I, Albert, on the other hand, would be interested in finding someone who could take the schematic of a Mk3 power supply/controller and make a new one from scratch (I would take care of the box).

t_bone January 14, 2010 13:49

Albert, apologies in advance for taking this thread off-topic. I wrote a VERY long post here and decided to trim it down. I can provide further details by mail if you want.

Frankpiet and Albert,
I just had a long chat with the gentleman at the Pioneer Service Center who repairs all the P3s and P3as which come in. I asked him a lot of very detailed questions regarding the P3, the P3a, and their differences, with a lot of stuff that the service manual will not show/explain.

According to him, the main differences are:
1) ARMTUBE - the armtube on the P3a is less resonant because they stuffed the armtube with more dampening material, and because the 'node damper' which is stuck on the arm is better. The P3a armtubes c-a-n-n-o-t be used on the P3 (he said Pioneer did this on purpose). The P3 arms can be 'tweaked' to approach the P3a, but it takes some work.
2) PHONO CORD - different phono cord, resulting in lower capacitance. He noted that it is easily replace-able (completely plug'n'play with the Oyaide and Ortofon) and that many P3a and P3 owners who like jazz had switched to the Oyaide cable. POWER CORD - it's thicker. He hadn't heard of anyone saying it was better or worse, but it has slightly different electric properties.
3) MOTOR ACCURACY - the P3a motor controller speed accuracy is theoretically up to 10ppm better, however the P3 'error' is reduced to less than half its spec'd level when repaired (or else they won't let it go out the door), and because of the already low starting level of potential speed error on the P3, it effectively means that P3s which have been serviced are practically identical to P3as in performance.
4) DRIVE SERVO AMP - the drive servo amp is different on the P3a from the P3. In fact, there are two versions of the electronics of the P3a (early, and later). The later P3a servo amp is the best, with a very wide servo range (i.e. very tweak-able if there is drift).
5) OTHER - while not really a performance issue, the later version of the electronics in the P3a (there were 2 versions (early, later), has a more adjustable drive servo amp (makes it easier to service should parts drift).

REPAIRABILITY
There is one IC in the P3, and P3as which is not replaceable. So far, not a single P3 or P3a has ever come in with that IC being bad, but if one did, they could not repair it.

WHERE THERE IS NO DIFFERENCE
The platter bearing, platter, motor/magnet construction, arm bearing/internals/base/plinth/springs, and almost everything else is the same.

WHERE DOES THE SNR DIFFERENCE COME FROM?
He ascribes this to what happened when the various mfrs started "spec wars" in the early 1980s. The late 1970s tables had DIN-B SN ratio specs which were "as-is". In the early 1980s, the various mfrs started using weighting methodologies across the noise curve to 'filter' the result, which meant that stated DIN-B SNR specs were substantially higher. Several times, he ascribed this to the 'numbers magic of marketers' and said there was nowhere near that difference, and that any difference which was likely to be heard was in the phono cord if your cart requires super-low capacitance (which I would ascribe as a 'quality' of high output MMs? - but this is easily fixed on a P3), and in armtube construction (which is less easily fixed on a P3), which would show up as a factor depending on cartridge choice.

WOULD BETTER PARTS MAKE IT BETTER?
I asked him about improving electronic parts. He said that it was possible that it would be better, but that the real part which mattered was the 'torque attenuator circuit' (and it really is like an attenuator) which is their most important adjustment to make when servicing/repairing a P3 - the other stuff either works or doesn't (within spec), and that shows up in the torque tests.

More detailed info is available on these points if you are ever interested.
Cheers,
Travis

t_bone July 14, 2009 10:05

Frankpiet,
Thanks for the info. I thought I'd answered but it appears to have either gotten lost in the ether... either that or two answers will pop up. I figured the difference was in the bearing in particular but when I asked the Pioneer service guy who worked on mine when I got my P3 fixed, he said the bearing/motor were the same. He mentioned differences in wiring, slight differences in controller, small weight differences (but he wasn't sure where they came from), and a slightly different structure of arm base. However, I think a difference in bearing material might also be the 'culprit.' Given the small price rise over 3-4 years since the previous price rise, and how fast top end equipment prices were rising at the time, it is unlikely that they added something hugely more expensive.

