PMC-05 PRO    "insides" and frequently asked questions.
Author: Version:	Reinhard Schulz    1. 3

 Introduction

 About PMC-05 PRO

 Vestax's catalogue information about PMC-05 PRO

 How many different versions of PMC-05 PRO ?

 Old- and new crossfader confusion

 Optical crossfader ?

 How does the crossfader-system work

 Cleaning the crossfader

 Fades on CF-05 PRO crossfader

 Hamster-switch - modification

 Monitor/cue - modification

 Input Level meter

 Recrystallization

 PMC-05 PRO vs. Technics SH-DJ1200

 Future Vision

 News, updates

 Bulletin-Board-System

 Contact the author, credits.

About the PMC-05 PRO

Actually the PMC-05 PRO was not designed for regular DJ's. It was special contructed for Turntablists: Scatching DJ's who use their system, especially the crossfader, to it's maximum.

A Turntablist is interested in the following features:

Most DJ's didn't complain about the price, because they were convinced about the quality of PMC-05 PROs. Unfortunately this changed, due to the release of a faulty crossfader-system from Vestax at the end of 1997. A lot of people started to examine their PMC-05 PRO's. So did I.

Suddenly DJ's started complaining that the electronics inside PMC-05 PRO is sold for way too much. Others talked about DJ's getting taken by marketers, because of misleading advertising concerning the crossfader-system. I think most reactions were caused by the anger of DJ's using faulty crossfaders which did not last longer than a few weeks. When I opened my PMC-05 PRO I was supprised as well, but I did not irritate, but started to improve. The results you will find in the following documentation. I am always openminded for any kind of suggestion or correction.

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Vestax's catalogue information about PMC-05 PRO

PERFORMANCE MIXERS

Performance mixers are evolving and moving forward. Innovations from Vestax have included Detachable Crossfader Modules, Short Pitch Crossfaders, Adjustable Crossfader Curve and many more. Now the new line up is here.

DJ's experienced in superfast Scratching and Cutting techniques, have reached the pinnacle of what they can achieve on current mixers. Even the smalles obstuctions such as Crossfader crews and fittings can slow down today's DJ's, or catch finger nails etc. Vestax, (pioneers of the removable crossfader and transformer buttons), now introduce the DOUBLE PANEL SYSTEM. The new PMC-05 PROfeatures a removable flat panel that covers all screws etc. that will impede fast mixing. The panel is easily removed for crossfaderand Lin/Phono switch replacement.

A "Selectable Position" input transformer switch is also fitted, which can be fitted EIGHT positions to suit any style or preference of the DJ.

PMC-05 PRO has a total of 6 inputs. (2 Phono, 2 Line, 2 Mic). The inputs are equipped with a 2 band equalizer. (Hi & Low +/- 12dB) and L-R balanced volume.

A superior grade crossfader is fitted to PMC-05 PRO enabling super smooth operation together with long life. Another first from Vestax is PHOTO COUPLER operation of the crossfader. This allows Crossfade Curve adjustment. Now differnt styles of mixing, from long running mixes, to scratching and cutting can all be catered for by simple adjustment to the crossfade, even whilst "in the mix".

PMC-05 PRO lives up to it's name by utilising the same method of construction as the most expensive studio mixers. Vertical PCB's behind the faders allow the most stringent of design criteria to be met.

SPECIFICATIONS:
Input: Phono x 2 (rca), Line x 2 (rca), Mic x 2 (1/4")
Output: Line x 2 (rca), Phones x 1 (1/4" stereo)
RMS Output: -7dBm
Freq. Resp: 25-25KHz +/- 1.5dB
THD: 0.02 %
Crosstalk: > 70dB @ 1KHz
S/N Ratio: > 75dB
Nominal Input Level/Impedance(Ohms): Phono -43dBv/56k, Line -10dBv/10k, Mic -54dBv/3.3k
Nominal Output Level/Impedance(Ohms): Line -7dBv/2k, Phones 58mW max.@ 47 Ohm / >= 8 Ohm
Dimensions: (WxHxD) 262x103x320mm, 10 3/8"x4"x12 1/2"
Wight: 3.5kg, 7.8lbs.
CROSS FADER: CF-05 PRO

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How many different versions of PMC-05-PRO ?

