change file extension
Hi,
For all PC users change the file extension into a gif for eq;
ax-stuffing.gif
ax-pcb.gif
Hi,
For all PC users change the file extension into a gif for eq;
ax-stuffing.gif
ax-pcb.gif
strange, but true.....
My gif (created by Photoshop 4) file was rejected many times over by this post software. The only way I could get the gif to post was by zipping it. Sorry for the inconvenience.
John Inlow
My gif (created by Photoshop 4) file was rejected many times over by this post software. The only way I could get the gif to post was by zipping it. Sorry for the inconvenience.
John Inlow
XA200 Pics?
Mr. Pass,
Where are those pictures of the inside of the XA200 you promised us about now.........
Thanks,
H.H.
Mr. Pass,
Where are those pictures of the inside of the XA200 you promised us about now.........
Thanks,
H.H.
Thread bumping, he?🙂
How is your Tex coming, Harry?
I am working on two final channel's using PCB,s.
I did put the 4,7k famous resistors back in my prototype
but there's no sonic difference with the 1 k. Getting the DC
offset at or near 0V is slightly more difficult with 4,7k.
Regards
How is your Tex coming, Harry?
I am working on two final channel's using PCB,s.
I did put the 4,7k famous resistors back in my prototype
but there's no sonic difference with the 1 k. Getting the DC
offset at or near 0V is slightly more difficult with 4,7k.
Regards
Harry, you used slightly modifed current sources for input differencial in your Tex-X. Any chance of seeing a schematic for it? That's the only thing that keeping me from finishing mine yet.😉
pcb observations
Hi all,
I'm laying out the pcb artwork on a copper clad board and noticed (after a bit of parts research) that the 9610 and the variable resistors solder pads should be spaced 0.1" on center. They are currently about twice that amount.
John Inlow
Hi all,
I'm laying out the pcb artwork on a copper clad board and noticed (after a bit of parts research) that the 9610 and the variable resistors solder pads should be spaced 0.1" on center. They are currently about twice that amount.
John Inlow
Aleph5 versus AlephX
Not so long ago I´ve found schematic of AlephX on this site. At first i wanted to build Aleph5, but I can`t decide which project to choose now.
I´d like to ask you:
1. Is it a finished project or is it under development?
2. How it compares sonically to original Aleph?(Aleph5)
3. Can I increase supply rails to +/-20VDC? Probably I´ll increase the number of output transistors (2 pairs per side are enough?). Can I use IRFP240s?
4. Parts C6,C7 in project Aleph5 are missing from AlephX. Are they necessary?Are resistors R1,4,44,45 necessary for the AlephX ?
5. Which project do you recommend to build: Aleph5 or AlephX with increased supply rails?
6. Is the speaker protection (output relays) for Aleph5 and AlephX necessary?
Thanks!
F.M.
Not so long ago I´ve found schematic of AlephX on this site. At first i wanted to build Aleph5, but I can`t decide which project to choose now.
I´d like to ask you:
1. Is it a finished project or is it under development?
2. How it compares sonically to original Aleph?(Aleph5)
3. Can I increase supply rails to +/-20VDC? Probably I´ll increase the number of output transistors (2 pairs per side are enough?). Can I use IRFP240s?
4. Parts C6,C7 in project Aleph5 are missing from AlephX. Are they necessary?Are resistors R1,4,44,45 necessary for the AlephX ?
5. Which project do you recommend to build: Aleph5 or AlephX with increased supply rails?
6. Is the speaker protection (output relays) for Aleph5 and AlephX necessary?
Thanks!
F.M.
F.M.
I can't answer all of your questions, because I haven't built one, but here are a few of my thoughts on this...
I don't think that it is a good idea to build the circuit with the rails as low as they are- if I were to build it, I would use +/- 20 volt rails. In the simulations I ran on the regular Aleph circuit, there was a lot of 2nd harmonic at high frequencies with the lower rail voltages. I have changed my mind, and decided I will build the Aleph 5, or a variation of it I should say. The only problem with the higher rails is that you start to run into major heat dissipation in the output stage!
Steve
I can't answer all of your questions, because I haven't built one, but here are a few of my thoughts on this...
