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Review and Measurements of Rane PS1 Phono Amp

amirm

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#1
This is a review and detailed measurements of the Rane PS1 Phono stage/preamplifier. It is on kind loan from a member. It has been discontinued and seems to have come out circa 2002 (?). I can't find a price for it.

If you are not familiar with Rane, it is a company focused on pro audio and has written some of the best tutorials on audio. Needless to say, my expectations are quite high here with respect to the engineering of the PS1.

The PS-1 is an industrial looking thing:

Rane PS1 Phono Preamplifier Audio Review.jpg

The back panel makes you even less proud to put it on display:

Rane PS1 Phono Preamplifier Back Panel Audio Review.jpg

An external AC transformer with split tap powers the unit using a phone/RJ-11 style cable.

There are both unbalanced (RCA) and balanced (screw terminals) for output. I had to make a bare wire XLR cable to mate with the balanced output.

The shell of the balanced screw terminals was quite lose so I opened it to see what is going on:

Rane PS1 Phono Preamplifier Teardown.jpg

Turns out there is no mechanical support for the plastic part of that terminal and hence the reason it wiggles.

The design is old school (no SMT parts here) and effort has been put in to make this a single sided board with those jumpers. WIth this type of cost cutting, I am hoping this was a cheap unit when it came out.

Phone Preamplifier Measurements
Here is the dashboard view using RCA outs with 5 millivolts input:

Rane PS1 Phono Preamplifier Audio Measurements.png


There is no distortion at all which is good. Then again the gain is a bit low side too. The THD+N then becomes really the "+N" dominated by mains harmonics. Better filtering of the rectified waveform would have helped here. The SINAD could be pushed near 100 dB had this been done. As it is, performance is wanting:
Best Phono Amplifiers Reviewed 2019.png


As noted in the dashboard view, after spending time building the cable, I was disappointed that the performance got worse, not better. You can see it clearly here with THD+N versus delivered output voltage:
Rane PS1 Phono Preamplifier THD+N vs Level Audio Measurements.png


We don't get the benefit of noise reduction or low distortion.

By the way, if you use the RCA outs, you better put the transformer way away from the unit. Being AC, it nicely couples into the unit, causing severe increase in hum.

SNR tells us what we already know from the dashboard:

Rane PS1 Phono Preamplifier SNR Audio Measurements.png


With a lot more playing with grounding one may be able to get to the specified level by Rane. Mere mortals best not apply.

Frequency response shows variations especially with balanced output:

Rane PS1 Phono Preamplifier Frequency Response Audio Measurements.png


Conclusions
With a name like Rane, I expected far better performance than I see. Maybe this was a budget product for its time. I don't know. Today, there are much better choices.

------------
As always, questions, comments, recommendations, etc. are welcome.

This is my second review for the day. It was raining outside so couldn't do much gardening. Seeing how I have gone beyond call of duty, I thought I ask for a raise from you all. Please donate generously using:

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anmpr1

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#2
With phonograph reproduction, the phono stage is just the beginning issue, and usually the one that is easiest to solve; at least today. In the heyday of phono oriented preamps (up through the early '80s), you could expect (and you wanted) a subsonic filter. Rane evidently has that. You wanted a convenient method to select phono cartridge impedance (Emotiva has that feature, and I see Rane also), and also a channel output selector switch (L, R, L+R--this was useful in setting up and trouble shooting cartridge installations, along with playing monophonic records). Prior to the late '50s you really needed a preamp with variable preemphasis, since RIAA had not been declared standard. And if you were using 78s, a high filter was not a bad thing to have, but tone controls could be helpful for that, too. Today, phono is more or less an afterthought, and amazingly, many high end megabuck phono/preamp stages don't have all the features one would really like. What is needed is a Pioneer SA-9500 integrated amp built to Benchmark specs. LOL
 
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maty

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#3
Talking about phonos, I would like to see measures from:

* PS Audio NuWave Phono Converter (SS, very expensive)

* Tisbury Domino Phono Preamplifier (SS, cheap)

* Pro-Ject Tube Box SE II Preamp or new Pro-Ject Tube Box DS2 (tubes). I think they are the only things I would buy from that brand.
 

Frank Dernie

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#4
Nice to see a rumble filter. THe output of a record player at frequencies less than ~ 2xFn of the system equivalent mass on the cartridge compliance is error since it is a seismic type of transducer.
I know some people prefer without but they are adding phasey garbage without one.
 

anmpr1

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#5
Nice to see a rumble filter. THe output of a record player at frequencies less than ~ 2xFn of the system equivalent mass on the cartridge compliance is error since it is a seismic type of transducer.
I know some people prefer without but they are adding phasey garbage without one.
Back in the day, the subsonic filter was engaged in order to save amplifier power. And this was before the ubiquity of subwoofers.
 

sergeauckland

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#6
Back in the day, the subsonic filter was engaged in order to save amplifier power. And this was before the ubiquity of subwoofers.
With valved amplifiers and bass reflex loudspeakers, it's pretty much essential as the LF excursion on the woofer from warps can and often do exceed the excursion from music. This isn't so obvious with sealed box loudspeakers. It's also essential for broadcasting as unwanted LF excursion just soaks up transmitter power.