There were several releases of the PMC-05 PRO.

2. PMC-05 PRO Silver I
I have not found a picture in an old catalouge of a PMC-05 PRO with a silver face-plate yet.
Anyone knows more ? Technically there should be no differences to the Grey version.

3. PMC-05 PRO Golden I see picture (82 kb)

4. PMC-05 PRO Q-Bert Limited Edition I
The PMC-05 PRO Q-Bert Limited Edition features a new layout and some new functions:

New features of the Limited Edition are:

People got confused when others talked about an ISP version of PMC-05 PRO. It's the same as the Q-Bert Limited Edition. (ISP stands for Invisible Scratch Pickls, a group to which Q-Bert belongs to). There is neither an ISP-crossfader around as some people claimed. There is no difference in the crossfader-system. The Limited Edition uses exactly the same system as the regular PMC-05 PRO.

5. PMC-05 PRO Golden II
It had a new crossfader-system build in: A modified new crossfader-unit and a new modified circuit.

6. PMC-05 PRO Q-Bert Limited Edition II
It had a new crossfader-system build in: A modified new crossfader-unit and a new modified circuit.

7. PMC-05 PRO Golden III
The Golden III still has the modified circuit of Series II, but the crossfader-unit was changed back to the old style of Series I.

8. PMC-05 PRO Q-Bert Limited Edition III
The Q-Bert Limited Edition III still has the modified circuit of Series II, but the crossfader-unit was changed back to the old style of Series I.

9. PMC-05 PRO Q-Bert Limited Edition Red
A Q-Bert Limited Edition III with a red design.

10. PMC-05 PRO Q-Bert Limited Edition Blue
A Q-Bert Limited Edition III with a blue design.

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Old- and new crossfader confusion

First of all be sure to be aware of 3 different declarations:

1) New circuitry
In order to sharpen the cut of the curve, Vestax modified the circuit inside PMC-05 PRO.

2) New squared edge crossfader-unit.
Vestax shortened the length the crossfader travels from one side to the other by a few millimeters. The crossfader was not stopped by the crossfader-resistor itself any more, but from the sqared-edged metal screwed onto the crossfader-resistor. The idea from Vestax was a fader with more stability and a better "cut-in time" for fast cutting DJ's. The squared crossfader-unit was supposed to cut sharper and smoother than the previous one.

Anyhow - Vestax released the new PMC-05 PRO II Series sometimes at the end of 1997, supposed to bring back the PMC-05 PRO to the top position of battlemixers with no doubt. What really happened was a disaster for Vestax: The new crossfader-system started bleeding after a few weeks of use !!! DJ's got very upset and still getting upset about their PMC-05 PRO's today - understandable.

Luckily (!) Vestax reacted and posted the "CF 05 PRO Crossfader Update" which is not online any more.
In this crossfader update Vestax admitted that the new squared shape of the crossfader-unit was the main reason for bleeding. Stopping PMC-05 PRO Series II in mid 1998 they started to deliver PMC-05 PRO Series III with the following configuation:

The slot on the main panel of the Double Panel System is always squared. The slot on the crossfader-unit can have two different shapes:

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Optical crossfader ?

One reason I put up this site was, that there was so much confusion about the crossfader-subject.
The only truth is: The crossfader-unit, that means the crossfader itself is not optical ! There is absoluteley no light as laser, infra-red or whatever in the fader.
The crossfader is a simple resitor, which is not necessarily controlled by a VCA circuitry (see below). Although simple is probably not the right word, because the scanning of the resistor is done quite differently than in regular faders (it is a high grade fader developed by alps and much bigger than regular ones). Usually the contacts (connected to the fader-knob) that move from one side to the other glide upright on the cole-based contact-rails. In the crossfader-unit of the PMC-05 PRO the contacts glide sideways on the cole-based contact-rails. Besides the contact-rails are much bigger than in regular faders. Therefore the friction is spreaded on a wide area, reducing the probability of wear. Also the hole mechanism glides on two round rods, one at the top, one at the bottom, holding it in an exact position. This gives a lot of stability. The result is a fader with an enormous durability.

