Reply to #60
I knew there was something wrong.Happily I played just one record.
Can you recommend not very expensive cartridge?
I knew there was something wrong.Happily I played just one record.
Can you recommend not very expensive cartridge?
AD797, a single in a DIP-8 format is a superb performer. Excellent voltage noise figure, and current noise is kept low by using low valued resistors around it, which that bean can easily drive.
I just look it up and the Digi-Key website lists the SOIC-8 version as obsolete. DIp-8 version was not available.
No, but I'm sure you will get lots of contradictory recommendations when you ask that question in a new thread in the analogue source subforum. 😉
No, not necessaryly.
To detect AM modulated RF-noise in the GHz range like DECT or GSM -
it only takes a nonlinear, slow input.
In the old days I did some investigations concerning RF immunity in the mid-wave and short wave radio band.
The then fast NE5532 was much more robust than slow MC1458, 4558 etc.
Last edited:
bucks bunny - My statement was in the context of PMA's measurement. The waveform looked like WiFi.
I have seen AM radio being picked up by speaker cables.
I have not experienced my audio designs picking up RF. I use input filters (except for the phono preamp due to the AT440ML), and my amplifiers have good open-loop linearity and moderate gain.
Ed
I have seen AM radio being picked up by speaker cables.
I have not experienced my audio designs picking up RF. I use input filters (except for the phono preamp due to the AT440ML), and my amplifiers have good open-loop linearity and moderate gain.
Ed
Here is high quality dual opamp im dip8 case:
https://www.diyaudio.com/community/threads/burr-brown-opa2228p-2pairs.412860/#post-7686564
This is pictures of real product that i sell. It is nos original part and it is used for audio.
https://www.diyaudio.com/community/threads/burr-brown-opa2228p-2pairs.412860/#post-7686564
This is pictures of real product that i sell. It is nos original part and it is used for audio.
Reply to #67
Thanks for the info.
I firmly believe that it is a great op amp but it would be too much including the shipping to the US.
Thanks for the info.
I firmly believe that it is a great op amp but it would be too much including the shipping to the US.
Thanks for the reply!
I looks like that have to do some research on that subject.
I just thought that you have enough experience to recommend something. You immediately noticed my fault.
Peteki recommended Doug Self's "Small Signal Audio Design" in post 25, but I would recommend Self's "Electronics for Vinyl" which is a distillation and enlargement on material in the first title. He mentions internal 'noise cancelling techniques' in such chips as the LT1028, which may speak to what batteryman and Mark were referring to in posts 27 and 35. In any case, Self presents a lot of information pertinent to analog recording, how to retrieve the information, reduce the rumble, minimize resistor noise, including filter designs for reducing scratch as well. He discusses circuitry for both moving magnet and moving coil cartridges, and enlarges on both the active and passive components, giving information on all things relevant. All good stuff to ponder as your design takes shape. I grew up with vinyl, and didn't totally miss out on the days of shellac, which has given me a great appreciation for the fragility of the medium. I have a fair amount of "stuff" that I treasure, and I know it will never be re-released in any other format. My philosophy now is to get everything into the digital domain as quick as possible, find good post-processing software to really clean things up, and then enjoy your vinyl/shellac treasures better than they ever sounded straight off the turntable!
The base current compensation circuit is one of the two reasons why the equivalent input noise current of an LT1028 (and LT1128 and LT1115) is so high. It's explained in https://audioxpress.com/article/boo...spice-models-to-simulate-vintage-op-amp-noise section 'Base Current Compensation Example'.
The other reason is that with a bipolar input stage, you need a relatively large collector current to achieve a very low equivalent input noise voltage, but that automatically leads to a relatively large base current, which has base shot noise. That base shot noise contributes to the equivalent input noise current.
The other reason is that with a bipolar input stage, you need a relatively large collector current to achieve a very low equivalent input noise voltage, but that automatically leads to a relatively large base current, which has base shot noise. That base shot noise contributes to the equivalent input noise current.
Last edited: