REVIEW - Pheonix Engineering PSU + Tachometer

[Wakefield Turntables]

Just thought I write a few words with regards my latest toys. I've been banging on about getting an external PSU for the Garrard 301 for some time and after 2 years worth of research and speaking to numerous 301 Guru's (Audiograil, Dr. Bastin, Loricraft etc) I plumped for this combination. Shipping time was 5 days :eek: customs took nine days and charged my £150 import duty :steam:, costs all in was probably £600-700. This system is the 25W version and specially designed for TT's that need a bit of extra poke to get that platter spinning.


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Setting was a doddle and took ~10 minutes. The tachometer takes ~1 minute to stabilise and then keeps the platter spinning rock solid at between +/- 0.001-2 RPM to 33RPM until you turn if off.

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The PSU & Tachometer come extremely well packed and I'd give Pheonix 10/10 was the quality of the boxes/packing indeed each unit has an individual bespoke set of packaging. Truly excellent. The instruction manuals and short, sweet and straight to the point, again I have to comment Pheonix.

The PSU is built like a small tank and exudes quality, this baby pumps cleans your mains and pumps a healthy 25W into the Garrard.

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The vast majority of the connecting leads are 3 & 5mm jack plugs which are all gold plated, this gained them some more browny points.

The system works by installing a small magnet beneath the platter a small PCB installed under the magnet detected platter speed and automatically corrects the platter so that it runs as close to 33.3333 rpm as possible. This was perhaps the worst part as I had to rejig and remount my Garrard 301's bearing by an additional 2mm this raised the platter and allowed the PCB to mounted near the magnet.

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The PCB has to be within 1/4" of the magnet otherwise it dosen't work and I must admit that I wasn't impressed with this area of the Tachometer's design. This is only a minor gripe and should not be taken out of context. The system is excellent and very easy to work with. So how does it sound? Well in a word, STUNNING! This system has really transformed my 301 listening experience. I was initially confronted with a leaner presentation to the music and couldn't quite understand why? It was only when I listened to several albums of piano music that the penny dropped. The pitch stability had improved no end and whilst previously I could hear instability in a notes decay I have to say that such a phenonomen had disappeared. My soundstage has an improved clarity and the 301 now seems better at placing and defining instruments in the soundstage. The soundstage has also deepened and become more 3D. The 301 really has come on leaps and bounds with this system. I would heartily recommend this system and you can transfer it to pretty much any deck. I do have two complaints. Firstly I think the buttons on the PSU and Tachometer could have been made from metal rather than plastic and secondly I did have to find a USA/UK plug converter (probably a couple of quid extra) to make the Tachometer work. If I'm spending £600-700 on a system some nice steel buttons and a cheapo plug converter wouldn't each too much into Pheonix Engineering's profit margin. The 25W version is only available directly from Pheonix but Bill who owns the company is very good at responding to emails. So, I'd give this system 9/10.

[daytona600]

Phoenix Engineering
Eagle High Power Digital Turntable PSU 25W £ 379
RoadRunner Digital Tachometer £ 165
Package Deal
Eagle + RoadRunner - Turntable Digital PSU & Digital Tachometer £ 519

[daytona600]

http://theartofsound.net/forum/showthread.php?43150-High-Power-Digital-Turntable-PSU

[Wakefield Turntables]

Scott I'd already ordered and paid for the system otherwise If I'd have known you would have had a sale. :( I'd not seen that review before so it's nice to see that I agree with the other reviewer.

[daytona600]

very well designed piece of kit as you found out andrew
client just fitted one to his £3500 VPI Prime & huge step up in sound quality to already very good sounding standard deck

once my 301 is rebuilt adding PSU & Tacho to mine
Brings DD speed stabilty to belt & idler decks

http://positive-feedback.com/reviews/hardware-reviews/phoenix-engineering-llc-roadrunner-and-eagle-psu/

http://www.analogplanet.com/content/phoenix-engineerings-falcon-psu-and-roadrunner-tachometer#ch3ze1b2E6QKxXI4.97

[Gazjam]

Interesting...

do-able on a Gyro you think?

