Post your Solid State pics here.

[AndrewT]

Originally Posted by HKC

Hi Andrew

It is the line stage of John Curl's JC-2 pre-amp. The voltage rail is +/- 15v and idle current @ the input JFets is 5.3ma while output bipolar pair is 50ma.

does that mean it will do +-13Vpk @ 50mA output? This is equivalent to driving 260r to 9.2Vrms sinewave.

[Bonsai]

"does that mean it will do +-13Vpk @ 50mA output? This is equivalent to driving 260r to 9.2Vrms sinewave.
"

Excellent!

[AndrewT]

Originally Posted by Bonsai

"does that mean it will do +-13Vpk @ 50mA output? This is equivalent to driving 260r to 9.2Vrms sinewave.
"

Excellent!

if it did then I agree.
But, he has not confirmed the output drive capability yet.

[Bonsai]

Lets hope he will confirm it!

Pre-amp output stages should have balls and be able to drive cables strongly- I don't believe in this wimpy hi Z output impedance stuff (apologies to the 'toob' guys).

[HKC]

Hi guys

In theory, output driver stage will still in class A operation under 130 Ohm and generate around 9.2Vrms. Thermal consideration is not considered. And despite the class A operation it may driver Ro <130 Ohm in circuit operation. But do you need that?

Since this is John Curl's design therefore I would also like to know what he would say.

[AndrewT]

could you measure and post the drive voltage, before clipping, into a range of load resistances? try 100r, 150r, 200r, 300, 430r, 1k0, 10k.

[john curl]

This is a low feedback, high open loop bandwidth design, that originally was designed as a cable driver of about 50 ft or more, for the Grateful Dead, 'Wall of Sound' PA system, designed in 1973. YES, we set the original idle at about 50 ma in the output stages in order to operate at peak beta of the 2W, heatsinked high speed devices that we chose. This was trimmed down slightly in the JC-2 line stage, because such need for long cable driving was not as important. 600 ohms was our design target and common in pro sound at the time. The original design used +/- 24 V power supplies, as well, for added headroom. It was pared down to +/- 15V for the JC-2, because the external power supply provided that voltage.

[HKC]

Hi John

Thank you for giving us the JC-2 information. No doubt it is a great pre-amp which even meets today's standard.

[FastEddy]

...
Specs: AussieAmplifiers.com -nxv300 = HPA-nxV300 380 watt MOSFET Audio Amplifier Module
Rail voltage under light load = +61.5 / 0 / -61.5.
Installed in Chassis #26 from BurningAmp Fest of last year. (Muchas grassiass, Nelson, Thanks.)
Oppo Digital -980H player is master controller. BottleHead Tube Preamp takes that digital edge off + SqueezeBox
Magneplan MG 1.6 Planar Flat Panel Speakers
Mmmmmm good!

[Nelson Pass]

Wow! That's great!