Re: Re: Wima caps
Upupa might shake your hands for that... 😀
Nice to hear that you are pleased with the symasym !
I won't call your heatsink oversized, with these you are on the safe side. As long as you drive 8ohm speakers your MJWs should do it, but for 4ohm and 40v supply you should replace them with the tougher MJLs.
Mike
still4given said:
Upupa might shake your hands for that... 😀
Nice to hear that you are pleased with the symasym !
I won't call your heatsink oversized, with these you are on the safe side. As long as you drive 8ohm speakers your MJWs should do it, but for 4ohm and 40v supply you should replace them with the tougher MJLs.
Mike
Re: Re: Re: Wima caps
Hi Mike,
I don't know why I used the MJW's. I'm sure I have some MJL's. I will check through my stuff. I know I ordered some and haven't use them for anything else. I know for sure I have some MJL4381A/MJL4303A. Will these work as well? Either way, I'll change them. I need to be able to drive 4ohm speakers.
Blessings, Terry
MikeB said:
Hi Mike,
I don't know why I used the MJW's. I'm sure I have some MJL's. I will check through my stuff. I know I ordered some and haven't use them for anything else. I know for sure I have some MJL4381A/MJL4303A. Will these work as well? Either way, I'll change them. I need to be able to drive 4ohm speakers.
Blessings, Terry
Hi Terry,
the MJL4381A/MJL4303A work, but i can not fully recommend them. Their beta degrades with current much earlier than the 3281/1302.
They seem to be designed for very high power amps, where you have to put many devices in paralell anyway.
This is especially a problem when driving 4ohms. The Toshibas sc5200/sa1943 do a very good job either.
If you have MJL3281/1302 at hand use these, or the Toshibas...
If you don't, use the MJL4381A/MJL4303A.
Pavel, "distorting stove", that's a good one ! 😀
Mike
the MJL4381A/MJL4303A work, but i can not fully recommend them. Their beta degrades with current much earlier than the 3281/1302.
They seem to be designed for very high power amps, where you have to put many devices in paralell anyway.
This is especially a problem when driving 4ohms. The Toshibas sc5200/sa1943 do a very good job either.
If you have MJL3281/1302 at hand use these, or the Toshibas...
If you don't, use the MJL4381A/MJL4303A.
Pavel, "distorting stove", that's a good one ! 😀
Mike
Thanks Mike,
I'll use the MJL3281/1302. I know I have them somewhere. I'm not even sure how I got these MJW's. I need to learn to pay better attention. 😀
Blessings, Terry
I'll use the MJL3281/1302. I know I have them somewhere. I'm not even sure how I got these MJW's. I need to learn to pay better attention. 😀
Blessings, Terry
Hi !
Here is a preview fresh out of sims for a high power version of symasym... I rejected the folded cascode thing, showing some bad behaviour. So i decided to go for cascoding. I still need to decide which devices for cascodes i will use, right now the schematic still shows 2n5551/2n5401, which are of course unadequate. Maybe some sb669 ?
The 2v voltagesources will be green leds and some other details are not completely finished.
Some specs:
max power: 500watt rms into 4ohms,>250 watts into 8ohms
THD: <0.04% for 500watts (20khz), <0.0006% for 20watts (20khz into 4ohm)
Bodeplot and stepresponse look fine... 🙂
I am not sure if 3 output pairs are sufficient, i doubt it.
What do you think ?
Of course i have no idea yet if it sounds good... (it should)
Mike
Here is a preview fresh out of sims for a high power version of symasym... I rejected the folded cascode thing, showing some bad behaviour. So i decided to go for cascoding. I still need to decide which devices for cascodes i will use, right now the schematic still shows 2n5551/2n5401, which are of course unadequate. Maybe some sb669 ?
The 2v voltagesources will be green leds and some other details are not completely finished.
Some specs:
max power: 500watt rms into 4ohms,>250 watts into 8ohms
THD: <0.04% for 500watts (20khz), <0.0006% for 20watts (20khz into 4ohm)
Bodeplot and stepresponse look fine... 🙂
I am not sure if 3 output pairs are sufficient, i doubt it.
What do you think ?
Of course i have no idea yet if it sounds good... (it should)
Mike
Attachments
Re: If you are telling me that!...no more Aleph!
I could send you some of the ones I used. You only need 4 for a 16V version. Mine are already matched.
Blessings, Terry
destroyer X said:
I could send you some of the ones I used. You only need 4 for a 16V version. Mine are already matched.
Blessings, Terry
Mike, try to think about Hitachi's 2SC2547 - it is good and cheap device with very flat beta curve.... 😉
Hello Gentlemen,
I was interested in finding out about these transistors (MJL4381A/MJL4303A) , but Motorola has no specs for them.
Is it possible there was a typo, and you're referring to the MJL4281A/4302A?
thanks
Joseph
I was interested in finding out about these transistors (MJL4381A/MJL4303A) , but Motorola has no specs for them.
Is it possible there was a typo, and you're referring to the MJL4281A/4302A?
thanks
Joseph
Hi Mike,
How about starting a new thread on your high power design? I think it will reduce confusion.
Didn't take you very long! I am a bit surprised.
-Chris
How about starting a new thread on your high power design? I think it will reduce confusion.
Didn't take you very long! I am a bit surprised.
