Hello All.
I`m the proud owner of those Amplifers. First of all I wanted Thank Zen-Mod for his courage to build me those Amplifers after my beloved first Aleph-X gave up after 8-9 yers of playing. The build quality is really great, and you have seen on the pictures. Many of yours are asking how do they sound. Well in very short: As I Like it , hooped for and way beyond that !!! ;-)
I`m sins one week not sleeping well because of those Amplifiers. You know why. Listening , Listening , admire aso.
After 2 days of continuous playing them, a friend came ( an audiophile freak ) and listened it with me. He`s a tube Lover ( Manley gear like : Manley Neo-Classic 300b and Monos Manley Snapper , Lodspeakers Davone Grande and MBL 1611F, 1621 )
This “Sisy” had tears in his eyes after 2 songs he wanted to hear. I must admit those ware very depressing songs ( don’t remember what those are ), but I think he was very delightful to hear / see this as it suppose to be reproduced.
On last Friday I had also some Audio - lovers at my home. Very different style music lovers. From Classic, Opera – singing style , Jazz and Popular music lovers. And must say That Everybody was satisfied about the reproduction.
It`s very hard to put in words what I`m hearing and write about that. English is not my Native language , so sorry for that!
In Compare to my Old Aleph-X ( like 60W on IRFP9610 ) every good aspects like : fullness of the sound , Emotions , easiness of reproduction remained as they are. Only more real. I mean that on the Old Aleph-X , sometimes the sound was like a drama. Calling for attention in some parts of the frequencies. This is not the case with those Amplifiers. They stay real , clean ,and no adds in the sound like it was with the old Aleph-X. Just Real , and yet FULL Loaded EMOTIONS presentation. Amazing performance and the bonus is what I missed totally was the Huge SPACE and sound localization in that space. That’s what is really amazing. I had this never before. For example PL 60.8 was the Space and pinpoint bass reproduction what I liked very much. In PL 160.5 was the softness on hights , midds very pleasant thing. And here I Have those things combined together plus many many more from them all. For example the Bass is far better then any of Amplifer i had and heard. Very well defined, and very tight. Midds are very real yet very full and reach. Hights are like a sparkle in the night sky. What was mentioned very often during last listening session was the Energy of sound coming from my system. Maybe that’s why everything sounded so damn real to us yet pleasant for long listening session ( we have been listening to 3.30 in the morning ;-) )
That’s all for now , hope you understood that I was trying to tell you all about those amplifiers. I wonder how will they sound after burn-in , and how long will it take to Burn them In ?
Thank you again ZEN for those wonderful peace of instrument!!
The comments above made me very curious I said I want to try it
Tonight I managed to finish a mono BJX channel (100W)
I did not abstain and played a bit of music.
I expected to be fine, but ... I have not been so impressed for a long time. It's extraordinary ! And I subscribe to everything Slowikpl wrote!!!
And yes, combine the best of XA.05 and XA.08. I am really impressed, very silent, the voices come out of the night and am amazed with their warmth and clarity. And bass ... very special.
Thanks a lot to ZenMod for this project, for the patience she had with me, there were some problems. But I managed to solve them. One tip, if you put only one pair or two MOSFETs for testing on the PCB, do not try to connect a speaker. I did it and I could not understand why I have oscillations in both channels. I've lost a lot of time before I realize that I have to put all MOSFET on the PCB. After I did it, everything went back to normal and it was fine. (between Hot Out and GND am 250mV, between both Hot OUT am 10mV) Bias 350mA on each MOSFET after 2 hours has not changed, as well as offset- very stable)
And the most important - the sound is super cool!
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Having slapped self hard several times, the smaller version you speak of in post #70 wont get out of head. If two 5U cases are sufficient for this smaller version, are there any links to boards, parts kits, etc I'm not aware of. Have read Erics materials before and this susy-X'd type Aleph wont dislodge from head.
If not, I will slap more and try to be content with box of parts for BBA3 mono blocks....but head keeps reminding me "It's not an Aleph" Grrrrr.
Russellc
If not, I will slap more and try to be content with box of parts for BBA3 mono blocks....but head keeps reminding me "It's not an Aleph" Grrrrr.
