Go Back   Home > Forums > Amplifiers > Solid State

Solid State Talk all about solid state amplification.

Please consider donating to help us continue to serve you.

Ads on/off / Custom Title / More PMs / More album space / Advanced printing & mass image saving
Reply
 
Thread Tools Search this Thread
Old 5th November 2009, 04:00 PM   #1151
AndrewT is offline AndrewT  Scotland
diyAudio Member
 
Join Date: Jul 2004
Location: Scottish Borders
Quote:
Originally Posted by HKC View Post
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.
__________________
regards Andrew T.
  Reply With Quote
Old 6th November 2009, 12:06 AM   #1152
Bonsai is online now Bonsai  Taiwan
diyAudio Member
 
Bonsai's Avatar
 
Join Date: Jul 2003
Location: Taipei, Taiwan
"does that mean it will do +-13Vpk @ 50mA output? This is equivalent to driving 260r to 9.2Vrms sinewave.
"

Excellent!
__________________
bonsai
Amplifier Design and Construction for MUSIC! http://hifisonix.com/
  Reply With Quote
Old 6th November 2009, 08:45 AM   #1153
AndrewT is offline AndrewT  Scotland
diyAudio Member
 
Join Date: Jul 2004
Location: Scottish Borders
Quote:
Originally Posted by Bonsai View Post
"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.
__________________
regards Andrew T.
  Reply With Quote
Old 6th November 2009, 09:03 AM   #1154
Bonsai is online now Bonsai  Taiwan
diyAudio Member
 
Bonsai's Avatar
 
Join Date: Jul 2003
Location: Taipei, Taiwan
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).
__________________
bonsai
Amplifier Design and Construction for MUSIC! http://hifisonix.com/
  Reply With Quote
Old 6th November 2009, 09:51 AM   #1155
HKC is offline HKC  Hong Kong
diyAudio Member
 
Join Date: Jan 2003
Location: Hong Kong
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.
  Reply With Quote
Old 6th November 2009, 10:00 AM   #1156
AndrewT is offline AndrewT  Scotland
diyAudio Member
 
Join Date: Jul 2004
Location: Scottish Borders
could you measure and post the drive voltage, before clipping, into a range of load resistances? try 100r, 150r, 200r, 300, 430r, 1k0, 10k.
__________________
regards Andrew T.
  Reply With Quote
Old 6th November 2009, 02:34 PM   #1157
diyAudio Member
 
john curl's Avatar
 
Join Date: Jul 2003
Location: berkeley ca
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.

Last edited by john curl; 6th November 2009 at 02:37 PM.
  Reply With Quote
Old 6th November 2009, 02:54 PM   #1158
HKC is offline HKC  Hong Kong
diyAudio Member
 
Join Date: Jan 2003
Location: Hong Kong
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.
  Reply With Quote
Old 7th November 2009, 07:46 PM   #1159
diyAudio Member
 
FastEddy's Avatar
 
Join Date: Jun 2006
Location: North Californie
Default AussieAmp Modules in Dr. Pass Chassis

...
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!
Attached Images
File Type: jpg Finterior2.jpg (606.7 KB, 1987 views)
File Type: jpg Finsato.jpg (712.4 KB, 1860 views)
File Type: jpg FAllup.jpg (723.0 KB, 1629 views)

Last edited by FastEddy; 7th November 2009 at 08:12 PM.
  Reply With Quote
Old 7th November 2009, 08:34 PM   #1160
The one and only
 
Nelson Pass's Avatar
 
Join Date: Mar 2001
Wow! That's great!

  Reply With Quote

Reply


Hide this!Advertise here!
Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off



New To Site? Need Help?

All times are GMT. The time now is 01:52 PM.


vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2014 DragonByte Technologies Ltd.
Copyright 1999-2014 diyAudio

Content Relevant URLs by vBSEO 3.3.2