Yes, a perfect built!
OK, too long for me, as I always go for 30cm deep HIFI2000 chassis. I can't go for deeper ones. Jeff, any chance supporting the files in order to shorten them for myself?
Cheers, Ernst
I did run some sims of a double-output version last year, but to really get anywhere you need more rail voltage. And that requires absolute faith in Toshiba or cascoding of the LTP and CCS (or a BJT CCS), at which point you'd like to make use of that and increase the rail voltage substantially.
Of course then you'll need even more output devices to make use of that voltage.
So I switched that project to a F4/BA-2 output stage.
Of course then you'll need even more output devices to make use of that voltage.
So I switched that project to a F4/BA-2 output stage.
I do not entirely agree with that.
The J2 is never about chasing the lowest distortion figures.
Rather it is about a certain sonic (or if you like distortion) signature.
If one wants to have lowest distortion, one can simply replace the drain resistor of the diff pair by a current mirror.
One of the weakness of the J2, if it can be so called, is in driving low impedance load.
First Watt J2 power amplifier | Stereophile.com
If one does intend to use it to drive a low impedance load, then using paralleled output devices will be a realistic solution.
But it does require well matched devices.
You will need at least a matched quad of Semisouths, even if you were to use MOSFETs in the SRPP.
My 2 cents,
Patrick
.
The J2 is never about chasing the lowest distortion figures.
Rather it is about a certain sonic (or if you like distortion) signature.
If one wants to have lowest distortion, one can simply replace the drain resistor of the diff pair by a current mirror.
One of the weakness of the J2, if it can be so called, is in driving low impedance load.
First Watt J2 power amplifier | Stereophile.com
If one does intend to use it to drive a low impedance load, then using paralleled output devices will be a realistic solution.
But it does require well matched devices.
You will need at least a matched quad of Semisouths, even if you were to use MOSFETs in the SRPP.
My 2 cents,
Patrick
.
Completely true. But remember that the J2 is going to be impossible to clone accurately if you do not have the output devices. And its the outputs that make the sound.
J2 will stay in production at FW for a long time. It's the perennial great seller, and the shelves there are packed with unobtanium magic transistors.
It's not like people are DIY-ing their own Modushop chassis. So what if someone wants a FirstWatt-style chassis? (I have several of them.)
Speaking of which, I am DIY-ing my own HPA-1 chassis. Here's a snapshot of me milling the frontplate on a circa-1955 Bridgeport:
I'm having to make some changes to the volume knob arrangement though, since small-batch anodising is too expensive.
Cheers,
Jeff.
Speaking of which, I am DIY-ing my own HPA-1 chassis. Here's a snapshot of me milling the frontplate on a circa-1955 Bridgeport:
I'm having to make some changes to the volume knob arrangement though, since small-batch anodising is too expensive.
Cheers,
Jeff.
Attachments
In the free world we live it luckily, one is allow to do what one wants, as long as it is legal.
For example :
10 Ferrari Replicas | Fast Car
The original was a Toyota Celica.
Patrick
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For example :
10 Ferrari Replicas | Fast Car
The original was a Toyota Celica.
Patrick
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