I'm only using ~600 VA EI transformers for 100 W/ch monoblocks (~300 W power draw). Double the VA rating seems plenty, despite that current is drawn in surges in the case of a C-input filter.
metalman, where do you buy your L's? I can't find power chokes locally for a good price. What size did you use for your Aleph-X?
6) the good ,the bad and the ugly
Well I did not purchase any transformers -- The good
I did purchase heat sinks suitable for a 15 V rail--- The bad
Now Im not sure If I should stay with 15 v rail---The ugly
Oh boy-- R and D surplus.
On a serious note, Whe modeling the Aleph x using PSUD what do you
use for a lod, When I use a current sink/source I get poor results.
I use 4.5 amps bias per mono block.
Thanks
J
Well I did not purchase any transformers -- The good
I did purchase heat sinks suitable for a 15 V rail--- The bad
Now Im not sure If I should stay with 15 v rail---The ugly
Oh boy-- R and D surplus.
On a serious note, Whe modeling the Aleph x using PSUD what do you
use for a lod, When I use a current sink/source I get poor results.
I use 4.5 amps bias per mono block.
Thanks
J
There's a simple solution to the heatsink issue. My own heatsinks are only half the size of a passive cooling system. Use a quiet large fan at a significantly lower voltage, driven by a separate small transformer. At low speeds it will be inaudible. A capacitor can be added to pass a higher voltage pulse on turn-on to guarantee the fan starts, which may not happen if you have very low voltage. It's even very simple to add speed regulation to the fan based on heatsink temperature. Still have the heatsinks vertical so that convection helps, but with the fins facing each other making a tunnel for the fan.
I'm using beryllium oxide wafers to attach the output devices to the heatsinks (eBay), and highly recommend them. They're great electrical insulators yet more heat conductive than the aluminum of the heatsink instead. Just don't breathe in the dust while machining them and put a warning sticker on the inside of the amplifier chassis.
I'm using beryllium oxide wafers to attach the output devices to the heatsinks (eBay), and highly recommend them. They're great electrical insulators yet more heat conductive than the aluminum of the heatsink instead. Just don't breathe in the dust while machining them and put a warning sticker on the inside of the amplifier chassis.
Don't blame a "sometimes" hum on the transformers. Check your power line for DC at those times. I've started having trouble in the last year or so. Used to happen at 13:00 every afternoon, but now it's at intervals throughout the day. So far I've just endured it, but the time is coming when I'm going to have to do something about it.
Grey
Grey
I used the Hammond 15B chokes (1.5mH, 5A) which I got from partsconnexion for around CDN$15 a piece. Locally I couldn't find anything for a decent price.
Well, if you have DC on your powerlines, just use a DC trap. Or don't use toroids -- EIs are much more tolerant of DC.
bias vs distortion
After reading som threads It seems that the distortion and capacitance
in the mosfets decreases as the rail voltage and bias increases. This is due to the fact that you are operating the device in a different region.
My delima is that I feel somewhat comfortable building the original version (+- 15~ 16 v rail) But may be a bit skidish building the high power version with my level of experience. The power difference does not concern me I use full range speakers(fostex 166 bhl) most of the time. What does concern me is the distortin. Just how much is the difference? something to be concerned about?
j
After reading som threads It seems that the distortion and capacitance
in the mosfets decreases as the rail voltage and bias increases. This is due to the fact that you are operating the device in a different region.
My delima is that I feel somewhat comfortable building the original version (+- 15~ 16 v rail) But may be a bit skidish building the high power version with my level of experience. The power difference does not concern me I use full range speakers(fostex 166 bhl) most of the time. What does concern me is the distortin. Just how much is the difference? something to be concerned about?
j
Re: bias vs distortion
The amplitude-related distortion is improved with the increased bias while the frequency-related distorsion is improved when the gain mosfet has low capacitance. Nevertheless, before soldering and listening, nobody can conclude the actual relation between the distortion and the sound.
tenderland said:
The amplitude-related distortion is improved with the increased bias while the frequency-related distorsion is improved when the gain mosfet has low capacitance. Nevertheless, before soldering and listening, nobody can conclude the actual relation between the distortion and the sound.
I think the lower powered AX sounds great, just don't overdrive it. Also, keep your power supply as clean as possible.
I used to use my AX to drive my high frequency horns. This kept the power output low, which lead to great sound--very direct, if I recall.
It's a nice amp.
As an aside, you can always explore different input/output transistors.
I used to use my AX to drive my high frequency horns. This kept the power output low, which lead to great sound--very direct, if I recall.
It's a nice amp.