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How does the crossfader-system work

(VCA = Voltage Controlled Amplified)

An audio signal is a mixture of frequenzies. Either your turntable or your cd-player converts this mixture of frequenzies into an electrical voltage. The purpose is to regulate this audio-signal-voltage in order to change the volume on the output.

Regular crossfader operation (no VCA technique, used in most mixers):
The audio-signal-voltage is regulated and sent through a crossfader-unit.

VCA crossfader operation. (used in high quality mixers like PMC-05 PRO):
The audio-signal-voltage is regulated and sent through a photo-optical unit.

In both cases the crossfader is NOT optical, but a simple resitor. The ONLY difference is that in one case the crossfader regulates the audio-signal itself (regular crossfader operation), in the other case the crossfader regulates an external generated control-voltage for the photo-optical unit (VCA crossfader operation).

Therefore audio-signal regulation in VCA technique is done in two steps.

• In step one the crossfader regulates the photo-optical unit with an external generated control-voltage.


• In step two the photo-optical unit regulates the audio-signal-voltage.

In my opinion the advantage of a VCA controlled mixer is not as high as it sounds in the first place. There is simply no physical contact between the crossfader-resistor and the audio-signal-voltage. That means the cracking from the crossfader caused by dirt dissapears. In most cases though, it is not the cracking, but real drop-outs caused by a damaged crossfader-resistor, due to havy use as scratching, ect. So the control-voltage going to the photo-optical unit has drop-outs as well, causing drop-outs in the audio-signal-voltage. You see that VCA is no big deal.

One nice feature Vestax build into the PMC-05 PRO is the "cut of the curve" adjustment. This adjustment is quite easy to realize, as soon as there is a VCA circuit available.

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Cleaning the crossfader

There are a lot of different opinions about how to clean the PMC-05 PRO crossfader (CF-05 PRO). I tried out a lot of different things from soap-water to oil-treatment of any kind. Usually gun-oil works fine on regular operating crossfaders, but here is what I found out about oil on a CF-05 PRO:

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Fades on CF-05 PRO crossfader

If you apply oil on the crossfader CF-05 PRO you might get the following effect: The signal which is supposed to cut emmidiently if you move the crossfader from one side to the other, does not cut, but fades away. I did not notice this effect right away, but listen carefully and you will hear. After cleaning the fader from oil, the effect dissappeard. I am not sure, but my assumtion would be the following:
Oil is a very good insulator. Its spezific resistance very high. Therefore oil between the contacts changes the resitor-characteristics of the CF-05 PRO. Arriving on one side, the contacts of the CF-05 PRO do not have their minimum resistance right away.

As long as your fader moves smooth enough it is probably the best way not applying anything to it. Cleaning with air pressure is still the most convenient way to get rid of possible drop-outs. If your fader seems to be not smooth enough, my suggestion would be to apply oil ONLY on the rods of CF-05 PRO (see section Optical crossfader ?). The easiest way is to treat only the upper rod, wich is directly accessable from the top panel. I used a syringe to apply just a small amount of oil.

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Hamster-switch - modification

Example: Moving the crossfader from left to right side:

Normal operation: causes a fade from channel 1 to channel 2
Hamster operation: causes a fade from channel 2 to channel 1

Inside PMC-05 PRO this inversion is done very easy: The two middle (out of 4) wires going to the crossfader are exchanged. Using a simple double-pole switch (switch-type # 5 see picture (50 kb)) you should be able to figure out how to get the 2 wanted states:

In position 1 the original configuration is retained.
In position 2 wires 2 and 3 are exchanged (switched, flipped, hamstered, or whatever you want to call it).

My recommandation would be not cutting the wires. Rather watch out for the original jack-connectors. If you can not get those, contact me and I'll see what I can do for you.

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Monitor/cue - modification

Only the PMC-05 PRO QBert Limited Edition has an extremly helpful feature build in. Especially for people who like to practice at home with headphones it is inalienable to monitor the master signal instead of just beeing able to cue over the small cue-monitor fader. On a regular PMC-05 PRO this is not possible, except you connect a seperate amplifier on the master-output and take you headphone-signal out of this amplifier.

