Lots of Questions
Hi Choky and other Babbelfishers,
I have lots of questions, but I have to start somewhere.
1. Did I read somewhere did I read that a Babelfish-J produces about 15 Watts? Is that about correct?
It looks like everyone here is experienced Aleph builder, so there is no comment about heat sinks.
2. How much heat will each of the IRFP150 transistors produce, so I can work out heatsink values.
I am trying to working out how many 2SJ109BLs to buy, and I was interested in "higher voltage/power" possibilities. I see that the thread has moved to talk about these variations.
3. Are you hopeful that Cascoding solve the limited voltage capability of the 2sj109 and not affect sound too much?
Originally, Choky, you said that the 2SJ109 will only drive about 2 output devices. I have been comparing IRFP140N and IRFP150N. The 150 looks like it is the equivalent of 2 pieces of 140N in parallel.
4. Which is "easier to drive": a 150N or two 140N's?
5. Same question for 240N and 250N?
6. Does cascoding help here too?
Now that you are talking about X-Jfet-Babbelfishing, I have to go back to read the story about the differences in power when an amp is X-ed. (I know about less noise, and different/reduced distortion characteristics. I am less sure about how power and speaker impedance relationships work together ... unless someone can summarize for me?!)
7. And finally, do you reckon I am better off going with a few 2SJ109BL's or should I get a whole lot of 2SJ74's and match them up?
That will do for now.
Regards,
George.
Hi Choky and other Babbelfishers,
I have lots of questions, but I have to start somewhere.
1. Did I read somewhere did I read that a Babelfish-J produces about 15 Watts? Is that about correct?
It looks like everyone here is experienced Aleph builder, so there is no comment about heat sinks.
2. How much heat will each of the IRFP150 transistors produce, so I can work out heatsink values.
I am trying to working out how many 2SJ109BLs to buy, and I was interested in "higher voltage/power" possibilities. I see that the thread has moved to talk about these variations.
3. Are you hopeful that Cascoding solve the limited voltage capability of the 2sj109 and not affect sound too much?
Originally, Choky, you said that the 2SJ109 will only drive about 2 output devices. I have been comparing IRFP140N and IRFP150N. The 150 looks like it is the equivalent of 2 pieces of 140N in parallel.
4. Which is "easier to drive": a 150N or two 140N's?
5. Same question for 240N and 250N?
6. Does cascoding help here too?
Now that you are talking about X-Jfet-Babbelfishing, I have to go back to read the story about the differences in power when an amp is X-ed. (I know about less noise, and different/reduced distortion characteristics. I am less sure about how power and speaker impedance relationships work together ... unless someone can summarize for me?!)
7. And finally, do you reckon I am better off going with a few 2SJ109BL's or should I get a whole lot of 2SJ74's and match them up?
That will do for now.
Regards,
George.
Re: Lots of Questions
1.same amount of power as Aleph 30,if you use +/-25V and Iq 2A
2.according to >1< that's 100W dissipation/ch so - if you use 2 150s as me- that is 50W per mosfet ; according to Mr. Hardware Wizz Magura- you can crank up to 100W per similar mosfet,if you can cool poor bstrd adequately
3. up to mentioned PSU voltage poor little jfet critter is completely fine without cascoding ; I didn't even tried cascoding that time,thinking- if it's good for Papa this way,it must be good to me
regarding 140 and 150 - you're right....input capacitances are critical factor ,that's why I choose to use one 150 and gain another issue-- no need for matching if you don't use paralleled mosfets
4. look at >3< ; less capacitance- easier drive task for little critter ; that's why I sez that 2 gates is max I think 109 is able to feed,thinking on ,say,140's gates , not 150's gates..........so to summ- either two 140s or one 150 in lower half of output.....hey- there is another drek idea- use 2 140s in one half and one 15o in other half of circ..........just joking,off course!
5. just look at input capacitances; I'm too preocuppied to do that right now- looking at Moto GP ........VIVA ITALIA!!
6.look under >3< ; when Steen my man do his homework (after vacation) I'll probably work little more on X Babelfish ,with included cascodes and more current in input stage ........probably using matched 2SJ74V ; cascodes will be used to decrease dissipation in jfet (not for voltage reasons) using more current through stage .....that will enable possibility of using multiple pairs in output.........crazy currents for greedy DiyAs even with Jfet input
differences between J and X amp you can read in my man Steen's posts regarding both amps .......all depends what your spks,room and listening habits are.....you know in most cases that lesser amp can be superior one.....and vice versa......
interesting-in last month or so ,my listening is exclusively with dreky 500mW amp..........
....to cite Babo......
7. if your plan is just to make Babelfish ,finding just two 109s is less complicated way ; if you plan to play little more with jfet thingies,than buy same amount of 74s and 170s ....and play;
don't get me wrong- choice is no one else's than yours- in case that you are solely interested in babelfish ,than easiest way is that you grab one of 4(in this moment) available Babelfish combos from me (mebbe even with 4 pcs of 150s if ya need them) ;
as I said -I have 4 pairs of 109bl left ...
all other trivias -including most cheapest (read free) alternative via PM.....
I hope that I give you all answers......
