Finished Aleph J Mono amps
I finally finished my Aleph J. After I heard that Buzzforb did a PS in one enclosure to 2 separate mono amps, I knew that was the way I wanted to go. Mainly the enclosures are made from 0.25" polycarbonate. The PS is dual mono with 2 Antek 300VA transformers. The AC in for each channel goes through a Omron relay with a 12V coil. I can turn it on with the DPDT switch either using the onboard homemade 12VDC supply or wth the 12v out of another piece of equipment. The heatsinks for the rectifiers are HeatsinkUSA 3.5". Each rail of each channel has CLC with 84,000uF before the 3.7mH choke and 86,000uF after the choke, with 56,000uF of that being in the amp enclosure to get it close to the amp board. I do not think 170,000uF is too much. The DC goes through a Neutrik connector to each amp.
The heatsinks on the amp are 2 HeatsinkUSA 10.08 cut to 18" wide. The machine work was done by their local shop. I can give the pdf files of the drawings to anyone who asks me. The sides are their 6" low profile. I got them gold anodized in Indianapolis. I really like that gold color. With a copper heat spreader, I adjusted the bias to 0.55V and they were about 46deg C in the open. They are about 49 deg C closed up. I tried them out on the floor first to make sure they worked before mounting them. They are dead quiet with no turn on thump and no turn off thump. I really like the looks in the evening with the amber LED's glowing. Oh, in case any one wants to know, they sound wonderful. I am still getting used to the great sound. Many thanks to Nelson, 6L6, and the others who drew up the boards and gave advice.
I finally finished my Aleph J. After I heard that Buzzforb did a PS in one enclosure to 2 separate mono amps, I knew that was the way I wanted to go. Mainly the enclosures are made from 0.25" polycarbonate. The PS is dual mono with 2 Antek 300VA transformers. The AC in for each channel goes through a Omron relay with a 12V coil. I can turn it on with the DPDT switch either using the onboard homemade 12VDC supply or wth the 12v out of another piece of equipment. The heatsinks for the rectifiers are HeatsinkUSA 3.5". Each rail of each channel has CLC with 84,000uF before the 3.7mH choke and 86,000uF after the choke, with 56,000uF of that being in the amp enclosure to get it close to the amp board. I do not think 170,000uF is too much. The DC goes through a Neutrik connector to each amp.
The heatsinks on the amp are 2 HeatsinkUSA 10.08 cut to 18" wide. The machine work was done by their local shop. I can give the pdf files of the drawings to anyone who asks me. The sides are their 6" low profile. I got them gold anodized in Indianapolis. I really like that gold color. With a copper heat spreader, I adjusted the bias to 0.55V and they were about 46deg C in the open. They are about 49 deg C closed up. I tried them out on the floor first to make sure they worked before mounting them. They are dead quiet with no turn on thump and no turn off thump. I really like the looks in the evening with the amber LED's glowing. Oh, in case any one wants to know, they sound wonderful. I am still getting used to the great sound. Many thanks to Nelson, 6L6, and the others who drew up the boards and gave advice.
Attachments
I used Mouser pretty much exclusively myself. I did get some caps from PartsConnexion, and some RCA and XLR jacks from Ebay. I also found some polycarbonate bypass caps on Ebay. Pretty much the same stuff Mouser/Digikey. I find searching for the parts a bit easier at Mouser, but thats just me.
Of course you need to get your matched transistors from other sources. I got Mosfets from Buzzforb, and JFets from Spencer. I guess you can get the JFets from the DIYAudio store now. I got my case and keratherms from the DIYAudio store, and the transformer from Antek.
sorry I have a question to ask because I need help:
as I said aleph j on the average high and just great but the low and shallow and not controlled properly.
do you think with 2 aleph j bianplificazione vertical I could get more oomph to the bass as a single amplifier in this case should only drive a speaker and almost all the current would go to the woofer of a speaker
thanks
as I said aleph j on the average high and just great but the low and shallow and not controlled properly.
do you think with 2 aleph j bianplificazione vertical I could get more oomph to the bass as a single amplifier in this case should only drive a speaker and almost all the current would go to the woofer of a speaker
thanks
I raised my IQ is improving but is still small, I still have the edge because the temperature of the heat sink is not 'over yet
forces to 6ohm my speakers are not very suitable but I would not give up to the sound of J that I like very much
so I would not build an amp more 'muscular and lose this sound.
turning the question there is an aleph more 'powerful with the same sophistication?
thanks
forces to 6ohm my speakers are not very suitable but I would not give up to the sound of J that I like very much
so I would not build an amp more 'muscular and lose this sound.
turning the question there is an aleph more 'powerful with the same sophistication?
thanks
maxst67, I am no expert but my experience with the Aleph J and my speakers (KEF 104/2's) is not too different from your own. My speakers are 90dB/W but at 4 ohm so the AJ does not rock the house in this amp/speaker pairing. In my case I think it's my speakers that are asking too much of the amp but I did change a few things I could...
