Aleph 3 with mods
Hi Aleph fans!
There is a little modified Aleph 3 with balanced input. Check this adress:
http://www.volksamp.com
About the Hexfets - what do you think about IRF450? Are these suitable for the Aleph?
Hi Aleph fans!
There is a little modified Aleph 3 with balanced input. Check this adress:
http://www.volksamp.com
About the Hexfets - what do you think about IRF450? Are these suitable for the Aleph?
Aleph Project & Volkamp
I emailed Volkamp several months ago on the prices of their amps. A reproduction of the Zen goes for about $1800. The Alephs are more. I built my Zen w/out enclosure for about $175.
Use Hexfets with the lowest voltage the circuit will allow safely. It's suppose to lower distortion figures.
I emailed Volkamp several months ago on the prices of their amps. A reproduction of the Zen goes for about $1800. The Alephs are more. I built my Zen w/out enclosure for about $175.
Use Hexfets with the lowest voltage the circuit will allow safely. It's suppose to lower distortion figures.
Pass DIY Addict
Joined 2000
Paid Member
commercial vs. DIY pricing
So, it appears that the 10:1 ratio of commerical cost vs. DIY cost holds up once again!!
I first heard about this with respect to speakers and was horrified to learn that the $1000 I spent on a pair of speakers bought me approximately $75-100 worth of drivers and crossovers!
Nothing but DIY for me from then on!
So, it appears that the 10:1 ratio of commerical cost vs. DIY cost holds up once again!!
I first heard about this with respect to speakers and was horrified to learn that the $1000 I spent on a pair of speakers bought me approximately $75-100 worth of drivers and crossovers!
Nothing but DIY for me from then on!
The lower the max. voltage the higher the max. current of an HEXFET and smaller the distortion of the amp.
Some comercial products are worth their money but some times it´s a clear ripoff.
I am taking a look at the Volksamps they don´t "look" so cool as the Pass ones but they do the same thing.
I still can´t decide what to do about the PCB.
This will probably take me a long time to finish.
So little time for so much to do . hahaha !
Some comercial products are worth their money but some times it´s a clear ripoff.
I am taking a look at the Volksamps they don´t "look" so cool as the Pass ones but they do the same thing.
I still can´t decide what to do about the PCB.
This will probably take me a long time to finish.
So little time for so much to do . hahaha !
Hoffmann Amp
I have the schematic of Reinhard Hoffmann's class A power follower with dynamic current source. (I was told this is not the project published in AudioXpress).
If you're interested, feel free to contact me. mail: tutekov@hotmail.com
Or contact Mr. Hoffmann himself:
Reinhard Hoffmann
Wiembecker Str.1
32657 Lemgo / Germany
Fax & Fon 05261 87586
[Edited by Asen on 01-19-2001 at 05:19 PM]
I have the schematic of Reinhard Hoffmann's class A power follower with dynamic current source. (I was told this is not the project published in AudioXpress).
If you're interested, feel free to contact me. mail: tutekov@hotmail.com
Or contact Mr. Hoffmann himself:
Reinhard Hoffmann
Wiembecker Str.1
32657 Lemgo / Germany
Fax & Fon 05261 87586
[Edited by Asen on 01-19-2001 at 05:19 PM]
Thanks for the schematic you sent me. It looks very interesting. The active current source is a different idea.
After searching a lot of schematics from the Pass designs and others I think the aleph 3 is very simple. I am not sure if any further developing of the curcuit will do good or not for the sound quality.
Thanks again Asen.
After searching a lot of schematics from the Pass designs and others I think the aleph 3 is very simple. I am not sure if any further developing of the curcuit will do good or not for the sound quality.
Thanks again Asen.
Why does Pass still use the third-generation HEXFET's (IRF244) and not the newer fith-generation? Are the 244's better sounding?
Also, if I change the IRF244's (Rds(on) of 0.28 ohm), with fifth-generation IRF530N (Rds(on) of 0.11 ohm) and the IRF9610 (Rds(on) 1.8 ohm) with IRF9530N (Rds(on) 0.20 ohm), what impact would this have on the cicuit, and what does Rds mean, apart from the resistance between drain and source on the HEXFET's?
Also, if I change the IRF244's (Rds(on) of 0.28 ohm), with fifth-generation IRF530N (Rds(on) of 0.11 ohm) and the IRF9610 (Rds(on) 1.8 ohm) with IRF9530N (Rds(on) 0.20 ohm), what impact would this have on the cicuit, and what does Rds mean, apart from the resistance between drain and source on the HEXFET's?
Actually he doesnt use them anymore since the aleph series is out of production from what I know.
In the new X series he uses new plastic hexfets. Probably in TO-247 case. Rds is the drain to source resistance. The smaller it is the more current it can handle with the same heat disipation.
The IRF 530N won´t do as substitute for the IRF244 because the second is only for 63Watts disipation and it´s small. It has a TO-220 case.
