I know I just posted here not to long ago, but I have a few more really quick questions. I am building lots at the moment, and have big plans for a future theater build (really really big plans).
This will be for movie watching, some music listening, and gaming. The "listening system will be in a separate room/different setup. What I am wondering is whether the Pass amps I am considering are good for this style setup, or if I should look elsewhere. Here are my consideration for amps.
Mains: Aleph-X, I was thinking somewhere between 150-250watts. I know it is a lot!!! I also know that it will be expensive!!!
Center: Aleph-X (undetermined wattage) or Aleph 5
Surrounds: Aleph 5
Sub: unknown, but leaning towards the X350 or something like it.
This is a very future and very slow going project, so expect anything soon. I have other projects right now...Aleph Mini and Aleph-X Mini currently to get my feet wet. Then some Aleph-3's for my room, along with JLH tweaks, addicted to this amp for some reason (sorry Mr. Pass...well I guess variety is the spice of life).
Comments, suggestions, it's all very welcome. Yes like I mentioned I know it is very big undertaking. Keep in mind I am new to audio and audio circuits, but am learning quickly. However I am very experienced with building electronics for/with my dad for his business, designing is not my strong suit, but I can build all day.
Another question though. I have looked a little at the JFET Aleph's, and I am curious, are the sonics better than the traditional IRF9610 input? Would the sonics benefit from a UGS style input, or has anyone tried this?
One more, I have been reading a lot recently about the SuSy setup, documents, studying circuits, reading patent info, what not. I have also been reading a lot about the XA's, but little about the straight X's. I know the Xxxx.5's are different at the input, are the regular X's just a pair of cascodes, or are they a cascoded differential pair? I did see a post somewhere a while back in the Pass forum where Mr. Pass mentioned the use of a current mirror with a cascode (I think) at the input on I believe the X1000? I don't know if you can comment on it or not, I have seen the X100 back-engineered thread, but is it different for the X350,600,1000?
Thanks in advance to all for the so far kind responses and help to a new Pass DIYer
BTW I apologize for my last thread where I was being a little thick about the unbalanced source to a balanced preamp or amp. I got it all straight, and much thanks to all who helped.
This will be for movie watching, some music listening, and gaming. The "listening system will be in a separate room/different setup. What I am wondering is whether the Pass amps I am considering are good for this style setup, or if I should look elsewhere. Here are my consideration for amps.
Mains: Aleph-X, I was thinking somewhere between 150-250watts. I know it is a lot!!! I also know that it will be expensive!!!
Center: Aleph-X (undetermined wattage) or Aleph 5
Surrounds: Aleph 5
Sub: unknown, but leaning towards the X350 or something like it.
This is a very future and very slow going project, so expect anything soon. I have other projects right now...Aleph Mini and Aleph-X Mini currently to get my feet wet. Then some Aleph-3's for my room, along with JLH tweaks, addicted to this amp for some reason (sorry Mr. Pass...well I guess variety is the spice of life).
Comments, suggestions, it's all very welcome. Yes like I mentioned I know it is very big undertaking. Keep in mind I am new to audio and audio circuits, but am learning quickly. However I am very experienced with building electronics for/with my dad for his business, designing is not my strong suit, but I can build all day.
Another question though. I have looked a little at the JFET Aleph's, and I am curious, are the sonics better than the traditional IRF9610 input? Would the sonics benefit from a UGS style input, or has anyone tried this?
One more, I have been reading a lot recently about the SuSy setup, documents, studying circuits, reading patent info, what not. I have also been reading a lot about the XA's, but little about the straight X's. I know the Xxxx.5's are different at the input, are the regular X's just a pair of cascodes, or are they a cascoded differential pair? I did see a post somewhere a while back in the Pass forum where Mr. Pass mentioned the use of a current mirror with a cascode (I think) at the input on I believe the X1000? I don't know if you can comment on it or not, I have seen the X100 back-engineered thread, but is it different for the X350,600,1000?