Russellc
what I had (briefly?) as intention , to answer on someone's demand/urge/request/wish , is to make smaller iteration , where one big OS pcb would be used as one channel ..... resulting in 5 mosfets per quadrant
say that 5U/500 Modushop case is base ; by my experience with smaller ones , that one is good for 150W of heat per side ...... maybe asking for Babysitter in Summer months ...but that's trivial
rails as absolut minimum for good mosfet behaving (think capacitance linearity) are 18Vdc ( 15Vac secondaries)
so , rails sum is 36Vdc , heat 150W , so Iq =150W/36V=4A17 .... that would be 417mA per vertical pair
output voltage envelope approx. rails sum minus mosfet/source res. loss and that twice .... say 64Vpp
output current envelope approx 2 x Iq = 8A34
on 8R load we have voltage as limiting factor , so 64Vpp .... resulting in P=Urms^2/Rload = approx 60W
where Urms ={Upp/2/1.41}
on 4R load we have current as limiting factor , so 8A34pp ..... resulting in P=Irms^2 x Rload = approx. 35W
entire thing is based on idea that smaller version must be smaller physically , but ... bridging is tricky thing - easy to get max output voltage , but physics is physics - we still need some current Cojones to make W from VA
regarding mono-block organization - no particular benefits of having two sides for heatsinks , when you have "just" 20 mosfets per channel
for that , one can use already made Babelfish XJ shown here , and starve it more , both with voltage and current , even leave out few mosfets from pcbs
when you starve it enough ...... damn - just make bigger regular (SE) Aleph J
edit: attached sshot of small Babelfish XJ FE pcb ; not checked in vivo ...... though , no reason for some special doubts will it work or no
say that 5U/500 Modushop case is base ; by my experience with smaller ones , that one is good for 150W of heat per side ...... maybe asking for Babysitter in Summer months ...but that's trivial
rails as absolut minimum for good mosfet behaving (think capacitance linearity) are 18Vdc ( 15Vac secondaries)
so , rails sum is 36Vdc , heat 150W , so Iq =150W/36V=4A17 .... that would be 417mA per vertical pair
output voltage envelope approx. rails sum minus mosfet/source res. loss and that twice .... say 64Vpp
output current envelope approx 2 x Iq = 8A34
on 8R load we have voltage as limiting factor , so 64Vpp .... resulting in P=Urms^2/Rload = approx 60W
where Urms ={Upp/2/1.41}
on 4R load we have current as limiting factor , so 8A34pp ..... resulting in P=Irms^2 x Rload = approx. 35W
entire thing is based on idea that smaller version must be smaller physically , but ... bridging is tricky thing - easy to get max output voltage , but physics is physics - we still need some current Cojones to make W from VA
regarding mono-block organization - no particular benefits of having two sides for heatsinks , when you have "just" 20 mosfets per channel
for that , one can use already made Babelfish XJ shown here , and starve it more , both with voltage and current , even leave out few mosfets from pcbs
when you starve it enough ...... damn - just make bigger regular (SE) Aleph J
edit: attached sshot of small Babelfish XJ FE pcb ; not checked in vivo ...... though , no reason for some special doubts will it work or no
Attachments
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Thanks!
Is there guidance on how much Iq is “needed” (similar to guidance about rail voltage you gave?). It seems double the current as the load needs, or 2*(1Vrms/8R)*1.414 at a minimum?
1W/8R is 8Vp-p and 1Ap-p
for that , usually 500mA Iq will suffice , speaking of strictly A class SE stages
useful reading , Papa talking about Klunk!!
however , that's too much around the bush , better to talk about exact case ..... ?
for that , usually 500mA Iq will suffice , speaking of strictly A class SE stages
useful reading , Papa talking about Klunk!!
however , that's too much around the bush , better to talk about exact case ..... ?
Like all of us, I like building Papa amps. Lots of devices and lots of heat. Nothing more pretty then the amps in this thread, with so many paralleled output devices.
However, I now have a hatred of volts. Of all my speakers I have built, I like Lowther DX4 in TP-1 front/rear horn.
It only needs 1V measured at speaker terminals to get loud enough at 1kHz.
So, I don’t need many volts and try and minimize them. In the end, F4 seems best amp for them. I have made balanced mono blocks. I still have itch to build more amplifiers, but they all have gain and that has to be dealt with and that is more of a pain than it’s worth, now I think.
Your post about minimum number of volts to make MOSFETs linear and happy made me think maybe I should start getting rid of amp(ere)s as well.
So, just curious that is all.
However, I now have a hatred of volts. Of all my speakers I have built, I like Lowther DX4 in TP-1 front/rear horn.
It only needs 1V measured at speaker terminals to get loud enough at 1kHz.
So, I don’t need many volts and try and minimize them. In the end, F4 seems best amp for them. I have made balanced mono blocks. I still have itch to build more amplifiers, but they all have gain and that has to be dealt with and that is more of a pain than it’s worth, now I think.
Your post about minimum number of volts to make MOSFETs linear and happy made me think maybe I should start getting rid of amp(ere)s as well.
So, just curious that is all.