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Old 12th March 2014, 02:31 PM   #1
Pyramid is offline Pyramid  United States
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Default Digital Turntable Tachometer and DDS based PSU

There has been enough interest in the two designs I have been working on to commercialize and offer these products for sale.

Some background on the products:

I purchased a commercially available PSU for my turntable and was disappointed with the design; it was woefully under-powered (voltage dropped from 120VAC no load to 94VAC when connected to a VPI table), off frequency (~ -0.3%) and the adjustment was too coarse (±0.1 RPM) to correct for belt tension and other anomalies in order to get the speed spot on. It used PWM (which accounts for its poor resolution) from a low cost µP and all through-hole discrete components made in China. I decided to do my own design based on Analog Devices DDS chip with the following requirements:

1. ±0.01RPM speed adjustments (35µHz min frequency step using 28bit DDS)
2. <0.5% distortion
3. 115VAC output nominal without a step up xfmr or coupling caps
4. 110VAC full load at 7W output
5. Programmable reduced output voltage when platter reaches speed
6. Soft Start mode to ramp speed up from ~20RPM to prevent "burn out" on belt.
7. Able to start from 33/45/78 RPM without user changing speeds
8. Small footprint: 3.25"L x 2.5"W x 1.1"H
9. Front panel selectable for 50/60Hz operation and small/large spindle options
10. Front panel selections for speed calibration, voltage reduction and factory defaults
11. High reliability using SMT components
12. Made in USA
13. Low cost (<$400USD Retail)

The result was the Falcon PSU with all of the design goals realized. During the development of the PSU, I searched for an accurate measurement instrument for platter speed, but was unable to find anything commercially available with the needed accuracy. The only digital tachometers were handheld and had 0.1RPM resolution. Strobes are only indicators of fast/slow and lack the needed resolution. As a result, I decided to create the RoadRunner Tach a digital tachometer for turntables, using a contactless sensor and having 3 decimal places of resolution (0.001 RPM).

During the testing of the Falcon PSU and RoadRunner Tach, I noticed that no matter how precisely the speed was dialed in initially, the table would slowly drift up in speed (~0.2RPM) over 20-30 minutes. The table was extremely sensitive to belt tension and belt location on the spindle as well as platter; any movement of the motor or belt location greatly impacted the speed. The RoadRunner Tach has a serial port on the back, originally intended for a PC logging function; it suddenly made sense to connect the Falcon PSU to the RoadRunner Tach to provide feedback and prevent long term drift of the speed or to correct for belt tension, placement, etc. The feedback is done in extremely small (±0.00041667 RPM steps) precise steps, applied evenly over the entire next revolution of the platter and will keep the speed synchronized to within ±0.005 RPM.

Both the Falcon PSU and RoadRunner Tach can be used standalone or connected together. When interconnected, the operation is completely automatic with no user intervention needed. The control is well damped and completely in-audible with no overshoot or wandering. The speed control works at 33/45/78 as well as with any "tempo" offsets (ie 33.4).

The RoadRunner sensor requires ~0.25" (6mm) clearance between platter and plinth.

Products are available directly from the mfr at:

Retail Pricing ($USD):

Falcon PSU: $379
RoadRunner: $235
Attached Images
File Type: jpg Falcon PSU.jpg (276.9 KB, 732 views)
File Type: jpg RoadRunner Tach.jpg (354.7 KB, 702 views)
File Type: jpg RoadRunner Lite.jpg (248.4 KB, 703 views)
Attached Files
File Type: pdf Falcon Comparison Chart.pdf (61.1 KB, 106 views)

Last edited by Pyramid; 15th April 2014 at 08:02 PM.
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Old 12th March 2014, 03:59 PM   #2
Pyramid is offline Pyramid  United States
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Default Digital Turntable Tachometer and DDS based PSU

Additonal info:

The Falcon PSU and RoadRunner Tachometer are not kits or a Group Buy. These are full production units.

Operator manuals for both units attached.

Some additonal photos that show the scale of products better. Both units are housed in the same aluminum extrusion and are about the size of a pack of cigarettes.
Attached Images
File Type: jpg Falcon-RoadRunner 33RPM.jpg (263.0 KB, 689 views)
File Type: jpg Falcon-RoadRunner 45RPM.jpg (262.9 KB, 667 views)
Attached Files
File Type: pdf Falcon Manual 1.pdf (607.0 KB, 93 views)
File Type: pdf RoadRunner Manual 1.pdf (764.6 KB, 69 views)
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Old 13th March 2014, 05:13 PM   #3
vgeorge is offline vgeorge  Greece
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Just got Pyramid' s Falcon and RoadRunner get my highest recommendation. Excellent built, working perfectly and can be adjusted to almost anything with high resolution.
I think it' the only controller with all these features.
The only thing is that the can output only 110V, so for the rest of us on 220V, you need a step up transformer. I built one in an outside box with an A/C voltage indicator so I can monitor it, as output voltage is adjustable.
Sound improved considerably. A big stepup for my system.
Also thanks a lot for the excellent support.
Attached Images
File Type: jpg IMG_2543.JPG (704.0 KB, 230 views)
"Without deviations from the norm, progress is not possible" - Frank Zappa
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Old 16th March 2014, 01:03 PM   #4
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hi there

is there any way of applying this to a technics 1200 / 1210?

I use turntables for making scratch music, and for that it is useful to have the platter moving at 16 rpm. turntables like vestax and stanton can do the slow speeds, but a technics with -50% pitch range is kind of a holy grail!

there is a DDS / PLL system from Timestep which can do exactly what I'm after .... but it's Ł2500!

any ideas?

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Old 16th March 2014, 01:46 PM   #5
Pyramid is offline Pyramid  United States
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Unfortunately, the SL1200 is direct drive, so a variable frequency supply like the Falcon will not work with that table (the Falcon PSU directly controls the speed of AC synchronous motors). There are some threads on this site that have mods for a SL1200, not sure if they address 16RPM or not. If you can get me a schematic of the drive circuit, I could most likely give you some suggestions for mods.
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Old 17th March 2014, 01:35 PM   #6
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Default Digital Tach and PSU review

Phoenix Engineering Product Review

The Phoenix Engineering Road Runner Tachometer (RRT) and Falcon Power Supply Unit (FPSU) are a duo of products intended to optimize turntable performance by reclocking the AC line for absolute stability and precision. Since all AC synchronous driven turntables obtain speed consistency by locking motor rpm to the 60Hz line frequency, it makes sense that the more stable the frequency, the more stable the platter rotation. The RRT tach provides feedback to the FPSU supply insuring rotational accuracy. The pair also offers the advantage of adjusting the speed between 33 and 45 rpm, eliminating the need for manual belt pulley changes. The FPSU features a speed “ramp-up”, minimizing belt “burn-out” and prolonging belt life. In total, a very well thought out and precision product.

Preliminary Observations
Having seen several competing products, the RRT/FPSU is quite startling. Small, compact, and elegant about the size of a couple of stacked Altoid tins. My evaluation set included all cables, power supplies, and manuals, very well packaged and professional. I received a near-production prototype, but except for the tach-to-supply cable, it appeared completely ready for primetime. Looking at the published specs, it appears that the system components are closer to lab grade test equipment rather than an audio component. It can be argued whether this degree of precision is really required, but as they say, the proof is in the pudding.

Evaluation Components
The system was evaluated with the three tables I had on hand, all custom built, Rega variants, using the original 110v Premotec motors.
Table 1 looks like a stock P3, 19mm MDF base, stock subplatter, ceramic bearing, 10mm acrylic platter, Herbies Donut mat, Rega R200 tonearm, Ortofon OM5E
Table 2 is a bit upgraded with an 19mm MDF/12.5mm Baltic birch laminated base, stock subplatter, ceramic bearing, 10mm acrylic platter, Herbies Donut mat, Rega RB300 tonearm, Ortofon 2M Red.
Table 3 uses a 37.5mm Baltic Birch base, alloy machined subplatter, ceramic bearing, 24mm acrylic platter, Herbies Donut mat, Rega RB250 tonearm, Ortofon 2M blue.
Ancillary equipment consists of several past DIY projects:
12AX7 based active feedback RIAA EQ phono stage.
6021 based line level preamp.
5891 PP tube poweramp.
Scanspeak Revelator based monitors, with an active sub.
I also plugged in a few pieces that I have been finishing up for repair/refurb; Cary CAD300SE 300B monoblocs, Thorens TD-125/SME 3009/Denon 103D, Dynaco Pas 3, Dynaco ST-70, Dynaco A-35.