-Chris
Good news right before new years
Hi Mike
I'm absolutely a nonbeliever, you started already the ball rolling!
The numbers are fantastic, may be a little too much of what I
was expecting, but it's OK, 250 W/8 ohms is really a treat. Three
pairs of outputs hein? It's going to be a killer...
We are going to be Mike's dependants for the next....humm, how
many months?
Don't worry, take your time, the only thing that I'm thinking at
this moment is to drop dead before the new amplifier's advent....
Terry
For me it never was nor will be an AlephX amplifier.
I took so many injections of the Aleph when I was a subscriber
of Audio Express that soon I got half depressed when I received
an issue of that magazine, never liked the amplifier and much less
the successive and continuous upgrades...But that's me!
You guys have a very happy and successful 2006!
Hi Mike
I'm absolutely a nonbeliever, you started already the ball rolling!
The numbers are fantastic, may be a little too much of what I
was expecting, but it's OK, 250 W/8 ohms is really a treat. Three
pairs of outputs hein? It's going to be a killer...
We are going to be Mike's dependants for the next....humm, how
many months?
Don't worry, take your time, the only thing that I'm thinking at
this moment is to drop dead before the new amplifier's advent....
Terry
For me it never was nor will be an AlephX amplifier.
I took so many injections of the Aleph when I was a subscriber
of Audio Express that soon I got half depressed when I received
an issue of that magazine, never liked the amplifier and much less
the successive and continuous upgrades...But that's me!
You guys have a very happy and successful 2006!
Upupa, do you have a datasheet at hand ? Excellent linearity might not be too important, these are "only" cascodes. Just low Cob... I'll keep the 2n5401/5551 as active devices.
Joseph, yes that was a typo, it is indeed MJL4281A/4302A...
I am looking forward to the MJL0281/0302, looks very promising and this time they got models that are functional... 🙄
Chris, the time it is functional i will start a new thread... BTW, since when are you moderator ?
Terry, it will play at the same volume as the smaller version, but this time you might need the gain, it already takes 1.5v input to get full output.
John, i thought, if increasing power, do it correctly... 60 watts, 100 watts who cares ? 250 will smoke some speakers... 😀
Oh my god... I just thought about the powersupply needed for such a monster...
Imagine a stereo version for 4ohms...
Mike
Joseph, yes that was a typo, it is indeed MJL4281A/4302A...
I am looking forward to the MJL0281/0302, looks very promising and this time they got models that are functional... 🙄
Chris, the time it is functional i will start a new thread... BTW, since when are you moderator ?
Terry, it will play at the same volume as the smaller version, but this time you might need the gain, it already takes 1.5v input to get full output.
John, i thought, if increasing power, do it correctly... 60 watts, 100 watts who cares ? 250 will smoke some speakers... 😀
Oh my god... I just thought about the powersupply needed for such a monster...
Imagine a stereo version for 4ohms...Mike
Mike,
Maybe you should consider the Sanyo 2SA1209 and 2SC2911, which look excellent on paper. Cob is only 4 pF. You can find datasheets at www.profusionplc.com who also sell them (something is wrong with certain manufacturers in their product list right now, so you have to search for the actual parts numbers to find them).
Maybe you should consider the Sanyo 2SA1209 and 2SC2911, which look excellent on paper. Cob is only 4 pF. You can find datasheets at www.profusionplc.com who also sell them (something is wrong with certain manufacturers in their product list right now, so you have to search for the actual parts numbers to find them).
Hi Mike,
Mod happened a short time ago. As with all moderators, I am just me unless required to do some work. So, no change and no cape.
You might consider dropping the power back to 150W to make things a little more reasonable. A 250W amp sounds like about 80 pounds or so. The protection network will need to be a little fancier at the higher powers. Sure enough, someone will attempt to drive a 2 ohm load with it too.
-Chris
Mod happened a short time ago. As with all moderators, I am just me unless required to do some work. So, no change and no cape.
You might consider dropping the power back to 150W to make things a little more reasonable. A 250W amp sounds like about 80 pounds or so. The protection network will need to be a little fancier at the higher powers. Sure enough, someone will attempt to drive a 2 ohm load with it too.
-Chris
Yes, this time i might not get away without some protection circuitry... 🙁 But i will make first prototype without, maybe it does not sound good...
What do you think, 50v supply for a more reasonable one ?
I could make 2 board versions, one with 2 pairs, and one with 4 or 5 ?
Mike
What do you think, 50v supply for a more reasonable one ?
I could make 2 board versions, one with 2 pairs, and one with 4 or 5 ?
Mike
Hi Mike,
I would definitely prototype without protection. Fuses would be in order in case something goes bang until the design is more stable.
I am thinking it might be easier to design for a higher voltage and start running it at +- 50VDC. Increase until things get too warm. That way you can find the safest higher power for that design. That will determine the number of outputs too.
Any advantage to going to MJ21195 / 6 devices? The TO-3 may help with heat.
-Chris
I would definitely prototype without protection. Fuses would be in order in case something goes bang until the design is more stable.
I am thinking it might be easier to design for a higher voltage and start running it at +- 50VDC. Increase until things get too warm. That way you can find the safest higher power for that design. That will determine the number of outputs too.
Any advantage to going to MJ21195 / 6 devices? The TO-3 may help with heat.
-Chris
It is superstition, guys.... correct designed protection circuit have any impact to sound... 😉