... hm, sorry for eventually generating confusion.
The complete data sheet for the CREE C3D02060 diode is attached.
My consideration took reference to figure 1, forward characteristics. This plots the forward voltage drop caused by the actual current through the diode (even for different temperatures; i.e. pls. respect the heat sink req.).
Anyhow, rule of thumb seems to be that the voltage drop is AROUND 1V for this SiC Schottky diode and I would definitely suggest to verify this upfront experimentally.
All the best,
Ulrich
The complete data sheet for the CREE C3D02060 diode is attached.
My consideration took reference to figure 1, forward characteristics. This plots the forward voltage drop caused by the actual current through the diode (even for different temperatures; i.e. pls. respect the heat sink req.).
Anyhow, rule of thumb seems to be that the voltage drop is AROUND 1V for this SiC Schottky diode and I would definitely suggest to verify this upfront experimentally.
All the best,
Ulrich
Dear Felipe,
I'm reading the C3D02060 datasheet such, that at around 1A a voltage drop of 1.2V "typically" happens. You can therefore use either 8 diodes (=9.6V) or 9 diodes to achieve 10.8V. In reality this might slightly vary, being the reason to check this upfront.
All the best,
Ulrich
Well,
in most cases I prefer to use wooden "chassis" as my manufacturing skills are limited regarding metallic parts.
One example is attached.
This is my current class A tube switching pre-amp.
It provides switching between the 01A and 2P29L tube and between Gyrator/Anode choke as well as between C-R-C and C-L-C filament power supply.
This tool helped me to decide on how to proceed further towards the next pre-amp implementation.
All the best,
Ulrich
Attachments
So, according the CSD01060A data sheet, I interpret that you run these diodes below 50mA, right?
All the best,
Ulrich
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Here is the review of the shootout we had with Andy yesterday.
Also Morgan Jones came today to my place and listened to the final system: 01a-VT-25 into 4P1L PSE. A very busy couple of days!
http://www.bartola.co.uk/valves/2018/08/09/dht-audio-shootout-london/
Cheers
Ale
Also Morgan Jones came today to my place and listened to the final system: 01a-VT-25 into 4P1L PSE. A very busy couple of days!
http://www.bartola.co.uk/valves/2018/08/09/dht-audio-shootout-london/
Cheers
Ale
Huge thanks to Ale for hosting this 10 preamp shootout, and for enabling us to hear the SIC diodes in the cathode. I converted my 01A preamp today and am delighted with the added clarity. I've ordered 100 more. Not cheap but I'm going to use them in the 2P29L preamps and the 10Y. 100 isn't going to last long! The 01A takes 12 and the 2P29L is going to take more like 26..... and then...... and then......
Sounds like fun with diode bias!
The SiC schottky diodes should look somewhat like LED bias, but with the advantage of lower (signal) resistance.
And unlike LEDs, they will not need to be covered (light-proofed), to prevent noise from ambient light sources - LEDs can work in reverse.
At 1-10A, the diodes present about 1Ω to the signal. At lower currents (below 100mA) the SiC diode is in the threshold region. At 4mA, it is very close to threshold, and I would expect it to be somewhat non-linear: you can see the forward transfer curve curling, and the low-end.
If the SiC rectifiers sound good in this position, a couple of further tests come to mind immediately:
- the forward voltage will be more stable, and the signal resistance will be lower, if the current is increased to at least 250-500mA. The easy way to achieve this would be to filament-bias the diode string. 250mA would bring the signal resistance of the C3D02060A down to around 1Ω.
Filament bias would also increase the forward voltage, so you would need fewer diodes to get the same bias-voltage.
- The great advantage of SiC rectifiers, i.e.: much lower reverse-recovery current pulses (lower overall noise) - is of no use in this application; they are only forward-biased. Before spending a large amount of cash on Wolfspeed diodes, it would be worth checking out ordinary diodes rated for high current - and compare the sound. The MUR860 (8A continuous) should do nicely. The general nature of the forward transfer characteristic is very similar - while the cost is around 20dB lower.
The SiC schottky diodes should look somewhat like LED bias, but with the advantage of lower (signal) resistance.
And unlike LEDs, they will not need to be covered (light-proofed), to prevent noise from ambient light sources - LEDs can work in reverse.
At 1-10A, the diodes present about 1Ω to the signal. At lower currents (below 100mA) the SiC diode is in the threshold region. At 4mA, it is very close to threshold, and I would expect it to be somewhat non-linear: you can see the forward transfer curve curling, and the low-end.
If the SiC rectifiers sound good in this position, a couple of further tests come to mind immediately:
- the forward voltage will be more stable, and the signal resistance will be lower, if the current is increased to at least 250-500mA. The easy way to achieve this would be to filament-bias the diode string. 250mA would bring the signal resistance of the C3D02060A down to around 1Ω.
Filament bias would also increase the forward voltage, so you would need fewer diodes to get the same bias-voltage.
- The great advantage of SiC rectifiers, i.e.: much lower reverse-recovery current pulses (lower overall noise) - is of no use in this application; they are only forward-biased. Before spending a large amount of cash on Wolfspeed diodes, it would be worth checking out ordinary diodes rated for high current - and compare the sound. The MUR860 (8A continuous) should do nicely. The general nature of the forward transfer characteristic is very similar - while the cost is around 20dB lower.
RS stocks the MUR860 at pretty much the same price as the Wolfspeed (60p+for 25), and it's discontinued at Farnell. Any other suggestions?
Ale was saying the same as you - try it out in filament bias because it needs more current. It does sound nice with the 01A despite everything. Next will be the 2P29L at 15mA but in filament bias we're really turning on the current. That should be interesting.
Ale was saying the same as you - try it out in filament bias because it needs more current. It does sound nice with the 01A despite everything. Next will be the 2P29L at 15mA but in filament bias we're really turning on the current. That should be interesting.
Absolutely love your final terminology. Puts alot of this into perspective.
Cheers
Hey Ale, love your site, some really nice things on there that I want to try out 
Rod's here too, have a bunch of his filament/bias boards here ready to go into amps.
Still on the fence about CCS/Gyrators in the anode circuit, have always preffered inductive loads and no solid state in the signal path. Maybe you'll convince me one day
sorry for the threadjack
Rod's here too, have a bunch of his filament/bias boards here ready to go into amps. Still on the fence about CCS/Gyrators in the anode circuit, have always preffered inductive loads and no solid state in the signal path. Maybe you'll convince me one day
sorry for the threadjack