Robin said:
I have always liked the sound of the Sankens however in high volt applications, they seem to blow easier than TOS or MJ's, i.e. 90v and above. Whenever I would Substitute a Sanken in one of my power amps with 90v rails, they would blow, 1302's and MJ's would live longer... just my personal experience. (PS: The Sankens I tried were the A1294/ C3263 pairs, 130w and 230vce devices.)
rajeev luthra said:
I think that the best solution is the MJE1503x, depending the power You need. This transistors sound great, but as I found need a bit more bias for good sound. So I use them at least 30-35mA...
sajti
MOSFET input impedances aren't 'high', they are capacitive! and they turn also into low-value resistive at LF when a reasonably low-value gate bleeder resistor is added to provide quick enough turn-off
This capacitive impedance due to Cgs, Cdg and Cds and the resistive component due to bleeder resistors may be actually lower than the input impedance of a conventional darlignton. Impedance advantages should be carefully analyzed for each circuit
This capacitive impedance due to Cgs, Cdg and Cds and the resistive component due to bleeder resistors may be actually lower than the input impedance of a conventional darlignton. Impedance advantages should be carefully analyzed for each circuit
Eva said:
If You use with low speed signal, the mosfet has high input impedance. Maybe subwoofer applications???
sajti
To sajti : By my mosfet amps is full power bandwidh over 300 kHz - if you know this, nothing is problem 😉 . I add, that they aren't some 10 W *******s, but 100 W and more. SR 100 V/ microsec 😎 .
Upupa Epops said:
With proper designed amplifier it's possible. I also made mosfet amplifier with IRFP240/9240 output devices. I not used predriver for the mosfets, but the VAS runs with 80mA bias, and drive them easily. I checked with scope, and with 150W/4ohm, the 200kHz sine wave was perfect. 😎
But with VAS stage designed for darlington connected BJTs, are not suitable to drive mosfets directly. Driving mosfet by BJT follower, can results oscillation, beacuse emitter follower hates capacitive load.
sajti
power tranzistors
i would recommend the mjl4302\mjl4281 complementary pair made by onsemi (same as the toshiba 2sa1302\2sc3281 but with increased linearity and ft)
i would recommend the mjl4302\mjl4281 complementary pair made by onsemi (same as the toshiba 2sa1302\2sc3281 but with increased linearity and ft)
I prefer the A985\C2275 complementary pair.I foun that they tend to sound a bit more accurate than the mj1503*(wider soundstage........more refined trebble.....although a bit analitical)
As drivers I like 2SA1837 and 2SC4793 from Toshiba. They feature low capacitances, flat gain and high bandwith but their weak point is current capability since their useful Ic range ends at 500mA thus one or more pairs of drivers is advised for each two pairs of output devices
i prefer mjl4302/mjl4281 with mje15035/mje15034 drivers
also
fjl4215/fjl4315 fairchild power transistors , those are very hard to find and expensive and i think they are great
also
fjl4215/fjl4315 fairchild power transistors , those are very hard to find and expensive and i think they are great
For lower rail voltages ?
Could anyone suggest a favorite BJT (NPN only would be OK) for a low voltage O/P stage, say a 30V rail (eg 15-0-15). Can I get any advantage from the low voltage rail, like more beta / lower cost ?
dave
Could anyone suggest a favorite BJT (NPN only would be OK) for a low voltage O/P stage, say a 30V rail (eg 15-0-15). Can I get any advantage from the low voltage rail, like more beta / lower cost ?
dave
Providing you are not looking to run into low impedances and high power, then yes. You can switch to smaller, higher gain, faster, possibly more linear and possibly cheaper devices in TO220 package. A lot of devices used for drivers would be suitable, such as MJE15034/5 and 2SB1037/2SD1459.
Re: For lower rail voltages ?
I will go out on a limb and say the 3055 is pretty detailed in low power applications..
😀
DRC said:
I will go out on a limb and say the 3055 is pretty detailed in low power applications..
😀
Question....NAD 218 THX++
If I want to make the most out of this....I am going to use a active filter and the NAD as a SUB-bass amplifier, and let the vocals and highers be handled by the in this respect superior Electrocompaniet (AW-60DMB).
The output devices in the NAD are the somewhat unknown 2SB1317/2SD1975.
Would it be a good idea to replace theese Panasonic BJT's with some (used, but 100% OK) 2SC3281/2SA1302 devices I am certain is original Toshibas ?
If I don't remember wrong the 3281/1302 devices is mentioned somewhere on the net as very capable (if not the best) of delivering bass-slam, and that is indeed my goal with this NAD-amp.
Lyra
If I want to make the most out of this....I am going to use a active filter and the NAD as a SUB-bass amplifier, and let the vocals and highers be handled by the in this respect superior Electrocompaniet (AW-60DMB).
The output devices in the NAD are the somewhat unknown 2SB1317/2SD1975.
Would it be a good idea to replace theese Panasonic BJT's with some (used, but 100% OK) 2SC3281/2SA1302 devices I am certain is original Toshibas ?
If I don't remember wrong the 3281/1302 devices is mentioned somewhere on the net as very capable (if not the best) of delivering bass-slam, and that is indeed my goal with this NAD-amp.
Lyra
2SB1317
Specs for this are 180V, 15A, 150W with gain 60-200. ft is 20Mhz. The Toshiba pair have a higher voltage rating, mostly very close for specs otherwise. Lower average current gain.
Could you swap them out, sure. Would you hear a difference, only if you can hear power cords too. I think you'd be wasting your money.
-Chris
Specs for this are 180V, 15A, 150W with gain 60-200. ft is 20Mhz. The Toshiba pair have a higher voltage rating, mostly very close for specs otherwise. Lower average current gain.
Could you swap them out, sure. Would you hear a difference, only if you can hear power cords too. I think you'd be wasting your money.
-Chris
Re: 2SB1317
It won't cost me anything but my time........and I am thinking that if the 2SB1317/2SD1975 pair was as good as 2SC3281/2SA1302, they would certainly have been used more !!??
Lyra
anatech said:
It won't cost me anything but my time........and I am thinking that if the 2SB1317/2SD1975 pair was as good as 2SC3281/2SA1302, they would certainly have been used more !!??
Lyra
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