Naim NAC 552 Preamp - 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 March 2009, 06:09 AM   #1
Banned
 
Join Date: Nov 2006
Default Naim NAC 552 Preamp

I have a couple of questions about this preamp.

1) I noticed they use a 800VA transformer which is larger than what they use in most of their power amps. What benefit would their be in using such a large transformer for a preamp?

2) The output of this preamp says 0.775v. This is less than unity gain what benefit would their be in using less than unity gain in a preamp?

I hope you guys can enlighten me a bit on this

Thanks
anyway
  Reply With Quote
Old 2nd March 2009, 06:35 AM   #2
Banned
 
Join Date: Nov 2006
Here is the link.

http://www.naim-audio.com/products/nac552.html
  Reply With Quote
Old 2nd March 2009, 07:44 AM   #3
diyAudio Member
 
analog_sa's Avatar
 
Join Date: Aug 2002
Location: Sofia
Default Re: Naim NAC 552 Preamp

Quote:
Originally posted by thanh1973

2) The output of this preamp says 0.775v. This is less than unity gain

Actually the gain seems to be x10 which is above unity


Many designers like the audible effects of an oversized PS. As this adds disproportionately to the cost of a commercial product it is not very commonly seen.
  Reply With Quote
Old 2nd March 2009, 11:04 AM   #4
Banned
 
Join Date: Nov 2006
How did you come up with a gain of 10, a CD player puts out 2V?

I understand about going with a bigger transformer I was a little confused though why they would go with something larger than what is actually in their poweramps which draw significantly more current
  Reply With Quote
Old 2nd March 2009, 11:33 AM   #5
diyAudio Member
 
traderbam's Avatar
 
Join Date: Jan 2002
Location: Earth
Quote:
Originally posted by thanh1973
I understand about going with a bigger transformer I was a little confused though why they would go with something larger than what is actually in their poweramps which draw significantly more current
Good question.

Naim are in the business of selling idiosyncratic hifi products for a profit.

Of course the preamp doesn't need 800W.
I'd think about what Naim Co. are trying to achieve (beyond sound quality) to understand why they made this decision.

There are many ways to skin a cat. A pre-amp certainly doesn't need an 800W psu to function. But it does need a very clean supply of energy. There are many ways to achieve this with a fraction of that transformer size and some additional components.
  Reply With Quote
Old 2nd March 2009, 11:50 AM   #6
diyAudio Member
 
Join Date: Jul 2003
Location: Bath, UK
Quote:
This is less than unity gain what benefit would their be in using less than unity gain in a preamp?
All Naim preamps actually have a gain of 13x and can swing over 7.5Vrms at the output.

Stating '775mv output' is essentially a marketing speak way of saying 'it's a line-level preamp'
  Reply With Quote
Old 2nd March 2009, 08:43 PM   #7
Banned
 
Join Date: Nov 2006
I don't have a turntable or tape decks, I only have a cd player.
So I am only interested what this preamp does while using cd as source.
If the preamp uses 13x gain regardless of source then you would be looking at 26V output while using a CD player.
From memory the Poweramp has an input sensitivity of about 1V.
So surely 13x gain can't be right while using cd as a source, that would definitely be asking for trouble.
  Reply With Quote
Old 2nd March 2009, 08:53 PM   #8
diyAudio Member
 
Join Date: Jul 2003
Location: Bath, UK
Remember that most recordings the average level is 20-40dB down from 'full scale', and you'll see why most preamps actually have some gain. And when did you last use a preamp 'wide open'? that's what the volume control knob is for! It feds the preamp with an attenuated input...

One might criticise Naim for having a touch too much gain at the preamp end, which can lead to a slightly cramped useful range on the volume knob, but that's actually entirely another discussion.
  Reply With Quote
Old 3rd March 2009, 07:57 AM   #9
Banned
 
Join Date: Nov 2006
I am not doubting you, but to me any company that would purposely add that much gain to a CD signal is either to lazy to develop something a bit more appropriate or has no idea.
Are you sure this is correct?
  Reply With Quote
Old 3rd March 2009, 08:27 AM   #10
Banned
 
Join Date: Nov 2006
I just did a spice simulation of the NAP 250.

To get 12W RMS into an 8 Ohm load the amp needs to see approximately 0.35V RMS at its input.
Divide this by 13 and you get 0.027V (seen by the preamp) divide this by 2V and you get 1.35% of the original CD signal.
Now that is a massive amount of attenuation.
  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
naim cdi dodge Digital Source 5 16th July 2009 09:12 PM
Naim NAC 112 haenisch Solid State 2 10th March 2009 12:51 PM
Naim DBL diy guy Multi-Way 2 23rd February 2008 02:04 AM
Naim style DIY Preamp Agisthos Solid State 4 15th November 2005 07:55 AM
Naim SL2 richie00boy Multi-Way 0 28th September 2004 09:33 AM


New To Site? Need Help?

All times are GMT. The time now is 11:14 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