FET-hex explendit amplifier

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de Ocampo

de Ocampo

Member
Joined 2010
Idefixes said:
So i'am in love for the second time in one week....
Clearly it's the same family as VSSA LC...a little less bright as mosfet one but what a strongness in the lower frequency. These version seems more aware with my speakers as the Latfet one. For the rest LC-VSSA and BG1-bjt have same profile on details, sound stage, dynamic, ... BG1_bjt is quite sound dead as VSSA. I apply same wiring configuration as LC indicate...that's for sure the way to go. Thanks LC for sharing on VSSA and Borys for iteration and sharing on BG1-bjt.
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Pretty conclusive report Marc, Thank you! VSSA BJT has come to life :cool:;):cheers:
 
borys

borys

Member
Joined 2005
pszyszka.googlepages.com/
jorgovanko said:
borys, can You tell us briefly what the difference in sound between fethex and BJT version VSSA? It seems to me that You love your fethex version :) . thx.
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I do not have good enough speakers to tell U everything but one difference is noticeable straight away - bass has better definition in irfp version, maybe due to lower rdson and current capabillity (I do not know really), another diffrence I can hear when I disconnect the amp and put my ear into the speaker, irfp is dead silent, from latfet version I can hear very tiny noise (that is prapobly due to different Ugs for 2sk/2sj and irfp transistor, noise has more distace to 3,7V ugs of irfp - I do not know really)
 
borys

borys

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Joined 2005
pszyszka.googlepages.com/
jorgovanko said:
Thx. And when it comes to higher frequencies, which is your favorite?
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It is hard to say, all of them are very neutral in sound in my opinion.
I think latfet and irfp version are equally good but bjt is bit different on the top edge (better or not I really do not know). I am spending to much time working on amps instead listening the music recently.
Regards
 
Idefixes

Idefixes

Member
Joined 2003
audiyofield.wifeo.com/index.php
Lazy Cat said:
Hi Marc. I really like your work, you're fast, always very reliable at realization and testing. Looking forward to see more of your future work. Congratulations :up:
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Thanks for compliment...BG1 goes fast because it use test chassis (soft start/dc speaker protection/power supply). I just have to swap heatsink with new amp board and to change configuration plus a little wiring job. For sure will keep the grounding schematic you suggest in VSSA doc...both amp are quite silent dead. I think i will rewire to this mod my Nbip....
I have plenty stuff to play with : TSSA BIGBT is alway on the "to finish list", i also want to try Borys Hexfet version (since i have nice IRFP240/9240 set in stock)

Marc
 
Idefixes

Idefixes

Member
Joined 2003
audiyofield.wifeo.com/index.php
fab said:
I like the use of a to-3 heat sink to install input RCA and speaker terminals :cool:
It is quite original and could even be used for final product and not only prototype..

Thanks

Fab
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It's why i found an easy way for the test plateform : no need to additional support for RCA and Speakon connectic. But for final product this heatsink are in to bad presentation form to be used but for test they are on top, one or two new hole doesn't matter....

Marc
 
Idefixes

Idefixes

Member
Joined 2003
audiyofield.wifeo.com/index.php
fab said:
Nice work:up:

Have you also tried with MJL0281/0302 or 2sc5200/2sa1943?
Can you comment on your selected Sanken output device.

Thanks

Fab
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I have MJL4281/1302, MJL3281/1302, NJW3281/1302 but goe for sanken for the "mythe" that represent these transistors. BG1 was the occasion to play with 2 pairs. Due the price it's non reasonnable to use them in a build where we they are several in parallel. I even match my transistor in this case....as i my Nbip where MJL3281 were clese matched in HFE at 50mA (the 3 pictures above was sc5200/sa1943 session for a friend and before bigining 100x 3281A and 100x1302A mesure session). MJL for TSSA BIGBT are comming from this session.

Marc
 

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Idefixes

Idefixes

Member
Joined 2003
audiyofield.wifeo.com/index.php
So BG1-BJT is running since yesterday all days long and what it deliever still remain as the first impressions. I had time to play many of my beloved album (Harry Conick Jr at this time), and nothing wrong appear : always a clear, detailed, airy sound reproduction with quite good bottom presentation...If i wasn't contaminated by DIY virus it could be my allday long amplifier. I think i will build a decent enclosure and it will goes to my office room at work beacause he can play really cool at low level without tiresome listening.

Marc
 
G

gaborbela

Member
Joined 2005
borys said:
Bellow
Not tested yet version with 3 pairs with optional bootstrap (you can solder it or not, and you can use 2 setups of bootstrap, resistor and diode one)
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I have a request
Can someone remove the copper side from PDF to me please:)
I use iron transfer method for my PC boards and for that I need to do some minimal mode so I can use it successful.:cool:
If you do not want to post here you can send it to my mail address gaborzoltan2@gmail.com
Greetings Gabor
 
borys

borys

Member
Joined 2005
pszyszka.googlepages.com/
gaborbela said:
I have a request
Can someone remove the copper side from PDF to me please:)
I use iron transfer method for my PC boards and for that I need to do some minimal mode so I can use it successful.:cool:
If you do not want to post here you can send it to my mail address gaborzoltan2@gmail.com
Greetings Gabor
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Just print the pdf file named ''bottom'', in printer select no scalling or 1:1 or 100% and print.

BTW
Did You put the darlington transistor in biasing circuit in the your amp ??
 
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