B of M conversation and cascode Aleph J-X pcb(s)
Is there a pcb for the cascode front end JFET avaible for Aleph J-X, if I had the ability to design and make pcb(s) I would have designed a cascode Aleph J-X with both the input JFETs and output MOSFETs.
The problem that I had with the capacitors from Panasonic is that they recomend that they are used only for 42 days before they need to be replaced when they are operated at 85degrees, operating hot is normal for this type of amplifier, 85 degree may be to hot but 60degrees is not and then we can estimate a length of life of no more than 120days to be safe. I keep my stereo on 24hrs a day 365 days a year, so I am very sensitive to the life expectancy of a component used.
Is this the right Bill of Materials for Peter Danials Aleph J-X circuit boards ?
Is there a pcb for the cascode front end JFET avaible for Aleph J-X, if I had the ability to design and make pcb(s) I would have designed a cascode Aleph J-X with both the input JFETs and output MOSFETs.
The problem that I had with the capacitors from Panasonic is that they recomend that they are used only for 42 days before they need to be replaced when they are operated at 85degrees, operating hot is normal for this type of amplifier, 85 degree may be to hot but 60degrees is not and then we can estimate a length of life of no more than 120days to be safe. I keep my stereo on 24hrs a day 365 days a year, so I am very sensitive to the life expectancy of a component used.
My God !! You wanna keep a class A amplifier on 24/7 !!!!
What an energy waste !!
No wonder the climate is changing ... Are you that cold in Canada
All of your conclusions seem to be faulty
The inside temp of your chassis should be less than *40 unless it is completely closed up. The caps will last a lot longer than 4 mos.
The BOM you have posted is for the Aleph J, designed by Nelson Pass. It is a single ended class A amp.
The X amp, and the JX are experimental amps designed by forum members, and modified to a high degree for differing reasons. They are based on the Aleph current source patented by Mr Pass, but he did not design these circuits. There are lots of completed JX amps with happy owners so we know they work well, but there is no set BOM for the JX as far as I know. It would be best for you to communicate directly with someone that has built one or two, and heed their advice.
Why don't you contact Peter Daniel?
Best, Bill
My God !! You wanna keep a class A amplifier on 24/7 !!!!
What an energy waste !!
No wonder the climate is changing ... Are you that cold in Canada
For sure keeping a class A amp on during the summer is wasteful as it is heating an area that needs no heat.
During the winter in Canada (that's about 45 weeks per year)
the volume that the amps are in is probably heated anyhow so he's merely trading one heat source (the amps) for another (whatever source is heating the room).And finally.... BC and Quebec is nearly all hydro power which contributes nothing to climate change but does admittedly have other issues (mainly flooding vast tracts of land in the case of Quebec). Ontario has a lot of nuclear - again no climate impact.
For sure though, Canada is the exception.
faulty Hypothesis leading to a theory
I am aware that I am no expert and some or all of my hypothesis are faulty, however, discussing them in this kind of fourm directs me towards a better understanding of the amplifier itself, and hopefully making some good choices in the end for purchasing components for a "state of the art" amplifier.
I do believe that purchasing long life components will be the correct choice all other variables being equal except price. Price is a constraint that we all are bound by, but yet, it should never be a variable where hypothesizing is done for the "state of the art".
Thank You for listening, your comments are very importent for me to make purchasing decisions on parts. I believe I will just follow the list BofM given because all of the capacitors I would like to buy are backordered for up to 14weeks before delivery.
Before I purchase, are all of the parts I need for the pcb's on the BofM I have attached ?
I am aware that I am no expert and some or all of my hypothesis are faulty, however, discussing them in this kind of fourm directs me towards a better understanding of the amplifier itself, and hopefully making some good choices in the end for purchasing components for a "state of the art" amplifier.
I do believe that purchasing long life components will be the correct choice all other variables being equal except price. Price is a constraint that we all are bound by, but yet, it should never be a variable where hypothesizing is done for the "state of the art".
Thank You for listening, your comments are very importent for me to make purchasing decisions on parts. I believe I will just follow the list BofM given because all of the capacitors I would like to buy are backordered for up to 14weeks before delivery.
Before I purchase, are all of the parts I need for the pcb's on the BofM I have attached ?
Nope, Bill already told you that - you posted an AJ BOM and you are building an AJ-X, right? With a schematic you can update the BOM to include the missing parts.
Remember the -X is symmetrical. You wouldn't be too far off doubling that BOM per channel (assuming it is right, which I can't verify without a schematic) That would give you a few extra parts, but you'd have everything.
Be sure to order extra output devices for matching - at least 50% extra. So if using 12 output devices per channel, get at least 36 devices. Better yet get 50 since they come in tubes of 25 and you have a better chance of getting devices from the same lot in a full tube.
Remember the -X is symmetrical. You wouldn't be too far off doubling that BOM per channel (assuming it is right, which I can't verify without a schematic) That would give you a few extra parts, but you'd have everything.
Be sure to order extra output devices for matching - at least 50% extra. So if using 12 output devices per channel, get at least 36 devices. Better yet get 50 since they come in tubes of 25 and you have a better chance of getting devices from the same lot in a full tube.
