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Converting LPs to Digital: Interface Turntable to Computer via USB

To get the best possible audio from your LPs then you should go directly from your turntable to your computer hard drive via a USB or Firewire device. If we choose to use a preamp to do this then the premap may introduce audio artifacts. Our initial problem is to convert analog to digital while maintaining as much of the original audio quality as possible. Or, in going from the analog LP to the digital file that we do not want to alter the audio signal in anyway... this would include any form of enhancement like putting a "tube" sound on top of the signal. The objective is to create a signal as close to the original audio signal as possible. Once we have recorded the audio, then we are free to enhance it anyway we like by using software to remove unwanted noise, using an equalizer, etc. The important thing to remember is that once we record the original, then it is next to impossible to try and undo anything that we may have done...intentionally or non-intentionally.

We will address two methods that we can use to prepare our LPs for digital playback. Each method consists of both an Input and an Output phase. Setup I consists solely of hardware. Note: some form of software will be used to interface the audio components with the computer's hard drive. Setup II introduces a software application to enhance the quality of the signal. The software here is not software that will interface to the computer, but software that actually works with enhancing the sound and removing pops and clicks. Here we are using an application to create as clean a digital signal as possible, and a signal that closely aligns itself to its analog equivalent. I am approaching this project from the perspective that I want the best signal for the least amount of investment. There are parts in the scenario where we will have to invest some money, but we do have options that will help reduce the over all costs.

Setup I
Our first setup is pretty straight forward: we will amplify the signal coming from the turntable and place it directly on the computer's hard drive. We will cover some of the options available for the phono preamp stage further below.

Setup I:
Input: phono -> phono pre-amp/LP-to-USB Converter -> file saved to hard drive as AIFF/WAV.
Output: open digital sound file -> Digital Analog Converter -> Output Device (record or play audio.)

Setup II
In some cases we may be working with vinyl that is scratched or we may simply want to "clean" the existing analog signal digitally. There are numerous applications available. Many are free and some come with a price. Here is a list of free applications that specifically targets pops and clicks. Here is a page of freeware/shareware links that targets audio restoration in general. On the free side is the ever popular Audacity, that comes with a noise removal tool. One of the applications you can buy to clean unwanted noise is Adobe Soundbooth, this is my application of choice.

Below is the flow diagram of our setup that now includes an application to clean-up any noise, clicks, and/or pops.

Setup II:
Input: phono -> phono pre-amp/LP-to-USB Converter -> clean-up software -> file saved to hard drive as AIFF/WAV
Clean-up: open digital sound file -> apply clean-up software-> file saved to hard drive as AIFF/WAV
Output: open digital sound file -> Digital Analog Converter -> Output Device (record or play audio.)

Recording Audio: The Turntable

Before we do any recording of vinyl we need to determine a few things like: do we need to purchase a new turntable or can we just provide our current turntable with a tune up, how will we connect the turntable to the computer, do we want to invest another $200 for Pure Vinyl, and what shall we use as a phono preamp?

Restore Turn Table: The first step to be addressed is the turntable. In my case, I have an older belt driven Technical that is in new condition. Since it is old and I live in an arid climate, then if I want to use it I will have to make a small investment. I will definitely a new belt, and since the turntable will be open then I will also replace the headshell leads, and the record-mat. When replacing the belt it is best to use some electrical contact cleaner and compressed air to clean the innards of the table...DO NOT USE WD40...and get some bearing lubricant to lube the main bearing. In choosing a cartridge realize that there are two types of phono cartridges: moving coil and moving magnet The magnetic cartridge seems to be the choice of audiophiles. Realize that if we go with "audiophile" components we are not necessarily locked into purchasing a high-priced unit, but are more concerned with recreating as pure a sound as possible. Again, here is a link on how to tune up your turntable.

Purchase New Cartridge. Some of the best prices can be found at LPTunes, but the best selection is at the Needle Doctor. For those of you who have never refurbished a turntable, then again, here are some instructions. If you do not have much in the line of audio equipment then you can pretty much start from scratch. If you already have a pre-amp and/or amplifier then you need to make certain that your cartridge is compatible. Check the users manual of your amplifier or pre-amp if you do not know.

