John Curl's Blowtorch preamplifier part II - Page 2302 - 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 10th May 2012, 06:04 PM   #23011
hags is offline hags  United States
diyAudio Member
 
Join Date: Nov 2004
Location: Chain o' Lakes
Oh, there it is, "the volume can be adjusted without clicking noises".

Which I read as some type of degradation thru whatever chip vol. control they use.
__________________
"Some lures are designed to catch fish, others are designed to catch fisherman."
  Reply With Quote
Old 10th May 2012, 06:04 PM   #23012
diyAudio Member
 
Join Date: Sep 2004
Location: UK
Quote:
Originally Posted by scott wurcer View Post
I assume it's one channel. The pinout on the unheatsunk IC makes sense, looks like some inverting connection with diode clamps to the rail. What's REL2?
REL2 is a SIP reed relay, single pole form A. D2 is its coil diode.

Cliff
  Reply With Quote
Old 10th May 2012, 06:09 PM   #23013
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 bcarso View Post
I see 3 inductors
The inductors are also in each of the input stages after the three inputs, so six times total for stereo, part CM types.
The Burr Brown without a heatsink could be a servo.

(the coil addition referred to both the number of inductors, plus the ample use of Hamlin reed & NAIS relays, plenty of the both of them residing under the 720 boards i posted )

A Boulder 2008 costs more, in TAS's view also kick's butz, but after a decade they likely needed something new for them to not look old

btw : the 720 phono boards are used in both the 720 preamp and the 750 phono stage. At $25K/€34.9K retail i'd expected at least a separate batch with 750 print.
__________________
The buck stops Here

Last edited by jacco vermeulen; 10th May 2012 at 06:23 PM.
  Reply With Quote
Old 10th May 2012, 06:19 PM   #23014
diyAudio Member
 
Chris Hornbeck's Avatar
 
Join Date: May 2011
Location: Little Rock
Quote:
Originally Posted by 1audio View Post
All in the eye of the beholder:
soulution 720/721 preamplifier
Here the slew rate is given as "400ns". Although I'm more familiar with furlongs per fortnight.

Thanks,
Chris
  Reply With Quote
Old 10th May 2012, 06:21 PM   #23015
bcarso is offline bcarso  United States
diyAudio Member
 
Join Date: May 2005
Location: Canoga Park, California
I see I lifted the wrong spec for slew rate: it's claimed as 400V/ns for the phono preamp (330V/ns was for the power amp). I would also suppose from the specifications in Valin's text that the cited 100dB S/N ratio is with the input shorted. I'd like to know what it measures open.

So, are there enough reed relays in other parts of the circuit to make them the plausible switches for gain control?
  Reply With Quote
Old 10th May 2012, 06:22 PM   #23016
bcarso is offline bcarso  United States
diyAudio Member
 
Join Date: May 2005
Location: Canoga Park, California
Quote:
Originally Posted by Chris Hornbeck View Post
Here the slew rate is given as "400ns". Although I'm more familiar with furlongs per fortnight.

Thanks,
Chris
Ah good, units of time now
  Reply With Quote
Old 10th May 2012, 06:26 PM   #23017
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 bcarso View Post
claimed as 400V/ns for the phono preamp
Is what i refer to as Fags & Mags.
__________________
The buck stops Here
  Reply With Quote
Old 10th May 2012, 06:29 PM   #23018
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 vacuphile View Post
Doesn't look like a relay to me, more like one of those flat opamps like JRC makes.
Out of curiosity, just how long have you been into audio electronics ?

Provided you can Reed : http://img.photobucket.com/albums/v5.../hr09-084b.jpg
__________________
The buck stops Here
  Reply With Quote
Old 10th May 2012, 06:33 PM   #23019
diyAudio Member
 
Steve Eddy's Avatar
 
Join Date: Sep 2002
Location: Sacramento, CA
Quote:
Originally Posted by john curl View Post
Parasound sells something nearly equal in chassis construction and certainly in parts quality for $2300, so this phono stage appears to be priced about 5 times over its general worth in the marketplace.
In what country is that $2,300 phono stage manufactured?

se
__________________
The Audio Guild
  Reply With Quote
Old 10th May 2012, 06:36 PM   #23020
bcarso is offline bcarso  United States
diyAudio Member
 
Join Date: May 2005
Location: Canoga Park, California
Quote:
Originally Posted by jacco vermeulen View Post
Out of curiosity, just how long have you been into audio electronics ?

Provided you can Reed : http://img.photobucket.com/albums/v5.../hr09-084b.jpg
Ah the benefits of a bit of perspective!
  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 02:02 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