Rumble itself isn't and hasn't been a problem with half-decent turntables, but LF excursion due to warps and as Frank mentioned, the cartridge mass/compliance resonance, has always been. A switchable 'rumble' filter is pretty much essential, provided it's at a low enough frequency and steep enough so it doesn't intrude into the music.

S
 

dreite

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#8
I think this unit dates to long before 2002. I have a schematic with a date of 1991. :) (At least an original version of it.)

Dave.
 

restorer-john

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#9
As noted in the dashboard view, after spending time building the cable, I was disappointed that the performance got worse, not better.
You can see why, the balanced puts another opamp stage in line:

1558129796277.png


Here are the original specifications:

1558130018512.png

An external AC transformer with split tap powers the unit using a phone/RJ-11 style cable.
So it's an 18V CT transformer... The PCB layout looks strange, the four caps aren't the same either. Consider the LT-1125 wants a typical +/-15V and the SSM-2142 wants +/-15-18V supply.

An 18V CT cannot do that conventionally (full wave bridge and CT) . You'd only end up with +/-11.5V after losses and prior to the voltage regulators. Smelling a rat, I looked up and found the schematic with the identical layout (1997).

And it uses +/- half wave voltage doublers and the CT is not actually earthed, only virtually earthed. All in all, a strange way to power this RIAA stage if you ask me and it's not surprising there are significant mains artefacts.

Why not just use a full wave bridge and a 36VAC CT external transformer? Is there regulatory limits on external AC supplies in Pro systems for safety and is that why they went the voltage doubler path? I've never struck a voltage doubler upstream from a LM7xxx, I reckon it's asking a bit much of it.

1558135354515.png


https://www.analog.com/en/products/ssm2142.html#product-overview
 
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amirm

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#10
And it uses +/- half wave voltage doublers and the CT is not actually earthed, only virtually earthed. All in all, a strange way to power this RIAA stage if you ask me and it's not surprising there are significant mains artefacts.
Good catch and it is very odd.
 

Frank Dernie

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#11
Back in the day, the subsonic filter was engaged in order to save amplifier power. And this was before the ubiquity of subwoofers.
It certainly stopped pointless cone wobble at sub-sonic frequencies. It is even more important to have one if you have a subwoofer since the whole point is to get rid of the spurious output of the transducer which is outside its operating window. The lower limit of accurate transduction of a transducer of this type is about 2xFn, which varies very slightly depending on the damping, as does the magnitude of the error. It -is- possible to build this type of transducer to be more accurate at low frequencies but that requires so much damping that the higher frequencies are then less accurate. In the end, if one wants the best (most accurate) output from a record player all frequencies below 2x Fn need filtering out. That means, typically, the reasonably accurate bandwidth starts at about 24Hz, typically.
 

Theo

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#12
Could the SNR be a consequence of aging caps? Anyhow, isn't the SNR of vinyl playing worse than 70dB? Then, this would be a good enough design...
 

sergeauckland

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#14
Good catch and it is very odd.
Especially when using a voltage doubler doesn't save on cost of components, indeed needs two extra capacitors. I'm not aware of any regulatory reason for not using a 36v transformer. The European Low Voltage Directive only applies above 50v although the Rane device may predate the LVD.

S
 

SIY

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#16
Could the SNR be a consequence of aging caps? Anyhow, isn't the SNR of vinyl playing worse than 70dB? Then, this would be a good enough design...
Possible, but then you'd expect the principal component to be at 120 Hz.

Even before playing, the cartridge will have an irreducible noise of -65 to -75 dB ref rated output. Playing a record will indeed make it worse. So yes, good enough, if it were a measurement with a cartridge attached (which Amir mysteriously doesn't do).
 

dreite

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#17
I believe that particular external transformer was used across many of the units during that vintage. I repaired a few Rane units in days past for some musician friends, and I remember them all having the same external PS. Also, if you look at some of the old schematics for other units you'll see very similar/same voltage-doubler schemes.

Rane has always been good about making schematics available for their products. That, and the Pro Audio Reference and Rane library is valuable stuff.

Dave.
 

restorer-john

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#18
if it were a measurement with a cartridge attached (which Amir mysteriously doesn't do).
Why not standardize on the ubiquitous AT-3600? It's virtually industry standard, still being manufactured, 5.3mV output, and is as cheap as chips ~$US10.
 

amirm

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#19
Why not standardize on the ubiquitous AT-3600? It's virtually industry standard, still being manufactured, 5.3mV output, and is as cheap as chips ~$US10.
It is $30 on Amazon. Where is it listed for $10?
 

restorer-john

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#20
Here you go, the prices have crept up a little in the last 12 months. I can assure you the carts are ATs- we've bought a number of them. It's just a higher tracking weight version of the AT91 made en-masse for the OEMs. The good thing about ATs is the consistency in coils, balance and output.


1558229196500.png


I've got half a dozen AT91s (original Japanese manufacture) here, I can easily compare them to the AT3600Ls for consistency.

1558230950869.jpeg
 
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