For those who want to start off with a new unit then the Needle Doctor is a good place to look, as is LP Gear, and Audio Advisor. If you feel comfortable with eBay, and know what you want, then you can find you some great gear there at a fraction of the cost of a new set-up. Okay, now that the turntable is taken care of we need to convert the signal coming from the phono into something that the computer can use. Basically, we need a preamp. A preamp can take many different forms and can cost you anywhere from $19.99 to $12,000. We are going to go for something that will give us the best audio signal at the lowest price. I am being very careful that I do not compromise the integrity of my sound signal with a cheap component.

In your owner's manual you need to check to see if it's just labeled 'Phono' or if there is a phono stage in the receiver. If there is a phono stage, there should be different specs for the phono input to all the other line level inputs. Typically a line level input is expecting a 2V signal. A Moving Magnet (MM) phono input would expect something in the mV range (e.g. 2 - 4 mV) and a Moving Coil input would expect 1/10th that of the MM input (so 0.2 - 0.4mV or thereabouts).

So, do you need a phono preamp and if so, then what should you get? It would help if you read on what a phono preamp does and so here is an article All About Phono Preamps.

There is an option to getting a pre-amp and that is to find a complete standalone solution that will feed your phono playback and LP archiving directly to your computer's hard drive or a CD burner. One option is The Ripper. Not only is The Ripper cheaper than a preamp, but it will give you one of the cleanest audio feeds currently available. Regardless of what you get, you will need to make sure that you have USB or Firewire capabilities. These are the most efficient means of interfacing with your computer -> hard drive.

Personally, I need to get a phono preamp and thus began an exhaustive search into the interfaces necessary for use between the turntable and the computer. What I am linking to below is what I have found to be some of the best equipment out there for the money. I have done extensive reading and have read a minimum of 3 professional reviews for each for it to make the list. The only exceptions are the very cheap products which seem to be grouped together as non-audiophile components. Some of the DIY preamps can also be purchased prebuilt. I shall build, but I will not let you down and will introduce you to some great pre-built gear as well. The questions to be asked at this point are: 1) Do I want tube or solid state, 2) do I want to go directly into the computer with a USB, 3) how much money am I willing to spend, 4) 16 bit or 24 bit recording and at what frequency, 5) Do I want to build my own preamp, or shall I buy a remanufactured one.

My logic is that I want the cleanest sound going in since this is going to basically be my master. I don't feel that I need to spend a grand at this phase since I have a limited supply of vinyl that needs converting, and even though I love a tube amp I feel that my money would be better spent in paying for the tubes for the output phase. In my readings I was convinced that the best way to approach audio is to go with 16-bit for recording, and then convert to 24-bit via a DAC for the audio output. One source is from Hagerman Technology. With all of this research I have decided to go with the "The Ripper." The Ripper is a piece of equipment that was specifically designed for converting vinyl to digital and it does it via a USB port and without tubes. Granted, it is twice as much as my second choice but it is a no-brainer. For my second choice I would go with the Cambridge Audio Azur 640P Phono pre-amplifier It costs about $170, and is credited with being one of the cleanest phono pre-amps out there and has consistently been chose as the best preamp under a grand.

The Ripper plugs straight into the computer via the USB (for the Azur you would need a Dual RCA Plugs x 1/8" Stereo Jack 6" Patch Cord that you could plug into your mic-jack and record using GarageBand or Audacity). With the The Ripper you can use Garage Band or Audacity. Since the Azur is an audio preamp, then you do not need to worry about the quality of the audio signal.

RCA to 1/8"

 

Preamps/Phono Stage/Analog to Digital Choices

Here are my top 3 choices. I am sold beyond a doubt that the best device for this job is The Ripper. Some may consider it pricey, but for what you get it blows away the competition. The Cambridge Audio would be a good choice if I wanted a solidstate pre-amp for vinyl playback, but all I want to do is record my vinyl... so it is The Ripper. The Bugle, also by Hagerman Technology, is a great little phono pre-amp that can give you noiseless battery powered capabilities for recording or just plug it in for future audio playback. Just for kicks, I have added some of the others that I considered but all of them dropped from the competition for various reasons. Though I will may be going to BottleNeck for some of my audio playback purchases.

