Modding your Turntable: Via Pro-Ject’s RPM 1 Carbon

Paul Rigby reviews the Pro-Ject RPM 1 Carbon but also throws a bunch of wide-ranging modifications at it to see how far the sound changes…if at all

The sector of the market occupied by the Pro-Ject RPM 1 Carbon — call it the budget or more likely ‘super-budget’ arena priced around £350-£800 – is busy with turntable variants that blend value for money with improved component choices and enhanced design implementations.  

Once you’ve made your turntable choice, whatever variant you plump for, the fun doesn’t stop there. There are plenty of ways to tweak and enhance turntables at this price point which adds value to your initial purchase because the outlay for these modifications tends to be smaller and more manageable yet the sonic improvements can be large, in relative terms. Hence, when funds allow, you can add a mod, then another and another, improving sound quality (hopefully) with each purchase, without splashing out big money on yet another new turntable. Modding your turntable gradually over time, is a low cost method of upgrading your vital vinyl source. 

This is the point of this feature, to see just how far you can go with a single deck. I’ve selected a Pro-Ject RPM 1 Carbon turntable as my victim. I’ll give it a brief basic review, to begin, but then I will add a range of products to see just how far you can push the basic design before the improvements lose their value for money and/or the sonic improvements become negligible. 

I’m roped in a heap of ancillaries including a replacement stylus, new mat, isolation feet, added plinth, new cables and even a replacement platter. 

The turntable itself arrives with a svelte chassis that, as you can see by the accompanying images, includes a glossy MDF plinth and platter, shaped and trimmed with no excess. A belt runs around the outside of the platter to a separate decoupled motor that sits in an outer plinth ring. The motor has access for a standard wall-wart power supply. A rocker power switch sits a-top the motor itself. 

The platter’s inverted main bearing utilises a ceramic ball, mounted onto a high-mass base plate. The 10″ S-shaped tonearm is a carbon fibre/aluminium resin construct. The RPM 1 Carbon tonearm is normally supplied with an Ortofon 2M Red cartridge. The arm arrives with a magnetic anti-skate mechanism. The supplied counterweight also utilises TPE damping in the form of an anti-resonant ring around the fixing point. 

Available in Red, White (my review choice) or Black high gloss finishes, the package doesn’t feature a dust cover but one can be purchase as optional extra.

SOUND QUALITY

I wanted to find a basic sonic reference for the RPM 1 Carbon (henceforth, RPM 1) so listened to the basic set-up, playing the old, old ELO track, First Movement.

The RPM, in its own right, is a top quality turntable, with a blend of upper and lower frequencies that form a nicely balanced output without misbehaving bass bloom or midrange smearing. Each frequency makes room for its brethren, allowing complimentary detail a fair crack of the whip. That means that bass is firm and characterful, allowing a massy impact with plenty of drive but never dominating the mix. Cello grunts, for example, were full of lower frequency textures that brought these instruments to life. Thus, upper mids were allowed to thrive. Guitar string information flowed with ease, cello vocals were emotive and clear while, in the treble regions, secondary percussion was precise. The soundstage was also a wide and amiable arena, projecting a busy yet relaxed performance. 

Could I hear room for improvement? Of course, but then I can with any turntable at this price point. When you review turntables in this sector, though, you take all of that into account and judge the turntable itself, built to its build budget while reflecting its necessary component selection. For a turntable of this class, though the RPM is a terrific design providing lots of detail, plenty of clarity and enough transparency to involve the listener. Allow the rest of the hi-fi to match its sonic highlights and the RPM will offer many hours of fun. 

That said, like any super-budget design, there is always room for tweaks and modifications to enhance what’s already there.

ORTOFON 2M BLUE

With any turntable, when you’re looking to improve its sonics you should always look towards the cartridge before moving elsewhere. After all, this is where the information is dragged from the grooves. You need to get rid of this potential bottleneck first. That’s what I did by upgrading the Ortofon 2M Red with a 2M Blue. You can easily perform the upgrade by swopping over the original Red stylus, which easily pulls out, with the Blue which easily plugs back in. You don’t even have to remove the cartridge from the arm. If you are performing this operation, though, be careful and patient. Don’t rush the job and be careful not to knock the cantilever/stylus tip. In fact, remove any floppy-sleeved jumpers before you replace the stylus, just in case it tags the cantilever and then perform the operation at eye-level so you can see what you’re up to. Lift the turntable up on a turntable or kneel/sit down to perform the change.

With the 2M Blue in place, the music featured less noise and greater precision in the upper mids. Guitar strings offered a better ‘twang’ while the accompanying cellos arrived with an enhanced focus. All were strong yet sprightly in tone. Both of these areas seemed sightly leaner because a touch of midrange smear (noticed more in hindsight, after fitting the 2M Blue than during the initial turntable review) had been further reduced, increasing transient speed. Finally, I was impressed with the treble. Cymbals not only sounded larger and delicate but the reverb tails attached to them travelled further. Adding the Blue upgrade was a winner and highly recommended.

THE MAT: LEATHER-IT & CORK-IT

I then looked at the platter and the default felt mat. I had two possible upgrades to hand here: a leather mat and a cork example. I swopped out the felt variety and first swopped in the leather upgrade.

