting point being that I'm in possesion of two large toroids, each giving out 650 VA and +/- 34 V to the rails, I found that the Aleph 60 would suit both the specs of those and my need of amplification - but I would like to have a Jfet input. Has anybody successfully built that or cold somebody tell or show how it could be done?
I would be very, very plaesed to hear about it!
And a happy new year to all of you!
I've been reading my eyes out, trying to aviod bothering fed up DIY-experts with asking silly questions. It seems though, I'm going to have to do it anyway.
My starting point being that I'm in possesion of two large toroids, each giving out 650 VA and +/- 34 V to the rails, I found that the Aleph 60 would suit both the specs of those and my need of amplification - but I would like to have a Jfet input. Has anybody successfully built that or cold somebody tell or show how it could be done?
I would be very, very plaesed to hear about it!
JFET A60
Hej Hr. Dansk!
There has also been pretty detailed and well documented explorations on adding a Jfet inputstage to the A30 - which has an inputstage which is identical to the A60 if my memory serves me well. This could give you all you need - layed out and everything
However, as I also recall, the tricky thing about the Jfet A30 was that the supply voltage was very near to the max of what the small Jfets could handle - so building a A60 with a Jfet input stage might require a second, lover voltage supply for the front end - and if this is able to sving the output stage to full - that is up to the more qualified personel on this forum to comment.....
My advice - if you want Aleph J performance - build an Aleph J - transformators are not that expensive! (solely based on my own tiresome and expensive experience)
Kind regards & happyt new year!
Hans
Hej Hr. Dansk!
There has also been pretty detailed and well documented explorations on adding a Jfet inputstage to the A30 - which has an inputstage which is identical to the A60 if my memory serves me well. This could give you all you need - layed out and everything
However, as I also recall, the tricky thing about the Jfet A30 was that the supply voltage was very near to the max of what the small Jfets could handle - so building a A60 with a Jfet input stage might require a second, lover voltage supply for the front end - and if this is able to sving the output stage to full - that is up to the more qualified personel on this forum to comment.....
My advice - if you want Aleph J performance - build an Aleph J - transformators are not that expensive! (solely based on my own tiresome and expensive experience)
Kind regards & happyt new year!
Hans
I believe it could, but it seems throughout my reading that people have considered it problematic raising the rail voltage to +/- 34 V combined with the Jfets - and I must admit that I haven't got the experience and skills to be able to figure out the consequences by myself.
So I was hoping for a little advise... Please...
So I was hoping for a little advise... Please...
- but the 2sj74's should be on their way already!
Sound of different IRFP's?
Hi everybody,
I'm still working on my J-fet Aleph 60 - gathering the right parts.
- Well, I guess we cannot all be as fast building as "Lucky" Steenoe.
I'm writing again because I have the ability of buying some very cheap IRFP140N's to replace the usual 240's. But what about the sound quality? Off course it's nice to save money, only if it still gives a soundwise comparable result.
Hi everybody,
I'm still working on my J-fet Aleph 60 - gathering the right parts.
- Well, I guess we cannot all be as fast building as "Lucky" Steenoe.
I'm writing again because I have the ability of buying some very cheap IRFP140N's to replace the usual 240's. But what about the sound quality? Off course it's nice to save money, only if it still gives a soundwise comparable result.
Happy new year!!!
As it can be seen from the dates of the postings in this little thread, it has been quite a struggle, but now it's working and the sound is amazing!
Maybe I'll write a little more about the amp and its sound in a later post, but for now I'll only wish everybody a happy new year and thank Papa Pass for giving people like me the possibility of owning a luxury version of the Volksamp 60 (I've named it The Volksamp PassAT). I would also like to thank Magura, Stenoe, and last, but absolutely not the least, Zen Mod for great patience and lots of help.
Enjoy tomorrow and remember to be careful about your ears, eyes and fingers...
As it can be seen from the dates of the postings in this little thread, it has been quite a struggle, but now it's working and the sound is amazing!
Maybe I'll write a little more about the amp and its sound in a later post, but for now I'll only wish everybody a happy new year and thank Papa Pass for giving people like me the possibility of owning a luxury version of the Volksamp 60 (I've named it The Volksamp PassAT). I would also like to thank Magura, Stenoe, and last, but absolutely not the least, Zen Mod for great patience and lots of help.
Enjoy tomorrow and remember to be careful about your ears, eyes and fingers...
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