I don't think that there are any active group buys, but someone may be willing to part with a set of boards.
The rest depends on how you build it. Builds typically set the gain at around 20 dB.
Power is set by rail voltage and bias. The AJX can scale fairly easily from around 30 to 100W, a straight (mosfet input) AX can go higher if you can live with the heat. So can an AJ-X if the inuts are cascoded.
The rest depends on how you build it. Builds typically set the gain at around 20 dB.
Power is set by rail voltage and bias. The AJX can scale fairly easily from around 30 to 100W, a straight (mosfet input) AX can go higher if you can live with the heat. So can an AJ-X if the inuts are cascoded.
The boards are still avaialble as described here:
AJ-X: http://www.diyaudio.com/forums/group-buys/163900-aleph-j-x-pcb-group-buy-2nd-run.html
PS boards: http://www.diyaudio.com/forums/audio-sector/149672-universal-power-supply-pcb.html
AJ-X: http://www.diyaudio.com/forums/group-buys/163900-aleph-j-x-pcb-group-buy-2nd-run.html
PS boards: http://www.diyaudio.com/forums/audio-sector/149672-universal-power-supply-pcb.html
is this true, 10watt 33k for RG
I am just looking at RG, RP, P1, RS. Can You tell me what you are useing for these components.
I am thinking of changing the Power Transistors to 190W 30A IRFP240 subsitutes, what do you think ? I am ready to order now but dont have enough money for everything if I buy $14. MOSFET(s). I have attached the data sheets below for the two MOSFETs I have considered.
http://www.vishay.com/docs/91210/91210.pdf
http://www.nteinc.com/specs/2300to2399/pdf/nte2376.pdf
I am just looking at RG, RP, P1, RS. Can You tell me what you are useing for these components.
I am thinking of changing the Power Transistors to 190W 30A IRFP240 subsitutes, what do you think ? I am ready to order now but dont have enough money for everything if I buy $14. MOSFET(s). I have attached the data sheets below for the two MOSFETs I have considered.
http://www.vishay.com/docs/91210/91210.pdf
http://www.nteinc.com/specs/2300to2399/pdf/nte2376.pdf
advantrage to using high current MOSFETs ?
High Bill,
I am stil looking for what parts to order for P1 & RP if I use JFET, is RP 1.5Kohms ?
I have to choose Power MOSFETs now and have noticed a replacement for IRFP240, the NTE2376 MOSFET, N–Ch, Enhancement Mode High Speed Switch by NTE Electronics Inc., it is 30amp & 190watts, here is the data sheet
http://www.nteinc.com/specs/2300to2399/pdf/nte2376.pdf , can I subsitute this power MOSFET for the IRFP240 20amp 150watt, I beleive it will last longer all other things being equal, and life span of the amplifier is a major concern of mine ?
Thank You for your help, I know I must ask allot of stupid questions, but I am trying as best I can, I probibly have allot of brain damage from all of the drugs I used to take for 20 years, because my memory is very poor these days, if I ask you the same question twice I am still doing the best I can.
High Bill,
I am stil looking for what parts to order for P1 & RP if I use JFET, is RP 1.5Kohms ?
I have to choose Power MOSFETs now and have noticed a replacement for IRFP240, the NTE2376 MOSFET, N–Ch, Enhancement Mode High Speed Switch by NTE Electronics Inc., it is 30amp & 190watts, here is the data sheet
http://www.nteinc.com/specs/2300to2399/pdf/nte2376.pdf , can I subsitute this power MOSFET for the IRFP240 20amp 150watt, I beleive it will last longer all other things being equal, and life span of the amplifier is a major concern of mine ?
Thank You for your help, I know I must ask allot of stupid questions, but I am trying as best I can, I probibly have allot of brain damage from all of the drugs I used to take for 20 years, because my memory is very poor these days, if I ask you the same question twice I am still doing the best I can.
J74 as constant current source
I am setting up my current source the same as you,with J74, can you tell me what you used for P1, RP, RG, RS, this is all I need so I can order my parts and begin to build this amp.
Thank You for listening.
I am setting up my current source the same as you,with J74, can you tell me what you used for P1, RP, RG, RS, this is all I need so I can order my parts and begin to build this amp.
Thank You for listening.
Scaiff001,
If in the end you decide on the standard IRFP240/9240 most recommendations here on the forum suggest you use the Fairchild parts instead of the International Rectifier items. Seems they have a better transistor.
