MM phono preamp gain

[Mosquito]

Hey there
How much gain must have an MM phono preamp if You use the Radio/Tape in/Aux of your integrated amp or preamp to be pair to the CDplayer out?
I mean to switch back and fort to CD and LP, to compare sound w/o any volume variation.
Maybe 52 dB at 1kHZ?
Thanks for Your attention to this matter.
JJT

 

[sergeauckland]

Typically, 40dB is right for a MM stage. That will result in an output of 500mV for a cartridge output of 5mV @ 5cm/sec recorded velocity.

It means that for a decent 20dB overload figure, the phono stage must be able to output 5V before clipping.

52dB is too high for almost any MM cartridge and too low for typical MCs.

S.

 

[Vincent Kars]

Maybe do the reverse.
Get a passive attenuator and reduce the output level of the CD player.

 

[JP]

I mean to switch back and fort to CD and LP, to compare sound w/o any volume variation.

Practically impossible with this approach. You'll need fine gain control to accomplish this.

 

[Redacted]

For matching volume, does it not depend on the output of your cartridge? They seem to vary.

 

[sergeauckland]

Practically impossible with this approach. You'll need fine gain control to accomplish this.

Also, any CD and LP will of necessity have different masterings, and possibly mixes, so any comparison will be pointless.

S.

 

[Redacted]

Also, any CD and LP will of necessity have different masterings, and possibly mixes, so any comparison will be pointless.

S.

As a side note, when ripping my CDs, I always run them through Foobar2000 to add the ReplayGain tags and my point is: I have found 14dB average album variations in my CDs....

 

[Mosquito]

Of course, I was talking about the same record, comparing the vinyl version with the CD version. Anyway, it seems that reducing the CD output is the right approach.

 

[Redacted]

I get you - I'm sure you get level variances, not just CD to CD (as I was 'complaining'), but also CD to vinyl for the same album. Basically, volume matching is a pain!


The worst thing is big and varying playlists, when a playback mechanism doesn't respect the track ReplayGain tags, but course not an issue with vinyl.

I had decades of good parties with people picking vinyl and also adjusting the volume - sometimes sensibly! - at the same time as dropping the needle, but with digital, it really needs to use RG, else it's hard work. Try my "drunk_dance.m3u" without RG - people want to volume adjust on every track.

 

[sergeauckland]

Of course, I was talking about the same record, comparing the vinyl version with the CD version. Anyway, it seems that reducing the CD output is the right approach.

But there's no such thing! The vinyl version and the CD version must be different as the mastering is different in each case.

In the first place, LP bass is mostly mono, as vinyl playback must minimise L-R difference, as this causes the stylus to move vertically. Secondly high frequencies are limited as disk cutters have to be protected from excessive HF due to the RIAA equalisation. None of these are needed for CD, which can be cut flat (although very rarely is!) CD tends to be compressed and limited heavily as that has no effect on the CD manufacturing process, whilst for LPs, heavy limiting and compression results in wider groove spacing and thus less time per side, so isn't done anything like as much as CD. Unless you produce your own CDs or LPs, there's no possible meaningful comparison that's possible betwen the two formats.

S.

 

[Redacted]

But there's no such thing! The vinyl version and the CD version must be different as the mastering is different in each case.

In the first place, LP bass is mostly mono, as vinyl playback must minimise L-R difference, as this causes the stylus to move vertically. Secondly high frequencies are limited as disk cutters have to be protected from excessive HF due to the RIAA equalisation. None of these are needed for CD, which can be cut flat (although very rarely is!) CD tends to be compressed and limited heavily as that has no effect on the CD manufacturing process, whilst for LPs, heavy limiting and compression results in wider groove spacing and thus less time per side, so isn't done anything like as much as CD. Unless you produce your own CDs or LPs, there's no possible meaningful comparison that's possible betwen the two formats.

S.

Yes, of course, but when I owned vinyl and CD versions at the same time (all vinyl got sold, happily) it was definitely the case that sometimes there were bigger volume variations between CD "A" and its (ostensibly similar) vinyl "A", than there was between CD "B" to vinyl "B", so apart from all the usual EQ issues, the basic recording level could vary a lot, if you get me (yes I know about compression, bass being mono, groove separation varying which meant vinyl got digitized to aid the cutting process at some date) . I can't remember an exact example, but I remember being slightly perplexed at the time!

Say what you like about the joy of vinyl, but life is easier now! Sorry - old theme here!

 

[Mosquito]

Thank you so much for all the opinions and experienced info. Things are much clearer now, and I see that the approach I was considering has little practical value.