feel free to send few dozens to Pa , for proper evaluation and mist production;
I'll bug him to forward few to me , for usual disposal procedure
then we'll talk further , about melting my Ferrari in small siccies
(disclaimer - my Ferrari is Matchbox , 312 model - probably one of greatest , old almost as moi )
and yes - I'm dreaming all the time about wasting several watts in input LTP or whatever stage ; LU1014 or SJEP550 are just .......... exactly spear above regarding current needs , looking at ohmic region
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And there is a wealth of interesting info at MSU on/by Dr. Jeffery B. Casady and Dr. Mazzola.
Well if one could help folks here understand how to make a solid state device dance like a triode that would be a very good thing.
Part of the game here is avoiding higher order harmonic distortion and see in mostly 2nd and 3rd harmonic, looking forward to more info from the OP.
Thanks for the OP.
Part of the game here is avoiding higher order harmonic distortion and see in mostly 2nd and 3rd harmonic, looking forward to more info from the OP.
Thanks for the OP.
Another wonderful characteristic of tubes is the clipping behavour. Turning a sine wave into a square wave, as in clipping, produces massive amounts of odd order distortion. A tube circuit generally has a very rounded, smoother looking peak when driven to clipping. This translates into a much less anoying sound and less distortion. Almost a slight amount of peak limiting rather than clipping.
I understand SITs also have this soft clipping behavour?
I understand SITs also have this soft clipping behavour?
Another wonderful characteristic of tubes is the clipping behavour. Turning a sine wave into a square wave, as in clipping, produces massive amounts of odd order distortion. A tube circuit generally has a very rounded, smoother looking peak when driven to clipping. This translates into a much less anoying sound and less distortion. Almost a slight amount of peak limiting rather than clipping.
I understand SITs also have this soft clipping behavour?
It's all in the available shapes of the output curves (Id vs. Vds). More in the next article (at least my beginner's stab in the dark on the question).
I'm not so sure that the "don't need" part of 1200v devices is exactly correct. A bit depends on your point of view as to what you want to build. Obviously for most audio applications that much voltage is nutz. But if you think about substitution for vacuum tubes, the voltage capability starts to look like a benefit...
but an even smaller market segment... being commercial is difficult.
Can we do this in a small building, in the dead of night, with just a few people, relatively small quantities, using surplus fab gear... or leasing time in a real fab?
but an even smaller market segment... being commercial is difficult.
Can we do this in a small building, in the dead of night, with just a few people, relatively small quantities, using surplus fab gear... or leasing time in a real fab?
You must have visited the fab we ran at the university (Edwards building) to get SemiSouth started. You've captured it nearly perfectly.
(By the way, I'm not kidding...)
bear: The sonic value of Vds = 1200V remains to be determined. A question maybe: are the lower Vds values of 25-200 V protected by the attendant patents of Casady et al?
A Vds "value", spec or breakdown capability, Is not patentable. It is the physical structure and materials as they relate to the unique construction of the device. It is possible to have almost the same electrical parameters with a physically different structure without patent infringment.
It is very likely that these devices can replace tubes with very little circuit modification. I doubt we'll be able to replace a 300B with an R100 but, something more like a Pentode is likely?
Personally, If you look at the LU1014D device Vds vs. Ids graph, you can see the Red and Pink colored Vgs curves start looking triode like changing from the Blue, Brown and Violet looking Pentode like curves. What do the R100 and R085 curves look like in this area? The data sheet for them does not go that low in Ids (Vgs).
I have a few of each but, for the price I paid and the availability I'm not sure I want to try to do these measurements and have an accident. Although, I have the equipment at home and I'm snowed in, and under a driving ban, I still have power though, for now. Maybe after a few more Expresso and Bailey's.
I'll think about it.
It is very likely that these devices can replace tubes with very little circuit modification. I doubt we'll be able to replace a 300B with an R100 but, something more like a Pentode is likely?
Personally, If you look at the LU1014D device Vds vs. Ids graph, you can see the Red and Pink colored Vgs curves start looking triode like changing from the Blue, Brown and Violet looking Pentode like curves. What do the R100 and R085 curves look like in this area? The data sheet for them does not go that low in Ids (Vgs).
I have a few of each but, for the price I paid and the availability I'm not sure I want to try to do these measurements and have an accident. Although, I have the equipment at home and I'm snowed in, and under a driving ban, I still have power though, for now. Maybe after a few more Expresso and Bailey's.
I'll think about it.
This may helpA Vds "value", spec or breakdown capability, Is not patentable. It is the physical structure and materials as they relate to the unique construction of the device. It is possible to have almost the same electrical parameters with a physically different structure without patent infringment.
It is very likely that these devices can replace tubes with very little circuit modification. I doubt we'll be able to replace a 300B with an R100 but, something more like a Pentode is likely?
Personally, If you look at the LU1014D device Vds vs. Ids graph, you can see the Red and Pink colored Vgs curves start looking triode like changing from the Blue, Brown and Violet looking Pentode like curves. What do the R100 and R085 curves look like in this area? The data sheet for them does not go that low in Ids (Vgs).
I have a few of each but, for the price I paid and the availability I'm not sure I want to try to do these measurements and have an accident. Although, I have the equipment at home and I'm snowed in, and under a driving ban, I still have power though, for now. Maybe after a few more Expresso and Bailey's.
I'll think about it.
Well, I put a little thought into it. I'm thinkin I can use the circuit attached below? Comments are welcome:
My Function Generator can produce a single + Pulse, I'm thinkin maybe 1ms long, so as not to get to much device heating. I will be going for the 25C data since anything else is a little difficult to do right now. Typically we do these measurements within 100-200uS. We'll see what the measurements look like? I can also vary the pulse amplitude in relatively small steps.
The 100 ohm should'nt induce much of any error but, save me from oscilating to death. One of those accidents I was thinkin of.
The .05 ohm Drain R is "current shunt" to measure the Ids. It's big enough to measure voltage accurately but, not big enough to eat up my Drain voltage when current is flowing. It's also big enough physically to not induce to much Tc variation from heating.
I will use a storage scope triggered on the Func Gen pulse to capture these 2 voltages. In the past I remember having to use some diodes in the set-up to avoid the scope input saturation due to the range it needs to be on but, I don't think that's an issue here. That's probably the Rdson test I'm thinkin of.
Does anyone see any issues? Have any suggestions?
My Function Generator can produce a single + Pulse, I'm thinkin maybe 1ms long, so as not to get to much device heating. I will be going for the 25C data since anything else is a little difficult to do right now. Typically we do these measurements within 100-200uS. We'll see what the measurements look like? I can also vary the pulse amplitude in relatively small steps.
The 100 ohm should'nt induce much of any error but, save me from oscilating to death. One of those accidents I was thinkin of.
The .05 ohm Drain R is "current shunt" to measure the Ids. It's big enough to measure voltage accurately but, not big enough to eat up my Drain voltage when current is flowing. It's also big enough physically to not induce to much Tc variation from heating.
I will use a storage scope triggered on the Func Gen pulse to capture these 2 voltages. In the past I remember having to use some diodes in the set-up to avoid the scope input saturation due to the range it needs to be on but, I don't think that's an issue here. That's probably the Rdson test I'm thinkin of.
Does anyone see any issues? Have any suggestions?
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