Leolabs said:
Hello fellow Malaysian, it is good to see you here regularly.
Both o/p trans. have a min. hfe of 55, strictly speaking you really should design to the lower end not norminal hfe of 100. Furthermore, thes are "fast" devices due to lower input and miller cap. I think the drivers like 2SC4793 and 2SA1837 and o/p transistors make an excellent combo or synergy.
I am trying to build a power/integrated amp about 50-100w/channel based on these combo. I believe my chipamp(whatever model) and yours too will not come close to the performance(*) I can get from these devices when I finished building it. Similarly this applies to other amp. that are based on these o/p devices, there many excellent DIY ones on these sites, all of them based on discrete devices.
It will not be designed from ground up, I use short cuts like using the LME49810 driver chip and ready made power module. That will cut down the amount of design work and testing time and also cheap to construct eg. parts and PCB alone about US$26-$40 per channel without heatsink of course. If you interested leave a message here I will follow up with more detailed descriptions.
* I mean it will give the drive(speed) and slam to produce a large soundstage than any chipamp, esp. the BASS end. The smoothness and graininess is more a function of the type of components used.
Wish me luck.
Leolabs said:
If you read my posting I said 50-100W, I mean 50W for 8 ohm and 100W for 4ohm, rating I think it is convervative rated for 45V rail.
I heard from most people that the 2SA1943/2SC5200 combo is fairly dynamic. Have you tried MJL1302/MJL3281 combo to make the comment you made, or just based on experience of others?
Also a pair of the discrete SA1943/2SC5200 will still give better performance esp. at the Bass end over any chipamp watt for watt say comparing a pair of SA1943/2SC5200 with LM3886. I read from a no. of amp reviews that that chipamp does not give you dynamic bass performance(my experience as well). I think it it because the die on the chipamp is too small to delivery PEAK current necessary for good bass performance. Hence I am going along the direction as explained in the previous post. I will compare it with LM3886 to see what I suspect is correct. If it works I may parrallel a no. of SA1943/2SC5200 together if necessary.
Hi ttan98!Yes,I did compare both:under +/- 50V,the Toshiba sounds better in term of mid and high,a little attractive too at the vocal and the
OnSemi sounds well balance at each band,more slam at the lower end.
But seen that u r running them at lower supply voltages,so the result should be different from my experience.
And of course,sure they are perform better than normal chipamp,esp the bass.
OnSemi sounds well balance at each band,more slam at the lower end.
But seen that u r running them at lower supply voltages,so the result should be different from my experience.
And of course,sure they are perform better than normal chipamp,esp the bass.
An additional reason for 2sc4793/2SA1837 is that they are readily available from Digikey. Same page as 2SA1943/2SC5200.
Apart from specs and performance, for DIY availability is important. Doesn't do much good to layout the perfect amplifier only to find the components you need are not to be had.
Apart from specs and performance, for DIY availability is important. Doesn't do much good to layout the perfect amplifier only to find the components you need are not to be had.
Sam,
your arguement holds more water for serial manufacturers, imo.
It's the DIY person who can afford the time to scout for parts, for instance : 1930 5171, take as many as you like.
I live at 5 miles from the BMM online audio parts store overhere, if i miss out on an item i can just drop by on the way to the mall.
Instead, as a DIY-git i obtain most parts from abroad, to save a lot and spend even more.
Back in the old days i had to wait 6 months till visiting Paris for a stop-over at the l'audiophile store.
your arguement holds more water for serial manufacturers, imo.
It's the DIY person who can afford the time to scout for parts, for instance : 1930 5171, take as many as you like.
I live at 5 miles from the BMM online audio parts store overhere, if i miss out on an item i can just drop by on the way to the mall.
Instead, as a DIY-git i obtain most parts from abroad, to save a lot and spend even more.
Back in the old days i had to wait 6 months till visiting Paris for a stop-over at the l'audiophile store.
Loekipoeki,
i've only bought Japanese item loads from MAK and they all checked out.
I gathered that friend K-amps Arif received fake Motorolas from them a number of years ago.