First Choice:

The Ripper LP-to-USB Converter - As of 1Jan2011 they are out of stock.
Hagerman Technology

The Ripper is a complete standalone solution for your phono playback and LP archiving to computer hard drive or CD. It combines a very clean and quiet phono preamp with an ADC/DAC especially designed to digitize audio to CD data rates (16-bit 44.1kHz). The USB output makes attachment to your computer a snap, no drivers to install! Record vinyl directly to disc using one of the many available software programs such as Audacity. Convert to MP3 or save as WAV files. Make your own CDs! Save files for playback via iTunes or download to your iPod. You can even playback the files on The Ripper, as it also works as a USB DAC. The headphone output makes monitoring and playback convenient.

The phono stage is borrowed from the very popular Bugle powered by super regulators and an always-on AC supply. Components are top-notch for superb sonics. The layout is extremely compact with short signal paths. Output can be either taken from the rear panel RCA jacks or the headphone jack on the front.

Others Choices With USB or Firewire:

Apogee Duet $495 (Mac only)
The Apogee Duet is a portable audio interface that features the amazing sound quality that made Apogee Electronics famous. With control functions built directly into Apple’s Logic Pro, Soundtrack Pro and GarageBand software, Duet empowers you to create professional recordings effortlessly.

With Duet, you can plug in guitars, keyboards and microphones and record your music, or simply experience how much better your favorite tracks in iTunes sound. Duet is compact and powered by FireWire, so you can pack up your studio and go anywhere your music takes you. Mac only.

Pro-Ject Phono Box USB Phono Preamp $199

The Pro-Ject Phono Box USB offers the features and refined sonic presentation of the Phono Box II, but it adds the versatility of a USB output. The USB output will come in handy if you're interesting in converting your records to digital files. It can handle almost any MM or MC cartridge you can throw at it.

Bellari VP-530 USB Phono Preamp $399

The vp530 is a usb/tube phono preamp for use with moving-magnet and high output moving-coil cartridges. It includes a built in headphone amplifier, Burr-Brown A2D converter w/usb output, and RIAA curve/flat EQ. The vp530 is designed to amplify an RIAA equalized phono signal to a hi-level signal or provide a usb digital output. Since the unit utilizes tube circuitry, the resulting output signal is more warm and musical than solid state preamplifiers. The real kicker aside from the price and stellar sound is that it's manufactured in the US.

ART USB Phono Plus V2 Phono Preamp Features: $99

• Improved internal circuit design for better performance
  
• Headphone level control
  
• Three-position headphone monitoring switch
  
• Dual RCA-type inputs
  
• Dual RCA-type outputs
  
• Supports both MC & MM cartridges

Audio Genie Pro USB Phono Preamp Digital Recording Interface $69

The American Audio Genie Pro is a great way to convert any analog signal into digital files without the use of a soundcard. This easy-to-use audio interface connects directly to your PC by its USB connection. Supports 48/ 44.1 Khz sampling rate for both playback & recording. Record audio with your computers built-in audio recorder or your favorite audio production software. (RCA cables not included)

Solid State/Tube Moving Magnet Stereo Phono Preamplifiers

 

The Bugle is a low cost solid-state phono preamplifier. It utilizes a split, passive RC-type equalization network that offers excellent flexibility for customization. The circuit is not the typical "feedback" type commonly used, but rather uses the opamps as pure frequency-independent gain stages. Two of these gain stages drive the equalization networks followed by a third gain/buffer stage to provide a low output impedance. The overall gain is thus optimally split between the three stages.

The beauty of this babe is that you can run it on batteries and thus eliminate the worries about AC noise. So, while recording the vinyl you could run on battery mode and thus insure a cleaner sound.

If you want to use your preamp for going from digital to analog once you record your vinyl, then this may be the way to go. It is also half the price of The Ripper. If you choose to forego USB/Firewire, then you have non-USB choices below.

Non-USB Choices:

Bottlehead DIY preamps are of the highest quality.

The Eros Phone Pramp (right) is kick-butt to the extreme.

