| demogorgon |
Hi!
im currently ordering all the parts im gonna need for building the ESP P3a amp.
unfortunatly i'm not getting a hold of the MJL4302 end MJL4281A, or the suggested repalcements 2SA1216 and 2SC2922.
im gonna place the order shortly, but need a replacement!
i'm thinking about going for the BUW12 and its PNP complimentary..
I'm really hoping it's possible to just swap trnsistors, but offcours it isn't.. any sugestions?
regards
a overly tierd marius |
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| hienrich |
:)
MJL21194/MJL21193
MJ15003/MJ15004
MJL21196/MJL21195
I GUESS THIS THINGS MIGHT WORK. |
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| demogorgon |
Hi Hienrich!
thanks for helping out!
unfortunatly the place i'm ordering from dont have'm..
any other transistor that you can think of?
regards
marius |
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| demogorgon |
well, i really have to order now, so i went for the original project 3 output devices. the MJE 2955T\3055T
I'l order the others in time i guess, when i can get them.
regards
marius |
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| li_gangyi |
dun use the 3055s and 2955s...they wun be as good...get the original parts from Onsemi...
www.onsemi.com |
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| hienrich |
:)
i thinhk li_gangyi's right he thinks what i think. before what i think!!!! |
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| demogorgon |
Can't..
you have to pay shipment for samples right?
and then you have to use a visa, and i'm 17, so i dont have a visa.. :bawling:
guess i'l wait untill this summer when i turn 18 with getting the original parts from on-semi.
-marius |
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| hienrich |
by the way what devices are now at you hands. if you think that you in doubt with that just try to look for its specs in the net.:) :)
:cool: |
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| demogorgon |
until then, the MJE 2955T\3055T will work.. right?
just not as good..
i bought 4 pears, needing only one pear per chanel, guess i could paralell two pairs to make up for missing power handeling. (right?)
Hienrich: i dont really have anything i could use as of right now.. only some darlingtons, but because og their high gain, they are not sutable for this amp i think.. |
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| hienrich |
yes, it good to have two pairs than one, even with 8 ohm loads.
for a rather cooler operation for a long time. are these devices prefered for the project? if so then , go on. force cooling is also a must. :) :) :) |
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| demogorgon |
having fidled around with rather advanced computer modification for quite som time now, i have no problems with cooling things.. :cool:
I actually plan to watercool my stereo.
this is'nt a requirement as of now, with only a gc and soon to come p3a, but when i get the krellclone or alephX in-house things are going to heat up. :hot: |
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| hienrich |
for me i'll try the LYNX rather than the krell . I've been with deep darlingtons. so for solid and massive output try the LYNX.
:) |
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| djk |
If you would like to try something different with your two pair of outputs per channel for yout ESP3A, use the Bryston connected outputs.
http://sound.westhost.com/ad_fig7.gif
The first schema is an EF, the second a CFP, the stock 3A is a CFP.
If you add another 220R from the emitter of the driver to the collector of the existing output, and then add the second output (of oposite polarity) connected as an EF, you will essentially have the Bryston connection. If you wanted to add a predriver transistor (a pair of $0.10 to92 plastic devices) you could copy the Bryston circuit.
http://www.bryston.ca/pdfs/3B-SST-SCH-1C(Oct02).pdf
I would try it without the extra parts first, as the ESP3A doesn't need the voltage gain in the output stage like the Bryston does.
I would increase the bias in the driver stage like Bryston does by changing the 220R to 51R (47R~56R is OK). |
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| demogorgon |
hey djk!
i'l look into it.
but just wondering: wont increasing the bias current make the amp work in class aa? (pushpull class a?) |
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| djk |
Hardly, the bias in the driver is being increased from 0.003A to 0.013A, the older Bryston 3B ran about 0.03A
In the Threshold S300 class A design the drivers idle at about 0.2A |
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| hienrich |
:D
djk hello,
you know I've had Bryston schemes with me for along time already. I'd just like to know if how does this beast sound compared to Crown or QSC , becuase I'm also planning to clone one
model, may be the 9Bsst...
:D :D :D :D |
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| djk |
I think execution matters more than the topology does.
One of the best sounding amps I own is a McIntosh MC2120. It has a diff input pair and a second voltage amp, resistors for the current sources. An output stage.
Not counting the outputs there are only three transistors per channel total.
All I did to this amp was add a bunch of high quality caps as needed, about $4 total. |
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| demogorgon |
djk: ok, i'm lost here: could you give me a quick deffinition of bias curent? I think i got it all wrong..
Hienrich: Never heard of the lynx.. just the krell, and that because of it's ability to drive insane loads, and that is a quality i like.
Massive output power isn't needed for me. One can come a long way with 2*25w, even for heavy bass duty. at least i think so. |
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| djk |
The bias is the voltage applied from base to emitter that sets the idling current through the device.
Sometimes the idling current is refered to as bias, tubes for instance. |
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| hienrich |
:rolleyes:
demogorgon,
for me a 25watt amp is just as tiny as it would be. you cannot actually feel its spirit, just for me :D , but if you're contented with this and avoid disturbing youre nieghbors its still ok. actually
you could feel the coolness of the music at this level:) , but im for hot
:hot:
I just want to feel crazy of my outcome speacially when you know that
youre the who build your own.:att'n:
hienrich |
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| rodolfo |
| IS BETTER MJ15022 & MJ15023 BUTT ARE TO-3 |
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| WorkingAtHome |
You can try getting your trans from this guy:
http://stores.ebay.com/id=112687152&ssPageName=L2
Just got some brand new vintage Toshiba from him. Has lots more parts than he lists. Reliable.
It;s paypal too, so you might be able to pay by check if you don;t have a Visa.
-WAT |
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| demogorgon |
Hi WAT.
i dont have check either, but i actually got a proposal from steenoe on the forum for some transistors, the elliot recommended ones ;)
best of all: he lives in denmark, that makes things so much easier!
but thanks either way.
Hienrich
I'm seventeen, so i hav lots of time to make up my mind all over again should the need arise :D
im just getting into diyaudio too.. lots of testing and making up my mind to do.
djk:
Is not the basis-emitter voltage 0.65v at all tims, or should be in a class ab amp? if you change that, then teh amplification of the signal will be all messed up! wont it?
thanks
marius |
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| djk |
"djk:
Is not the basis-emitter voltage 0.65v at all tims, or should be in a class ab amp? if you change that, then teh amplification of the signal will be all messed up! wont it?"
Maybe you should buy a book on how this stuff works, the D. Self books are good. |
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| awpagan |
toshiba replacements are 2sa1943 and 2sc5200
slighty better i've been using them for over a year |
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| demogorgon |
Thanks! i'l chekc them out, if anyone has'em, i'l try them.
marius |
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