[daytona600]

Tacho fits any turntable
PSU if your Gryo is AC motor

[lurcher]

once my 301 is rebuilt adding PSU & Tacho to mine Brings DD speed stabilty to belt & idler decks

Not strictly true. A stable 50Hz will help, which the PSU will do, but all the Tacho is doing is adjusting the 50Hz slowly to make the platter rotate at the target speed. A typical direct drive responds to speed variation every 20ms, this responds every 1.8 seconds.

[Wakefield Turntables]

Not strictly true. A stable 50Hz will help, which the PSU will do, but all the Tacho is doing is adjusting the 50Hz slowly to make the platter rotate at the target speed. A typical direct drive responds to speed variation every 20ms, this responds every 1.8 seconds.

Still sounds bloody good especially when it's filetered through the P10 power regenerator enabling a decent stable 50hz (THD usually <0.1%) and all the DC crap filtered out :).

[lurcher]

Still sounds bloody good especially when it's filetered through the P10 power regenerator enabling a decent stable 50hz (THD usually <0.1%) and all the DC crap filtered out

I am sure it does, as I said, not saying its not a good idea, just the comparison with a direct drive is a bit bogus (not that you made that comparison)

I take it you are feeding the supply from the P10, not the other way around :-)

[Wakefield Turntables]

I take it you are feeding the supply from the P10, not the other way around :-)

Yep!

[struth]

I found a regen made a fair bit of improvement with my thorens. Pretty night n day

[Wakefield Turntables]

I wonder if the update rate can be improved by adding additional magnets on the underside of the platter, I've just emailed Bill to find out. I wonder if this would improve pitch stability.

[lurcher]

I wonder if the update rate can be improved by adding additional magnets on the underside of the platter, I've just emailed Bill to find out. I wonder if this would improve pitch stability.

You would have to get the magnets exactly spaced around the platter, not a issue with just one and setting the average speed to 33.3, but next to impossible to do with more than one. You would need a rotary encoder or a toothed wheel frequency generator like direct drives use. You would then face the issue that the motor and platter is designed to work at a fixed speed driven by the AC motor, you could not drive the phase of the 50Hz and expect to see control like a direct drive system.

Not that I have ever heard a problem with pitch stability will a well fettled garrard. I would expect a good 50Hz supply would work wonders which is what the supply you have should provide. I am messing with such a thing myself, you can compare it to the one you have if Its done by the time the preamp is ready.

You can see how the UK mains supply frequency varies here: http://www2.nationalgrid.com/uk/Industry-information/electricity-transmission-operational-data, and I am sure a lower distortion sine will help reduce motor vibration. It was interesting looking at the mains on a scope compared to a quartz referenced 50Hz and see how it wanders around the target value.

[Wakefield Turntables]

You would have to get the magnets exactly spaced around the platter, not a issue with just one and setting the average speed to 33.3, but next to impossible to do with more than one. You would need a rotary encoder or a toothed wheel frequency generator like direct drives use. You would then face the issue that the motor and platter is designed to work at a fixed speed driven by the AC motor, you could not drive the phase of the 50Hz and expect to see control like a direct drive system.

Not that I have ever heard a problem with pitch stability will a well fettled garrard. I would expect a good 50Hz supply would work wonders which is what the supply you have should provide. I am messing with such a thing myself, you can compare it to the one you have if Its done by the time the preamp is ready.

You can see how the UK mains supply frequency varies here: http://www2.nationalgrid.com/uk/Industry-information/electricity-transmission-operational-data, and I am sure a lower distortion sine will help reduce motor vibration. It was interesting looking at the mains on a scope compared to a quartz referenced 50Hz and see how it wanders around the target value.

Bugger that then!

[paulf-2007]

I was interested in these some time ago when I had several idler drives and didn't get around to buying one. It certainly looks a nice bit of kit but I had to smile when you said it stabilises in a minute. The Denon DP80 gets up to speed in 0.9 seconds. Admittedly the speed stability is not as accurate at 0.002% but then it's technology is 40 years old.

[daytona600]

I was interested in these some time ago when I had several idler drives and didn't get around to buying one. It certainly looks a nice bit of kit but I had to smile when you said it stabilises in a minute. The Denon DP80 gets up to speed in 0.9 seconds. Admittedly the speed stability is not as accurate at 0.002% but then it's technology is 40 years old.

