OPENAMP1 - MM phono preamp open project - diyAudio
Go Back   Home > Forums > Source & Line > Analogue Source

Analogue Source Turntables, Tonearms, Cartridges, Phono Stages, Tuners, Tape Recorders, etc.

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 27th December 2012, 02:20 PM   #1
PMA is offline PMA  Europe
Design engineer, consultant
diyAudio Member
 
PMA's Avatar
 
Join Date: Apr 2002
Location: Prague
Default OPENAMP1 - MM phono preamp open project

For those who might be interested, I have prepared an open project of the phono preamplifier for MM cartridge. It has very low noise and very low distortion. Gain is 40dB/1kHz. Output is capable to drive 50 ohm load, so one may directly connect headphones via 100 - 220 ohm pot. Please feel free to download documenation from

Preamplifier for MM cartridge
__________________
Pavel Macura
http://web.telecom.cz/macura/audiopage.html
  Reply With Quote
Old 27th December 2012, 02:33 PM   #2
Mooly is online now Mooly  United Kingdom
diyAudio Moderator
 
Mooly's Avatar
 
Join Date: Sep 2007
It looks really good Pavel (and all immaculately presented too). The buffers seem an unusual addition (in a good way) and should make for total compatability. Nice...

Thanks for sharing with the forum
__________________
-------------------------------------------------------
Installing and using LTspice. From beginner to advanced.
  Reply With Quote
Old 27th December 2012, 02:48 PM   #3
diyAudio Member
 
Join Date: Oct 2012
Default Kit?

Is this available as a kit? Price? Shipping?

Thanks

MLStrand56
  Reply With Quote
Old 27th December 2012, 02:53 PM   #4
PMA is offline PMA  Europe
Design engineer, consultant
diyAudio Member
 
PMA's Avatar
 
Join Date: Apr 2002
Location: Prague
Mooly, thanks for the kind words.

MLStrand56, not yet as a kit. But PCBs will be available by the end of January 2013. I have been very busy this year with industrial automation projects, namely plasma spraying, and have had almost no time for audio. Now in December I finally got some time for audio projects. Let's see, at the moment I cannot promise the kits.
__________________
Pavel Macura
http://web.telecom.cz/macura/audiopage.html
  Reply With Quote
Old 27th December 2012, 02:58 PM   #5
PMA is offline PMA  Europe
Design engineer, consultant
diyAudio Member
 
PMA's Avatar
 
Join Date: Apr 2002
Location: Prague
Quote:
Originally Posted by Mooly View Post
The buffers seem an unusual addition (in a good way) and should make for total compatability.
The buffers make 2 or 3 improvements:

1) feedback network may use lower impedance resistors (100 ohm between -IN and GND) to get lower noise. This results in higher capacitances, that are easily driven with buffer.

2) buffered output is much less sensitive to output cable type and length.

3) output is able to drive headphones.

To demonstrate buffer capabilities, please see attached distortion measurement of this MM preamplifier into 50 ohm load.
Attached Files
File Type: pdf openamp1_loop_50_ohm_load.pdf (105.5 KB, 323 views)
__________________
Pavel Macura
http://web.telecom.cz/macura/audiopage.html
  Reply With Quote
Old 27th December 2012, 05:40 PM   #6
Mooly is online now Mooly  United Kingdom
diyAudio Moderator
 
Mooly's Avatar
 
Join Date: Sep 2007
Thanks for the explanations and distortion plot. Impressive for 50 ohm loading.
__________________
-------------------------------------------------------
Installing and using LTspice. From beginner to advanced.
  Reply With Quote
Old 27th December 2012, 06:33 PM   #7
diyAudio Member
 
Joachim Gerhard's Avatar
 
Join Date: Mar 2009
Hello Pavel. If you like i can contribute an MC head.
It is super simple and works very well.
  Reply With Quote
Old 27th December 2012, 06:42 PM   #8
PMA is offline PMA  Europe
Design engineer, consultant
diyAudio Member
 
PMA's Avatar
 
Join Date: Apr 2002
Location: Prague
Hello Joachim, thanks, we may put it together.
__________________
Pavel Macura
http://web.telecom.cz/macura/audiopage.html
  Reply With Quote
Old 27th December 2012, 06:56 PM   #9
diyAudio Member
 
Joachim Gerhard's Avatar
 
Join Date: Mar 2009
Here we go.
Attached Files
File Type: pdf Bal MC Head for PMA.pdf (63.8 KB, 544 views)
  Reply With Quote
Old 27th December 2012, 06:57 PM   #10
diyAudio Member
 
Joachim Gerhard's Avatar
 
Join Date: Mar 2009
The servo will even be not necessary.
  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
Best rbb transistor, for MM phono preamp claudio Solid State 27 31st January 2013 01:58 AM
MM phono preamp with accu and solarcells Koifarm Analogue Source 5 4th November 2012 10:32 AM
Swiss Physics model 5 preamp MM phono input Eric Tang Analogue Source 10 5th October 2010 02:53 PM
Phono preamp mm cartier20002000 Analogue Source 8 27th November 2007 04:17 AM
LT1028 mm phono preamp? miziq Analogue Source 9 27th April 2007 06:10 AM


New To Site? Need Help?

All times are GMT. The time now is 10:27 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