Hello all,
I am VERY intreagued by these Pass designs, the symmetry simply rings true in my mind, so wouldn't mind having a bash as constructing my own amp based on these wonderfully simple designs (something else which rings true, the simplicity). Hence I like the designs that use simplicity plus super-symmetry (am I right in assuming the Aleph-X?)
But! Where to start, so many long threads, so many options, so please allow me to ask the question of where to start!
My aim is to produce a 30Watt amp, that will drive some full-range speakers I built (thnx Planet10). I wouldn't mind implementing the Lightspeed attenuator idea into the design too.
Hence what PSU / pre-amp / amp combo should I be looking at & where can I find some 'finalized' schematics?? Getting hold of PCBs would be useful too as this would ease the construction pain somewhat.
Thanks in advance,
Andy
I am VERY intreagued by these Pass designs, the symmetry simply rings true in my mind, so wouldn't mind having a bash as constructing my own amp based on these wonderfully simple designs (something else which rings true, the simplicity). Hence I like the designs that use simplicity plus super-symmetry (am I right in assuming the Aleph-X?)
But! Where to start, so many long threads, so many options, so please allow me to ask the question of where to start!
My aim is to produce a 30Watt amp, that will drive some full-range speakers I built (thnx Planet10). I wouldn't mind implementing the Lightspeed attenuator idea into the design too.
Hence what PSU / pre-amp / amp combo should I be looking at & where can I find some 'finalized' schematics?? Getting hold of PCBs would be useful too as this would ease the construction pain somewhat.
Thanks in advance,
Andy
An Aleph-X is not for the faint of heart
Better start with something simpler and more final, like the super-popular F5. Less symmetrical but nevertheless cute are the Burning Amps BA1 or BA2.
If it has to be an Aleph, the Aleph30 is a good option to start with.
As preamp the B1 is favoured by many.
F5/BA1/BA2 boards you get from the DIYAudio-store, Aleph30 boards maybe from someoneelse in Swap-meet.
Have fun, Hannes
Sure!
First of all, the circuit itself is not series production level mature and might need tweaking (e.g. to get acceptable DC-offset) depending on actual circuit and power level. There exist also a number of variations, like with jfet frontend, that have other potential issues as well, like limited number of output fets due to little drain current of the jfet LTP.
Also thermal design (thermal coupling of mosfets) plays a role to get stable dc-offset, so good mechanical and thermal construction is well advised.
The X'ed amps are also a little sensitive on the impedance at their inputs, so dc-offset might become a small issue depending wether they're driven balanced or single ended.
Last, as there exists quite a number of variations, it might be difficult to get professionally made boards for the variation you're interested in, as most do their own board design at this level.
Hannes
First of all, the circuit itself is not series production level mature and might need tweaking (e.g. to get acceptable DC-offset) depending on actual circuit and power level. There exist also a number of variations, like with jfet frontend, that have other potential issues as well, like limited number of output fets due to little drain current of the jfet LTP.
Also thermal design (thermal coupling of mosfets) plays a role to get stable dc-offset, so good mechanical and thermal construction is well advised.
The X'ed amps are also a little sensitive on the impedance at their inputs, so dc-offset might become a small issue depending wether they're driven balanced or single ended.
Last, as there exists quite a number of variations, it might be difficult to get professionally made boards for the variation you're interested in, as most do their own board design at this level.
Hannes
This is the sort of thing you could end up with, not cheap, a project for the dedicated builder. If you are a member of the fearless amp builders, go for it.
Pic is from the AX thread.
Attachments
Just so's you's know's my profession is electronics engineer (high power controllers at Penny & Giles, so using & clamping MOSFETs is my bag, baby ).
So not much is putting me off the actual 'doing' side of things. I have much kit and bits available to hand as one would expect being in such an industry. Having said that, amps are one of those things I lack experience in, so I take on board what you guys mention re: tuning & matching etc.... Hence the thread question!
Cheers,
Andy
). So not much is putting me off the actual 'doing' side of things. I have much kit and bits available to hand as one would expect being in such an industry. Having said that, amps are one of those things I lack experience in, so I take on board what you guys mention re: tuning & matching etc.... Hence the thread question!
Cheers,
Andy
I would suggest a look at the F5. It 'checks the box' of your requirements, namely power, simplicity, and symmetry. It is a very popular amplifier right now, and justly so... Everybody who builds it is very pleased with it's performance and quality.
Boards are available from 2 legitimate (and authorized) sources, and there are stolen, pirated rip-offs from that auction site. Many people have built the amp on this forum, so you will find plenty of resource and help.