The easiest way to create this feature is to use a 2-position "special" switch. This switch must be able to switch 4 connections at the same time. Besides the two possible positions of the switch must NOT be "on-off" BUT "on-on" (this is not very common, therfore "special"). Of course you can also use a 3-position switch ("on-off-on") were the middle position ("off") does not generate an audio signal at all (your crossfader is "turned off").

In the example below I used a 2-position switch (switch-type # 7 see picture (50 kb) ):

In the 1st position the audio signal from channel 1 and 2 are re-directed to their original destination.
To find the 2 original plugs from channel 1 and 2 inside of you PMC-05 PRO is quite easy. Just take a look at the two exactly same looking sections of channel 1 and 2. On each you will find the 2-pin jack-connector ("Original plug" in the drawing below). If you are still not sure, contact me.

In the 2nd position the audio signal from channel 1 and 2 is no longer passed to the monitor-section. Instead it is directly passed to the master-output of the PMC-05 PRO. Unfortunately there is no plug to directly connect to the master-output section. Therefore you have to solder the 2 master-output wires onto the master-output section. If you are an expert you should be able to figure out before what is the left and what is the right channel. Otherwise go ahead and solder one wire to pin R54 and one wire to pin R56 and try subsequently if this configuation is right - if not switch the wires.

Of course BE CAREFUL. If you have no equipment at all, trying would be the last method before soldering. Just connect the wires for a very short time while checking the result. The labeling of the circuitry board on other PMC-05 PROs could be done differently. Who knows ?
If you do this modification, please let me know.

Once again I would recommend not cutting the wires. Rather watch out for the original jack-connectors. If you can not get those, contact me and I'll see what I can do for you.

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Input Level meter

The Input Level meter of the PMC-05 PRO consists of two led-indicators for PGM-1 (program 1) and PGM-2 (program 2). Each indicator should monitor the left and right channel of the selected program.

The only truth is, that the PMC-05 PRO does not monitor the right channel at all !

There should be a possibility to add a circuit which considers both channels. Does anybody want this modification ? (I have not done it yet.)

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Recrystallization

Recrystallization occurs especially on parts which are often moved. The PMC-05 PRO RCA sockets are directly attatched to the board. This causes the board to move inside PMC-05 PRO when pluggin in and out the RCA plugs. Very small cracks start to develop on the RCA sockets solder-points. That is going so far that the audio-signal is not passed properly any more.

I had to re-solder some of the solder-points on my PMC-05 PRO in order to get a correct audio-signal again.

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PMC-05 PRO vs. Technics SH-DJ1200

Here are just a few points about the Technics SH-DJ1200:

• excellent cut-in time on the crossfader and overall fast operation.
• you must cut the lead wires to the old fader and resolder the lead ends to the new fader !? (no jack connector to facilitate the replacement ?!).
• input selectors oppose each other, a setup causing DJ's accustomed to conventional switches to rethink their technique.

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Future Vision

This is my PMC-05 PRO with two Technics SL-1210MKII. Of course the colors where changed.

Wouldn't it be a challenge to develop a crossfader-system which has no physical contact to its moving elements ? This should already be possible. Light barriers with calculation of the missing segment-space is one possibility to do it. Distance-measuring-units are also available. The probably best way would be something like a piezo-technique using semiconductor components.

It is fun though, but sometimes I ask myself: Why don't we all use a simple switch instead of thinking about such complex techniques ?

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News

Update-history:

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Bulletin Board System

In the BBS area you can post any kind of comment or question. I intentionally designed this board very simple to avoid tiresome waiting periods while loading the document. Lowering the number of displayed messages will accellerate your loading speed as well.

  Bulletin Board System

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Contact the author, credits.

Make sure you posted your question concerning PMC-05 PRO in the BBS first, otherwise contact me (Reinhard) for any kind of reason at schulz@reinhard.de or use the following form:

Thanks to the following persons:

This page was done by Reinhard Schulz at Technische Universität Berlin / Germany.

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