John Curl's Blowtorch preamplifier part II - Page 575 - diyAudio
Go Back   Home > Forums > Member Areas > The Lounge

The Lounge A place to talk about almost anything but politics and religion.

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 16th August 2010, 05:12 AM   #5741
diyAudio Member
 
john curl's Avatar
 
Join Date: Jul 2003
Location: berkeley ca
That makes sense.
  Reply With Quote
Old 16th August 2010, 05:35 AM   #5742
diyAudio Member
 
Joachim Gerhard's Avatar
 
Join Date: Mar 2009
Did it sound any good, because that is what counts and not stories about the privat life of geniusses. Einstein had a chalenged child with his first wife he never met. I whould say from the spiritual point of few he was an a......h....
but boy, what has given that man to the modern world !
  Reply With Quote
Old 16th August 2010, 06:26 AM   #5743
diyAudio Member
 
john curl's Avatar
 
Join Date: Jul 2003
Location: berkeley ca
John Iverson made an excellent power amp, especially his first units. His Eagle was amazingly good for the parts that he used to make it.
  Reply With Quote
Old 16th August 2010, 06:28 AM   #5744
diyAudio Member
 
Johnloudb's Avatar
 
Join Date: Feb 2008
Quote:
Originally Posted by john curl View Post
How about an M derived passive filter before the buffer. Let's get serious here. ;-)
John, what do plan to do about the poor stop band attenuation the M-types reportedly (i.e. wikipedia) have. Incorporate a k-type? Or is it even an issue?

Constant k filter - Wikipedia, the free encyclopedia

m-derived filter - Wikipedia, the free encyclopedia

I was just comparing our old Pioneer TX-9100 to our Sony tuner. I gave the Sony the benefit of our outdoor antenna. The Sony did lock onto stations real good, and sounded a bit cleaner and more defined.

Where the Pioneer sounded a bit warmer and didn't pickup as many stations, but obviously the antenna is a big factor there. It's always had a slight warmth to the sound though, which can be a nice thing.

I didn't notice the grain you mention, just lack of definition in comparison to CD. Although, in comparison to the tuner you had, it could very well sound grainy. We have a pretty resolving system, and I only listened to FM stations.

John
__________________
My Website: Hyperacusis, Tinnitus, My Story
  Reply With Quote
Old 16th August 2010, 11:37 AM   #5745
diyAudio Member
 
jacco vermeulen's Avatar
 
Join Date: Oct 2004
Location: At the sea front, Rotterdam or Curaçao
Send a message via Yahoo to jacco vermeulen
Quote:
Originally Posted by 1audio View Post
Much more fun than (myself included)
Mr Martin,

you don't sound like it.
Da.n, how i enjoy non-unsavory nut folks and the stories about them, thanks for sharing.
  Reply With Quote
Old 16th August 2010, 12:55 PM   #5746
forr is offline forr  France
diyAudio Member
 
forr's Avatar
 
Join Date: Dec 2004
Location: Next door
Quote:
Originally Posted by scott wurcer View Post

Hi Scott,

Thanks for the link. A real story à la Connelly.

Since 1981, I've been interested by Johm Iverson because of what he said at the end of this interview (in french) :

Electro Research, interview de John Iverson (K.Renner)

Iverson speaks about "an amp configuration looking more or less like a bridge where output impedances are automatically set such as the current in one branch increases or decreases according to the state of the other branch".

I've never been able to discover more about this circuit, but I think it could be some kind of error correction.
  Reply With Quote
Old 16th August 2010, 02:59 PM   #5747
diyAudio Member
 
john curl's Avatar
 
Join Date: Jul 2003
Location: berkeley ca
That's John Iverson all right! Thanks for sharing. It does show his power amp and a peek at what is inside. He used an internal fan and small vent holes (as I remember) in the heat sinks as the exhaust. Good idea.
Personally, I found him very enterprising, almost dangerous, and a lot of fun to party with.
  Reply With Quote
Old 16th August 2010, 06:04 PM   #5748
diyAudio Member
 
scott wurcer's Avatar
 
Join Date: Jan 2004
Location: cambridge ma
Quote:
Originally Posted by forr View Post
Hi Scott,

Thanks for the link. A real story à la Connelly.

Since 1981, I've been interested by Johm Iverson because of what he said at the end of this interview (in french) :

Electro Research, interview de John Iverson (K.Renner)

Iverson speaks about "an amp configuration looking more or less like a bridge where output impedances are automatically set such as the current in one branch increases or decreases according to the state of the other branch".

I've never been able to discover more about this circuit, but I think it could be some kind of error correction.
Can't tell from this, scarey picture though a little like Roudolph Hess. Can't anyone post some circuits from the A-75 for some engineering discussion?
__________________
"This logos holds always but humans always prove unable to understand it, both before hearing it and when they have first heard it."
  Reply With Quote
Old 16th August 2010, 07:03 PM   #5749
The one and only
 
Nelson Pass's Avatar
 
Join Date: Mar 2001
I had one on my bench in 1975, brought over by Ed
Wodenjack of Sound Advice. I didn't get the opportunity
to dissect the front end, but I was able to confirm good
performance using parallel complementary TO-220
bipolars as followers. They were biased respectably,
but short of the 75 watt rating. According to Jon, it used
hella feedback, and that appeared to be the case.

  Reply With Quote
Old 16th August 2010, 08:39 PM   #5750
diyAudio Member
 
Join Date: Nov 2008
Location: Oakmont PA
Electro Research A 75V1 Class A Stereo Power Amplifier - eBay (item 320550755912 end time Aug-17-10 17:45:20 PDT)

If you want the Electro Research A-75 on eBay It is going for $2500.00.

I'll pass.
  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 05:37 AM.


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