The RRT requires the user to attach a tiny (approximately 4mm dia x 1mm) neodym magnet to the underside to the platter. I dislike the idea of introducing anything that can upset the balance of the rotating assembly, although this would later prove to be a non-issue. But to minimize any such problems, I elected to place the magnet on the subplatter, reasoning that the smaller the radius that the magnet is mounted from the spindle, the less likely the magnet mass would be an issue. I also thought that any magnetic induced field on the cartridge (both for induced signal and magnetic attraction tracking weight variances) would be minimized if the magnet was located under the record label instead of the grooves. Probably not a real world issue, but this did make me feel better. If the system was running a 2” thick platter, this will likely never be a problem, but with a 10mm acrylic platter Rega ?

The magnet was attached using thin double-stick tape, to make it easily removable and transferable between tables. I could have used CA or some other type of adhesive for a more permanent mount, but I think I will eventually drill and press fit the magnet into the solid subplatter, reasoning that the removal of material will, at least partially, offset the mass of the magnet.

On the tables with the stock Rega subplatters, I mounted the magnet on the inside rim, presenting the magnet field 90 degrees offset from normal. Sensor placement became a bit more fussy, but it still worked just fine.

Hookup and operation is very straight forward. All jacks are clearly labeled so hookup is quick and easy. Some of the display functions may require a quick read of the manual, like what the blinking decimal point means, but everything appears to be well thought out and logically functional. This is truly a set-then-forget product. It should be noted that the FPSU can operate stand alone, but setting this with a strobe disk will not provide the accuracy that the supply is capable of (but you still receive the sonic benefits).

Since the pair was sent to me for review, I did my best to try to blow it up. I tried rapid power cycling, running them unloaded, ramping up voltage on a variac, and it never faltered. The one thing I did do that got the system a bit distressed was to operate it on the 45rpm pulley while adjusting for 33 rpm. With this, the motor got noisy which was audible in a quiet room (the manual does specify using this at the 33 rpm pulley size).

Subjective analysis
Having gone through the Linn LP12 Valhalla and Lingo upgrades, I somewhat knew what to expect and listen for, and the RRT/FPSU did not disappoint.

The first think I notice is an increase in dynamics and “aliveness” that Linnies refer to as PRaT (pace, rhythm, and timing). I think this is generally caused by an increase in dynamic range, allowing you to hear details with greater clarity. It’s been awhile since I’ve done the Linn mods, but I would place the RRT/FPSU as an equivalent improvement to that of the Lingo (which I think was in the $1500 neighborhood back then) My test table 1 was always a bit dull and listless, which I always attributed to the MDF base. But the RRT/FPSU made the greatest difference that I heard of the 3 test tables.

The 2nd item that I’ve listened for and heard was a much broader and deeper soundstage. Image width easily extended beyond the speaker edges, central image steps forward, and the sense of recorded hall ambiance becomes larger and more defined. I’ve often wondered how/why a system would be capable of imaging beyond the speaker edges. I used to think it was transient response, or maybe just HF resolution. Back in the 80’s all speakers based on an Audax HD-100 tweeter (a particularly sweet but slow sounding tweeter) could never image outside of the box. But then out came the Spica TC50 using this same tweeter that had a huge image. Obviously it was something other than HF resolution or transient performance, maybe phase relations in the upper midrange. I’m not at all sure why this could be affected by a turntable; lower speed fluctuations = greater midband purity? In any case, the image width enhancement with the RRT/FPSU was distinct, pronounced, and measurable (how?)

With the RRT/FPSU removed from the system, play an album, close your eyes, and listen for an instrument playing to the extreme left or right. Point directly at it, then open your eyes. Chances are you will be pointing directly at a speaker. Insert the RRT/FPSU, and repeat the procedure, listening for the same instrument. When you open your eyes you will be pointing at a wider point, almost guaranteed. (Unless you are listening to an old pair of Audax HD-100 based systems).