PSU limited by the drive train in idler & belt drive turntables

comparism between PLL ( Phase locked loop ) & DDS ( Direct Digital Synthesis )

add the matching tacho this forms a closed loop speed control system for 33.000 & 45.000 rpm


https://www.youtube.com/watch?v=DTP8HE7pmEQ

Direct Digital Synthesis is a digital frequency generator that uses a crystal controlled master clock to increase the count in an accumulator register by a fixed amount on each clock transistion. The register "accumulates" the count on each clock which increases linearly, until the maximum count is exceeded, the counter overflows to zero and the processes begins again and continues indefinitely. The amount the accumulator changes on each clock input is determined by the frequency control register: The larger the number, the faster the count accumulates, the lower the number, the slower the output changes. The accumulator contains a binary number between 0 and 2^N where N= the width of the register in bits. DDS accumulators are usually 24, 28 or 32 bits wide. The smallest number it can increase by is 1, so the frequency output resolution becomes MClk/(2^N); the higher N is (or the lower the Master Clock frequency) the finer the resolution. The output frequency is Freq Count x (MClk/2^N). For example, if the crystal frequency (MClk) is 4.096 MHz and the accumulator is 24 bits, the frequency resolution is .244140625 Hz (~ a quarter of a Hz). For 60Hz the Freq Count=246 (60.0585 Hz). If the crystal reference is divided down to 32kHz (÷128), the frequency resolution is 0.001907 Hz and Freq Count for 60Hz becomes 31,457 (59.9995 Hz). The same MClk with a 32 bit accumulator has a frequency resolution of 0.00000745 Hz and Freq Count for 60Hz becomes 8,053,064 (60.0000024 Hz).

The highest order bits of the accumulator are used as an address in a look up table that converts the linear phase accumulation into a sinewave amplitude value. This value is then sent to a digital to analog convertor (DAC) which produces an analog sinewave output. The DAC resolution is typically between 8 and 14 bits.

Because DDS is a feed forward system, it doesn't require a feedback loop and frequency changes take place on the next MClk input, are phase coherent and settle to the new frequency in uSecs. The output frequency will have the same stability as the crystal reference clock and phase noise will be better than the crystal by a factor of MClk/N where N is the frequency count. DDS is a type of sampling convertor, so the maximum frequency output is MClk/2 (Nyquist limit), but in practice, the output is usable to ~MClk/10. The closer the output frequency is to this limit, the worse the noise and spurious performance will be. Analog filters at the output of the DAC can reduce the noise and spurious content to low levels.

DDS is usually done by dedicated ICs that are complex to program and configure. A microprocessor is needed to compute the frequency count and perform the programming and communications with the DDS chip. DDS is commonly used in bench top test equipment and high end signal generators.

[Wakefield Turntables]

I was interested in these some time ago when I had several idler drives and didn't get around to buying one. It certainly looks a nice bit of kit but I had to smile when you said it stabilises in a minute. The Denon DP80 gets up to speed in 0.9 seconds. Admittedly the speed stability is not as accurate at 0.002% but then it's technology is 40 years old.

It stabilises usually within 10-15 seconds due to the fact that the tachometer updates the PSU every 1.8 seconds and not every few milliseconds like all DD's. It is a nice piece of kit, you should buy one.

[paulf-2007]

It stabilises usually within 10-15 seconds due to the fact that the tachometer updates the PSU every 1.8 seconds and not every few milliseconds like all DD's. It is a nice piece of kit, you should buy one.
Its not something I could use with the Denon DP80. It has its own built in speed stability:)
Who knows what the future holds, never say never

[al2002]

Hello Rexton. Nice report!

A couple of questions:

1. Is this a two phase or one phase supply? If two phase, is the phase angle between the two phases adjustable?

2. Does the supply drop the operating voltage relative to the startup voltage?

[Wakefield Turntables]

Hello Rexton. Nice report!

A couple of questions:

1. Is this a two phase or one phase supply? If two phase, is the phase angle between the two phases adjustable?

without doing a little research I couldn't answer your question, email Bill and he will tell you.

2. Does the supply drop the operating voltage relative to the startup voltage?

Now you can't. I did drop the voltage down to 200v using my P10 regenerator but noticed no difference. If your worried about motor resonance entering the deck chassis them decouple the motor. If your using a 301 remove the eddy current brake but I noticed no difference when I did this and ended up putting it back.