Sorry for the intrusion, I am having a problem with inrush current on the Calvin buffer. I have opened a post here
https://www.diyaudio.com/community/threads/calvin-buffer-large-inrush-current.408207/#post-7576254
Can anybody kindly help me with this?
Many thanks!
https://www.diyaudio.com/community/threads/calvin-buffer-large-inrush-current.408207/#post-7576254
Can anybody kindly help me with this?
Many thanks!
@avinunca, current mouser bom for the main boards and calvins Inc sk75 heatsink is about £330 a pair. That includes upgrading nichicon caps to wurth organic polymer 30v and Panasonic fc for the 10uf 25v higher impedance caps.
But that doesn't include binning a s.tonne of 327/337 to match, and likewise cost of matched parts for the calvins.
£400 would be entirely fair.
But that doesn't include binning a s.tonne of 327/337 to match, and likewise cost of matched parts for the calvins.
£400 would be entirely fair.
Given what we now know about semiconductor noise performance, why not consider replacing the paralleled 327/337s by one ZTX 851/951 pair and omit the emitter resistors. No need too spend time matching transistors and you’d lower noise to boot. Of course, some changes will need to be made to the existing circuit but nothing major. Not an original idea it was suggested by Hans Polak.@avinunca, Snip
But that doesn't include binning a s.tonne of 327/337 to match, and likewise cost of matched parts for the calvins.
£400 would be entirely fair.
Just FYI, the Calvin buffer, even though a good interesting buffer, has significant asymmetries slew rates for fall and rise, and also has a poor big signal response and if used INSIDE a feedback loop it is prone to unstability. Sound wise, I found it to be good, but ultimately I preferred both sonically and technically speaking a BJT diamond buffer.
With that said, not saying to not used the Calvin buffer, but I wanted to share my take on this.
With that said, not saying to not used the Calvin buffer, but I wanted to share my take on this.
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