View Full Version : Pro-Ject RS Box Series
I needed a Pre Amp with balanced outputs and started looking at the Pro-Ject Pre Box RS.
The more I looked at this the more I liked it and the rest of the range for that matter.
I've put this together so people can get a feel for my personal experience of owning these devices, others may have different views, these are just mine, which may or may not help anyone considering a purchase. I started with the Pre Amp, but the Phono stage is looking rather tasty as well.
http://www.jkwynn.co.uk//Project_Images/Pro-Ject/Proj_01.JPG
This is my unit and the rear view shows it is the later version using a mini XLR connector for the DC voltage input. Even Pro-Jects own site still shows the original barrel type DC connector, so I thought this would be useful. This cable is attached to a laptop style Power Supply brick. The Pre Amp is dual mono and has valve output stages, being supplied with a pair of Electro Harmonix 6922 valves. These are not the best and can be upgraded using something like NOS Russian Military spec 6N23P to improve the sound quality. The power brick is another area for upgrading and a separate high quality linear power supply, like Pro-Jects own will improve things a lot.
There are a couple of quirks that I feel should be pointed out to anyone thinking of purchasing one of these.
First - The Two RCA outputs in the top corners are not volume controlled, they put out whatever source is selected at full volume and are meant for connection to a tape recorder etc. Do not connect your power amp to these or you will get a nasty surprise when you turn on and it is running flat out. If you need unbalanced RCA output, the Pre comes with a short set of XLR to RCA adapter leads that you can connect to.
Second - Is that the RCA input-1 and the XLR input-4 have a higher gain of RCA 6dB & XLR 12dB for use with Phono stages etc. The other inputs are meant for connection to things like a DAC/CD player which have a higher signal level and require less gain, the level for these inputs is RCA 0dB & XLR 6dB. This gives quite a bit of flexibility, 0dB/6dB/12dB gain options, depending on the input you plug into.
I will report back on how the unit sounds as it burns in.
I've been looking at their balanced input/output phono stage. I'm moving towards an all-balanced system, from source to speaker, and I like the look of these units with their facility to easily adjust gain and loading.
http://thumbs.ebaystatic.com/images/g/W0cAAOSw-vlViBGo/s-l225.jpg
Barry - I agree, the phono is very flexible, as well as the loading options, if you are prepared to mix and match balanced/unbalanced it has 6 gain levels selectable. With the three gain levels on the Pre that gives you a choice of 18 gain level combinations to choose from in that part of the chain. If using just balanced connections you still have 3 options on the Phono and 2 on the Pre (6), takes some beating - subject to it actually sounding any good in the first place, which by all accounts it does.
The balanced input on the phono is less crucial as the feed from the cartridge can only ever be pseudo balanced and you may have to insulate the cartridge from the headshell if the Green cartridge pin is attached (grounded) through the cartridge body, but it is never the less still attractive. Neutrik make a Mini XLR to XLR adaptor so you could use the type of connector on my picture in the first posting. If like me, you run the leads from the cartridge pins straight to the inputs on the phono stage, the size and weight of the connectors might matter. I use thin (less than 1mm in its shielded jacket) and delicate solid Silver wire, hanging a full size XLR connector off this is asking for trouble, but using the mini XLR's might be more practical in my case.
As you can probably tell, I've also been giving the RS phono stage some serious thought.
I gave the RS Phono some serious thought as well, but I don't have that many cartridges that need the loading altered, and I am not likely to grow my cartridge collection by a huge amount.
I think that the Pre Box RS is a pretty good Pre amp, and I have been happy with mine for the last 18months.
The EH6922 valves don't do it justice, and they are fiddly to remove as they are stuck to the PCB with silicone. The SMPS needs upgrading with a decent PSU, although some people have reported that battery power worked well. I never tried mine on a battery so can't give any feedback on it, but the linear PSU certainly raised the performance of the pre.
Here are my first observations using the RS Pre Amp.
The very bright LED's are a PITA!
There is a short warm up period for the valves, before the unit comes to life.
When you turn on the unit, it does not remember the last source used and always defaults to input #1 at start up, so you have to toggle through every time, unless you happen to use input #1 of course, which is a high gain RCA input.
The lever for selecting the source works the wrong way round. When you press the lever down it increases the source number, when you lift it up it decreases the number. This is the opposite to what you would expect, and goes against everything I was taught to be good practice. I studied ergonomics as part of my 8 years of design training, so its a minor niggle with me.
The volume control is motorised and this plus the source can be selected from the remote control. Manual volume adjustment on the motorised Alps pot is a little stiff, but not overly so, in fact I think this damping leads to smoother adjustments, with less likely hood of wanging it round excessively.
Overall build is solid and well put together.
Lets get down to it then, first, its a very quite unit and when I ran it in for 10 to 15 hrs a day, the case barely got above room temperature.
SOUND
Day1
Course treble and overall bright presentation with reasonable bass and no mid range.
Day2
Mid range coming through, but very bloated and mushy.
Day3
Mid range and top end cleaning up now and starting to come into focus, which is making the bass now sound weak and too far back in the mix.
Day4
Mid range properly filled out and treble is clean and detailed, bass level has lifted and I think there is little if any changes after about 50 hours use (82hrs now on it).
As a comparison, with the rest of my system being unchanged and using tracks I am very familiar with, the bass is lacking, not as kicking or deep as my Croft Micro 25. However, there is a greater amount of detail in the upper mids and voices have a more natural tone.
This is just my first impression using the stock valves and power supply. Other users report, as Kevin does, that fairly substantial improvements can be gained by upgrading these two elements, so perhaps room for improvement bass wise.
Overall I am very pleased with it, but I will have to improve the bass, couldn't live with it knowing I'm missing out on so much. I'm not too worried about this, as I know its not giving its best due to the aforementioned - Just to clarify, the bass isn't bad, its just I had cracking bass with my previous set up and that's my yard stick.
I must make up some balanced leads to try, parts arrived this afternoon, Neutrik XLR's and Klotz MC5000 cable, though this should not effect sound quality based on the short lengths involved.
EDIT: 03/04/16
It's got about 120 hours on it now, believe it or not the bass continued to improve very very gradually, it has more kick to it now and goes a bit deeper, so the gap has closed a bit with the Croft, but it's still not quite there, I suspect the PSU/Valve upgrades would bring it up to match the Croft, we will have to see, when I get round to trying that.
rubber duck
31-03-2016, 19:39
However, there is a greater amount of detail in the upper mids and voices have a more natural tone.
More natural than the Croft 25? I'll be following this with interest. Thanks for the write up.
As always, I can only comment on how its working in my system and its subtle not knight and day.
I liked my Croft a lot, but yes, female voices are less sibilant, on recordings I had noticed this with, there are subtle changes in tone I wasn't picking up on previously.
When listening to JazzFM and Radio4 plays I am finding the speech more in the room and life like.
But with the out of box set up, the Croft beats it by a mile in the bass, more kick and impact to drum hits and goes very noticeably deeper. (Malia/Boris Blank, OMD, Sam Smith)
EDIT: See my revised comments on post #5
Its early days yet, I have a lot of things to do and try before I can give my final judgement, but the foundation seems pretty sound to build on.
I gave the RS Phono some serious thought as well, but I don't have that many cartridges that need the loading altered, and I am not likely to grow my cartridge collection by a huge amount.
I lost my MM only phono stage, as it was built into the Croft which I sold on, so I'm in the market for one anyway and I like the totally balanced connectivity it is possible to have with the RS system. It gets good reviews and I was impressed when I heard it at last years NW audio Show. So with the advantage of being able to handle a wide range of Cartridge types it's at the top of a very short list for me.
daytona600
31-03-2016, 21:02
Cracking bits of kit the RS range & upgrades with the external Psu for one or multiple RS units & you can tube roll NOS valves as well for a upgrade - http://img4.audio.de/Pro-Ject-CD-Box-RS-Pre-Box-RS-Digital-Audio-f630x378-ffffff-C-73504032-108267182.jpg
have some loan units if you ever want to try one out
RS Phono Review - think he liked it !
http://www.analogplanet.com/content/pro-ject%E2%80%99s-mmmc-phono-box-rs-chronic-overachiever#iOztS68imGaGb0IG.97
Floyddroid
31-03-2016, 21:25
Ken, try a Schiit Mani. Worth every penny. I have one if you want to give it a go.
I lost my MM only phono stage, as it was built into the Croft which I sold on, so I'm in the market for one anyway and I like the totally balanced connectivity it is possible to have with the RS system. It gets good reviews and I was impressed when I heard it at last years NW audio Show. So with the advantage of being able to handle a wide range of Cartridge types it's at the top of a very short list for me.
Cracking bits of kit the RS range & upgrades with the external Psu for one or multiple RS units & you can tube roll NOS valves as well for a upgrade
have some loan units if you ever want to try one out
RS Phono Review - think he liked it !
http://www.analogplanet.com/content/pro-ject%E2%80%99s-mmmc-phono-box-rs-chronic-overachiever#iOztS68imGaGb0IG.97
Thanks for the offer.
I had a look inside a Power Box (single) and wasn't that impressed with what you get for your money, component wise.
The unit for multiple connections is about the same weight on the spec sheet, so its got a similar size transformer and there just seems to be a separate bank of caps for each output. Multiple single supplies would probably be better.
The Supply for the Phono stage is a different animal, its a +/- 18Vdc supply (dual symmetrical) and is basically a battery pack with intelligent charger, if I'm understanding the blurb correctly, it has its own wall wart supply! If the power in the batteries drops too low the mains takes over.
I'm open minded as to how I tackle the PSU upgrade, I have a man in China willing to make a supply in a nice case to what ever input/output voltages I specify (within this range) for £65 plus £15 P&P, even if I have to pay duty its a good deal and I've seen what he puts into them, R-Core Transformer, x2 Toshiba 2SC5200 and a decent amount of capacitance made up of multiple small values, even the wiring is neater than the Pro-Ject Power Box so I'm undecided.
Ken, try a Schiit Mani. Worth every penny. I have one if you want to give it a go.
Thanks for the offer Steve, if I don't get fixed up maybe a demo at NEBO? It's not a name I have come across, I looked it up and it has a fair amount of adjustment and suitable for MM/MC.
I'm pretty much sold on the Pro-Ject and ready to pull the trigger, my priorities, which it almost meets are these.
1). <£800 - Yes
2). Sound Quality - Yes
3). Valve based - No
4). MM or MC - Yes
5). Plenty of adjustment - Yes
6). Balanced outputs - Yes
The fact that I will get a one brand styling match with the Pre Amp is also a bonus.
I've been thinking about this system change since November so a lot of things have been considered.
I'm new to the whole balanced connections thing so I needed some XLR leads. They vary in price/quality by quite a bit, so being the skinflint that I am, I decided to make my own, which gives the best price/quality ratio achievable.
I've been using Klotz MC5000 cable for a while now on my unbalanced set up, I'm very pleased with it, so see no reason to change, it was intended for this type of set up in the first place. Not being one for fancy (expensive ) connectors, I went for the Neutrik NCXX range, good solid construction with Gold plated contacts and less than £4 a piece.
One thing to note here, the Klotz cable is thicker than many of the studio type cables, not by much but it is enough to stop the boot screwing on all the way, due to the cable clamp (chuck) bottoming out too early. There is a simple remedy for this, which no doubt is common knowledge for those who make these up on a regular basis, but I had to work it out myself. The separate clamping piece has two narrow nose pieces that locate in the body to stop it rotating when you screw it all together. Reduce the nose length by half by snipping the plastic off with a pair of wire cutters, so you are removing about 2mm off the length. This still allows it to engage in the body, but now the boot screws up all the way and gives a good amount of clamping force on the cable.
http://www.jkwynn.co.uk/Project_Images/Pro-Ject/Proj_02.JPG
If there is a wrong way of connecting leads to an amp, you can bet I will find it. Because of this I tend to colour code my leads with either electricians tape (sticky) or heat shrink sleeving. Neutrik have two methods to help you achieve this in a tidier fashion on the NCXX range. They make coloured rings at 20p each and coloured boots at 68p each, nine colours of each available plus the standard fitted Black. You can use which ever method you prefer, but I have used a combination of both, Red and White rings for Left and right channels and coloured boots to identify their use, I'm using a Black boot for Pre to Power Amp, Blue for DAC to Pre and Violet for Phono to Pre, see the picture above. It should make life easier when picking a lead out of the rats nest at the back of my rack.
When I tried the leads to connect my Cambridge DacMagic to the Pre Amp, two things were noticeable, first, it was louder, apparently balanced is 6dB louder than unbalanced, nothing to do with my unit, its the way the two methods work. Second it sounded better, I wasn't expecting this, I looked into this on the web and its because my DAC combines the balanced elements through an additional opamp to produce the unbalanced output. What I am hearing is one less opamp per channel in the chain, a small but significant improvement in clarity at the top end. This is a recognised upgrade path for my DAC which I wasn't aware of till now, so that's a plus.
Ken,
We (Stargazer and I) have just spent an enjoyable day listening to the Pre Box RS - If you can find some Tungsram E88CC they are worth trying.
They seemed to have better tonal accuracy than the Reflektor, so if that is what you are after it's well worth giving them a go. The Reflektor seem more musical overall, but it depends on what you are after.
I used the MC5000 with my pre and power combination, and never saw the need to change either.
Ken,
We (Stargazer and I) have just spent an enjoyable listening to the Pre Box RS - If you can find some Tungsram E88CC they are worth trying.
They seemed to have better tonal accuracy than the Reflektor, so if that is what you are after it's well worth giving them a go. The Reflektor seem more musical overall, but it depends on what you are after.
I used the MC5000 with my pre and power combination, and never saw the need to change either.
Yes, the Tungsram E88CC were top of my list till you mentioned the Reflektor's.
It will be after the NEBO meet in May before I get round to thinking about valve rolling and I think I will try the Tungsram.
Frazeur1
02-04-2016, 15:12
Nice looking cables, Ken! Enjoy the Pro-ject gear, it is cool looking little boxes!
From yesterday's back to back test, the Reflektots were more "velvety" if that makes sense. Very musical, but lacking the outright detail of the Tungsram. Graham left here with the Tungsram. They really do raise the bar compared to the EH6922 valves.
Kevin - I read some of what you and others had said about the Tungsram and various other tubes for the Pro-Ject Pre, on the Wam.
Detailed and with tonal accuracy, I believe you also stated they were very quite, sounds good to me.
Watford Valves used to keep them if my memory serves, but I'm in no rush.
Just pulled the trigger on the Pro-Ject Phono Box RS.
Subject to getting an invoice and paying for it, one should be heading my way soon, so watch this space. ;)
http://www.jkwynn.co.uk/Project_Images/Pro-Ject/Proj_03.JPG
The Pro-Ject Phono Box RS arrived today.
It has both balanced and unbalanced inputs/outputs and plenty of adjustment for impedance, capacitance and gain, which should cater for most cartridges, whether MM/HOMC/LOMC it also offers RIAA or DECCA EQ curves. It's powered by a wall wart style dual symmetrical SMPS of +/- 18Vdc so there is an upgrade path using a better power supply if I feel the need.
I will give it a few days running, before making an assessment of its performance.
http://www.jkwynn.co.uk/Project_Images/Pro-Ject/Proj_04.JPG
Time for a bit of valve rolling, this was supposed to be happening later, but some valves came up at a good price, so I grabbed them while available.
They are NOS (New Old Stock) valves for the Pre Amp, early 1970's Tungsram E88CC Red label, from the Hungarian factory.
These will be the first valves I have ever fitted.
http://www.jkwynn.co.uk/Project_Images/Pro-Ject/Proj_05.JPG
Removed the top on the Pre Amp, the stock Electro Harmonix 6922 can't be pulled straight out as they are glued in place at one end, probably to reduce vibrations or from coming loose in transit. White silicon is applied to the PCB and Black to the valve. I found the easiest way of removing them, was to take off the side panels of the enclosure and just cut through the center of the silicon with a sharp knife. Once the valve was taken out it was easy to remove the remaining silicon from both parts.
http://www.jkwynn.co.uk/Project_Images/Pro-Ject/Proj_06.JPG
As the valves are fitted horizontally, I installed some silicon rings on the ends of the valves to support them. I fitted them in the same place that the adhesive had been used, this avoided blocking any of the ventilation holes in the PCB. So they are not really being used for microphony damping in this location, just used as supports. The clearance underneath these particular valves is 3.5mm and the silicon rings are 5mm thick so I cut a small flat in one spot, reducing the thickness to 3.5 and positioned this on the underside, worked a treat.
I'll give them a day or so running to settle and see how they sound.
Well the valves have had quite a while to settle in and the RS Pre Amp is sounding very nice, the bass I was missing with the stock valves is back in place.
The delivery now has no real vices, the Pre just gets on with the job, without anything standing out as being noticeably forward or lacking, very neutral overall.
The RS Phono has also had time to settle and my Goldring 1042 MM sound's very nice, with a level of detail and black background that betters what my Croft Micro 25 did. The two sound different rather than one being outright better, they are both great phono stages and I could live with either, I'm just glad I've lost nothing in the change.
I switched over to MC and dropped in my Denon DL-301 mkII, this was an even bigger improvement, over my DIY moving coil or Cambridge 651P stages, a very rich full sound I am liking a lot and prefer over the Goldring MM.
Both cartridges produced really taut and deep bass using this Phono stage, I've gone from a bass light system to a nice deep bass.
Very impressed with the Phono stage and Pre combination.
I need to look at my DAC (DacMagic) at some point as my Digital sources had been besting my vinyl for some time.
The vinyl has finally gelled and is back to being king, there's not much in it, I just seem to enjoy the vinyl more now.
Less sibilance with my vinyl set up compared to CD.
Taking both these units to the NEBO meet next weekend if anyone wants to try them with their set up.
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