I don't think that it is a good idea to build the circuit with the rails as low as they are- if I were to build it, I would use +/- 20 volt rails. In the simulations I ran on the regular Aleph circuit, there was a lot of 2nd harmonic at high frequencies with the lower rail voltages. I have changed my mind, and decided I will build the Aleph 5, or a variation of it I should say. The only problem with the higher rails is that you start to run into major heat dissipation in the output stage!
Steve
SteveG,
Your distortion problem was related to other factors and is not an indication of the circuits ability to operate on low rails. Indeed Aleph-X along with the Mini-A are fine with the low rails.
F.M.
1)It's still in development but is apparently very similar to the commercial circuit. I'd probably add the compensation capacitor unless you have the experience and equipment to properly test the amp before using it.
2)Apparently better bass but still with the sweet mid and treble of the Aleph
3a)You can if you need the power but you would have to rejigger the gain if you want to maintain the same input sensitivity
3b)Should be ok
4)See 1
5)Unless you are willing to do some testing ect i'd suggest you stick with the Aleph 5
6)If you are referring to adding a protection circuit between the amp and the speaker, it shouldnt be required in this case.
Your distortion problem was related to other factors and is not an indication of the circuits ability to operate on low rails. Indeed Aleph-X along with the Mini-A are fine with the low rails.
F.M.
1)It's still in development but is apparently very similar to the commercial circuit. I'd probably add the compensation capacitor unless you have the experience and equipment to properly test the amp before using it.
2)Apparently better bass but still with the sweet mid and treble of the Aleph
3a)You can if you need the power but you would have to rejigger the gain if you want to maintain the same input sensitivity
3b)Should be ok
4)See 1
5)Unless you are willing to do some testing ect i'd suggest you stick with the Aleph 5
6)If you are referring to adding a protection circuit between the amp and the speaker, it shouldnt be required in this case.
just for the sake of discussion...
a quote from THE MAN himself (Nelson Pass):
So, drain to source voltage IS a factor, even if it isn't the culprit in my situation.
Steve
a quote from THE MAN himself (Nelson Pass):
So, drain to source voltage IS a factor, even if it isn't the culprit in my situation.
Steve
I always like to give the Mosfets a few volts left over on
the rails so that there is maybe 2 to 4 volts left over at
clipping.
If you are using Mosfets as followers and driving them
from a front end using the same supply voltages, then
you automatically get this voltage margin because the
front end falls a couple volts short of rail, and the Vgs
of the output device drops another 4 volts or so, meaning
that at clipping there is still maybe 6 volts across the output
Mosfets. This results in better high frequency performance
near clipping and better dynamic quality at highest output
levels, but is slightly wasteful of power.
You choose. 😎
the rails so that there is maybe 2 to 4 volts left over at
clipping.
If you are using Mosfets as followers and driving them
from a front end using the same supply voltages, then
you automatically get this voltage margin because the
front end falls a couple volts short of rail, and the Vgs
of the output device drops another 4 volts or so, meaning
that at clipping there is still maybe 6 volts across the output
Mosfets. This results in better high frequency performance
near clipping and better dynamic quality at highest output
levels, but is slightly wasteful of power.
You choose. 😎
hi.
in relation to cases and heatsinks we have quite a few black anodized heatsinks ( 200mm x 120mm x 40mm) with a 10mm baseplate.
we are selling these for $12 each and could talk about discount for a larger qty. , they are ideal for sides in a case (thats what we have used them for) and they can easily be stacked to about any heigth 🙂
the c/w is about 0.6 deg C/W for one piece.
you can get a better idea here; http://www.cadaudio.dk/elektrpr.htm
regards k madsen - cadaudio.dk
in relation to cases and heatsinks we have quite a few black anodized heatsinks ( 200mm x 120mm x 40mm) with a 10mm baseplate.
we are selling these for $12 each and could talk about discount for a larger qty. , they are ideal for sides in a case (thats what we have used them for) and they can easily be stacked to about any heigth 🙂
the c/w is about 0.6 deg C/W for one piece.
you can get a better idea here; http://www.cadaudio.dk/elektrpr.htm
regards k madsen - cadaudio.dk
Re: just for the sake of discussion...
Yes, it's a factor that must be accounted for. That doesnt exclude low voltage operation, it just means you must take this into consideration during the design process.
