Suzy
Could Q15 and Q17 be getting hotter than Q16 and Q18, thus unbalancing preceeding stages ?
SandyK
Could Q15 and Q17 be getting hotter than Q16 and Q18, thus unbalancing preceeding stages ?
SandyK
2sa1381/c3503
Hi,
they're really good at 100V. P(100v)=6.7W, I(100v)=67mA.
but Sanyo cheat with the Cob quoting the 30Vce value.
At 10Vce Cob=4pF & 4.6pF still pretty good and excellent for a 300Vce0 device.
Can one order hFE (10mA) F rank (160 to 320)? and judging by the graphs these hold steady (+0-10%) from 0.5mA to 30mA.
Hi,
they're really good at 100V. P(100v)=6.7W, I(100v)=67mA.
but Sanyo cheat with the Cob quoting the 30Vce value.
At 10Vce Cob=4pF & 4.6pF still pretty good and excellent for a 300Vce0 device.
Can one order hFE (10mA) F rank (160 to 320)? and judging by the graphs these hold steady (+0-10%) from 0.5mA to 30mA.
Re: 2sa1381/c3503
Unfortunately Mouser currently sells only rank E ( hFE(10mA) 100 to 200) devices. Still very good for the price.
AndrewT said:
Unfortunately Mouser currently sells only rank E ( hFE(10mA) 100 to 200) devices. Still very good for the price.
Hanging my head in shame
Now I'm really embarrassed.
In transferring parts from one of these amps to a 100W board, so I could prototype it using TO-126 VAS transistors, I found I'd used 33K load resistors in the input diffamp, rather than 18K ones.
Further investigation revealed that my 18K resistor stash was half full of 33K resistors. Of course, they're too small to read, unless you're looking under a microscope.
After putting the correct resistors in to the other one (I made a stereo pair), I'm now getting 0.0027% THD at 1KHz, and the output offset is solid as a rock.
I'm such a dork.
That said though, the single-ended to differential stage with separate SOT-23s is still way too sensitive to random air drafts and stuff for my liking.
So I'll still build the cool tiny TO-126 version, 'cos it's, well, tiny. And cool. But I'll definitely knock a version together using IMT8s and IMX4s as the second-stage diffamps, 'cos that might be even cooler.
Now I'm really embarrassed.
In transferring parts from one of these amps to a 100W board, so I could prototype it using TO-126 VAS transistors, I found I'd used 33K load resistors in the input diffamp, rather than 18K ones.
Further investigation revealed that my 18K resistor stash was half full of 33K resistors. Of course, they're too small to read, unless you're looking under a microscope.
After putting the correct resistors in to the other one (I made a stereo pair), I'm now getting 0.0027% THD at 1KHz, and the output offset is solid as a rock.
I'm such a dork.
That said though, the single-ended to differential stage with separate SOT-23s is still way too sensitive to random air drafts and stuff for my liking.
So I'll still build the cool tiny TO-126 version, 'cos it's, well, tiny. And cool. But I'll definitely knock a version together using IMT8s and IMX4s as the second-stage diffamps, 'cos that might be even cooler.
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