Yes. It is a pity that there is not a driver to really match the 1302/3281.
The 1930/5171 enter second breakdown too early for my plans.
Has anyone considered a FET as a driver? Seems like it may be a suitable application.
Best wishes
David
These folks seem to understand lateral power FETs for audio. Wonder why they don't release a 1 Amp driver and become the go-to source:
Magnatec. ALFET Lateral MOSFETs
They don't care about your bipolar driving problems? Their 8 Amp model doesn't get linear until too high current, and has 600p input capacitance compared to 90 for the old Hitachi parts...
Magnatec. ALFET Lateral MOSFETs
They don't care about your bipolar driving problems? Their 8 Amp model doesn't get linear until too high current, and has 600p input capacitance compared to 90 for the old Hitachi parts...
I am interested in the potential speed of MOSFETs for use in advanced compensation schemes. So the laterals are less attractive to me, no real improvement on the 15034/35 which is my current benchmark.
Some of the verticals have ~100pF. I am not very familiar with FETs but total (gate stopper + intrinsic) resistance of 10 ohms looks reasonable so roll-off around 160 MHz, a substantial jump from the 15034/35.
Best wishes
David
Some of the verticals have ~100pF. I am not very familiar with FETs but total (gate stopper + intrinsic) resistance of 10 ohms looks reasonable so roll-off around 160 MHz, a substantial jump from the 15034/35.
Best wishes
David
The product is SEMELAB who also do a nice line of audio power transistors. Profusion handle the same LATFET parts with different marking and more - They are probably the "go-to" source now.
Medium Power-Driver
Sadly, this option for through-hole parts is disappearing too. Even JFETs have almost vanished since Fairchild cut production of many US types. I can only suggest buying stocks to last into the forseeable future, if they become available as this is a sure sign of obsolescence. I really don't like the option of building anything new based on NOS or high-risk fake parts.
I have to sort my low-med power transistors for Hfe now too. That's why the parts selected must be cheap and designs need to be centred on the available range. However, I don't think you will have problems getting a good yield with 100-200 spec.
Thanks for the link to Profusion. However,the web site states : "For a lateral MOSFET amplifier you are better served with Sanyo's 2SA1209/2SC2911. Why? The low output capacitance (Cob) of these devices translates to reduced "Miller" effect, resulting in lower distortion..."
But the table of transistor provided does not include the 2SA1209/2SC2911 nor using the search engine...
Fab
OnSemiconductor owns Sanyo Semiconductor now and the 2SA1209/2SC2911 is EOL:
ON Semiconductor (some stock)
ON Semiconductor
ON Semiconductor (some stock)
ON Semiconductor
I favor building a ROBUST solid state amp that will not self-destruct with a 1-ohm load. I make sure that no transistor exceeds its spec's with a 1-ohm load in both Spice and on-bench testing.
Triple T Class-AB with low Class-A bias Output Stage:
--- output: NJL3281D NPN, NJL1302D PNP
--- driver: MJE15034 NPN, MJE15035 PNP -- do not destruct with 1 ohm load
--- VAS Hawksford Enhanced Cascode or standard Cascode: Low Voltage High Beta signal driver BC560C or 2SA970 PNP, BC550C or 2SC970 NPN. High Voltage Cascode 2SC3503 NPN and 2SA1381 PNP
I want to protect my speakers over my amplifier. Instead of putting a SPEAKER-CONNECT-RELAY in series between the amp output stage and speakers I have my "safe operation" protection circuits control a LARGE MOSFET with a 1ohm shunt resistor connected to the amp output terminals. If DC is detected, or if the output signal does not closely follow the input signal the MOSFET+1ohm is shunt connected and AC power disconnected to protect the speakers.
Save the Planet! Go Green! For low Class-A bias with Class-AB Output Stages I favor using ThermalTrak NJL3281D (NPN) and NJL1302D (PNP). The thermal diode really does reduce thermal transient distortion, especially for the first 30 minutes after turn-on.
For high Class-A bias, high power Class-AB amps with many output transistors pairs where fast Vbe thermal transisents do not occur the Sanken NPN 2SA1216 and Sanken PNP 2SC2922 have superior sound and thermals.
Triple T Class-AB with low Class-A bias Output Stage:
--- output: NJL3281D NPN, NJL1302D PNP
--- driver: MJE15034 NPN, MJE15035 PNP -- do not destruct with 1 ohm load
--- VAS Hawksford Enhanced Cascode or standard Cascode: Low Voltage High Beta signal driver BC560C or 2SA970 PNP, BC550C or 2SC970 NPN. High Voltage Cascode 2SC3503 NPN and 2SA1381 PNP
I want to protect my speakers over my amplifier. Instead of putting a SPEAKER-CONNECT-RELAY in series between the amp output stage and speakers I have my "safe operation" protection circuits control a LARGE MOSFET with a 1ohm shunt resistor connected to the amp output terminals. If DC is detected, or if the output signal does not closely follow the input signal the MOSFET+1ohm is shunt connected and AC power disconnected to protect the speakers.
Save the Planet! Go Green! For low Class-A bias with Class-AB Output Stages I favor using ThermalTrak NJL3281D (NPN) and NJL1302D (PNP). The thermal diode really does reduce thermal transient distortion, especially for the first 30 minutes after turn-on.
For high Class-A bias, high power Class-AB amps with many output transistors pairs where fast Vbe thermal transisents do not occur the Sanken NPN 2SA1216 and Sanken PNP 2SC2922 have superior sound and thermals.
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Pretty much all of the good old TO-126 parts for VAS are now obsolete. Their mainstream purpose was CRT drivers, and this role is now obsolete by the fact that CRT is obsolete, and before that, they were made obsolete by CRT driver IC's such as LM2470. There's pretty much only Fairchilds KSA1381/KSC3503, and they are becoming a pain to get. I'll be willing to bet Fairchild discontinue them soon, too.
SMD parts are inevitable in this hobby I think. Fortunately they are not all microscopic and impossible to use. SOT223 isn't that small. It's not impossible to heatsink them.
SMD parts are inevitable in this hobby I think. Fortunately they are not all microscopic and impossible to use. SOT223 isn't that small. It's not impossible to heatsink them.