I changed my preamp to something with more gain, that helped and adjusted my speaker room position as now new frequencies are at play (the AJ is a very nice amp emphasizing a different part of the music spectrum), that helped...but I still think the matching of speaker to amp in this case is a difficult one. (I know from other systems that the room can be bass friendly...)
I could either change my speakers entirely or my crossovers to accommodate bi-amping and build a new bass amp or build another AJ and change them both to monoblocks or...introduce a subwoofer.
The subwoofer is the best option. The whole spectrum down to about 56Hz is so beautiful with the AJ and my long time friends the KEF 104/2s but...Bass is a whole different beast - needs a different speaker and a different amp given My present situation. YMMV.
The AJ is a great amp but it is always a matter of amp and speaker combined
I changed my preamp to something with more gain, that helped and adjusted my speaker room position as now new frequencies are at play (the AJ is a very nice amp emphasizing a different part of the music spectrum), that helped...but I still think the matching of speaker to amp in this case is a difficult one. (I know from other systems that the room can be bass friendly...)
I could either change my speakers entirely or my crossovers to accommodate bi-amping and build a new bass amp or build another AJ and change them both to monoblocks or...introduce a subwoofer.
The subwoofer is the best option. The whole spectrum down to about 56Hz is so beautiful with the AJ and my long time friends the KEF 104/2s but...Bass is a whole different beast - needs a different speaker and a different amp given My present situation. YMMV.
The AJ is a great amp but it is always a matter of amp and speaker combined
what you need is more current ; so , with Aleph principle , that means - more output parts , greater overall Iq , which means more heat , heftier PSU
no free lunch
and , then you can call that Aleph whatever you want ..... Aleph J turbo ......
choose whatever FE you want - mosfet , Jfet or bjt
then choose whatever OS you want - 1,2, 100 deep
then cascode FE LTP , if PSU dictated by OS is demanding that.
Aleph is ....... state of mind ....... not exact schematic carved in stone
thanks to all for the answers even if not 'what I would not have wanted to hear
@ Zen Mod you please rewrite your last message so simple that I can not translate it thanks
Maxst67,
Zen mod means this -
There are many ways to build an Aleph Amplifier.
The Front-end Long-tailed pair (LTP) gain stage can be Mosfet, Jfet, or BJT.
The output stage and Aleph constant current source may be as many devices (pairs) as you want to build - 2, 3, 10, etc... More output devices can pass more current, and more easily drive lower impedance loads. Voltage an be increased for more power. Of course, more devices and / or more voltage will make more heat.
If your output stage is higher voltage than the Front-end LTP can handle, you may need to cascode to protect the gain transistors.
You can build the Aleph as small or as large as you want - the limit is almost always going to be how many heatsink you have.
````
As for your question of a bigger Aleph for better controlled Bass, I would suggest investigating bi-amplification and perhaps a BA-3 amplifier for the bass.
Zen mod means this -
There are many ways to build an Aleph Amplifier.
The Front-end Long-tailed pair (LTP) gain stage can be Mosfet, Jfet, or BJT.
The output stage and Aleph constant current source may be as many devices (pairs) as you want to build - 2, 3, 10, etc... More output devices can pass more current, and more easily drive lower impedance loads. Voltage an be increased for more power. Of course, more devices and / or more voltage will make more heat.
If your output stage is higher voltage than the Front-end LTP can handle, you may need to cascode to protect the gain transistors.
You can build the Aleph as small or as large as you want - the limit is almost always going to be how many heatsink you have.
````
As for your question of a bigger Aleph for better controlled Bass, I would suggest investigating bi-amplification and perhaps a BA-3 amplifier for the bass.
thanks 6L6
someone here in Italy has put in vertical bi-amping 2 aleph 3:
every aleph 3 pilot a speaker and you can also make the cutoff frequency with a capacitor on the input that drives the mid / high eighth by the edge of the middle of the diffuser so as to convey to the low everything 'it needs, he said that doing so has solved the piloting of the lower part. (not the same as my speakers)
I would like to do the same thing with 2 aleph j. what do you think?
alternatively costrurne one more powerful with the same sophistication but which pass labs is so?
thanks
someone here in Italy has put in vertical bi-amping 2 aleph 3:
every aleph 3 pilot a speaker and you can also make the cutoff frequency with a capacitor on the input that drives the mid / high eighth by the edge of the middle of the diffuser so as to convey to the low everything 'it needs, he said that doing so has solved the piloting of the lower part. (not the same as my speakers)
I would like to do the same thing with 2 aleph j. what do you think?
alternatively costrurne one more powerful with the same sophistication but which pass labs is so?
thanks
for every driver...
Someone with an acute technical sense can pipe in here (please but it must be observed that speaker drivers all have their quirks and your bass drivers will have theirs. Finding out more about those drivers will assist you in selecting an amp that will handle those specific drivers.