One thing the Spica TC-50 did was to surround the tweeter with a thick felt blanket to eliminate diffraction and the resultant “time smearing” of the delayed/diffracted signal. I theorize that the RRT/FPSU also reduces the time smearing effects, perhaps due to lower motor cogging, which may also be the reason that the effect is most prominent on the lightest platter version tested (most susceptible to cogging).

Listening to the RRT/FSPU on tables 2 and 3 was interesting. Table 2 (which used the same drive mechanics to table 1) yielded almost identical results and benefits, but less so with table 3. Dynamics increased, but less than tables 1 and 2, and ultimately I think that table 2 with the RRT/FSPU sounded superior to table 3 with the RRT/FPSU. I really scratched my head over this one. Table 3 has a superior subplatter, with a platter mass twice that of table 2. Prior to receiving the RRT/FPSU, I’ve always thought that table 3 sounded superior. I even swapped the 2M red and blue styluses to keep everything the same (2M cartridge bodies are the same, only the stylus is different) Not sure what to make of this. I’m going to swap the cartridges to see if there is some sort of “symbiotic relationship” going on here.

It may be that I am hearing the immediate degree of improvement, and confusing this for the ultimate net performance. Not sure, but I don’t think so. For now, all that I can conclude is that cheap tables receive greater benefit from the system.

This issue bothered me enough to take the RRT/FPSU to a friend's house for a listen. He has a pretty decent system consisting of an early generation Sota Saphire/Premier MMT/Koetsu Black, Audio Research SP3A/D76, and a pair of Quad 63 ESL speakers. The RRT/FPSU seemed to provide more bass, and HF extension, but did little for the image width or depth (although this was already pretty good) Overall, I would classify the improvement in performance as noticeable but marginal.

Just for fun, I installed the set on an old Dual 1229Q that I just got on Ebay. Wow, what a difference. Maybe this is the optimum accessory for an idler drive table. Wish I had a Lenco lying around.

One sonic aspect of the supply is the apparent alteration of tonal balance. I say apparent because I am not 100% sure if I hear a difference in tone, or if it is only a perceived effect due to something else. It seems to get a little brighter, with a little less bass, although tighter with greater impact. When running the FPSU, I always felt the need to turn up the sub level a bit, but generally left it alone because it is only a temporary effect that you perceive immediately after installation. This was also not consistent with every table I ran them with, primarily tables 1 and 2.

Reclocking power supplies for turntables are an indispensable component for the serious vinyl enthusiast. Ironically, the more modest your table, the more you need one. While I did not test the RRT/FPSU on a modern high-end table like a VPI or Clearaudio, I assume the benefits would be somewhat subtle. But put this on a Rega P3 or Pro-ject Carbon and get ready for high-end performance at budget $. As a testament to the product, I’ve decided to keep the review sample. Aloha!
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Old 18th March 2014, 11:56 AM   #7
kffern is offline kffern  Australia
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Originally Posted by Big Kahona View Post
Phoenix Engineering Product Review

Just for fun, I installed the set on an old Dual 1229Q that I just got on Ebay. Wow, what a difference. Maybe this is the optimum accessory for an idler drive table. Wish I had a Lenco lying around.
Would this really drive a lenco motor?

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Old 19th March 2014, 12:25 AM   #8
Pyramid is offline Pyramid  United States
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Originally Posted by kffern View Post
Would this really drive a lenco motor?

Most likely not. The Lencos used a 15W induction motor (the Falcon is for AC synchronous motors), so not only would it draw too much power, but speed control would not be as easy.
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Old 20th March 2014, 01:39 PM   #9
Pyramid is offline Pyramid  United States
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Default Falcon PSU on Lenco turntable


If you go to the Lenco Heaven website Here there are a number of regenerative power supplies that use an XR2206 function generator to create a sinewave and audio amps to boost the voltage.

I did not see anything there that looked like precision control (most of them used 10T pots to adjust the frequency and were prone to temp drift and other variables), but with the idler drive system that Lencos use, how close could you hold the speed anyway? When I posted my system on their website, the moderator likened it to "Putting a McLaren fuel injection system on a lawnmower". I don't think I could've come up with a better metaphor myself....
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Old 22nd March 2014, 06:47 PM   #10
RCruz is offline RCruz  Switzerland
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Following with interest
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