I used those TTC and TTA on my build without issue; good parts
Assuming a 400mm 4U store chassis and a 4 ohm load... 6 deep versus 8 deep?
My interest is in having headroom for high current transients. I am not looking for PA scale high average powers and as I am comfortable with own marginally adequate `manliness' I don't want one of Pico's compensation enclosures (that, and I might not be able to lift it).
😉
It looks like you can get the 8 deep board on the 400mm heat sinks and given the 4 ohm load it seems like the right choice. However, the heatsink sets the maximum total bias current and running the 6 deep boards with slightly higher bias per device might sound better than dividing the same total bias current across more devices...
As always your considered guidance much appreciated
My interest is in having headroom for high current transients. I am not looking for PA scale high average powers and as I am comfortable with own marginally adequate `manliness' I don't want one of Pico's compensation enclosures (that, and I might not be able to lift it).
😉
It looks like you can get the 8 deep board on the 400mm heat sinks and given the 4 ohm load it seems like the right choice. However, the heatsink sets the maximum total bias current and running the 6 deep boards with slightly higher bias per device might sound better than dividing the same total bias current across more devices...
As always your considered guidance much appreciated
this is clear case when winner solution is one which gives you wider green and better sleep
in short - if 8 deep warms your heart more - go for it
same for 6 deep
with decent speakers in home arrangement, you'll hardly hear any difference
in short - if 8 deep warms your heart more - go for it
same for 6 deep
with decent speakers in home arrangement, you'll hardly hear any difference
Impressive, what DC rail voltage are you running?
Looks like a CLCRC psu, with added motor run caps. looks like a 500va toroid or so per channel.
Looks like a CLCRC psu, with added motor run caps. looks like a 500va toroid or so per channel.
DC rail voltage will be +/- 36V.
It is actually CLCc with the resistors in parallel with the chokes to control the Q factor. Toroids are 300VA with 28V secondaries.
The interior of the chassis is relatively narrow due to the size of the fins. I have the 8 deep OS boards and will set final bias current based on temperature.
It is actually CLCc with the resistors in parallel with the chokes to control the Q factor. Toroids are 300VA with 28V secondaries.
The interior of the chassis is relatively narrow due to the size of the fins. I have the 8 deep OS boards and will set final bias current based on temperature.
That is the rail voltage I have chosen as well, boards are loaded and will use the 6 transistor OS from ZM. Power supply is still to be resolved.
For the outputs, I have some Sanken 2SA2223A/2SC6154A or 2SA2151A/2SC6011A. From what I can gather these are not made anymore, but might still be available at a few places. I got mine from Digikey a few years ago now. The first pair I mention were actually used by Dan D'Agostino in his big amps, not sure what he uses now.
For the outputs, I have some Sanken 2SA2223A/2SC6154A or 2SA2151A/2SC6011A. From what I can gather these are not made anymore, but might still be available at a few places. I got mine from Digikey a few years ago now. The first pair I mention were actually used by Dan D'Agostino in his big amps, not sure what he uses now.
Those Sankens should work really well. I have four tubes (two different types of NPN & PNP) to sort through. I don’t have the part numbers, but they all looked like good devices intended for linear audio applications.
I might try disconnecting one N&P pair to get more current through the rest of the OS devices. See if there is a sweet spot based on voltage and current.
I might try disconnecting one N&P pair to get more current through the rest of the OS devices. See if there is a sweet spot based on voltage and current.
Digging through my stash of parts..
From Digikey I have 2SC4468 and 2SA1695; both 10A and 140V
From Mouser I have FJA4313 and FJA4213; O grade 17A and 250V
I was tentatively reserving the higher voltage parts for a larger build in 2pico's 'Toxic' chassis with higher voltage rails and 400VA transformers. But the boards that are built with those may start out in the smaller chassis just for fun.
I also seem to have an extra tube of FJA4313; must have been for science experiments of some sort.
From Digikey I have 2SC4468 and 2SA1695; both 10A and 140V
From Mouser I have FJA4313 and FJA4213; O grade 17A and 250V
I was tentatively reserving the higher voltage parts for a larger build in 2pico's 'Toxic' chassis with higher voltage rails and 400VA transformers. But the boards that are built with those may start out in the smaller chassis just for fun.
I also seem to have an extra tube of FJA4313; must have been for science experiments of some sort.
What about Sanken 2SC2922 - 2SA1216.
I know they are not in the correct house, but they are 200 W units and I have some in house.
I was thinking 5 pairs?
The data seems to be fine for the job..
I know they are not in the correct house, but they are 200 W units and I have some in house.
I was thinking 5 pairs?
The data seems to be fine for the job..
Just a quick question for those that have this amp built and running - what quiescent current (mV across 1R OS emitter resistors) did you settle on - and how many parallel OS transistors did you use and at what DC rail volts?
See my post on 1339, that’s what I used on mine
https://www.diyaudio.com/community/threads/new-stasis-front-end.363701/post-7323102
https://www.diyaudio.com/community/threads/new-stasis-front-end.363701/post-7323102