As an aside, you can always explore different input/output transistors.
HI
Next week I would like to power up my Aleph X amplifier using Kristijan pc boards.
Would you please some one let me know if I have to use heat sink on the driver mosfet (IRFP9610). If yes what size must be . I plan to use TO220 heat sink on each IRFP9610 but I'm not sure if that will be OK .
Any advise before I power up the amp I would greatly appreciate it .
Today I just finished my first Aleph amp .I really like it . Aleph 30 using pc board design by Peter Daniel .I would like to say a big thank to Mr.Pass for such a great amp .
Thank you very much to all .
Regards
Next week I would like to power up my Aleph X amplifier using Kristijan pc boards.
Would you please some one let me know if I have to use heat sink on the driver mosfet (IRFP9610). If yes what size must be . I plan to use TO220 heat sink on each IRFP9610 but I'm not sure if that will be OK .
Any advise before I power up the amp I would greatly appreciate it .
Today I just finished my first Aleph amp .I really like it . Aleph 30 using pc board design by Peter Daniel .I would like to say a big thank to Mr.Pass for such a great amp .
Thank you very much to all .
Regards
gaborbela said:
if that X is mirrored Aleph 30 (with different voltages and currents) mosfets in input LTP will be just warm ;
give link to his exact schmtc,so we can check ;
anyway-if that is not already prepared,put them on small heatsink together; not to cool them,but to keep them on same temp
HI
Thanks for the answer , these would be the high power verizon Aleph X or some people call it industrial verizon . Supplied from 2x18V AC 1.5K VA transformer which would be around 22V DC .
Only difference between these and Grey Rollins design these one use 8 power mosfet per channel not 12. Everything else is the same .
You can see the the schematic and more information on his website .
www.kk-pcb.com
Thanks one more time for the help .
Regards
Thanks for the answer , these would be the high power verizon Aleph X or some people call it industrial verizon . Supplied from 2x18V AC 1.5K VA transformer which would be around 22V DC .
Only difference between these and Grey Rollins design these one use 8 power mosfet per channel not 12. Everything else is the same .
You can see the the schematic and more information on his website .
www.kk-pcb.com
Thanks one more time for the help .
Regards
gaborbela said:
they will have same dissipation as in your A30.
just put them on same piece of tin or small heatsink ,from before mentioned reasons.
same applicable for your A30
Hi,
I am looking for a set of v.1.0 schematic by Hifizen boards if anyone has some spare and would like to sell them.
Thanks
Greg
I am looking for a set of v.1.0 schematic by Hifizen boards if anyone has some spare and would like to sell them.
Thanks
Greg
PixelPlay said:
Greg,
Have a look here:
http://www.diyaudio.com/forums/showthread.php?postid=1093335#post1093335
Cheers,
Dennis
Hi!
Is it a good idea to use the aleph-x with increased ac current gain (e.g.: 75%) for frequencies below 300Hz in an active speaker system?
For example:
+-25V rails
5A Bias
->200W@4ohm (according Williams spreadsheet)
Dissipation will be only 270W!
Robert
Is it a good idea to use the aleph-x with increased ac current gain (e.g.: 75%) for frequencies below 300Hz in an active speaker system?
For example:
+-25V rails
5A Bias
->200W@4ohm (according Williams spreadsheet)
Dissipation will be only 270W!
Robert
You can try it. The result is usually less distortion at the lower
power levels, but more distortion as the current source starts
to go into cutoff on the negative swing. If you increase the
idle bias you can get rid of that as well.
😎
power levels, but more distortion as the current source starts
to go into cutoff on the negative swing. If you increase the
idle bias you can get rid of that as well.
😎
HI
Please help with my AX .
Today I power up the Aleph X amplifier for a few second but I afraid to leave the power on because it goes up right away over 7A .
I connected one tester between the board (using Kristijan type of boards) and the power supply on the positive .
All 3 trim pots were adjusted on the highest value before I powered up .
Unfortunately it draw over 7A and the thermistor burning .
I know many people use the same boards like mine , would you please help .
Unfortunately I don't have variac to power it up slowly .
Thanks for the help..
Regards
Please help with my AX .
Today I power up the Aleph X amplifier for a few second but I afraid to leave the power on because it goes up right away over 7A .
I connected one tester between the board (using Kristijan type of boards) and the power supply on the positive .
All 3 trim pots were adjusted on the highest value before I powered up .
Unfortunately it draw over 7A and the thermistor burning .
I know many people use the same boards like mine , would you please help .
Unfortunately I don't have variac to power it up slowly .
Thanks for the help..
Regards