Going Linear with the Caiman

[HighFidelityGuy]

Thanks Martin, I'll be interested to hear if you think it makes any change to the sound.
I've ordered a few other types/makes of caps (tant and film) to try out, so I'll post my findings.

I've mostly done the same mods as you although I'm using Murata regs and currently have some Jensen caps for the passive mod (I'm trying lots). I've also swapped the resistor behind the 5V reg for a wire link but I've also swapped the fuse for a wire link. My next mod will be to swap the diode of a hexfred to see if that makes a difference. I'm trying to get the cleanest power possible into the DAC so that I can forget about that side of things and concentrate on tuning the sound with the choice of passive output caps.

[MartinT]

My next mod will be to swap the diode of a hexfred to see if that makes a difference.

Someone correct me if I'm wrong, but since that diode is permanently conducting in the forward direction and not switching, the speed of a hexfred diode will make no difference.

[Clive]

Someone correct me if I'm wrong, but since that diode is permanently conducting in the forward direction and not switching, the speed of a hexfred diode will make no difference.

Isn't it just there to protect from incorrect polarity? If you are careful with polarity why not replace it with a wire link?

[chrism]

If you take the diode out with a wire link remember to drop the voltage into the Caiman by around 0.5v if you are already feeding above 15.5v or so. The only way around this is to swap out the smoothing cap rated at 16v and any others in front of the voltage regs rated at 16v.

Regards

Chris

[Reid Malenfant]

Someone correct me if I'm wrong, but since that diode is permanently conducting in the forward direction and not switching, the speed of a hexfred diode will make no difference.

If that is indeed the case then you are absolutely spot on They aren't that fast anyway, there is much faster & softer recovery diodes out there for switching applications.

If it's voltage drop someone is worried about fit a schottky barrier

[HighFidelityGuy]

Someone correct me if I'm wrong, but since that diode is permanently conducting in the forward direction and not switching, the speed of a hexfred diode will make no difference.

Isn't it just there to protect from incorrect polarity? If you are careful with polarity why not replace it with a wire link?

If you take the diode out with a wire link remember to drop the voltage into the Caiman by around 0.5v if you are already feeding above 15.5v or so. The only way around this is to swap out the smoothing cap rated at 16v and any others in front of the voltage regs rated at 16v.

Regards

Chris

If that is indeed the case then you are absolutely spot on

You are of course all correct. It was really just the lower forward voltage drop that I wanted, whilst keeping the protection. I guess it's highly unlikely that I'll accidentally reverse the polarity and seen as I've already removed the fuse it would seem a little hypocritical to keep the diode. So I guess I'll bypass it. That would fit in better with my mission to ensure minimum voltage drop and maximum current delivery anyway.

They aren't that fast anyway, there is much faster & softer recovery diodes out there for switching applications.

If it's voltage drop someone is worried about fit a schottky barrier

That's an interesting point Mark, I thought HexFred's were supposed to be almost as fast as a schottky but smoother and therefore better for audio applications. What do you recommend as being fast but smooth?

Cheers.

[Reid Malenfant]

That's an interesting point Mark, I thought HexFred's were supposed to be almost as fast as a schottky but smoother and therefore better for audio applications. What do you recommend as being fast but smooth?

Cheers.

As i say a schottky barrier These are perfect for using as commutating diodes in class G & H power amplifiers as they switch very cleanly (far better than any epitaxial diode). They also have much less voltage drop when carrying a similar current (assuming the same current rating). They are majority carriers unlike any epitaxial diode which is a minority carrier. They don't store charge in the junction like epitaxials which needs to be removed to shut the thing down when reverse biased all of a sudden.

I'm not sure what the current draw is of the DAC you are using. Let me know or tell me the diode you are/have removed & i'll suggest a schottky replacement

[HighFidelityGuy]

As i say a schottky barrier These are perfect for using as commutating diodes in class G & H power amplifiers as they switch very cleanly (far better than any epitaxial diode). They also have much less voltage drop when carrying a similar current (assuming the same current rating). They are majority carriers unlike any epitaxial diode which is a minority carrier. They don't store charge in the junction like epitaxials which needs to be removed to shut the thing down when reverse biased all of a sudden.

I'm not sure what the current draw is of the DAC you are using. Let me know or tell me the diode you are/have removed & i'll suggest a schottky replacement

Ah, I see. I'm not 100% sure on the Caiman's current consumption but I don't think it's more than 2.5A. So what would you recommend for that?

While we're on the subject, what type of diodes/bridge rectifier would you recommend for use in a SuperTeddy reg based supply?

Thanks.

[StanleyB]

I'm not sure what the current draw is of the DAC you are using. Let me know or tell me the diode you are/have removed & i'll suggest a schottky replacement

150mA .

[HighFidelityGuy]

150mA .

Thanks Stan.