Post by sq225917 on Jun 4, 2020 18:40:36 GMT
You can go all out with discrete solid state parts, you can mix it up with valves or you can put your faith in Op-amps. There, I've said it.
Linn make a decent stab at the phono stages with their Uphorik and Urika models, both Op-amp designs and well regarded for their sound quality and performance. But I owned the Uphorik and it just wasn't my cup-of-tea. A bit mechanical sounding, great in the bass, but a litle busy sounding and a touch synthetic at times.
So when I was given a commission to build a MM/MC phonostage I thought why not? Richard Marsh has a great history with his phonoclone design so i thought I'd punt on a build with his latest pcbs.
I built it up with a dual mono PSU in separate chassis for all the heavy lifting. Traffos are selected to be multi-region and can be wired for 100v, 110, 200, 220v, 230v and 240v operation. I wired these up so the 230-240v swap over can be done by moving a single wire. I've never seen so many input taps on a traffo. These are followed by a rectifier cap bank with a big old home wound inductor and then wired straight to the output to the smaller main chassis.
I'm not a fan of the boxes but the thin front panel does come in handy. Being a switchable design I wanted to put all the switches where you can get to them; so the main chassis has a row of four SPST switches on the front, flanked by a pair of RCA sockets. The switches select between high and low gain, 61db and 40db respectively and also select between the fixed 47k MM input loading and the front mounted RAC sockets for MC loading, so the owner can make up plugs to suit whatever MC cart he's using.
The little white boots pull off the switches so he can choose between the tactile or polished option.
On the back it's business as usual. With Nuetrik in/out sockets for each channel and a pair of earth connections with the croc clip going straight to signal gnd and the gnd post going back to mains 0v in the main chassis via a DDRC (back to back diodes, cap and resistor).
To be fair I wasn't expecting a whole bunch from it. It does use a simple and effective pair of shunt regulators on each main board to deliver the rails for the two Op-amps. I was suprised at just how quiet the power rails actually are, it certainly shows in the performance. This is actually a very grown up sounding phonostage. The RIAA is ruler flat, better than 0.1 db across the board. It slams when it's meant to slam and finesses when it's meant to finesse.
Noise is none existant, no hum, no nothing. Seperation and instrument placement is spot on and timbre is unlike any Op-amp stage I've ever heard in my set-up. It's a right little thing.
If you fancy a phono project that won't break the bank RJM Emerald phono
Linn make a decent stab at the phono stages with their Uphorik and Urika models, both Op-amp designs and well regarded for their sound quality and performance. But I owned the Uphorik and it just wasn't my cup-of-tea. A bit mechanical sounding, great in the bass, but a litle busy sounding and a touch synthetic at times.
So when I was given a commission to build a MM/MC phonostage I thought why not? Richard Marsh has a great history with his phonoclone design so i thought I'd punt on a build with his latest pcbs.
I built it up with a dual mono PSU in separate chassis for all the heavy lifting. Traffos are selected to be multi-region and can be wired for 100v, 110, 200, 220v, 230v and 240v operation. I wired these up so the 230-240v swap over can be done by moving a single wire. I've never seen so many input taps on a traffo. These are followed by a rectifier cap bank with a big old home wound inductor and then wired straight to the output to the smaller main chassis.
I'm not a fan of the boxes but the thin front panel does come in handy. Being a switchable design I wanted to put all the switches where you can get to them; so the main chassis has a row of four SPST switches on the front, flanked by a pair of RCA sockets. The switches select between high and low gain, 61db and 40db respectively and also select between the fixed 47k MM input loading and the front mounted RAC sockets for MC loading, so the owner can make up plugs to suit whatever MC cart he's using.
The little white boots pull off the switches so he can choose between the tactile or polished option.
On the back it's business as usual. With Nuetrik in/out sockets for each channel and a pair of earth connections with the croc clip going straight to signal gnd and the gnd post going back to mains 0v in the main chassis via a DDRC (back to back diodes, cap and resistor).
To be fair I wasn't expecting a whole bunch from it. It does use a simple and effective pair of shunt regulators on each main board to deliver the rails for the two Op-amps. I was suprised at just how quiet the power rails actually are, it certainly shows in the performance. This is actually a very grown up sounding phonostage. The RIAA is ruler flat, better than 0.1 db across the board. It slams when it's meant to slam and finesses when it's meant to finesse.
Noise is none existant, no hum, no nothing. Seperation and instrument placement is spot on and timbre is unlike any Op-amp stage I've ever heard in my set-up. It's a right little thing.
If you fancy a phono project that won't break the bank RJM Emerald phono
