The IXCP10M45S is sold as a current regulator so the usual mosfet parameters are not shown in its datasheet. It could be a normal depletion mosfet but I wouldn't take the risk of using it as a follower. It cannot be used as a CCS in the PSU, the current to feed the zener is 1.7mA, and the IXCP10M45S has a minimum of 2mA. It could be used as a CCS (10mA) in the follower stage, but I don't know about the result. It would be a $3 saving each. Again, I wouldn't take the risk.
I bought a bunch of 10 IXTP01N100D and selected them for the minimum |Vgs| to use as followers and maximum |Vgs| to use as CCSs.
An STF3LN80K5 (cheap but good) can be used as a follower (also as a voltage regulator in the PSU), but the midpoint will go down around 5/6V because of its positive Vgs. This is only cosmetic, with no impact on the sound.
Before some ask: I tried the DN2535/40, as a CCS, but it seems below a certain current it doesn't work. Some in this forum say its sound is not the best.
I bought a bunch of 10 IXTP01N100D and selected them for the minimum |Vgs| to use as followers and maximum |Vgs| to use as CCSs.
An STF3LN80K5 (cheap but good) can be used as a follower (also as a voltage regulator in the PSU), but the midpoint will go down around 5/6V because of its positive Vgs. This is only cosmetic, with no impact on the sound.
Before some ask: I tried the DN2535/40, as a CCS, but it seems below a certain current it doesn't work. Some in this forum say its sound is not the best.
I am thinking to use two J113 parallel as the follower.
When diying BabyHue tube power amp, two mosfets with samll Ciss(300p) and Crss(0.85p) were used as buffer (follower with BJT CCS) between two tube stages(12AX7 and KT88). Subjectively speaking, I think it sounded not like a tube amp(I might be wrong).
If just from dadasheet, JFet has much smaller Ciss and Crss is comparable. I think it is worth trying.
When diying BabyHue tube power amp, two mosfets with samll Ciss(300p) and Crss(0.85p) were used as buffer (follower with BJT CCS) between two tube stages(12AX7 and KT88). Subjectively speaking, I think it sounded not like a tube amp(I might be wrong).
If just from dadasheet, JFet has much smaller Ciss and Crss is comparable. I think it is worth trying.