You can use the IRFP 150 rated at 100v 40a 230w
or the IRFP 250 rated at 200v 30a 190w.
I think the lower voltage the better it is for the aleph.
For the IRF9610 you can use the IRF9530 With lower Rds.
Notice : the IRF244s are in metal TO-3 case
and the IRFP are in TO-3p or TO247 which ic easier to mount and is fully isolated so you can put it on the heatsink directly.
In the new X series he uses new plastic hexfets. Probably in TO-247 case. Rds is the drain to source resistance. The smaller it is the more current it can handle with the same heat disipation.
The IRF 530N won´t do as substitute for the IRF244 because the second is only for 63Watts disipation and it´s small. It has a TO-220 case.
You can use the IRFP 150 rated at 100v 40a 230w
or the IRFP 250 rated at 200v 30a 190w.
I think the lower voltage the better it is for the aleph.
For the IRF9610 you can use the IRF9530 With lower Rds.
Notice : the IRF244s are in metal TO-3 case
and the IRFP are in TO-3p or TO247 which ic easier to mount and is fully isolated so you can put it on the heatsink directly.
Yeah the IRFP044´s are a good choice, if you dont use high voltage. In the article of the Zen amp, I think the best choice was IRF040. Maybe you can check that out, to see what Nelson Pass has to say about chosing the fets and the distorion related to them.
I have never used hexfed´s and I can´t say if they are better. They are commonly used in hi-end equipment, but I am not convinced that they can help in amplifiers.
They are capable of giving hi current in very short time. What do you need that for, when the power supply is rectifying only 50-60 Hz.
The best thing to do for the RF emitted by the diodes, is to use a mains filter on the mains power supply before the primary of the trafo and rf blocking capacitors parallel on all the bridge diodes.
I have never used hexfed´s and I can´t say if they are better. They are commonly used in hi-end equipment, but I am not convinced that they can help in amplifiers.
They are capable of giving hi current in very short time. What do you need that for, when the power supply is rectifying only 50-60 Hz.
The best thing to do for the RF emitted by the diodes, is to use a mains filter on the mains power supply before the primary of the trafo and rf blocking capacitors parallel on all the bridge diodes.
I am planning to build the Aleph 5 with some modifications.
This amp. uses -+34V (68v), would it be ok to use the IRFP044N rated 55V? Would there be 34 volts over each
MOS-FET since there are 2 in series.
Also, would it be smart to use some caps. in parallel with the zener diodes, what size and type?
This amp. uses -+34V (68v), would it be ok to use the IRFP044N rated 55V? Would there be 34 volts over each
MOS-FET since there are 2 in series.
Also, would it be smart to use some caps. in parallel with the zener diodes, what size and type?
I think the Irf244 are small for that voltage rating.
The fets have half the voltage on them only when there is no signal at the output. When there is voltage swing at the output they can reach close to full voltage. So I think you need at least 100 Volt rating.
Which zeners do you mean ?
The ones protecting the gate dont need caps.
They would act like filters in the input changing the signal amplitude response.
At the current sources maybe a small electrolytic one could be a good idea to stabilize the voltage at the gate. Maybe a 10 uf from zener to ground.
But I dont know if it will do much.
The fets have half the voltage on them only when there is no signal at the output. When there is voltage swing at the output they can reach close to full voltage. So I think you need at least 100 Volt rating.
Which zeners do you mean ?
The ones protecting the gate dont need caps.
They would act like filters in the input changing the signal amplitude response.
At the current sources maybe a small electrolytic one could be a good idea to stabilize the voltage at the gate. Maybe a 10 uf from zener to ground.
But I dont know if it will do much.
HEXFET
What does HEXFET mean?
These devices are rather expensive. I checked for IRF150 (IR), but they wanted 20 UK pounds per pcs. May be because these were made by Int. Rectifier. After that I found IRFP150 for 2 UK pounds. The cheaper ones have better specs too (very funny). In the datasheet it is not mentioned HEXFET. Do you think HEXFET means something so important that one cannot build an Aleph without it?
What does HEXFET mean?
These devices are rather expensive. I checked for IRF150 (IR), but they wanted 20 UK pounds per pcs. May be because these were made by Int. Rectifier. After that I found IRFP150 for 2 UK pounds. The cheaper ones have better specs too (very funny). In the datasheet it is not mentioned HEXFET. Do you think HEXFET means something so important that one cannot build an Aleph without it?
I usually buy the hexfets from Harris/Intersil They are cheaper and the same. They even have the same codes.
Hexfet is a mosfet. With a new construction technic thats make them better. They can have higher current ratings.
The name comes from the way they are made. It looks like hexagons or a like bee cells.
Hexfet is a mosfet. With a new construction technic thats make them better. They can have higher current ratings.
The name comes from the way they are made. It looks like hexagons or a like bee cells.
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