Thanks in advance to all for the so far kind responses and help to a new Pass DIYer
BTW I apologize for my last thread where I was being a little thick about the unbalanced source to a balanced preamp or amp. I got it all straight, and much thanks to all who helped.
JPeitzman said:
The earliest X amplifiers had a single differential pair which was
cascoded and then fold-cascoded which formed the VAS.
Later the design was altered to a single differential pair which
was cascoded and then level-shifted with a low gain common-
source pair forming the VAS.
The more recent circuits have dual differential pairs which are
cascoded and level-shifted with low gain common-source pairs
forming the VAS.
jupiterjune said:
I love folded cascodes (done properly), but the transconductance
of the input jfets vs the original Mosfets is lower by a factor of
about 5, and I can't get enough gain coming out of the cascode,
so I made up the difference and did my level shifting with a low
gain common-source device.
nobody special said:
All depends on what you call a gain stage. My working definition
is, "Does it contribute substantially to the gain?" A cascode
would not qualify (although it does increase gain slightly as a
general rule). A level shifter can be set to unity, and when that
occurs I would think of it as not a gain stage.
I could parallel 5 sets of JFETs to make up the transconductance,
but I run into bandwidth vs input impedance trade-offs, and
besides, 2SK389's and 2SJ109's have become unobtainium
and my stock keeps getting smaller.
Nelson Pass said:
................. and
besides, 2SK389's and 2SJ109's have become unobtainium
and my stock keeps getting smaller.
knowing that , Papa's offer from this post
http://www.diyaudio.com/forums/showthread.php?postid=1224133#post1224133
was even more generous
hehe
there are numerous ways to even more spoil greedy boyz.........
So from any builders of the Babblefish J or any other Aleph J or Aleph-X J, is the JFET input any more musical than the MOSFET's? I would guess a finer top and mid, with a slightly decreased low end, would I be right in thinking this?
I know that 150 to 250 watts on the mains seems like a lot. Although when I am listening to music I love finesse...low to medium power amps with fairly efficient speakers; or low power with efficient full ranges. But for movies and games I like drive and kick-yo-in-tha-teeth bass. At the same time though I like it all to be in control, punchy tight bass, and fine mids and highs...not that blaaaaa bass you get from a $200 all-in-one system, and the blended dreadful mids and highs that come with it.
I know that 150 to 250 watts on the mains seems like a lot. Although when I am listening to music I love finesse...low to medium power amps with fairly efficient speakers; or low power with efficient full ranges. But for movies and games I like drive and kick-yo-in-tha-teeth bass. At the same time though I like it all to be in control, punchy tight bass, and fine mids and highs...not that blaaaaa bass you get from a $200 all-in-one system, and the blended dreadful mids and highs that come with it.
Ya, I do sound kind of greedy, sorry, I do want it all...have my cake and eat it too. Though I can compromise, my music system is where there is not compromising, the movie/game/tv one can be a give or take.
I never considered the A75, I will have to look into it. Thanks a ton for the suggestion!
JFET's suck!?
I never considered the A75, I will have to look into it. Thanks a ton for the suggestion!
JFET's suck!?
Nelson Pass said:
All depends on what you call a gain stage. My working definition
is, "Does it contribute substantially to the gain?" A cascode
would not qualify (although it does increase gain slightly as a
general rule). A level shifter can be set to unity, and when that
occurs I would think of it as not a gain stage.
I could parallel 5 sets of JFETs to make up the transconductance,
but I run into bandwidth vs input impedance trade-offs, and
besides, 2SK389's and 2SJ109's have become unobtainium
and my stock keeps getting smaller.
I was wondering where everyone seems to find these. Have you tried the LSK389 that are being made by linear systems?
http://www.linearsystems.com/datasheets/LSK389.pdf
This may be an ignorant question, but...
Are the 389's and109's that much better than anything more commonly available from Vishay or fairchild? I'm not that up on jfets and what specs really matter the most.
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