SteveG said:
Yes, it's a factor that must be accounted for. That doesnt exclude low voltage operation, it just means you must take this into consideration during the design process.
Hi Aleph-X fanatics,
I am the lucky owner of a pair of Thiel CS3.6 speakers. The CS3.6 average efficiency is 86 dB and the normal impedance is 4 ohms with a minimum of 2.5 ohms. The recommended power to drive these speakers is 100 - 400 watts into 4 ohms. Ideal amps would be Pass X350/X600, Mark Levinson 336 or Classe CA401/CAM350. Because all mentioned amps are over my budget I decided to build Aleph-X.
The commercial XA-200 would also be an ideal partner for my speakers. This weekend I read the whole thread about the Aleph-X. Most people who have plans to build an Aleph-X use voltage rails between 15 an 20 V. Because of my power requirements I made some calculations to build an Aleph-X that meets the commercial XA-200.
The most difficult part to find would be an transformer with an low voltage and high current. Amplimo delivers a transformer with the following specs. 1000 VA, 2 x 22V 22,73A. Amplimo and Plitron work together so quality is not an issue. The two secondaries will give voltage rails with +31V/-31V. With these voltage rails the total bias current (both sides) will be 9,68 Amps. The output power will be in the order of 375 W into 4 ohms. The total heat dissipation would be about 620 W.
The maximum amount of output devices that can be used without redesigning the front end is 12 per side (24 per channel). The schematic of the output stage lookes like a bridged (or mirrored) Aleph 2. To dissipate the total amount of heat the dissipation per device will be 26 W. A little more then the 23 W Nelson runs his output devices, but still very reasonable.
To dissipate the heat and keep the operating temperature at about 60 degrees Celcius two huge heat sinks will be needed. To dissipate 620 W, I use two R-Theta #65340 heat sinks with size 11”x25” (That are four parts per channel as shown in Peter’s pictures).
Mosfets for the input and ouput stage will be matched IRF9610 and IRFP240.
The only thing to which I can’t make up my mind is the power supply. Will about 150000uF do the job or does this thing need an PI filter?
So far I don’t see any problems mostly because of:
- I have you (the members of this forum) as backup.
- The Master himself build one succesfully.
- I can always can make an Aleph 2 or Aleph 1.2 from the parts (except the transformer).
Maybe I’m the only one that sees no problems? The only thing that kept me from building an Aleph-X is that except Nelson nobody has succesfully build two channels!!! Maybe it is time to fire up the contest and give a prize to the first one that completes succesfully building two channels? Prize could be an cd of his or her choice.
So if you see one please let me know otherwise I will start collecting parts.
I am the lucky owner of a pair of Thiel CS3.6 speakers. The CS3.6 average efficiency is 86 dB and the normal impedance is 4 ohms with a minimum of 2.5 ohms. The recommended power to drive these speakers is 100 - 400 watts into 4 ohms. Ideal amps would be Pass X350/X600, Mark Levinson 336 or Classe CA401/CAM350. Because all mentioned amps are over my budget I decided to build Aleph-X.
The commercial XA-200 would also be an ideal partner for my speakers. This weekend I read the whole thread about the Aleph-X. Most people who have plans to build an Aleph-X use voltage rails between 15 an 20 V. Because of my power requirements I made some calculations to build an Aleph-X that meets the commercial XA-200.
The most difficult part to find would be an transformer with an low voltage and high current. Amplimo delivers a transformer with the following specs. 1000 VA, 2 x 22V 22,73A. Amplimo and Plitron work together so quality is not an issue. The two secondaries will give voltage rails with +31V/-31V. With these voltage rails the total bias current (both sides) will be 9,68 Amps. The output power will be in the order of 375 W into 4 ohms. The total heat dissipation would be about 620 W.
The maximum amount of output devices that can be used without redesigning the front end is 12 per side (24 per channel). The schematic of the output stage lookes like a bridged (or mirrored) Aleph 2. To dissipate the total amount of heat the dissipation per device will be 26 W. A little more then the 23 W Nelson runs his output devices, but still very reasonable.
To dissipate the heat and keep the operating temperature at about 60 degrees Celcius two huge heat sinks will be needed. To dissipate 620 W, I use two R-Theta #65340 heat sinks with size 11”x25” (That are four parts per channel as shown in Peter’s pictures).