GeorgeBoles said:
1.same amount of power as Aleph 30,if you use +/-25V and Iq 2A
2.according to >1< that's 100W dissipation/ch so - if you use 2 150s as me- that is 50W per mosfet ; according to Mr. Hardware Wizz Magura- you can crank up to 100W per similar mosfet,if you can cool poor bstrd adequately
3. up to mentioned PSU voltage poor little jfet critter is completely fine without cascoding ; I didn't even tried cascoding that time,thinking- if it's good for Papa this way,it must be good to me
regarding 140 and 150 - you're right....input capacitances are critical factor ,that's why I choose to use one 150 and gain another issue-- no need for matching if you don't use paralleled mosfets
4. look at >3< ; less capacitance- easier drive task for little critter ; that's why I sez that 2 gates is max I think 109 is able to feed,thinking on ,say,140's gates , not 150's gates..........so to summ- either two 140s or one 150 in lower half of output.....hey- there is another drek idea- use 2 140s in one half and one 15o in other half of circ..........just joking,off course!
5. just look at input capacitances; I'm too preocuppied to do that right now- looking at Moto GP ........VIVA ITALIA!!
6.look under >3< ; when Steen my man do his homework (after vacation) I'll probably work little more on X Babelfish ,with included cascodes and more current in input stage ........probably using matched 2SJ74V ; cascodes will be used to decrease dissipation in jfet (not for voltage reasons) using more current through stage .....that will enable possibility of using multiple pairs in output.........crazy currents for greedy DiyAs even with Jfet input
differences between J and X amp you can read in my man Steen's posts regarding both amps .......all depends what your spks,room and listening habits are.....you know in most cases that lesser amp can be superior one.....and vice versa......
interesting-in last month or so ,my listening is exclusively with dreky 500mW amp..........
....to cite Babo......7. if your plan is just to make Babelfish ,finding just two 109s is less complicated way ; if you plan to play little more with jfet thingies,than buy same amount of 74s and 170s ....and play;
don't get me wrong- choice is no one else's than yours- in case that you are solely interested in babelfish ,than easiest way is that you grab one of 4(in this moment) available Babelfish combos from me (mebbe even with 4 pcs of 150s if ya need them) ;
as I said -I have 4 pairs of 109bl left ...
all other trivias -including most cheapest (read free) alternative via PM.....
I hope that I give you all answers......
Conversion in progress... 
My Aleph30 with Elna Cerafine, silver mica.. etc, etc..
Brothers Mini-A, pretty standard..
Parts used are industrial standard.. nothing fancy to start with..
PHE426 1uf and 4.7uf
Elna RJH Lowimpedans Elyts.
Arcol AC05 source resistors 0.33ohm.
Resistors 1% 0.6w metallfilm.
All parts on table.. Realised I forgot some parts, but they are in tha mail over..
Allmost there...
Mini-A Chassi and PSU. 2x160VA, 2x12Volt, 120,000uf, CRC, 0.1ohm...
Aleph30 Chassi and PSU. 800VA, 2x18Volt, 112,000uf, CRC, 0.1ohm..
My Aleph30 with Elna Cerafine, silver mica.. etc, etc..
Brothers Mini-A, pretty standard..
Parts used are industrial standard.. nothing fancy to start with..
PHE426 1uf and 4.7uf
Elna RJH Lowimpedans Elyts.
Arcol AC05 source resistors 0.33ohm.
Resistors 1% 0.6w metallfilm.
All parts on table
.. Realised I forgot some parts, but they are in tha mail over.. An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
Allmost there...
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
Mini-A Chassi and PSU. 2x160VA, 2x12Volt, 120,000uf, CRC, 0.1ohm...
An externally hosted image should be here but it was not working when we last tested it.
Aleph30 Chassi and PSU. 800VA, 2x18Volt, 112,000uf, CRC, 0.1ohm..
An externally hosted image should be here but it was not working when we last tested it.
hehe
nice
5. pic from top - it's essential - especially if you use Babelfish in DC mode - to have output mosfets on mutual plate (Alu or Cu) - because you use two htsnks per side....to keep them on same temp.........in that case DC offset on output will not wander tnx to different case temperatures......
nice
5. pic from top - it's essential - especially if you use Babelfish in DC mode - to have output mosfets on mutual plate (Alu or Cu) - because you use two htsnks per side....to keep them on same temp.........in that case DC offset on output will not wander tnx to different case temperatures......
Yunick said:Conversion in progress...
My Aleph30 with Elna Cerafine, silver mica.. etc, etc..
Brothers Mini-A, pretty standard..
Parts used are industrial standard.. nothing fancy to start with..
PHE426 1uf and 4.7uf
Elna RJH Lowimpedans Elyts.
Arcol AC05 source resistors 0.33ohm.
Resistors 1% 0.6w metallfilm.
All parts on table
Hi, man!
What is Elna RHJ? Four black elko's on the board?
Evox-Rifa PHE is very good choice...
Very nice work, very nice photos....
When you will "start engine"?
I waiting for sound results and impressions...
Just driveeeee!
My brother Benjamins boards are finished
Famous little J-Fet thinge....
An externally hosted image should be here but it was not working when we last tested it.
Famous little J-Fet thinge....
An externally hosted image should be here but it was not working when we last tested it.
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