In general, SE amps don't do so well with large bass, long throw drivers, that's just my experience talking. You can look outward to what other people's pairings too.
My best friend (an engineer) holds that logically one amp should drive everything in your system with the fewest errors while my best amp designing friend (more of an artist) holds that specialized amp/driver combinations will allow the best adjustments. I have chosen a 1W SET tube amp for everything down to 56Hz in my main system (horn loaded) and a 200W AB amp for a sub woofer set to augment that. I am finding this holds for my second system where the Aleph J is driving those KEF 104/2's. I am building a Nelson Pass F5t v2 for the needed sub woofers in my second system. I am even building a DIYHoney Badger just in case the F5t v2 is not enough. Hey, isn't this all about building and exploration?
Someone with an acute technical sense can pipe in here (please
but it must be observed that speaker drivers all have their quirks and your bass drivers will have theirs. Finding out more about those drivers will assist you in selecting an amp that will handle those specific drivers.In general, SE amps don't do so well with large bass, long throw drivers, that's just my experience talking. You can look outward to what other people's pairings too.
My best friend (an engineer) holds that logically one amp should drive everything in your system with the fewest errors while my best amp designing friend (more of an artist) holds that specialized amp/driver combinations will allow the best adjustments. I have chosen a 1W SET tube amp for everything down to 56Hz in my main system (horn loaded) and a 200W AB amp for a sub woofer set to augment that. I am finding this holds for my second system where the Aleph J is driving those KEF 104/2's. I am building a Nelson Pass F5t v2 for the needed sub woofers in my second system. I am even building a DIYHoney Badger just in case the F5t v2 is not enough. Hey, isn't this all about building and exploration?
compliments jdg123
I know that the virus can not be defeated easily diy, I'm testing on my skin
I built the speakers are speakers with the Ekta Grande scan speak, the impedance is 6ohm.
Today I did a test, I connected the 2 channels to a single speaker to hear the difference and then I heard the same speaker with a single canale.così at first listen there is huge difference between the two collegamenti.però I noticed a 'other thing and that is the fact that now I'm less difficulty amp to drive the speakers and I can not figure out if he needed to break or I got used to the sound, although I believe that one can not get used to a low sound weak.
it is possible that the amp you're road testing and getting better?
I know that the virus can not be defeated easily diy, I'm testing on my skin
I built the speakers are speakers with the Ekta Grande scan speak, the impedance is 6ohm.
Today I did a test, I connected the 2 channels to a single speaker to hear the difference and then I heard the same speaker with a single canale.così at first listen there is huge difference between the two collegamenti.però I noticed a 'other thing and that is the fact that now I'm less difficulty amp to drive the speakers and I can not figure out if he needed to break or I got used to the sound, although I believe that one can not get used to a low sound weak.
it is possible that the amp you're road testing and getting better?
Maxst, your experiment proves Zen Mod's advice is the correct answer if you want to use an AJ. Simply double the number of output devices if you have enough heat sink.
You may just want to go louder than the AJ is capable of driving your speakers. They look to be roughly 90 dB/W Ekta-Grande Not terribly insensitive, but the impedance drops down to about 3.5 ohms. For an Aleph amp that means you want to have a lot of bias. At least double the number of output devices. More than double, you probably want to use another set of input devices and increase the differential bias to allow enough drive for the increased number of outputs.
The same high bias current requirement holds true for any amp that you want to keep in class A with low impedance speakers like yours. You might like an F5T similar to jdg123's with 4 sets of output devices rather than the 2 he has, but keep 30V rails to manage dissipation.
You may just want to go louder than the AJ is capable of driving your speakers. They look to be roughly 90 dB/W Ekta-Grande Not terribly insensitive, but the impedance drops down to about 3.5 ohms. For an Aleph amp that means you want to have a lot of bias. At least double the number of output devices. More than double, you probably want to use another set of input devices and increase the differential bias to allow enough drive for the increased number of outputs.
The same high bias current requirement holds true for any amp that you want to keep in class A with low impedance speakers like yours. You might like an F5T similar to jdg123's with 4 sets of output devices rather than the 2 he has, but keep 30V rails to manage dissipation.
I thought only ZM can really call something fugly...but thanks..much appreciated.
For those worried about needing a soft-start on the AJ...I basically used Nelson's PS circuit for the F5 using a CL60. With all the caps that I used, the CL60 works just fine as a soft start.
After my AJ has broken in, the sound is superb (yes, transparent) and I think it has good bass to a 8ohm speaker, especially for a SE amp. The bass is not quite up to a huge powerhouse push-pull with lower output impedance that can drive 4 ohms at full power, but I like the AJ better everywhere else. Besides, my plan all along is to allow the AJ do what it does best and put a 2nd order high pass filter at 80 Hz to it (probably make it from j-fets, is there a post with a circuit already?) which will make it a 4th order at my sealed speakers. I will mate it all with a subwoofer with a 4th order low pass input.