The new "un-case" 2U amp enclosure works well with VHEX+ amp. Abletec SMPS and CRC filters are working well. Super wide soundstage, very clean, clear with superb dynamics an headroom.
Heatsinkusa.com sold by the inch. These are 7.28in deep and x 3in high (direction of extrusion) for $2.63/ inch plus $5 cut fee. With shipping both cost about $30.
7.280" - HeatsinkUSA
7.280" - HeatsinkUSA
That's actually an incredibly good deal compared to what I've seen.
I need to order one for my LM3886 -- as I have two heatsinks slapped together right now with thermal paste between.
I need to order one for my LM3886 -- as I have two heatsinks slapped together right now with thermal paste between.
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X, that's a cool arrangement. An idea for the top cover, if any - it can be done out of plexiglass, nicely glowing with the on-board LEDs in the dark 😉
Cool idea with plexiglass top cover. It's interesting how the LEDs are much more than just a visual indicator in this amp - they provide the low noise CCS voltage references.
Yes, they are thermally stable and low noise enough - red LEDs are especially good, giving around 1.8V reference. Green ones are also good (2.1V). Blue ones (3.4V) are a little bit more noisy - in some cases (output stage follower) it does not really matter, but in more critical locations (e.g. input stage CCS) it's better to use the red ones or a double-transistor arrangement with feedback, as I did in VHex.
I have just modelled PSRR - simulation of VHex+ shows 64db.
The newer version - VHex+BT (coming soon, prototyping now) will provide 70db.
What frequency is the PSRR at? There is the 50Hz line frequency and then higher value like 2kHz - but the PSRR is similar to what I observe.
Hi Valery,just for the story,this time it's impossible to find red led 1.8v reference,all stay around 2+ volt.
Hi Thimios, the ones I use (Kingbright, 3mm) give 2V at 20mA, but normally I keep them at 2-4mA, getting 1.7-1.8V reference in this case.
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Exactly,that is what i measure on a 5mm red one.
Your's is a high eficiency ,my seller said that is a standard one 5mm.😕
I've been using Kingbrite WP710A10LID, which Mouse calls "standard" leds. Kingbrite lists them as high efficiency too. Is there any issue using high efficiency as long as the voltage drop is correct? Is there a difference in thermal characteristics?
http://www.mouser.com/ds/2/216/WP710A10LID-231305.pdf
http://www.mouser.com/ds/2/216/WP710A10LID-231305.pdf
Pdf clearly say,this is a high efficiency device(2mA)
Are these suitable for Pitchfork pre-amplifier?
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This is an ongoing issue with Mouser's website. The parts descriptions are inaccurate often. It leads to a lot of wasted time and reodering of parts. They can't even get transistor package correct sometimes!
That was my thinking as well, so I've been using them up. Standard red leds are disappearing as fast as TO-92s.
Are 3mm red LEDs just as good as 5mm ones? I have a bag of 100 of the little 3mm variety. They do seem to get used up in my latest projects pretty fast.
The voltage drop is all that is really matters. The package of the led doesn't matter as long as it fits the board.