Sony vFET Amplifier Part 2

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#2,262
Nelson Pass said:
Was special ZM edition.
Click to expand...

nope

ZM's having some other special editions , but not that one

even we , Supergirls , are not having absolute precognition
 

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#2,266
Studley - Of course.

But honestly, the normal FirstWatt recipe will work just fine here, (8x 15,000uF caps, 8 0.47ohm 3W resistors, etc...) Remember to use 35v caps. The 4U 300mm chassis gets pretty tight with the T-brackets, and there's not really room for the discrete diode bridges. I just use bridge blocks. (Which I prefer anyway...)
 
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#2,267
6L6 said:
Studley - Of course.

But honestly, the normal FirstWatt recipe will work just fine here, (8x 15,000uF caps, 8 0.47ohm 3W resistors, etc...) Remember to use 35v caps. The 4U 300mm chassis gets pretty tight with the T-brackets, and there's not really room for the discrete diode bridges. I just use bridge blocks. (Which I prefer anyway...)
Click to expand...

That's great. I'm on a steep learning curve and really appreciate the leg up that generous people like you provide here on DIYA.
 
#2,268
6L6 said:
Studley - Of course.

But honestly, the normal FirstWatt recipe will work just fine here, (8x 15,000uF caps, 8 0.47ohm 3W resistors, etc...) Remember to use 35v caps. The 4U 300mm chassis gets pretty tight with the T-brackets, and there's not really room for the discrete diode bridges. I just use bridge blocks. (Which I prefer anyway...)
Click to expand...

Here is a 35mm 105º 33000uf capacitor.

http://pt.mouser.com/ProductDetail/...=sGAEpiMZZMtZ1n0r9vR22Yj4l4UaFwO0QRc9ayIn3uw=

You can have quite a large capacitance using the universal psu board.
 
#2,270
Bridged power output

If I'm lucky enough to get a second kit then I'd like to bridge the amps. I want to work out how many wpc a bridged amp would deliver into a 20 ohm load. The stereo amp does 20wpc into 4ohms, so using the doubling rule a bridged amp could potentially do 40wpc into 8ohms. By my calculations that equates to about 18v (V sqd = P x R). Using P = Vsqd / R I get P = 324/20 = 16
So that's 16wpc into 20 ohms.

Is that correct or have I (very likely) overlooked something?
 
#2,273
I think I see where 6L6 is going with this.

Studley, for my just completed F4, I have enough volume with 0.9v max from my DAC. In an active setup. With a Radian compression driver.

It seems like one VFET should be plenty, unless I'm missing something...
 
#2,275
The output devices have approx. 18V rails. That's 36V pk-pk.

Bridging doubles your output voltage, to 72V pk-pk

Power is Vrms^2/load=watts

72v pk-pk *.3535=25.45vrms

25.45v^2 = 647.8

647.8/20 = 32w

Studley said:
The stereo amp does 20wpc into 4ohms, so using the doubling rule a bridged amp could potentially do 40wpc into 8ohms. By my calculations that equates to about 18v (V sqd = P x R). Using P = Vsqd / R I get P = 324/20 = 16

So that's 16wpc into 20 ohms.
Click to expand...
 
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#2,279
6L6 said:
The output devices have approx. 18V rails. That's 36V pk-pk.

Bridging doubles your output voltage, to 72V pk-pk

Power is Vrms^2/load=watts

72v pk-pk *.3535=25.45vrms

25.45v^2 = 647.8

647.8/20 = 32w
Click to expand...

Thanks Jim. I can see that I didn't do the right thing to calculate the Vrms of the bridged amp.
The pad will effectively reduce that 32wpc to about 3w, but the CD has a sensitivity of >100dB, so that's enough 😀
Thanks
 
#2,280
I have a large 18-18VAC 600VA transformer - it is used for my L'amp project but is "outboard" from that cabinet - can I also use it for this project? (or do I need to use a 22-22VAC transformer as I have read here?).

What kind of power output are we talking from these modules into a an 8 ohm load? (specifically, Fostex Fe206en?)

thanks!
 
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