Crossover for Naim - diyAudio
Go Back   Home > Forums > Loudspeakers > Multi-Way

Multi-Way Conventional loudspeakers with crossovers

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 6th November 2001, 08:51 PM   #1
diyAudio Member
 
Join Date: Jul 2001
Location: CHESHIRE (UK)
I am starting to design an active crossover to work with naim 42.5 and a pair of 90.2's.
The speakers are tannoy m1's @ 2.5KHz 12dB per octave.
Any last second advice on op-amps or any other areas?

Regards
Kieran
  Reply With Quote
Old 6th November 2001, 09:09 PM   #2
Geoff is offline Geoff  United Kingdom
diyAudio Member
 
Join Date: Apr 2001
Location: UK
Kieran

There are many options for op-amps etc, by why not go discrete and use the Naim Naxo circuit. Details can be found here:

http://www.neilmcbride.co.uk/naxocircuits.html

Geoff
  Reply With Quote
Old 6th November 2001, 10:15 PM   #3
diyAudio Member
 
Join Date: Jul 2001
Location: CHESHIRE (UK)
Default xover

Thanks for the link.I have decided to use op-amps because there are less conections and simple to write a report on compared to tranys.
I am now interested in what you said and if I am sold the idea i will continue with it.If i made the trany one i could make a dedicated PSU and use it on other naim kit????
  Reply With Quote
Old 7th November 2001, 12:58 AM   #4
diyAudio Member
 
Join Date: Feb 2001
Location: Columbia, SC
Kieran,
A discrete crossover circuit need not be particularly complicated. A Sallen-Key circuit using followers has minimum parts and minimum connections.

Grey
  Reply With Quote
Old 7th November 2001, 05:33 AM   #5
diyAudio Member
 
Join Date: Oct 2001
Location: Alvesta, Sweden
Geoff,
thanks for that link.
Looks like a very interesting circuit worth to take a closer look at.
Interesting way Naim connected the transistors, haven't seen anything like it before.

Janne
  Reply With Quote
Old 7th November 2001, 07:05 PM   #6
diyAudio Member
 
Join Date: Jul 2001
Location: CHESHIRE (UK)
Ok what order is it and are the 2 groups of four tranys replacing op-amps??I admit I am leaning towards making it but i need to make it 2.5kHz and understand it a bit more.I can handle electronics so throw it at me
  Reply With Quote
Old 7th November 2001, 08:26 PM   #7
Geoff is offline Geoff  United Kingdom
diyAudio Member
 
Join Date: Apr 2001
Location: UK
Kiernan

If you redraw the schematics in a more traditional layout form you will find them easier to understand. In each set of four transistors, one ZTX384 and the ZTX214 form a compound pair emitter follower, with a constant current source made from the other two ZTZ384.

The first set of four transistors and associated components is a unity gain input buffer. This is followed by a passive 6dB/8ve filter stage and a 12dB/8ve active filter utilising the second set of four transistors in place of an op-amp.

The crossovers are therefore 3rd order 18dB/8ve and have been designed primarily for use with Naim SBL and Linn Kan speakers but I see no reason why they should not work well with other two-way designs. A search on the Naim site might elicit more information regarding the use of the Naxo crossover.

Geoff
  Reply With Quote
Old 7th November 2001, 08:55 PM   #8
diyAudio Member
 
Join Date: Jul 2001
Location: CHESHIRE (UK)
Geoff

Thank you I will try and dig out more info and take on the challenge (then again I am half way down a very nice red wine).Joking apart It makes sence to use the circuits due to the fact it is designed for Naim, all I might do is put the regs in the same box and see if I can upgrade any parts.

Nice wine
  Reply With Quote
Old 7th November 2001, 11:28 PM   #9
jam is offline jam  United States
diyAudio Member
 
jam's Avatar
 
Join Date: May 2001
Location: Auburn, CA, USA
Kieran

Naim uses a cross-coupled buffer used extensively in video circuits, an improved version is used by Levinson. The circit can be improved by current sourceing the emitters of the input pair.
Another approach is to use two complementary j-fets which simplifies the circuit down two active devices per buffer.

Jam
  Reply With Quote
Old 8th November 2001, 01:30 PM   #10
ALW is offline ALW  United Kingdom
diyAudio Member
 
Join Date: Jun 2001
Location: UK
Default Kieran

Hi there again,

The ZTX384 / 214 combination is often known as a complementary or series feedback pair.

A hunt through some electronics books should help you understand it, it's a little more complex than just a follower, owing to the feedback, but it's not too difficult.

It offers exceptionally good linearity for a simple circuit.

Jam's comments are interesting - may take a look at this.

Andy
  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 Nat 250 hollyann Solid State 0 18th July 2008 06:58 AM
Naim DBL diy guy Multi-Way 2 23rd February 2008 02:04 AM
FS Naim IXO chris maw Swap Meet 2 22nd November 2007 07:34 AM
Naim Crossover board SNAXO 2 way macka Swap Meet 0 9th October 2006 07:13 AM


New To Site? Need Help?

All times are GMT. The time now is 07:05 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