Use a "Flat" phono-pre amp if at all possible - a pre amp that applies no equalisation is undoubtedly the best type to use when transcribing any record for restoration purposes. There are several reasons for this:

• Scratches and other physical damage were not part of the original recording content and should not have equalisation curves applied that may inhibit their repair/removal.
• There are many brands of records and many different equalisation standards. It is often better to choose the turnover frequency that sounds best at a later stage.
• Computer generated equalization curves are mathematically superior to those generated from passive or active filter components in a physical phono-pre amp.

Below are images from my "DIY" phono-pre amp which was based on the phono-pre amp featured in ETI's July 1981 edition of the Series 5000 Control Preamplifier unit. It uses several ultra low noise NE5534AN op-amps and boasts total harmonic distortion of <0.001% as well as a flat sound/noise (s/n) ratio of 87dB for <5mV input. Not to be laughed at! If you or a friend can build something similar then you can save yourself a fortune compared to purchasing a pre-built unit. This pre amp had an adjustable level, balance, buffered L+R and L-R settings as well as other features (flat vs RIAA etc). In the end, your pre amp doesn't need to be this complicated as all this can be done better using software. Really you only need a good low noise pre amp that can record L and R channels separately and preferably without the RIAA equalisation. If you're technically minded like me, then I would recommend building this: Multi Standard 78 RPM and RIAA Phono Equaliser.

The two circuit boards on the right in photos 1 & 2 (starting from left above) are the phono-pre amps which can be seen close-up in photo 3. I built both the RIAA version (back right corner) for normal listening to LP's and another version with the filter components removed (front right corner) which I use when transcribing records. The larger board on the left nearest the power supply (photos 1 & 2 and close-up photo 4) allows L+R, L-R and gain/balance changes to the pre-amplified phono signals. Again, all these can be readily achieved using digital software.

If you use a DC power supply like I did, make sure you provide plenty or regulation and filtering to avoid hum generation. Otherwise, you may get better results or prefer to use a battery as the power source.

In the end any reasonably good low-noise phono-pre amp circuit will do. Photo's 5 & 6 show you how the above pre amp performs when loaded with a Stanton 500 cartridge (correctly terminated) when not playing (yellow trace) and when playing an excellent condition 78rpm record lead-in groove (red trace) respectively. On average, the phono-pre amp performs about 30dB better than the noise floor of the record optimally played with a 3.0mil stylus AND this is even under the noisiest conditions (earth loop issues and mixed mains-audio cabling!). It may be possible to improve these results by relocating RCA cables and optimising equipment layout. It's not perfect but it more than meets the requirements. It's probably also worth noting the s/n amplitude offset present - I ensured the pickup circuit was engaged and not grounded, so the fact that the cartridge s/n ratio is sitting around the sound card s/n ratio (-110dB) is likely due to the pre-amp's master gain setting. In the end, it is the difference between this noise floor and the record noise floor that is important. When I get the chance I will re-test these conditions for a more accurate graph.

If you are unsure of the impact of RIAA equalisation on a 78rpm recording then try the examples below to hear the difference between a 78 played using a Flat and RIAA equalised phono-pre amp and then the impact this has on de-clicking: