Rega P1+ with RB303 Tonearm and Rega Exact Cartridge Review and Measurements

[Stephen H]

Below you will see my Rega P1 Plus with several modifications:

• Rega RB303 tonearm with upgraded stub and counterweight (came with the arm).
• Rega Exact MM cartridge.
• 10mm Glass Platter.
• Custom made isolation feet.

The Rega P1 is the entry-level product produced by Rega, the "plus" merely indicates it has a phono stage built-in. As standard, the player comes with a much lower-end tonearm with fixed anti-skating. Meaning it is limited as to what cartridges it can support. They come with a Rega Carbon (AT3600 rebrand) cartridge, which is a very competent low-end moving magnet cartridge.

For the price, I really think the P1 is a lovely turntable. Higher-end models come with a slightly thicker plinth bolstered with some additional bracing from the platter bearing to the base of the tonearm. Which is very pretty, but I question how much this truly affects performance.

Currently I am still using the built-in phono stage. At some point, I may bypass this and use an external one as there is no way to adjust resistive/capacitive loading.

I recently purchased an Ortofon Test LP to perform a few sanity checks in regards to anti-skating etc. However, I couldn't help but plug the phono-stage into my Nihtila ADC to perform a few other measurements and tests.

I thought some viewers of this forum may be interested to see the results. Given that we're all so used to seeing DACs with virtually impeccable performance, I thought this might make a dramatic change!

I'll start off showing the noise generated by the built-in phono stage with nothing playing. Arm situated in it's home position.

The peaks on the right channel (green) are all slightly higher than the left (red). I live in the UK, which explains the peak seen @50hz. However, the rest is for you to decide!

Next I'll show frequency sweep results. Unfortunately, the Ortofon LP doesn't play anything below 800hz. So I have no data for this:

The Ortofon LP has the sweeps "Linear cut" meaning they have no RIAA applied. Given that I captured these results via the built-in phono stage. I had to apply a calibration file to flatten out the response.

Calibration file can be found here.

Notice the right channel is slightly louder than the left. This ties in with the elevated noise floor seen on the previous measurement. I guess this must be a defect of the built-in phono stage.

The bump at around 12k could probably be smoothed out with correct resistive/capacitive loading for the cartridge.

Next, stereo separation at 1khz. I played the left 1khz Ortofon test tone through the left channel of REW, and then through the right channel and plotted the results together:

You can see there is about 30dB of stereo separation. There is probably a better way to capture this measurement. However, I am no expert in this field by any stretch of the imagination!

Lastly, 1Khz distortion captured from Ortofon LP:

As you would probably expect, lots of noise and distortion. I left this result in dBFS to highlight the channel imbalance seen here.

I like the fact the distortion spikes are trailing off as they increase in frequency. However, for anyone who is used to looking at DAC measurements. These results are nothing short of awful.

To be perfectly honest, I am not a huge fan of record players for their sound quality or "Analogue magic". I just think they're really cool and fun to tinker with. Some records do sound surprisingly good and the channel imbalance is something I very rarely notice. However, I would be curious to know if a different phono stage would equal this out.

For super accuracy, I play music through my network streamer, or chuck on a CD. However, there is something very satisfying about spinning up an LP once in a while!

Given the above measurements, this record player has no right to sound as good as it does. You would bin any DAC or streamer that measured this poorly!

 

[Thomas_A]

Nice to see more measurements. If you wish, there is a formula that adjusts the RIAA cutting error of the Ortofon test record. This can be applied on the file in the Nyqvist prompt in Audacity and then run in the frequency response script.

(setf *track* (biquad-m *track* 7.9682567668766300E+00 -5.2724672933908900E+00 -1.4469430767688700E+00 1.0000000000000000E+00 3.6557310000000000E-01 1.4996620000000000E-02))
(biquad-m *track* 1.10057904093330000E+00 -6.65301031771105000E-01 -4.30266896696176000E-01 1.00000000000000000E+00 -5.75527420000000000E-01 -3.79604780000000000E-01)
(biquad-m *track* 0.73137993061956 -0.39063797071820 -0.27569578143734 1.0 -0.59106473412185 -0.39977762693709)

 

[Stephen H]

Nice to see more measurements. If you wish, there is a formula that adjusts the RIAA cutting error of the Ortofon test record. This can be applied on the file in the Nyqvist prompt in Audacity and then run in the frequency response script.

Ahh thank you! This could come in handy

 

[Thomas_A]

Ahh thank you! This could come in handy

I just saw the title said no correction, but it is applied. This was a error made when the record was cut at half-speed - the RIAA constants were not applied correctly.

If the script is run, the left and right files can be split (the right channel also needs to swap channel, so that the right goes to left). And then drop the files in the advanced mode (left and right channels). Don't mind the record type, just fill in TRS-1007.

 

[Stephen H]

Yeah that's right. I applied some correction in REW by using an RIAA calibration file. However, it's good to see other methods of achieving this

 

[Thomas_A]

Yeah that's right. I applied some correction in REW by using an RIAA calibration file. However, it's good to see other methods of achieving this

Note though that Ortofon sweep needs an additional special correction due to a mistake in production. It is different from the usual RIAA cal files.

 

[Stephen H]

Note though that Ortofon sweep needs an additional special correction due to a mistake in production. It is different from the usual RIAA cal files.

Ok thanks. At some point I'll try out the method you posted above.... Or use a different test record if I can get my hands on one

 

[Stephen H]

@Thomas_A

Had some free time this morning, so I tried out your method and got the below results:

Definitely looks to me like different loading is required to flatten out the response. Shame there is no way to change it on my phono stage.

 

[DSJR]

It's very kind of the OP to post these results, but I have to politely comment that the deck is a Frankenstein model really and neither one thing or another. When I read what had been done to the arm I freaked out, as there's nothing wrong with the original counterweight and stub on a 300 series model (maybe a higher mass tungsten counterweight would help with a massier pickup they used to be cheap but no more sadly). The Exact doesn't usually measure as flat as this, so my worry is that the built in phono stage is equalising this nearer to flat - the channel imbalance is dire however, but this I think is normal for these. The current ND series may not change the tonal balance, but the internals do look neater so hopefully past imbalance is designed out better?

Does your P1 have the better main bearing of the P2 and 3? Earlier ones had a more basic type which is fine for the bakelite platter of the P1, but may not last as long with massier float glass...

Umm - yes, the plinths DO make a slight difference as well as the massier platters (and thinner mats that go with them). The lighter plinths on say, the P3, are made more rigid from arm to bearing with that (to me ugly) reinforcement strap. You may have got round it a bit with the 'feet' you've gone over to, but direct coupling to the glass shelf it's on, may add potential resonances from the glass into the deck, but my tatty dealer hat is getting in the way again now, so I must shut up here (I still felt the best sonics from ANY Rega were from using their dedicated wall bracket away from corners, which avoided a conventional 'shelf' altogether.

Apologies folks, I'm trying to ditch my old dealer hat, but it keeps coming out where decks like this are concerned as I knew them so well and had such fun recently when restoring a P3-2000 to full working order...

P.S. The Carbon cartridge (posh 2g tracking AT91, NOT a rebadged 3g tracking 3600L) can be usefully upgraded by the Carbon Pro elliptical stylus, which cleans up the highs so very well and sounds well integrated in a -to me - slightly warm-toned package).

 

[Stephen H]

It's very kind of the OP to post these results, but I have to politely comment that the deck is a Frankenstein model really and neither one thing or another. When I read what had been done to the arm I freaked out, as there's nothing wrong with the original counterweight and stub on a 300 series model (maybe a higher mass tungsten counterweight would help with a massier pickup they used to be cheap but no more sadly). The Exact doesn't usually measure as flat as this, so my worry is that the built in phono stage is equalising this nearer to flat - the channel imbalance is dire however, but this I think is normal for these. The current ND series may not change the tonal balance, but the internals do look neater so hopefully past imbalance is designed out better?

Does your P1 have the better main bearing of the P2 and 3? Earlier ones had a more basic type which is fine for the bakelite platter of the P1, but may not last as long with massier float glass...

Umm - yes, the plinths DO make a slight difference as well as the massier platters (and thinner mats that go with them). The lighter plinths on say, the P3, are made more rigid from arm to bearing with that (to me ugly) reinforcement strap. You may have got round it a bit with the 'feet' you've gone over to, but direct coupling to the glass shelf it's on, may add potential resonances from the glass into the deck, but my tatty dealer hat is getting in the way again now, so I must shut up here (I still felt the best sonics from ANY Rega were from using their dedicated wall bracket away from corners, which avoided a conventional 'shelf' altogether.

Apologies folks, I'm trying to ditch my old dealer hat, but it keeps coming out where decks like this are concerned as I knew them so well and had such fun recently when restoring a P3-2000 to full working order...

P.S. The Carbon cartridge (posh 2g tracking AT91, NOT a rebadged 3g tracking 3600L) can be usefully upgraded by the Carbon Pro elliptical stylus, which cleans up the highs so very well and sounds well integrated in a -to me - slightly warm-toned package).