Mosfets for the input and ouput stage will be matched IRF9610 and IRFP240.
The only thing to which I can’t make up my mind is the power supply. Will about 150000uF do the job or does this thing need an PI filter?
So far I don’t see any problems mostly because of:
- I have you (the members of this forum) as backup.
- The Master himself build one succesfully.
- I can always can make an Aleph 2 or Aleph 1.2 from the parts (except the transformer).
Maybe I’m the only one that sees no problems? The only thing that kept me from building an Aleph-X is that except Nelson nobody has succesfully build two channels!!! Maybe it is time to fire up the contest and give a prize to the first one that completes succesfully building two channels? Prize could be an cd of his or her choice.
So if you see one please let me know otherwise I will start collecting parts.
nice dream, make it so.........
I am in the process of creating one low voltage AX using Grey's layout and TVI's pcb that I modified. The pcb is etched and ready to be drilled. If I achieve success, I'll fabricate its mate and then I'm going for the big guns to compliment my bass horn. Since the X appears to be an Aleph mirror, I thought that I could create a larger amp by duplicating the outputs of any one of the Aleph series. I would double the PS v/a accordingly. It seems that you are doing much the same. I wish you luck, please keep us posted. I'm going to be following in you steps one day.
My parts are on order, I'm going nuts with anticipation!
I've enhanced the pcb further than the one posted recently. It has beefer rails for the speaker outputs and power inputs. I've also relocated the 9610 and Vresistor pads and given them 0.1" spacing. Email me if you want a copy. Instead of using two 60 ohm resistors to ground at the output, I've decided to use one 30 ohm 25 watt power resistor from Dale. The new pcb reflects this as well.
John Inlow
I am in the process of creating one low voltage AX using Grey's layout and TVI's pcb that I modified. The pcb is etched and ready to be drilled. If I achieve success, I'll fabricate its mate and then I'm going for the big guns to compliment my bass horn. Since the X appears to be an Aleph mirror, I thought that I could create a larger amp by duplicating the outputs of any one of the Aleph series. I would double the PS v/a accordingly. It seems that you are doing much the same. I wish you luck, please keep us posted. I'm going to be following in you steps one day.
My parts are on order, I'm going nuts with anticipation!
I've enhanced the pcb further than the one posted recently. It has beefer rails for the speaker outputs and power inputs. I've also relocated the 9610 and Vresistor pads and given them 0.1" spacing. Email me if you want a copy. Instead of using two 60 ohm resistors to ground at the output, I've decided to use one 30 ohm 25 watt power resistor from Dale. The new pcb reflects this as well.
John Inlow
So, enlighten me... what do you do to account for this? The only thing I can see that you could do is not to run it near clipping. Really shouldn't be that big of a problem with 38watts into efficient speakers. As has been said before, speakers are probably distorting more at that point than the amp anyway.
MEnsing,
In the last 3 weeks, I have been enjoying the sound from a pair of Aleph X. These were buildt according to Grey´s schematic. I did try with two transistor-pairs at the outputs, but as this resulted in some loss in detail and clarity, I desided to change it back to the original and wait for someone on the forum to present a solution for this problem.
I am using irf 640 on the outputs, and 2k7 resistors in the common-mode feedback to the diff pair sources for stabilising the DC offset, not the 30 ohm resistors from output to ground. This works just fine.
This circuit performs-in my opinion, better than an Aleph 3, with a more detailed soundstage,
and an absolutely amasing bass, very deep and defined.
😉
In the last 3 weeks, I have been enjoying the sound from a pair of Aleph X. These were buildt according to Grey´s schematic. I did try with two transistor-pairs at the outputs, but as this resulted in some loss in detail and clarity, I desided to change it back to the original and wait for someone on the forum to present a solution for this problem.
I am using irf 640 on the outputs, and 2k7 resistors in the common-mode feedback to the diff pair sources for stabilising the DC offset, not the 30 ohm resistors from output to ground. This works just fine.
This circuit performs-in my opinion, better than an Aleph 3, with a more detailed soundstage,
and an absolutely amasing bass, very deep and defined.
😉
Steve I am somewhat surprised that you are asking me this question, as Nelson answered it in his post above. This ensures that even upto clipping there is still over 5V VDS left.