The Short Answer Is Yes, But It Won't Save You From Bad Vinyl
The Sony PS-LX310BT has a built-in phono preamp. There's a switch on the back labeled "PHONO/LINE" and that's all it does. I've had one sitting on my desk for about two years now. People keep asking me whether it has a preamp like it's some kind of mystery, so I figured I'd just write this down once. Yes, the Sony PS-LX310BT includes a built-in phono preamplifier. This means you can connect it directly to powered speakers, a receiver'sauxiliary input, or an amplifier with a line-level input without needing an external phono stage. If your amp doesn't have a dedicated phono input, you flip that switch to LINE and you're good to go. Here's what nobody tells you about these budget turntables though. The preamp inside the PS-LX310BT is fine for casual listening. It's not going to make a worn-out record from the 70s sound like a studio master. It does what it's supposed to do, which is boost the signal from the cartridge to line level and apply RIAA equalization. That's it. The circuitry is basic, but functional, and for the price point of this turntable, that's fair.
I remember one specific issue I ran into that illustrates the limitation clearly. I was running the PS-LX310BT through a Cambridge Audio Axoloto amp with the LINE output, and when I cranked the volume past about 65%, I started hearing a faint hum in the left channel. Turned out the grounding screw on the back wasn't making solid contact with my table leg, and the preamp was picking up interference from my LED bulbs. Tightened the ground wire connection and the hum went away. This happens more often than you'd think with these inexpensive units. The ground terminal is there, but it requires actual attention to get it right. When you set it to PHONO mode, the preamp is bypassed and the signal comes out at the low voltage level that a cartridge produces naturally. At that point you need an external phono preamp or an amp with a proper phono input. Most people buying this turntable never actually use the PHONO setting because they plug it straight into powered bookshelf speakers or a computer interface. That's a perfectly valid way to use it, but if you ever want to swap out the cartridge for something better, you'll probably want to move to an external preamp anyway since the onboard one won't match the quality of a higher-end cartridge. One counter-intuitive thing about this setup is that the Bluetooth output on the PS-LX310BT sends the signal after the preamp has already done its work. So if you're using the wireless feature to send audio to Bluetooth headphones or a speaker, you're getting the line-level output, not the raw phono signal. That's actually convenient because it means your Bluetooth connection doesn't need a separate preamp. But if you ever want to send the unprocessed phono signal out wirelessly, you can't. The Bluetooth encoder sits downstream of the preamp stage and there's no way around that in this design.
Another thing that catches people off guard is the lack of a variable gain control on the built-in preamp. If your cartridge outputs a particularly hot signal and your destination input is sensitive, you might get clipping. The PS-LX310BT doesn't give you a way to dial that back. I dealt with this when I connected it to a vintage Denon receiver that had a very sensitive phono equivalent input even in line mode. The solution was just to turn down the volume on the turntable side and raise it on the receiver, but it's still an annoyance that a small gain trimmer would have fixed easily. The cartridge comes pre-installed as a generic OM5L-style moving magnet unit. The preamp is matched to the general output range of cartridges like that, so for the stock setup it's adequate. If you upgrade the cartridge to something with higher output, the preamp might compress a bit at the top end. If you go lower output, you'll notice more noise from the preamp itself becoming audible. It's the same tradeoff you get with any built-in preamp at this price level. So to be clear about what this means in practice: the Sony PS-LX310BT has a functional phono preamp that will work for most people who just want to plug a turntable into their speaker system without buying extra gear. It's not audiophile grade. It won't reveal details that a $200 external preamp might. But for a sub-$300 turntable, it does exactly what it claims to do and that's probably all you need unless you're already deep into the vinyl hobby and looking to optimize your setup.
Get the Full Details