Just a note. Also, Future electronics has the best price I have found on the mosfets. They are MUCH cheaper. Name brand and all.
Tad
If in the end you decide on the standard IRFP240/9240 most recommendations here on the forum suggest you use the Fairchild parts instead of the International Rectifier items. Seems they have a better transistor.
Just a note. Also, Future electronics has the best price I have found on the mosfets. They are MUCH cheaper. Name brand and all.
Tad
There's more to substitution suitability evaluation and reliability calculations than just looking at the device's maximum ratings. Generally, you'll find folks stay away from NTE devices because they are very expensive. The NTE device you linked to has an input capacitance that is double an IRFP240. It may be a dual die device. You could theoretically use half as many, but heat sinking becomes an issue.
Hundreds, if not thousands, of Aleph type amps have been built with the IR (now Vishay) IRFP240 types. You can expect long life IF YOU PROVIDE ADEQUATE HEAT SINKS.
Fairchild has stopped producing IRFP240 and their replacements, FQA19N20C. The closest Fairchild substitute I found at Mouser, FQA32N20C, has 50% higher gate capacitance, which would probably mean the top end would be affected. They are cheap, though...
Hundreds, if not thousands, of Aleph type amps have been built with the IR (now Vishay) IRFP240 types. You can expect long life IF YOU PROVIDE ADEQUATE HEAT SINKS.
Fairchild has stopped producing IRFP240 and their replacements, FQA19N20C. The closest Fairchild substitute I found at Mouser, FQA32N20C, has 50% higher gate capacitance, which would probably mean the top end would be affected. They are cheap, though...
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Nte2356 mosfet
High Bob,
Because of the price I will go with only eight per channel insted of twelve, do you see no problem with this susitute asside from the price, I might have to waight annother month to complete it, I might also have some more wiggle room with my bias as well, will I ? I am out of my current skill set with this decision.
Thank You for your Help.
High Bob,
Because of the price I will go with only eight per channel insted of twelve, do you see no problem with this susitute asside from the price, I might have to waight annother month to complete it, I might also have some more wiggle room with my bias as well, will I ? I am out of my current skill set with this decision.
Thank You for your Help.
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With only 8 output devices, will you increase the bias per device or accept lower output power? If you up the bias, Are your heat sinks up to the task? You need bigger sinks with fewer devices dissipating the same power. Do you know what you'll need to change to accomplish this?
The NTE is really a waste of money. Without doing any reliability calculations, I'd guess it's the difference between 80 and 100 years.
You've agonized over the sound of each capacitor and resistor, and now you're ready to possibly have a rolled off top end? Even 8 NTEs have 1/3 higher gate capacitance than 12 IRFP240s. Nobody has used it, so we don't know how linear it will be in this circuit.
When you can get the Nelson Pass approved IRFP240 for $1.83 each @25 pieces http://www.alliedelec.com/search/searchresults.aspx?N=0&Ntk=Primary&Ntt=irfp240, why would you want to spend so much on NTEs?
The NTE is really a waste of money. Without doing any reliability calculations, I'd guess it's the difference between 80 and 100 years.
You've agonized over the sound of each capacitor and resistor, and now you're ready to possibly have a rolled off top end? Even 8 NTEs have 1/3 higher gate capacitance than 12 IRFP240s. Nobody has used it, so we don't know how linear it will be in this circuit.
When you can get the Nelson Pass approved IRFP240 for $1.83 each @25 pieces http://www.alliedelec.com/search/searchresults.aspx?N=0&Ntk=Primary&Ntt=irfp240, why would you want to spend so much on NTEs?
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Fqa19n20c
You can still find some FQA19N20C here:
FAIRCHILD FQA19N20C is in stock! | Buy FQA19N20C | FQA19N20C | Onlinecomponents.com
I personally would choose these over the NTE part.
Cheers,
Dennis
You can still find some FQA19N20C here:
FAIRCHILD FQA19N20C is in stock! | Buy FQA19N20C | FQA19N20C | Onlinecomponents.com
I personally would choose these over the NTE part.
