F5 with cooling aggregate
Pics of an F5 project, the heatsink is rated at 0.06 Deg. C/W with the 12 V fan at full speed. Unfortunately the noise that the fan creates at full speed makes it unuseable so an Arduino controller pulses the fan motor at 25 Hz/2% duty cycle. The fin temperature of the heatsink never goes more than 10 Deg. C above ambient, and the noise created is considerably less than that made by a PC. The cooling aggregate costs less than half of what passive heatsinks cost and allows a smaller footprint.
The two PSUs are 30+ year old Farnell linear regulated, each has six 2N3055s for the series pass element, and are rated at 10 A output with a presetable voltage range of 20 - 30 V. The PSUs were rescued from a skip at my workplace, as was the silver coated PTFE insulated wire
The F5 is presently running with +/- 26.5 V rails and biased at 1.5 A, and it sounds better than anything I've previously heard through the old Quad 57s.
Pics of an F5 project, the heatsink is rated at 0.06 Deg. C/W with the 12 V fan at full speed. Unfortunately the noise that the fan creates at full speed makes it unuseable so an Arduino controller pulses the fan motor at 25 Hz/2% duty cycle. The fin temperature of the heatsink never goes more than 10 Deg. C above ambient, and the noise created is considerably less than that made by a PC. The cooling aggregate costs less than half of what passive heatsinks cost and allows a smaller footprint.
The two PSUs are 30+ year old Farnell linear regulated, each has six 2N3055s for the series pass element, and are rated at 10 A output with a presetable voltage range of 20 - 30 V. The PSUs were rescued from a skip at my workplace, as was the silver coated PTFE insulated wire
The F5 is presently running with +/- 26.5 V rails and biased at 1.5 A, and it sounds better than anything I've previously heard through the old Quad 57s.
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Fugly. I should have seen that coming, ZM ! 
But wait to see the Götterdammerung sliding bias class A cascode-SIT! With power switch made from lapis-lazuli and level meters from an ancient Sony cassette deck! (Sony TC-K80 on thevintageknob.org)
/RK
But wait to see the Götterdammerung sliding bias class A cascode-SIT! With power switch made from lapis-lazuli and level meters from an ancient Sony cassette deck! (Sony TC-K80 on thevintageknob.org)
/RK
Baking pans were a standard chassis material for me in the 1960's -- used for my first sweep-tube ham radio transmitter. I subsequently found that material from "No Parking" signs led to less ringing and could be fashioned with a bench vise and a rubber mallet -- no need of a metal brake here!
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
I'll take this box and I'll build F5T V2, everything is ready, only the lack of 800VA toroidal which is being built in Toroidy.
Always curious - with V2 and a 800VA toroid what power do you expect, and what speakers will you be driving?
Thanks for the feedback guys, I didn't want to spend much money on the case as I've spent too much on audio gear of late..The pan was $9.99 and I had spare plywood, the switcher PSU was something I got for free and some of the hardware was taken off my old ESP preamp.
I like the ODAC, its almost too small as it can flop around if the cables are disturbed.
I compared it to my old CD player which is a Sony SACD mid priced unit. The sound is crisper and less 'muddy', cleaner and more precise. The bass is also noticeable 'lighter' but I'm wondering if Sony has some kind of artificial enhancements which make it unrealistic.
I'm working on some new speakers next, smallish 2 ways with Vifa tweeters and Peerless woofers, increased sensitivity compared to my old speakers to compliment the lack of gain from the B1. My power amp is a penultimate Zen.