As to my comment about the price difference between the SP-10Mk3 and the P3/P3a... the SP-10Mk3 was less than half by itself (JPY 250k), but when paired with arm and base, it was JPY 500-520k, and the SL-1000Mk3 package was usually sold with a cart. Then a year later, the P3a came out at JPY 650k (up from the P3's JPY 600k until 1982), and the same year Technics splashed out an SL-1000Mk3D which added a special armwand an EPC-100CMk4 cart standard, bringing the whole package to JPY 650k. You got a cart with that whereas you did not with a P3a but when both were on the shelf with a JPY 650,000 price tag, I guess it came down to which one you lusted after.

Please keep us posted on the P3a.

t_bone July 03, 2009 02:25

Thanks Albert,
I agree that at this level, the tables sound more alike than different as long as the arm and cart match well. The FerriShield underlay platter (I assume it is a like a platter mat?) sounds like a great idea. I have used a copper sheet on the P3 and that improves things quite a bit, but I had thought of it as being a materials interface issue rather than a shield. Perhaps it serves as both. I will have a closer listen.

t_bone July 02, 2009 03:39

Albert, I have not noticed an RF/EMI issue with my Exclusive P3. Given how it is put together, adding a foil/etc screen to the inside of the wooden plinth covering would be easy. I do not know much about the plinth construction of the big Onkyo (PX-100M if that is what you are referring to). The Denon DP-100M should be similarly easy to add an RF/EMI screen to.

The real problem with both the P3a and the Denon DP-100M is that they are rare. They are rarer, in my opinion, than the SP-10Mk3 (though perhaps that's just me). They are also not any cheaper than SP-10Mk3s.

I have yet to find a definitive list of the differences between the P3 and P3a. I am inclined to think that at least part of the difference was that when the P3 came out in 1979, the SP-10Mk2 was top of the price heap, but when the SP-10Mk3 (especially in SL-1000Mk3 or Mk3D format) came out in 1982 (and the -D in 1983), the price was comparable to the P3, which meant "improvements" and a model change to a new P3a was in order to maintain its place as top-price flagship DD player.

Japanese websites speak of differences in the arm, the power cord, etc (note that some websites think the power cord change was one for the worse), and some change to wiring material. Pics of the innards of the P3 and P3a show that there are no real differences in construction, which means the changes made there are probably in materials interfaces, construction of the springs, and perhaps also a quieter arm. The whole thing is 5% heavier, but who knows where that comes from...

Based on the pics and what I have seen on mine, I can easily think of mods which might improve it:
1) RF/EMI shielding
2) an IEC jack and separate power cord
3) changes to caps/diodes/etc in PS
4) replacing the base which the springs are mounted on to a hardwood or hardwood+alumina sandwich rather than particle-board shown (in the P3a at least).
5) replacing the 'footer base' with real footers
6) improving tonearm wiring? and/or running it from cart leads to phono stage inputs (or if not, improving the jacks).

t_bone July 02, 2009 01:52

Oops. I originally meant to say "I would take the ST-10 because they are still reasonable."

t_bone May 24, 2009 14:16

$900 for an ST-20 is too much in my opinion. I would take the

I use an ST-10, and a 700g Japanese one made by a company called Jeweltone, which had a thing for 'crystal' (they made a crystal record mat which works quite well actually). It says it is a 'Crystal Stabilizer' but I think it is at least 3 materials, two of them being acrylic and gunmetal. It came on a TT I bought, and I kind of like it so I use it. Ditto with the ST-10. I like the ST-10 and I can get them cheaper than I can usually find the newly made recreations, so I buy them from time to time. They are better than most of what I have come across (I have used the Orsonic, and a few other lighter ones, but I always come back to the ST-10) though I certainly have not heard everything out there.