Again you only really notice that an issue exists when a modification ‘fixes’ it. In this case, the leather mat lowered veiling noise, creating a much smoother mid band, allowing the Spanish guitar to reach further in dynamic terms while giving the cellos more room to manoeuvre. They seemed like a greater presence in the mix now. There was no balance issues mids you, just a slightly enhanced strength from this area. There was, however, a blanket of warmth over the upper areas of the sound frequency spectrum with a slight roll-off at the top edges. Not devastating in its effects, the effect was relatively minor but it was there.

Because of that, I preferred the cork mat which was a tad less warm and slightly more dynamic in terms of the upper mids. In fact, the frequency extremities seemed to be further apart with the cork mat, giving a wider spectrum of sonic colours to experience, adding to the richness of the soundstage and enhancing the sheer detail within via improved midrange insight. Guitar string resonance appeared to be enhanced, for example.

What was more important, even at this early stage, I could feel the basic sound of the RPM moving away from the sound I originally heard from the turntable, out of the box. There was a real distance in quality developing here. 

Next? I replaced the default MDF platter with an acrylic model. This was simple to install. Simply lift the old one off and gently lower the replacement into place. 

A NEW PLATTER: ACRYL-IT

The effect was to add a tremendous maturity to the entire soundstage. Sound quality really moved a-pace here with a wholly new soundstage installed, giving a low noise performance, a solid basic musical structure plus impressive precision and focus that not only added a measure of pace to the track as a whole but also improved the tonality throughout. The installation of the new platter was, in itself, a major component upgrade that moved the track up several rungs in terms of clarity.

The soundstage of this track is quite intricate. You’ve got rock-type and classical-type instruments working cheek by jowl here with a host of intricate musicianship swamping the area so any turntable has to work hard to working it all out. The platter enabled the RPM to do just that.

That sonic improvement was further enhanced by adding the cork mat on top of this replacement platter.

THE FEET: ABSORB-IT

Next up, I reached for the three isolation feet. The feet were excellent in terms of enhancing bass and providing a stronger and more significant range of lower frequencies.

On the reference track, the feet provided real traction for the cellos and provided drums with significant presence but I would have liked more control over these enhanced frequencies and also the upper frequencies which were slightly weakened in the meantime. I felt that the feet were good, solid designs but I wanted…more. 

PLATFORM BASE: GROUND-IT

I was hoping that the platform base would provide that. It did too. Bass improved with the platform but the lower frequencies were enhanced in a balanced fashion along with the midrange and treble. Hence, the platform enhanced the sonic improvements evenly and across the board to allow for a neutral yet detailed and clear presentation.

The enhanced bass provided a full and weighty element to the soundstage, while the music moved along with a mass but it never dragged. The bass section remained quite sprightly.

Upper midrange highlights were just as detailed and light on their feet but, this time, the string plucks for the Spanish guitar, for example, added a more substantial and slightly portentous resonance. 

NEW PHONO CABLES: CONNECT-IT CC

To round off this modification sequence, I replaced the phono cables.

Despite a slight lift in the midrange which added a slight stridency to the upper mids, the response of the new cables was to lower noise further which enhanced the overall soundstage again, especially the percussion which moved left and right towards the outreaches of each channel but also improved in terms of tonal quality.

Precision and focus was also improved over all frequencies. 

CONCLUSION

What I have learnt here is to respect the inherent Pro-Ject turntable design as a core. A base to add and improve upon. That is, I now realise that when you buy a basic RPM 1 Carbon and then you play that turntable, out of the box, you’re really hearing something like 65% of its overall capabilities because it arrives with a large, normally untouched, capacity. You won’t hear any more either, until you start adding upgrades such as those listed above. 

And after adding all of the modifications, what are you left with? Well not a RPM 1 Carbon, that’s for sure! That is, the final sonic difference is so large, the sound is actually completely different and in a good way. It’s more like a RPM 4 Carbon! The overall sound quality is so far away from the original that this deck sounds like a completely new design. It also should provide confidence and added security for those RPM 1 Carbon buyers out there. But not just RPM1 owners and not just owners of Pro-Ject turntables, all turntable owners need to take a look at these and other upgrades. Your own turntable most probably includes untapped potential. Potential that can be accessed for not a great deal of money.

A bit fed up with your current turntable’s sound quality and feel like an upgrade? Well, before you reach for your wallet to buy an expensive turntable replacement, seriously consider one or more (or all) of the above upgrades. You won’t regret it.

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PRO-JECT RPM 1 TURNTABLE & MODIFICATIONS

Tel: 01235 511166

Website: www.henleyaudio.co.uk

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ACCESSORY PRICE & RATINGS

Pro-Ject RPM 1 Turntables

Price: £375

Rating: 8

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Ortofon 2M Blue

Price: £185 on its own or £110 as an upgrade for a 2M Red

Rating: 8

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Leather-IT leather platter mat

Price: £50

Rating: 7

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Cork-IT platter mat

Price: £20

Rating: 8

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Acryl-IT Platter

Price: £165

Rating: 9

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Absorb-IT isolation feet

Price: £140 for pack of 4

Rating: 7

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Ground-IT Deluxe Platform

Price: £250

Rating: 8

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Conect-IT RCA-CC phono cables 

Price: £99

Rating: 7

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Overall – 8

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All vinyl was cleaned using an Audio Desk’s Ultrasonic Pro Vinyl Cleaner