Chip phono preamp - diyAudio
Go Back   Home > Forums > Amplifiers > Chip Amps

Chip Amps Amplifiers based on integrated circuits

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 21st November 2007, 02:22 AM   #1
diyAudio Member
 
Join Date: Mar 2003
Location: Central NY
Default Chip phono preamp

I'm looking for inexpensive, but good, DIY moving coil phono preamp. I'm familiar with the phono clone, but it seems that the OP27 is obsolete. Are there other designs or is it possible to update the phono clone to current opamps - perhaps the LM4562 since I have a few?

Thanks!
  Reply With Quote
Old 22nd November 2007, 10:13 AM   #2
AndrewT is offline AndrewT  Scotland
diyAudio Member
 
Join Date: Jul 2004
Location: Scottish Borders
is the 627 a near equivalent to the 27?

The thread surely gives modern opamp substitutions.
__________________
regards Andrew T.
  Reply With Quote
Old 22nd November 2007, 05:36 PM   #3
diyAudio Member
 
Join Date: Mar 2003
Location: Central NY
Do you mean the phono clone & vsps 'help desk' thread? I noticed that after posting here.

I'll probably do so, but I'm quite intimidated by a 100+ page thread. I'll probably read it backwards.

Thanks for the reply. I'll check out the 627.
  Reply With Quote
Old 22nd November 2007, 06:24 PM   #4
diyAudio Member
 
Juergen Knoop's Avatar
 
Join Date: Jan 2007
Blog Entries: 3
Hi,
OP27 from Analog Devices and OPA27 from TI are still active.
Regards
Jürgen
  Reply With Quote
Old 23rd November 2007, 09:18 AM   #5
Electrons are yellow and more is better!
diyAudio Member
 
peranders's Avatar
 
Join Date: Apr 2002
Location: Göteborg, Sweden
Blog Entries: 4
OPA637 is slightly better in a high gain application such as a phono amp.
__________________
/Per-Anders (my first name) or P-A as my friends call me
Super Regulator SSR03 Group buy
  Reply With Quote
Old 23rd November 2007, 09:20 AM   #6
Electrons are yellow and more is better!
diyAudio Member
 
peranders's Avatar
 
Join Date: Apr 2002
Location: Göteborg, Sweden
Blog Entries: 4
Quote:
Originally posted by AndrewT
is the 627 a near equivalent to the 27?

The thread surely gives modern opamp substitutions.

If you compare datasheets, these devices are quite different.
__________________
/Per-Anders (my first name) or P-A as my friends call me
Super Regulator SSR03 Group buy
  Reply With Quote
Old 23rd November 2007, 11:20 AM   #7
diyAudio Member
 
nelsonvandal's Avatar
 
Join Date: Nov 2006
LM4562 is low-noise, and in spite of having bipolar inputs has low bias current. It sounds qite good with a very clean treble and nice bass. Compared to FET-input opamps, it's a bit cold or sterile and give the impression of having a recessed mid. I don't know what gain there is in this RIAA stage, but DC-offset could be a bit higher than with OPA627. Since there's no volume control in front of the RIAA stage, bias current can be balanced. I can't see why you shouldn't try LM4562 since you already have them, and since OPA627 is very expensive and hard to get and soon there will be OPA827 available.
  Reply With Quote
Old 23rd November 2007, 03:20 PM   #8
diyAudio Member
 
Join Date: Mar 2003
Location: Central NY
I've found a few vendors that indicate stock of the OPA627, but they average around $38. Yeah, that's too expensive for me.

How about the OPA227? Would that work?

Oh, and when do they expect to have the 827 available?

Thanks.
  Reply With Quote
Old 23rd November 2007, 03:24 PM   #9
Nordic is offline Nordic  South Africa
diyAudio Member
 
Nordic's Avatar
 
Join Date: Sep 2005
opa 227 is a diffirent beast alltogether... pretty hard to stabalise and will sound thin and uninvolveing if all is not 100%...

give those 827's a chance...
  Reply With Quote
Old 23rd November 2007, 07:02 PM   #10
diyAudio Member
 
nelsonvandal's Avatar
 
Join Date: Nov 2006
Quote:
Originally posted by Paul Ebert
Oh, and when do they expect to have the 827 available?
I don't know, but some claim they've already got samples.

Give LM4562 a shot. If you want a warmer tonality - use OPA2134 (cheap, easy to find) for one stage and LM4562 for the other. Toghethter they'll give a warmer than neutral tonality (at least they do in my headphone amp). LM4562 can be a bit cranky, but just use decoupling caps in close proximity and have a good shield and ground. LM4562 is very prone to pick up radio interference.

The most neutral match for LM4562 I've found is LMH6654, but that amp has very high bias currents and the max voltage supply is +/- 6.
  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
Tube Preamp Popping on Source Input Change (?) / 6DJ8 Preamp On Chip Amps MartyM Tubes / Valves 3 16th October 2008 04:52 AM
new phono stage or old preamp with phono? flohmann Analog Line Level 2 2nd October 2008 09:51 PM
simple chip phono preamp dewdude Chip Amps 4 23rd May 2008 04:37 PM
Dual phono chip carlmart Chip Amps 5 27th July 2005 03:22 PM
Single chip MC phono stage DrewP Analogue Source 12 7th August 2002 02:42 PM


New To Site? Need Help?

All times are GMT. The time now is 01:24 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