Pheonix Engineering Road Runner

@cleeds,

I've gone a similar route to you, with an original TNT and multi-upgrades over the years.  But I would never give up the lead/acrylic platter.

The PE Eagle is at least the equivalent of the SDS and, in fact, measures better and is somewhat easier to use.  The Eagle (or Falcon) used with the Roadrunner does create a feedback loop and is a brilliant set-it-and-forget-it design.  I sold my SDS when I bought this combo and even made a few bucks on the deal.  The Phoenix stuff was a real bargain in its day.  I hope it is revived by Sota for general sale.

The Roadrunner actually measures a running average of about three complete rotations so that the speed adjustments, when they are made*, are relatively few as compared with the continuing micro-adjustments of the typical DD TT.  The adjustments can't be heard, certainly not by me nor by anyone else who has written about these combos.

*the speed, of course, is MOSTLY controlled by the precision line frequency synthesized in the Eagle.

it originally retailed for $234 (it was the Falcon and Eagle that sold for more)

I still have the receipt in the packaging for the Roadrunner I bought near when they first offered. $ 234 is what I paid Bill for it with a couple extra magnets and even an extra sensor so I could have it ready for both tables with simply plugging the sensor cable from one to the other. So much better than strobe discs or blinking lights on the wall. After a belt swap, bearing clean and re oil, or just to check RPM with stylus in the groove for accurate quick reading, its perfect.

I get how some OCD fusspots would drive themselves mad as the RPM’s shift a few thousands off of 33.333 while the stylus navigates the record . But IMO , those people would be best to keep digital. If one cannot accept that analog playback using a turntable is a series of compromises, and balancing the absolutes with the moving exemptions to the rules that experience and opinion will bring, including which drive method is being used, it just becomes a not so merry go round of annoyance and idiotic bias.

All drive methods have their short comings and advantages. Which floats your boat isn’t a matter of which one is better or not. It is just a matter of which one sounds more appealing to the owners ability, understandings and personal bias. I have heard/owned drives of all methods that I felt excelled remarkably well in "their" presentations of sound playback. I have owned and enjoyed them all over the last 45 plus years as they each have a specific sound, tempo and drive to the music. Choice is a good thing, not an argumentative foil to endure ad nauseum. I gravitated towards mostly belt drives the last 15 or so years as , for me personally , it sounds more natural to me . I think its we humans who hear much different than we acknowledge and instead make it a right and wrong thing. I think some of us are very susceptible to hearing interruption in soundwaves that "hunting" even on better spec’d DD’s have, an uneasiness to some. The belt has a much more gradual "smoothing" that feels more natural to some.

The DD user obviously , many key in on minor belt drifts as timing errors. But realistically, very few can hear it at all as even modest belt drives are accurate enough that a musician maybe could pic up a minute error but the average audiophile, no , not at all. Idler drive users with a good set up simply couldn’t live without the drive to the sound they bring . The only thing wrong is that many " music lovers " make out that one drive is better than the other, empirically. They are not , they are options that offer different presentations and interpretations of the same recording, and they all have strengths and weaknesses and they all are made in different levels of quality, and addressing or focusing on different obstacles from designer to designer.
The caveat is , choose "your own" medicine, or pick "your own" poison. Even though I mostly lean towards a good belt drive now, I think its really nice to see the higher end DD’s now currently being made, something I never thought would happen again. They are quite outstanding and likely will contribute to the other drive options still moving forward as well. For an all analog guy...….that’s a really good thing, not something to fuss  about or knock them.

has2be, you’ve posted a practical statement which, I would guess, most are capable of understanding. I’ve been in the process of modifying a Thoren’s TD 145 but still haven’t replaced the weakest link, the TP-16 tonearm. So to offset the tonearm’s limitations, I’ve mounted it with the AT 33 mono cartridge.I wish I could spend $30,000.00 on a turntable however like most, I cannot. So I’ve learned to expect and accept certain limitations from my TT. I would say that my greatest dissatisfaction comes from wow and flutter and from vintage offset pressings.
So this is where digital comes in and given that I have a good analogue sounding DAC and that almost all classical recordings are currently in digital format, it’s a no brainer.
So any recommendations on which replacement tonearm I should consider?

Sorry, I mean to ask, if a tonearm should be my sole focus or if a roadrunner tachometer would make any sense with a Thoren's belt drive TT?The way I understand this thread is that a tachometer would show the inconsistencies in my rotation speed but it wouldn't offer a way to correct it.

Goofy 

Your correct on mine it only display what speed your table is turning at.  As did the Roadrunner, but it could “talk” to the Falcon power supply which corrected any speed irregularities as well as is possible on a belt driven table.  

I dont know much about the TD124 if it has an asynchronous AC motor it should work with it. As I mentioned above Sota is reintroducing the combination next month.

Good Listening 

Peter