So far i've burnt myself once with American TO3s, other than pics i know Jack-S about US devices, safer for me to buy garanteed genuine items straight from the distributor.
MAK changed their higher volume discount rates, makes it less attractive to buy overthere.
This year's birds on the beach are prime beef quality again, (skipping the topless and overcooked stringed old hags of course)
You weekend motorcycle lot don't know what you're missing.
i've only bought Japanese item loads from MAK and they all checked out.
I gathered that friend K-amps Arif received fake Motorolas from them a number of years ago.
So far i've burnt myself once with American TO3s, other than pics i know Jack-S about US devices, safer for me to buy garanteed genuine items straight from the distributor.
MAK changed their higher volume discount rates, makes it less attractive to buy overthere.
This year's birds on the beach are prime beef quality again, (skipping the topless and overcooked stringed old hags of course)
You weekend motorcycle lot don't know what you're missing.
Jacco,
Sometimes there are items that you can only get if you are willing to buy really big minimum quantities. Usually these will be an IC of some kind, but once had a lot of frustration buying some TO-126 devices. Unless you want to risk fakes you need to beware of obscure/unknown websites selling items not otherwise available. (I once got a great deal on some 2SA1943/2SC5200 except that they were fake.)
Sometimes there are items that you can only get if you are willing to buy really big minimum quantities. Usually these will be an IC of some kind, but once had a lot of frustration buying some TO-126 devices. Unless you want to risk fakes you need to beware of obscure/unknown websites selling items not otherwise available. (I once got a great deal on some 2SA1943/2SC5200 except that they were fake.)
Hi ttan98
TIP41/42 are no good as drivers!
ft=3...6 MHz
BD139/BD140 are OK up to about 90V (Vceo 80, Vcer 100V) and have fT ~ 100 MHz.
2SC2238 and A968 are TO-220s, not like TO-92's Lineup mentioned.
THey were very popular, but not currently made by Toshiba.
I've got Magnatec's in my 100W amp, which seem to run OK. Don't know if Magnatec supply old stock or build equivalents, but they appeared to have similar fT's to BD139-BD140, but rated at 160V.
Latest versions from Toshiba would be fine.
cheers
John
TIP41/42 are no good as drivers!
ft=3...6 MHz
BD139/BD140 are OK up to about 90V (Vceo 80, Vcer 100V) and have fT ~ 100 MHz.
2SC2238 and A968 are TO-220s, not like TO-92's Lineup mentioned.
THey were very popular, but not currently made by Toshiba.
I've got Magnatec's in my 100W amp, which seem to run OK. Don't know if Magnatec supply old stock or build equivalents, but they appeared to have similar fT's to BD139-BD140, but rated at 160V.
Latest versions from Toshiba would be fine.
cheers
John
Another vote here for the MJE15034/35 drivers. I used just one pair to push 5 pairs of MJL4281/4302 for a 350W @ 4 ohm amp with +/- 75V rails, and the amp so much drive current, it's amazing! I can run it at 2 ohms under testing with no problem too, the drivers and outputs don't run out of gain.
They have really high gain and high power handlng. I've even put peaks of 12A
in them without them blowing.
I use them in SMPS totem pole pairs because of their superior drive capability, and the high gain allows me a higher base resistor to keep the loading off the PWM chip in the SMPS.
Since I like the MJE's so much............
I'm about to try the newer MJW0281/0302 transistors as drivers in an amplifier, to have some oversized, robust drivers. They are sustained beta too, and since they are bigger, I'm hoping for even better gain.
They have really high gain and high power handlng. I've even put peaks of 12A
in them without them blowing. I use them in SMPS totem pole pairs because of their superior drive capability, and the high gain allows me a higher base resistor to keep the loading off the PWM chip in the SMPS.
Since I like the MJE's so much............
I'm about to try the newer MJW0281/0302 transistors as drivers in an amplifier, to have some oversized, robust drivers. They are sustained beta too, and since they are bigger, I'm hoping for even better gain.
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