Thanks for your comments. I realise this is far from an original P1. However, I still thought people may find it interesting. I like to tinker with things and the original P1 arm had fixed antiskating. Meaning I couldn't try out different cartridges so easily. I bought the arm off ebay second hand. It already had the "upgraded" stub and weight fitted. Ideally I wanted one stock, but it was listed for a good price and figured it's unlikely to cause any harm. I doubt the phono stage equalises anything. It's the built in one on the P1+ which is particularly basic. If anything, I would say it's more likely to do with the measurement. The result I posted above your comment is probably more accurate. Another forum member helped me correct the response of the Ortofon LP to use Sjplot. Unfortunately, it has the smaller bearing housing and not the beefier 18mm version found on the P3. At some point I may swap out the bearing as I realise it's more catered to glass platters. I have also thought the same thing about the brace. It could transfer resonance from the platter to the arm. Which is contradictory to the design philosophy of other manufacturers who try to isolate the 2 elements completely. Anyway, as I change things, I may comment on this post if anything makes a measureable difference. Lowers distortion or flattens out the frequency response etc. People may find it interesting, regardless of it being a "Frankenstein model" as you put it. It's also good to have measurements confirmed as I'm not an expert by any stretch. There are some proper boffins on this forum who may comment if they spot something which looks erroneous.

 

[JeffS7444]

It might be fun to see how effective those isolation feet are by repeating the first test, but with the stylus lowered into a stationary groove. You might be surprised at how much subsonic energy is picked up.

 

[Thomas_A]

@Thomas_A

Had some free time this morning, so I tried out your method and got the below results:
View attachment 529771
Definitely looks to me like different loading is required to flatten out the response. Shame there is no way to change it on my phono stage.

Looks like it could be an AT type of curve, with a fair bit of channel balance issue. If you have the original raw file to share, I could make an analysis to verify.

 

[DSJR]

Thanks for your comments. I realise this is far from an original P1. However, I still thought people may find it interesting. I like to tinker with things and the original P1 arm had fixed antiskating. Meaning I couldn't try out different cartridges so easily. I bought the arm off ebay second hand. It already had the "upgraded" stub and weight fitted. Ideally I wanted one stock, but it was listed for a good price and figured it's unlikely to cause any harm. I doubt the phono stage equalises anything. It's the built in one on the P1+ which is particularly basic. If anything, I would say it's more likely to do with the measurement. The result I posted above your comment is probably more accurate. Another forum member helped me correct the response of the Ortofon LP to use Sjplot. Unfortunately, it has the smaller bearing housing and not the beefier 18mm version found on the P3. At some point I may swap out the bearing as I realise it's more catered to glass platters. I have also thought the same thing about the brace. It could transfer resonance from the platter to the arm. Which is contradictory to the design philosophy of other manufacturers who try to isolate the 2 elements completely. Anyway, as I change things, I may comment on this post if anything makes a measureable difference. Lowers distortion or flattens out the frequency response etc. People may find it interesting, regardless of it being a "Frankenstein model" as you put it. It's also good to have measurements confirmed as I'm not an expert by any stretch. There are some proper boffins on this forum who may comment if they spot something which looks erroneous.

Please forgive me if you thought I was being over-critical here... I'm currently playing with a once bottom model Pro-Ject, which as well as being potentially quite capable, it's shown me just how much better andmore solid Rega decks are, at least to UK buyers not having to deal with high export prices. Assuming the hole in the plinth is the right size, a standard Rega bearing isn't expensive should you feel the need to replace it.

I remember decades back, my then employer investigated upgrading a Thorens TD160, which had a pressed sub-chassis and the main bearing also pressed hard into place on it. The upgrade consisted of a wooden piece glued to the bearing and bolted all round it, further glued along the path to the arm end an extension upwards at the arm end with cut top plates to accommodate different arms. Looked really ugly, but did 'sound' better as the sub-chassis dodn't go 'boing' if tapped when playing. UK reviewer Martin Colloms also did a posher bearing reinforcement on the earlier 80s Linn LP12 bearing to sub-chassis using a perspex block glued into place around the bearing and to the sub-chassis (Linn bypassed all of that with the original Cirkus update). So, please don't totally dismiss the strap Rega have added to their turntables, as no doubt it really does benefit the lighter plinths they're now using

 

[Stephen H]

Looks like it could be an AT type of curve, with a fair bit of channel balance issue. If you have the original raw file to share, I could make an analysis to verify.

Very kind of you to offer! You can download the files here:

Left Channel
Right Channel

They have already had the Nyquist script ran against them. However, if you need them with out this, let me know and I will re-record them. Many thanks!

 

[Stephen H]

Please forgive me if you thought I was being over-critical here... I'm currently playing with a once bottom model Pro-Ject, which as well as being potentially quite capable, it's shown me just how much better andmore solid Rega decks are, at least to UK buyers not having to deal with high export prices. Assuming the hole in the plinth is the right size, a standard Rega bearing isn't expensive should you feel the need to replace it.