Cheers,
Dennis
sodering tempiture and time
Durring my research into capacitors and resistors the ones I am committed to have very specific sodering tempiture and time the heat is applied. I beleive I require a sodering station, is this true or am I becomming parinoid of distroying the components with unbridaled heat. Do You have any suggestions or is the sodering station I have found ok, but it is expensive to which will put my project behind another month at $171.63 . Is their something else I can buy having tempiture control that is cheeper, or is the one I have looked over good because I can use it for the rest of my life ? Here is a link to it
SPC TECHNOLOGY|4004|Soldering Station | Newark Canada
Thank You for your time helping us out.
Durring my research into capacitors and resistors the ones I am committed to have very specific sodering tempiture and time the heat is applied. I beleive I require a sodering station, is this true or am I becomming parinoid of distroying the components with unbridaled heat. Do You have any suggestions or is the sodering station I have found ok, but it is expensive to which will put my project behind another month at $171.63 . Is their something else I can buy having tempiture control that is cheeper, or is the one I have looked over good because I can use it for the rest of my life ? Here is a link to it
SPC TECHNOLOGY|4004|Soldering Station | Newark Canada
Thank You for your time helping us out.
That should be fine. I use this Circuit Specialists Inc. - CSI Deluxe Station w/Analog Display (CSI-STATION1A) changing tips depending on what I am soldering.
Oddly enough, having enough power and a high enough tip temperature is important to avoid overheating the components you are soldering.
Oddly enough, having enough power and a high enough tip temperature is important to avoid overheating the components you are soldering.
Scaiff001,
You would have to look quite hard to find a better soldering station than this one. Many diyers here have suggested this to me. I bought one and am extremely happy with it. It has a bunch of different tip assortments to choose from and you can replace the heat element when needed.
You could also buy some Quad Eutectic solder from Cardas. Fabulous silver bearing solder. Check out there website.
Hakko 936 ESD Safe Soldering Station | 936-12 (93612) | Hakko
Tad
You would have to look quite hard to find a better soldering station than this one. Many diyers here have suggested this to me. I bought one and am extremely happy with it. It has a bunch of different tip assortments to choose from and you can replace the heat element when needed.
You could also buy some Quad Eutectic solder from Cardas. Fabulous silver bearing solder. Check out there website.
Hakko 936 ESD Safe Soldering Station | 936-12 (93612) | Hakko
Tad
Weller tend to be the most popular followed by Hakko where I am from.
Check out these
COOPER TOOLS / WELLER|WES51|Analog Soldering Station | Newark Canada
COOPER TOOLS / WELLER|WESD51|Digital Soldering Station | Newark Canada
Regarding temperature and time. I find that a hotter temperature is better because the solder melts much more quickly, so you are in and out of there much faster than at a colder temperature.
When I say hotter I don't necessarily mean 100 degrees hotter, it might be 10 to 20 degrees hotter.
Practice on a bit of proto board with some offcut lead wire and you will see what I mean. In the end it will probably come down to personal preference.
It will also depend on the solder composition you are using
Check out these
COOPER TOOLS / WELLER|WES51|Analog Soldering Station | Newark Canada
COOPER TOOLS / WELLER|WESD51|Digital Soldering Station | Newark Canada
Regarding temperature and time. I find that a hotter temperature is better because the solder melts much more quickly, so you are in and out of there much faster than at a colder temperature.
When I say hotter I don't necessarily mean 100 degrees hotter, it might be 10 to 20 degrees hotter.
Practice on a bit of proto board with some offcut lead wire and you will see what I mean. In the end it will probably come down to personal preference.
It will also depend on the solder composition you are using
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A passive line-level crossover (PLLXO) is a good solution
A passive line-level crossover (PLLXO) is a very good solution for a xover that uses no op-amps which destroy sound quality. I need to create a highpass xover for my Aleph J-X at 100Hz just so I am not waisting amp power on low frequency for my satalites, I can use 6 or 12 db for the PLLXO, the formulas I will use are at the following link:
http://www.t-linespeakers.org/tech/filters/passiveHLxo.htm
So, can someone tell me what the input impedance is for the Aleph J-X for my PLLXO calculations
Thank You for all of the suggestions with respect to the sodering station, I have looked at them all and have not made a choice yet because I am not shure, do I need the desodering vacume ? Is it best if I just get it now for all of the changes I will be making with my stero now, I will have to take out and change parts I am not happy with or just to see how different parts sound ?