SCAIFF001,
If you are using the Aleph j-x pcb's which Peter Daniel designed and had made you should have gotten a complete hand written schematic and BOM with the boards. The separate X frontend board was also provided. If you need a copy of that BOM and schematic, which has the J and JX layout printed on it, I can email it to you.
You can also find the .6 watt resistors at Digikey with the 0204 commercial designation which is a smaller footprint in a .6 watt power rating. They might be hard to buy in very small quantities.
Tad
If you are using the Aleph j-x pcb's which Peter Daniel designed and had made you should have gotten a complete hand written schematic and BOM with the boards. The separate X frontend board was also provided. If you need a copy of that BOM and schematic, which has the J and JX layout printed on it, I can email it to you.
You can also find the .6 watt resistors at Digikey with the 0204 commercial designation which is a smaller footprint in a .6 watt power rating. They might be hard to buy in very small quantities.
Tad
I have found one subsitution for the 50 series resistors
I have recieved all of the expensive parts excluding an enclosures parts, each channels weight so far is 41.5lbs, I better put wheels on them when I assemble the enclosure.
I am going to attempt to find as many close to .6watt resistors I can find, then look at the other components of the psb(s), I am still waiting for my camera to show everyone a picture of the components I have purchased before assembly in their shipping crates.
Thank you for your help.
For the enclosures I believe I will build negative presure boxs with a insulated tube for wood stoves to vent the heat outside the house by cutting two holes in the wall through the bricks to attach each insulated pipe to.
This information is critical that you have given me, I dont know how you know so much about this amplifier, but I am glad you do. The MRS16 series of another Vishay resistor I believe I can directly subsitute for the CMF50 series.
I have recieved all of the expensive parts excluding an enclosures parts, each channels weight so far is 41.5lbs, I better put wheels on them when I assemble the enclosure.
I am going to attempt to find as many close to .6watt resistors I can find, then look at the other components of the psb(s), I am still waiting for my camera to show everyone a picture of the components I have purchased before assembly in their shipping crates.
Thank you for your help.
For the enclosures I believe I will build negative presure boxs with a insulated tube for wood stoves to vent the heat outside the house by cutting two holes in the wall through the bricks to attach each insulated pipe to.
I read a lot and retain most of what I read.
Rather than metal tubes that could resonate and amplify fan noise, why not go with soft fiberglass ductwork? Not as pretty but helps keep the mechanical noise down. Won't be long before you'll want to keep the heat in the room.
Any 1/4W resistor will do for the .6W parts - dissipation is minimal, you could probably get away with 1/8. I don't subscribe to the boutique resistor theory, but plenty of folks do. Pass Labs uses standard grade Panasonic, AFAIK.
Rather than metal tubes that could resonate and amplify fan noise, why not go with soft fiberglass ductwork? Not as pretty but helps keep the mechanical noise down. Won't be long before you'll want to keep the heat in the room.
Any 1/4W resistor will do for the .6W parts - dissipation is minimal, you could probably get away with 1/8. I don't subscribe to the boutique resistor theory, but plenty of folks do. Pass Labs uses standard grade Panasonic, AFAIK.
SCAIFFOO1,
You could also try these resistors. They are full 0.6 watt in a small body.
http://www.mouser.com/catalog/specsheets/mbxsma.pdf
Tad
You could also try these resistors. They are full 0.6 watt in a small body.
http://www.mouser.com/catalog/specsheets/mbxsma.pdf
Tad
Hi SCAIFF001,
did you have any success to find the correct BOM?
Any info is very welcome
Plenty designers too.
Sorta depends on the design foremost, and the location of the part, imso.
For a manufacturer, logistics and cost versus gain are key elements, a rare amp producer sells on image.
Most non-commercial folks are into fetishism, about as meaningfull as a Ducati Superbike when you're 6'3".
Attachments
looking for help
My jx channel is built now. Buuuuut..... When I power up I have 24v dc on the output and the RG resistors of 100r from both outputs to ground get very hot and start to smoke if i leave the amp on...
I have a 2x18v toroid with a crc psu 35,000uf - 4 x 0.47r - 35,000uf . This I split to power both sides of the boards. My Jx uses a 2sj109 with a 2sj74bl as current source p1 as 100r and rp jumpered (RS is 10k). I have no components on the other current source option.
Can anyone advise me of where to look for the source of the issue ?
regards
dave
I cant figure out what is going on.
My jx channel is built now. Buuuuut..... When I power up I have 24v dc on the output and the RG resistors of 100r from both outputs to ground get very hot and start to smoke if i leave the amp on...
I have a 2x18v toroid with a crc psu 35,000uf - 4 x 0.47r - 35,000uf . This I split to power both sides of the boards. My Jx uses a 2sj109 with a 2sj74bl as current source p1 as 100r and rp jumpered (RS is 10k). I have no components on the other current source option.
Can anyone advise me of where to look for the source of the issue ?
regards
dave
I cant figure out what is going on.