Designing a phono stage - Page 2 - diyAudio
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 2nd May 2001, 11:13 AM   #11
diyAudio Member
 
Join Date: Apr 2001
Location: UK
A very interesting article. Nice one Alex, I will build this one and see what I can learn from a design point of view.
  Reply With Quote
Old 2nd May 2001, 12:37 PM   #12
Alex M is offline Alex M  United Kingdom
diyAudio Member
 
Join Date: Apr 2001
Location: Hampshire, UK
Brownlow,

Mail me privately with your address and I'll send you
a photocopy of the JLH article.

Alex
  Reply With Quote
Old 2nd May 2001, 07:14 PM   #13
diyAudio Member
 
Join Date: Feb 2001
Location: Columbia, SC
*28* transistors!?!
Whew!
Clearly, the JLH phono stage isn't designed in the simpler-is-better mode...
I just had a second and took a quick look at the Hart electronics site. You'd think for throwing that much silicon into the thing that they could do better than a 26 dB S/N ratio.

Grey
  Reply With Quote
Old 3rd May 2001, 08:16 AM   #14
Alex M is offline Alex M  United Kingdom
diyAudio Member
 
Join Date: Apr 2001
Location: Hampshire, UK
Looking at the Williams Hart website, I noticed that the
specification is "26dB below surface noise", rather than
"26dB S/N". I haven't seen this spec before. Does anyone
know what this means? Is there an ANSI standard surface noise?.

I assyme that the real S/N is much better than 26dB.

Alex
  Reply With Quote
Old 3rd May 2001, 09:21 AM   #15
Alex M is offline Alex M  United Kingdom
diyAudio Member
 
Join Date: Apr 2001
Location: Hampshire, UK
I don't know about the version supplied in the kit, but
the original JLH circuit has 14 transistors per channel,
which seems fairly normal. The stereo board has 28 in
total.

Alex
  Reply With Quote
Old 3rd May 2001, 02:21 PM   #16
diyAudio Member
 
Join Date: Feb 2001
Location: Columbia, SC
Alex,
I understood that it was 14 per channel. (Hoping, anyway. Egad, the idea of 28 per channel is horrifying.) I, for one, don't regard the idea of 14 transistors per channel as encouraging. I do make an exception for circuits that run multiple gain devices in parallel to lower noise and/or output impedance, but somehow I don't think that's the case, here.
It's been a long time since I've seen anyone use the "below surface noise" phrasing. Note the vagueness--surface noise of a new record? of a ragged out party record? of a special test album? It says nothing. It's safest to assume that this thing is noisy, and that they're being vague in order to avoid being pinned down. In the past (and I mean a long time ago) people used to use semantic tricks like this to sidestep measurements that could be meaningfully compared to their competitors' numbers. (Yet another reason not to join the "Specifications Are Everything" crowd--you can't trust many of the published numbers...) Assume that -26 dB is a *best* case scenario and go from there.
Caveat emptor.

Grey
  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


Similar Threads
Thread Thread Starter Forum Replies Last Post
DIY phono to replace roksan phono stage seroxatmad Analog Line Level 6 14th December 2008 05:46 PM
new phono stage or old preamp with phono? flohmann Analog Line Level 2 2nd October 2008 09:51 PM
Designing a phono pre. #1: high gain block Onvinyl Analog Line Level 11 6th November 2007 07:16 AM
Help designing Input and Vas stage's DoomPixie Solid State 28 13th January 2006 09:28 PM
Should I replace Scott 222C phono stage with Claret phono stage? Bing Yang Analogue Source 0 22nd August 2005 06:41 AM


New To Site? Need Help?

All times are GMT. The time now is 07:39 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