I expect the TT weight I would most like to have is one an example of Thom Mackris' old stainless steel "Anvil" that he is not selling any more.

t_bone May 24, 2009 04:59

The ST-10 is gunmetal anodized black, the ST-20 is gunmetal and polished (or possibly copper-coated). The ST-20 (have pics if you want) has a nipple on the top to accept the Micro strobe, and a wider base. It is not any heavier than the ST-10. I have seen someone sell a copy of an ST-10 on Audiogon made of stainless steel which actually looks like a cross between and ST-10 and an ST-20. The real ST-20s these days go for entirely too much money. FWIW, many Micro afficionados who get tables with gunmetal platters eventually look for stainless steel plattered versions.

t_bone May 24, 2009 00:44

Mike, I guess it depends on whether the record is flat or not. If the record is flat, it lies on the mat/platter just fine. If not, it will have give/spring over a certain portion, which is Ken's issue.

It sounds from your description like the Rockport vacuum system is different to the others I have seen (Micro, Luxman, AT, etc), and well-designed at that. However, neither your Garrard, nor any of my tables, benefits from having a Rockport clampdown system however, so then the question comes of what to do on tables not so equipped. Do you know of a similarly-constructed aftermarket clampdown system? I, for one, would love one, because not all my records are flat. I guess at a certain point, one could just buy an Orb Record Flatter (they retail in Japan at a lot less than people sell them for overseas).

t_bone March 15, 2009 02:52

Kftool, aren't the vacuum clamp-down systems built so that there is a very thin cushion of 'vacuum' between the platter and the record (other than where the rubber lips meet the vinyl)? I have never used one but I have always assumed that from looking at them up close.

t_bone March 14, 2009 02:39

Thanks Albert. I look forward to your update.

t_bone February 28, 2009 09:51

Albert, have you looked into custom-built power supplies for either of the SP-10s? If so, have you found anyone who could build one for you?

t_bone February 28, 2009 01:20

Thanks Albert and John. I just did a bit of digging and found this page detailing the acoustic impedance properties of a variety of metals (and indeed, cast iron looks like great bang for acoustic impedance buck). On other pages within the same site there is a discussion of acoustic impedance (use the search box at the top of the above link and search for "acoustic impedance") and a java applet. I have not been able to get it to work yet, but it looks worthwhile, especially because the applet is supposed to demonstrate that a change in acoustic impedance significantly affects how much acoustic energy is transmitted from material to material, which directly relates to what materials one wants to put together, and in what order, which is what plinth-builders are trying to solve for.

Acoustic impedance, when you break it down to its base parts, comes to be calculated as:

Acoustic Impedance = Density x SQRT(elastic constant/density)

which at first glance makes intuitive sense to me (as well as confirming what you noted above, that density is a major factor in the calculation)

t_bone January 22, 2009 10:48

Thanks Albert,

Iron is near the top of the heap in it's ability to absorb energy...

Where does one find the info on which materials 'absorb energy', and to what extent, and what kind of measurement is used?

t_bone January 22, 2009 05:39

Albert, could you elaborate on the thinking behind and design of the implementation of your rod+iron block 'drainage' system, drawing vibrational energy from the SP-10's bearing well to the iron block? What exactly is the connection between the bearing well and the rod? It appears as if the iron plate is fixed into the plinth, in which case it would not act as a pendulum? Does a certain material have to be used for the rod? Is there a sequence of hardness (or shall we perhaps say, of combination of material density and elasticity constant?) which has to be followed from the bearing well material to rod to iron block? I am quite curious on how this is supposed to work.
Thanks

Before I forget, let me add to the chorus saying this is a beautifully designed and built plinth, and I quite like the way the bevel on the top edge references the original plinth.

t_bone January 22, 2009 03:47