Im trying to build a preamp for my Hitachi Turntable. Its got a MM cartridge.
I know that it worked really well with my Akai Amp. Which used LA6458SS IC. (When the AMP was working).
Ive had a look over the various Pre AMP circuits on Passdiy as well as some other sites.
Ive also been trying to build and test some popular Tone Control Boards that also work as Pre-Amps. These boards all run NE5532 ICs.
Was wondering if some of the more experienced and knowledgeable members could guide me as to which route makes more sense. i.e. Go with a LA6458 IC or one of its compatible IC. Or to go the route of the NE5532. Or if you could explain the difference to a layman.
Right now plan is to finish the NE5532 tone control preamp boards and test them with the Turntable. If it doesn't sound right then scrap the NE route and try building a small PCB just copying the Phono stage from the Akai.
Attacked is the schematic showing how the Akai Phono stage is configured. USing the LA
I know that it worked really well with my Akai Amp. Which used LA6458SS IC. (When the AMP was working).
Ive had a look over the various Pre AMP circuits on Passdiy as well as some other sites.
Ive also been trying to build and test some popular Tone Control Boards that also work as Pre-Amps. These boards all run NE5532 ICs.
Was wondering if some of the more experienced and knowledgeable members could guide me as to which route makes more sense. i.e. Go with a LA6458 IC or one of its compatible IC. Or to go the route of the NE5532. Or if you could explain the difference to a layman.
Right now plan is to finish the NE5532 tone control preamp boards and test them with the Turntable. If it doesn't sound right then scrap the NE route and try building a small PCB just copying the Phono stage from the Akai.
Attacked is the schematic showing how the Akai Phono stage is configured. USing the LA
I built / bought 4 different preamps that use the NE IC. None match the ICs used by Akai in terms of quality. Or clarity. Also tested with one more Akai amp which sounded really good. This used LA3312. Anybody knows how to source this or LA6458SS in India.
I have a doubt about the akai schematic. Where is says C = 100p that is easy to understand 100 pf. But when it says 1 (M). What does it mean ?. What does the M stand for.
I have a doubt about the akai schematic. Where is says C = 100p that is easy to understand 100 pf. But when it says 1 (M). What does it mean ?. What does the M stand for.
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I copied Kenwood circuit from my amp, it had 6556, changed IC to TL072, had to change input and output resistors, then it was clear.
It is adequate for most purposes, good response, good slew rate.
5532 was sold here as Kia (INR 20), and NJM (INR
30) at that time.
Others, try in local market.
It is adequate for most purposes, good response, good slew rate.
5532 was sold here as Kia (INR 20), and NJM (INR
30) at that time.
Others, try in local market.
Try changing supply voltage to higher side of rated in data sheet, that may improve clarity.
Use a ground connection from pre amp to amp. Try and put the pre-amp in a metal box, and connect to Earth as a shield against stray noise.
I used a 'false earth' using 470 uF caps to get earth, from a supply, which was 12V 500 mA linear, gave about 16+ on load, as the pre consumes only a few mA.
There are some shops who have odd items in the Bangalore market, but a personal visit to that congested area will be needed to find them.
Use a ground connection from pre amp to amp. Try and put the pre-amp in a metal box, and connect to Earth as a shield against stray noise.
I used a 'false earth' using 470 uF caps to get earth, from a supply, which was 12V 500 mA linear, gave about 16+ on load, as the pre consumes only a few mA.
There are some shops who have odd items in the Bangalore market, but a personal visit to that congested area will be needed to find them.
200pF (100pF +100pf) plus whatever your cables and wiring add (maybe another 75 to 100pF?) is a lot of capacitance for loading a MM cartridge.
You might want to make some changes there ...
mlloyd1
You might want to make some changes there ...
mlloyd1
mlloyd1 I spent the last few months studying this book.
http://www.mh-audio.nl/Library/Vinyl/The Sound of Silence.pdf
It did help me answer one long standing question I had i.e. if you have a bag full of transistors how do you pick the best one for your build. (He has some good ideas to build test gigs).
The conclusion I came is that just find something that is really pleasing to your ear. And implement that.
I loved the phono sound off the Akai. I have tried to get a phono NE based circuit going but it just does not match.
So my hunt for the LA6458S continues.
http://www.mh-audio.nl/Library/Vinyl/The Sound of Silence.pdf
It did help me answer one long standing question I had i.e. if you have a bag full of transistors how do you pick the best one for your build. (He has some good ideas to build test gigs).
The conclusion I came is that just find something that is really pleasing to your ear. And implement that.
I loved the phono sound off the Akai. I have tried to get a phono NE based circuit going but it just does not match.
So my hunt for the LA6458S continues.
I can strongly recommend this one:
https://www.diyaudio.com/community/threads/openamp1-mm-phono-preamp-open-project.226508/
I built one some years ago.
It works quite well.
https://www.diyaudio.com/community/threads/openamp1-mm-phono-preamp-open-project.226508/
I built one some years ago.
It works quite well.