I remember decades back, my then employer investigated upgrading a Thorens TD160, which had a pressed sub-chassis and the main bearing also pressed hard into place on it. The upgrade consisted of a wooden piece glued to the bearing and bolted all round it, further glued along the path to the arm end an extension upwards at the arm end with cut top plates to accommodate different arms. Looked really ugly, but did 'sound' better as the sub-chassis dodn't go 'boing' if tapped when playing. UK reviewer Martin Colloms also did a posher bearing reinforcement on the earlier 80s Linn LP12 bearing to sub-chassis using a perspex block glued into place around the bearing and to the sub-chassis (Linn bypassed all of that with the original Cirkus update). So, please don't totally dismiss the strap Rega have added to their turntables, as no doubt it really does benefit the lighter plinths they're now using

No problem! I'm always open to some constructive criticism. That's interesting, it must be said, my Rega deck is particularly microphonic. You can here any slight taps or knocks to the plinth come through my speakers whilst it's playing. That's why I decided to make some new feet for it. Not really sure how much it helped. I didn't have a test LP back when I made them. However, my ears tell me there is an improvement. Especially in the bass region. One thing I forgot to mention on my previous reply. The feet aren't directly coupled with the glass as it may look. The pads they sit on have some recessed rubber domes on the bottom. Also, these are older photographs. I have also created another shelf which sits on top of the glass which also has the same rubber domes. So there should be plenty of isolation/absorption.

I didn't realise the plinths were lighter on the newer models. So, given that, what do you think is better? The older heavier plinths, or the newer ones with the metal brace?

 

[Stephen H]

It might be fun to see how effective those isolation feet are by repeating the first test, but with the stylus lowered into a stationary groove. You might be surprised at how much subsonic energy is picked up.

Yeah definitely! If I'd had a test LP back when I made the feet, I absolutely would have made some before/after measurements. I may do this as an experiment at some point, I still have the original feet, so I could swap them back.

 

[Thomas_A]

Very kind of you to offer! You can download the files here:

Left Channel
Right Channel

They have already had the Nyquist script ran against them. However, if you need them with out this, let me know and I will re-record them. Many thanks!

I filtered out some low frequency junk but it fits quite well. Channel imbalance is 1.5 dB, and dip at 5-6 kHz is ≈1 dB, followed by the peaking at ≈12 kHz.

 

[DSJR]

No problem! I'm always open to some constructive criticism. That's interesting, it must be said, my Rega deck is particularly microphonic. You can here any slight taps or knocks to the plinth come through my speakers whilst it's playing. That's why I decided to make some new feet for it. Not really sure how much it helped. I didn't have a test LP back when I made them. However, my ears tell me there is an improvement. Especially in the bass region.

I didn't realise the plinths were lighter on the newer models. So, given that, what do you think is better? The older heavier plinths, or the newer ones with the metal brace?

Just my take here, is that it needs to be extreme heavy or light and rigid. The Pro-Ject Essential here tends to thrum a bit if the plinth is tapped (I need to try some spike-type feet like yours to prove a hunch). The P3-2000 has quite a solid slab which is chamfered to the edge, making it look thinner than it is and it's a very muted thud through the stylus if tapped when playing.

I believe @Frank Dernie here suggested that the tripod arm-fixing screws should have one done up sensibly and the other two just nipped up to prevent rocking. I preferred older Regas to be done up tight, the rubber feet allowing some rotation rather than clamping them up (I was told this at the factory but they may have changed their minds today).

More pertinent to this thread, have you tried the better belts they offer? My EBLT makes mine run at pretty much the correct speed (using a sensitive 300Hz Linn strobe).

 

[Stephen H]

I filtered out some low frequency junk but it fits quite well. Channel imbalance is 1.5 dB, and dip at 5-6 kHz is ≈1 dB, followed by the peaking at ≈12 kHz.

View attachment 529970

Thanks for that! It's interesting, I've seen other Rega Exact measurements also showing a channel imbalance. I read that one member thought there must be something wrong with the cartridge, so sent it back to Rega. But they said there was nothing wrong with it. So I guess it's just a characteristic of these cartridges.

 

[DSJR]

I filtered out some low frequency junk but it fits quite well. Channel imbalance is 1.5 dB, and dip at 5-6 kHz is ≈1 dB, followed by the peaking at ≈12 kHz.

View attachment 529970

Can someone try the Carbon Pro with elliptical tip fitted? To me it sounds better integrated and less subjectively 'splattery' up top when the going gets toughg...