A passive line-level crossover (PLLXO) is a very good solution for a xover that uses no op-amps which destroy sound quality. I need to create a highpass xover for my Aleph J-X at 100Hz just so I am not waisting amp power on low frequency for my satalites, I can use 6 or 12 db for the PLLXO, the formulas I will use are at the following link:
http://www.t-linespeakers.org/tech/filters/passiveHLxo.htm
So, can someone tell me what the input impedance is for the Aleph J-X for my PLLXO calculations
Thank You for all of the suggestions with respect to the sodering station, I have looked at them all and have not made a choice yet because I am not shure, do I need the desodering vacume ? Is it best if I just get it now for all of the changes I will be making with my stero now, I will have to take out and change parts I am not happy with or just to see how different parts sound ?
Input impedance is whatever resistance you're using input to ground.
A solder sucker and wick are useful for rework. However, if you plan to do more than a couple of parts swaps, consider installing sockets until you settle on your final parts. Multiple reheating risks lifting the traces off of the board. Something like this 310-43-164-41-001000 Mill-Max IC & Component Sockets - just snap off a socket. Check lead diameters of the parts you want to swap. There are individual sockets that will accept larger leads a few pages earlier in the Mouser catalog.
A solder sucker and wick are useful for rework. However, if you plan to do more than a couple of parts swaps, consider installing sockets until you settle on your final parts. Multiple reheating risks lifting the traces off of the board. Something like this 310-43-164-41-001000 Mill-Max IC & Component Sockets - just snap off a socket. Check lead diameters of the parts you want to swap. There are individual sockets that will accept larger leads a few pages earlier in the Mouser catalog.
input impedance
So the input impedance on the given schematic would be R2=221kohms before additional parts for the passive xover ? Is that correct ? I thought it would be R1=22.1kohms ?
So the input impedance on the given schematic would be R2=221kohms before additional parts for the passive xover ? Is that correct ? I thought it would be R1=22.1kohms ?
Attachments
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nope
R1 is input impedance - for unbalanced
2x R1 is input impedance for balanced
R2 is there to reference gates to gnd , and usually one range higher in value than R1 ;
so - their influence on input impedance is max 10%
example - both R1s are 10K
both R2s in range of 100K
both R4s in range of 47K
gain is ~ 4,7 in balanced mode
input impedance for unbalanced 10K // 100K
input impedance for balanced 2x(10K // 100K)
everything is clearer when you know that gates are virtual ground(s)
in any case - this rough calculation is pretty close to what you can measure or sim
R1 is input impedance - for unbalanced
2x R1 is input impedance for balanced
R2 is there to reference gates to gnd , and usually one range higher in value than R1 ;
so - their influence on input impedance is max 10%
example - both R1s are 10K
both R2s in range of 100K
both R4s in range of 47K
gain is ~ 4,7 in balanced mode
input impedance for unbalanced 10K // 100K
input impedance for balanced 2x(10K // 100K)
everything is clearer when you know that gates are virtual ground(s)
in any case - this rough calculation is pretty close to what you can measure or sim
If you're planning to use a balanced output preamp to drive this, you'll need a PLLXO on both branches of the signal. Play with it in a circuit simulator to see what happens if you only filter one side.
ZM, I agree with your balanced case, but I think it's R2 (+R1) for single ended. For the low frequency intended for the PLLXO in this case I don't think the 10% matters. If this was a mid-tweeter XO, I'd be concerned. Papa's A75 design uses R1=475R and R2-75K. Input impedance quoted in the article is 75K. I thought opamp - inputs were the virtual ground and the positive needs a DC reference. Mixing signals into the positive input generates crosstalk, but the go into the negative and there is no crosstalk. Could be wrong, though.
Edit:
Following the calculations outlined in the A75 article, the positive input impedance is 243K, and the negative input about 11.5K.
ZM, I agree with your balanced case, but I think it's R2 (+R1) for single ended. For the low frequency intended for the PLLXO in this case I don't think the 10% matters. If this was a mid-tweeter XO, I'd be concerned. Papa's A75 design uses R1=475R and R2-75K. Input impedance quoted in the article is 75K. I thought opamp - inputs were the virtual ground and the positive needs a DC reference. Mixing signals into the positive input generates crosstalk, but the go into the negative and there is no crosstalk. Could be wrong, though.
Edit:
Following the calculations outlined in the A75 article, the positive input impedance is 243K, and the negative input about 11.5K.
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