Here is the manual, written my Nelson Pass. It is in 2 parts, the 'owners manual' in the beginning, and the 'how-to' after that.
http://firstwatt.com/pdf/prod_f5_man.pdf
Boards are available from 2 legitimate (and authorized) sources, and there are stolen, pirated rip-offs from that auction site. Many people have built the amp on this forum, so you will find plenty of resource and help.
Here is the manual, written my Nelson Pass. It is in 2 parts, the 'owners manual' in the beginning, and the 'how-to' after that.
http://firstwatt.com/pdf/prod_f5_man.pdf
So, what exactly IS an Aleph, an Aleph-X and an Aleph J-X.
I guess the J-X is the JFET frontend version.... Hmmm I like JFETs, something inherent about them that wants me to use them! And which of these pre-amps are designed to drive which power amps... or can they be mixed and matched? Basic questions I'm struggling to find the answers to really.
So many looooong threads to wade through! With my poor memory I just end up confused.
Now for a REALLY stupid question that has been bugging me. (Sorry about this one!!!
):
Most amp designs I see a signal coming in, ref to GND, pre-amped and then amped to the speakers. Simples. However on some of these designs I see a In+ and In- on the pre-amp, (a la op-amp). This then drives a preamped Out+ and Out-, connected to In- and In+ on the pwr amp. I LIKE THIS. balanced. Makes much sense to me... but how to connect the 'line-in' to the preamp In+ and In-... I guess the In- doesn't just get strapped to GND ref of incoming signal does it?
Andy
I guess the J-X is the JFET frontend version.... Hmmm I like JFETs, something inherent about them that wants me to use them! And which of these pre-amps are designed to drive which power amps... or can they be mixed and matched? Basic questions I'm struggling to find the answers to really.
So many looooong threads to wade through! With my poor memory I just end up confused.
Now for a REALLY stupid question that has been bugging me. (Sorry about this one!!!
):Most amp designs I see a signal coming in, ref to GND, pre-amped and then amped to the speakers. Simples. However on some of these designs I see a In+ and In- on the pre-amp, (a la op-amp). This then drives a preamped Out+ and Out-, connected to In- and In+ on the pwr amp. I LIKE THIS. balanced. Makes much sense to me... but how to connect the 'line-in' to the preamp In+ and In-... I guess the In- doesn't just get strapped to GND ref of incoming signal does it?
Andy
But would you agree that although it may not be to everyone's taste, it is still high quality and good performing? That's what I was trying to say.
... but how to connect the 'line-in' to the preamp In+ and In-... I guess the In- doesn't just get strapped to GND ref of incoming signal does it?
Andy
Yes. It does.
Most cases however will benifit from a balanced source...
Andy
Here is a link to show the difference between Aleph 3 and Aleph X
http://www.kk-pcb.com/amps.html
Here is a link to show the difference between Aleph 3 and Aleph X
http://www.kk-pcb.com/amps.html
@Bill, no dis taken! But, once I get my head around what goes with what and what I need to figure out I'll get there! Not entirely stupid with this stuff and am more than capable. Honest guv! But like I said, I am struggling with all the variants and spin-offs, trying to suss exactly what the basic stages actually are (if u catch my drift)... quite typical of forums in general I guess!
Andt
Andt
Andy; forgive me if I'm stating the obvious but a lot depends on whether your sources have balanced[xlr] or single ended[rca] outputs. I don't think its worth building a balanced power amp if your going to run it single ended; negates any benifit I believe. I'm sure someone will correct me if I'm wrong.
underwurlde
take a look at CheffdeGaar's ( wakoo Frenchy - it's hard to remember that spelling
) amp :
http://www.diyaudio.com/forums/pass-labs/108683-ugs-power-its-u-p.html
it's more elegant than Aleph X ( at least for my wakoo brain) , even if sonic difference between them is matter of taste
from engineering point of view , it's superior - better temp/offset behavior ..... and - at least to my knowledge - more like PL AX amps , considering that Aleph X is more like predecessors - PL X amps
and yes - SUSY is best served when hot ........ oups - when fed balanced
take a look at CheffdeGaar's ( wakoo Frenchy - it's hard to remember that spelling
) amp :http://www.diyaudio.com/forums/pass-labs/108683-ugs-power-its-u-p.html
it's more elegant than Aleph X ( at least for my wakoo brain) , even if sonic difference between them is matter of taste
from engineering point of view , it's superior - better temp/offset behavior ..... and - at least to my knowledge - more like PL AX amps , considering that Aleph X is more like predecessors - PL X amps
and yes - SUSY is best served when hot ........ oups - when fed balanced
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