Hi, first post on here so apologies if I don’t provide enough information or if the question has already been answered elsewhere (had a look and couldn’t tell).
I’ve set myself a project of learning how to build a 2 channel stereo mixer in the dj format and have become puzzled in regards to Phono Preamps with RIAA.
I’m using the Ortofon Concorde DJ S Needle/Cartridge with a 6mv output voltage as my frame of reference. Ortofon - Concorde DJ S
Each channel on the mixer will have a phono and line inputs so I’m assuming I’m going to need to boost the phono input up to 2V CD line level. Is this correct or do I only need to amplify the phono signal up to an acceptable level so it can drive amplifiers later in the chain.
Using a design taken from page 190 of Small Signal Audio Design and building in Proteus 8 the phono signal only appears to have been amplified up to approximately 175mV. http://www.pearl-hifi.com/06_Lit_Archive/14_Books_Tech_Papers/Self_Douglas/Small_Signal_Audio_Design.pdf
I thought the point of a preamp was to bring up the phono level to line level (with applied RIAA EQ), if so would someone mind giving me some pointers in regards to what I’m misinterpreting or doing wrong.
Apologies again for the blatantly amateur question.
Attached is the Proteus file if anyone would like a nosey.
I’ve set myself a project of learning how to build a 2 channel stereo mixer in the dj format and have become puzzled in regards to Phono Preamps with RIAA.
I’m using the Ortofon Concorde DJ S Needle/Cartridge with a 6mv output voltage as my frame of reference. Ortofon - Concorde DJ S
Each channel on the mixer will have a phono and line inputs so I’m assuming I’m going to need to boost the phono input up to 2V CD line level. Is this correct or do I only need to amplify the phono signal up to an acceptable level so it can drive amplifiers later in the chain.
Using a design taken from page 190 of Small Signal Audio Design and building in Proteus 8 the phono signal only appears to have been amplified up to approximately 175mV. http://www.pearl-hifi.com/06_Lit_Archive/14_Books_Tech_Papers/Self_Douglas/Small_Signal_Audio_Design.pdf
I thought the point of a preamp was to bring up the phono level to line level (with applied RIAA EQ), if so would someone mind giving me some pointers in regards to what I’m misinterpreting or doing wrong.
Apologies again for the blatantly amateur question.
Attached is the Proteus file if anyone would like a nosey.
Having Source Signals coming out at the same level is a big advantage.
You can do this by amplifying and/or attenuating.
If the CDP level @ 2Vac is too high for your next stage, then you need to be able to attenuate that to what you require.
If the phono level is too low, then you need to amplify that to the level you need.
Identify the levels you NEED.
Then you can decide on amplification ratios and attenuation ratios.
You can do this by amplifying and/or attenuating.
If the CDP level @ 2Vac is too high for your next stage, then you need to be able to attenuate that to what you require.
If the phono level is too low, then you need to amplify that to the level you need.
Identify the levels you NEED.
Then you can decide on amplification ratios and attenuation ratios.
.
You're right, audio orbits around "line level." Confusingly, these days there's more than one definition of line level, but you won't go far wrong by using the classic one volt.
Also confusingly, "preamp" is a pretty vague term, it means about what you say it means. A general purpose preamp might have a gain around 5 or 10, a microphone preamp might have a gain of 500 (a lot!).
It's all intended to get the audio signal up to line level, because amplifiers and other devices generally develop their full output with an input of...you guessed it.
Phono cartridges don't put out a whole lot of power, they tend toward the lots of gain side. All of which is meant to lead up to the idea that this or other circuits by Mr. Elliott might be of interest: Hi-Fi RIAA Phono Preamp
.
You're right, audio orbits around "line level." Confusingly, these days there's more than one definition of line level, but you won't go far wrong by using the classic one volt.
Also confusingly, "preamp" is a pretty vague term, it means about what you say it means. A general purpose preamp might have a gain around 5 or 10, a microphone preamp might have a gain of 500 (a lot!).
It's all intended to get the audio signal up to line level, because amplifiers and other devices generally develop their full output with an input of...you guessed it.
Phono cartridges don't put out a whole lot of power, they tend toward the lots of gain side. All of which is meant to lead up to the idea that this or other circuits by Mr. Elliott might be of interest: Hi-Fi RIAA Phono Preamp
.
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