Signal wiring is all point to point with Teflon insulated wire and solid core shielded twisted pair cable. Thepower supply is easily assembled on PC boards. It is an efficient Schottky rectifier supply feeding dual active loaded hybrid (12BH7/LM431) shunt regulators in parallel with each channel of the preamplifier circuit. The DC heater supply is a full wave bridge of super quiet Schottky rectifiers feeding a Linear Technology regulator. Each channel of the preamplifier circuit is a C4S isolated EF86 voltage amplifier direct coupled to 1/2 of a C4S isolated 6DJ8 voltage amplifier, with the passive RIAA equalization network positioned between the two gain stages. Only one output coupling capacitor is in the signal path of each channel - a metallized polypropylene type. Resistors are a combination of high quality metal film, carbon film and carbon composition resistors, each chosen for optimal performance in the intended application. Filter capacitors are overrated for long life. Tube sockets are high quality ceramic with aluminum shields. A ground post is provided for phono cable and turntable grounding.

Bugle" Phono - $149 ($39 kit/2) 30-day free trial - Order now! Hagerman Technology

The pre-amp that had the greatest review feedback was the Azur 640P Phono pre-amplifier. This pre-amp topped many of its predecessors up to and including $800 pre-amps. If I was buying a manufactured pre-amp this would be the one.
Azur 640P Phono pre-amplifier
The 640P phono pre-amplifier (sometimes known as a phono stage) also uses superior amplification circuitry for its MM and MC stages to provide the lowest possible distortion and noise. In addition, the flagship model employs multi-parallel capacitors to achieve exceptional RIAA accuracy of only 0.3dB up to 50kHz and features a defeatable subsonic filter. The Azur 640P phono pre-amplifier employs a comprehensively specified Moving Magnet stage, as well as the higher gain needed for compatibility with high-end Moving Coil (MC) cartridges. This raft of technologies combines to offer a hugely dynamic, involving and open sound.

The 640P features the now customary Azur acoustically damped steel chassis and a robust anodized aluminum front plate.

LKG-PRE600 Moving Magnet Phono Preamplifier $29.99

This high quality stereo preamplifier will allow you to replace a Crystal or ceramic stereo cartridge with a better quality magnetic stereo cartridge while using the original stereo amplifier supplied with your turntable. The us of the preamplifier in conjunction with a magnetic cartridge will give you CD quality sound out of your vintage turntable. This may be the ticket if funds are low, but don't expect it to be on the same level as the Ripper or Bugle.

Radial J33 Turntable DI $199.00
•  Stereo RCA inputs
•  Stereo RCA, ¼" TRS and 3.5mm outputs
•  Balanced mic level XLR outputs
•  Low frequency rumble filter
•  Choice of 48V phantom or DC supply

The Radial J33 is a high quality combination turntable (phono) preamp and direct box that offers a choice of balanced mic-level and -10dB consumer line-level outputs. This allows a 33-RPM record player to be connected directly to a professional mixing console or mic preamplifier. This makes the Radial J33 ideal for use in studio for re-recording, sampling and archiving, while offering DJs an improved interface for recording scratch and remix performances over typical DJ mixers or other stand-alone turntable preamps. For maximum flexibility, the Radial J33 is equipped with a rumble filter to eliminate low-frequency resonance and may be powered with remote 48Volt phantom or local external DC supply.

Seduction Phono Preamplifier kit $279 plus shipping. Delivery averages four to five weeks.

The solid state high voltage supply uses fast recovery soft start rectifiers and our unique Reverse Recovery Spike Filter that makes our rectifiers as smooth sounding as tube rectifiers without sacrificing speed or dynamics. The heaters are supplied with filtered DC from Schottky rectifiers, which do not exhibit the switching spikes of lesser rectifiers, and the heaters themselves are bypassed with wide bandwidth ceramic capacitors to filter out interference. The passive RIAA components are high quality Vishay Dale 1% metal film resistors and Panasonic EPCQ(U) polypropylene capacitors with copper leads. Carbon composition grid and plate stopper resistors round out the RFI filtering that lets this 6DJ8/6922/7308 based preamp perform without the edginess sometimes associated with this fast, articulate tube. Tube bias is set via Agilent LEDs, a special model that has excellent noise and linearity characteristics for this application. This preamp is recommended more for audio playback.

Cables

So, we have the turntable that will plug into the pre-amp that will then plug into the computer. All about cables

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