Conference napalm::commusic_v1

    I may be able to make some comments soon as the guitar player in
    my band just bought an SPX-90 to go along with the Tascam Studio
    8 he also bought for our new recording studio.
    
    On second thought, maybe I'll do a review of both once I've had
    some time to experiment with them.  The studio part is finished;
    the control room is not so it should be about another 2-3 weeks
    before we have the gear all hooked up.
    
    By the way, there is a review of the SPX-90 in this month's addition
    of _Keyboard_ magazine.

    			Derek

    I was very tempted when I heard the SPX-90 at LaSalle's, also. 
    The unit was demo'd with voice input, though, so I couldn't
    really tell how quiet it is.  In this notes file, everyone
    said that the MidiVerb was as quiet as anything, so I grabbed
    one.  Hook it up to some Yamaha FM gear, though, and the
    nonharmonic noise of so many FM patches really starts to sing
    (8^(.  Is that an antialiasing filter problem or what?  Derek,
    please put some lightly distorted source into both, and let
    us know what you think.  If I decide to get a second reverb/eff
    box before the current generation becomes obsolete, it'll
    probably be an SPX-90, so I still want to know about that box.
    (I agree, the SPX-90 is really neat, with decent reverb patches.
    All I miss is the capability to alter params in real time.  But
    that's what the $1000+ reverb/effects market is for.)
    
    GW

    Since getting a MIDIVERB, I have noticed that I use it all the time
    for every instrument I play/record.  This leads me to believe that
    if I had purchased an SPX-90 unit, I would almost always use the
    reverb settings, and rarely use the other functions (by mutual
    exclusion).  I guess my suggestion is to get a midiverb *and* an
    SPX-90 (if that is indeed within budget).  Use the midiverb all
    the time for reverb, and use the SPX-90 for the all the individual
    effects.
    
    Todd.
    

    RE .-1 If you wern't going to use the reverb on the SPX wouldn't
    it be cheaper and much more versatile to buy the other effects
    singularily. Apart from the harmonizer I think that most of it could
    be done with a good DDL. Can't help but agree about the MIDIVERB
    though. Does yours run hot? I can fry eggs on mine.
                               
    				PK.
    

    Probably would make more sense to buy the effects individually.
    That way one could buy a noise gate/compressor combo, and use *both*
    at the same time, and still have money left over for somthing else.
    I guess the SPX is a prime example of building the features around
    the architecture rather than vice-versa.
    I havn't checked to see if my MIDIVERB runs hot or not.  I will
    check that ASAP and let you know.
    
    Todd
      

    Some of the effects in the SPX-90 are not available separately,
    at least as far as I've seen (e.g., auto pan).
    
    Reverbs seem to run hot as a rule.  Both my old Alesis XT and the
    Roland SRV-2000s that replaced it ran/run hot.
    
    len.
    

    What is this in relation to the "original" SPX-90?  (Mark S. mentioned
    it in one of the compressor/reverb-type notes.)
    
    Richard

    FYI, regarding SPX-90 Mark B's:

    Someone at Sam Ash told me that old SPX-90's will be upgradeable.

    I just talked to Louie in service at LaSalle's in boston.
    He said: installed SPX-90 upgrade is $120 (at least I think that's
    what he said).  
    He said: parts and a little documentation for installation are $90-$95.
    He said: the etch is tiny; he needed an 800 degree iron to desolder
    leads from the ground plane (I remember this from DEC CSS prototyping
    days).  The EPROM is socketed, the RAMS to quadruple the memory
    are soldered.  Maybe I can socket them if they are DIPs.  I forgot
    to ask.  His work is not really warranteed unless he goofs.
    He did one last week and it was fine. I don't know if the upgrade
    obliterates your programs; my programs are all written down.

    Gee, I havn't posted really useful information for a long time.
    Tom

>< Note 346.9 by ANGORA::JANZEN "Tom 296-5421 DTN LMO2/023" >
>His work is not really warranteed unless he goofs.

    .. interesting concept .. perhaps you can ASK him to make some error
    so the work is warranteed.. or does that mean 'then he fixes his
    goof'.. or does that mean if it works, it's NOT warranteed.. or..
    
    karl

    he also said that if you bring it in before 10:30 saturday it should
    be done saturday, but you'll spend the day in boston.
    Tom

I installed my own SPX90 effects box upgrade to SPX90-II.
Saturday I went over to LaSalle's Boston and bought the kit for the SPX90
upgrade.  The sales people told me that the service guy, Louie, wanted to
discourage people from doing it themselves, and I now agree, having
installed it myself.  The kit was $90 +Tax.  The kit comes in a little 
white cardboard box holding 7 integrated circuits on an anti-static pad, 
and one foleded page of instructions.  Actually, the instructions
are about 50 words in a corner.  Your guide is the silkscreen printing on the 
printed-circuit board.  One side of the page gives all of the factory
patches with the new ranges.  One of the chips is an EPROM with new
software, presumably holding the new limits or perhaps a real program.
The other 6 are the new NMOS RAMs, with four times more capacity
than the old ones.

I also went to Active and bought a bulb solder sucker and 6 18-pin sockets.
I went to Radio Shack and bought two little anti-static pads (not truly
useful, I really needed a big conductive mat to work on) and a little
spring-loaded solder sucker, not as nice as the ones we get at work.
This was a windy dry day; the static electricity on such a day could 
blow the circuits, but I don't think it did.
I built a static-strap with a spade connector soldered to a 1MOhm 1/4 W resistor
to a handy solid copper wire, which bare end I wrapped around the wrist of the
hand in closest contact with ICs at any time.
I believe the 1 megohm resistor has two purposes; 1: slow the static discharge
should it occur (and it will); 2: protect you from ground faults on the
power grid.

The SPX90 top and bottom covers come off, revealing both sides of all boards.
The instructions give IC location numbers found on the silkscreen.
I marked the chips on both sides of the board with white-out and double-
checked the locations to avoid accidentally removing the microprocessor
or the D-A convertors.

The EPROM was socketed.  I gently rocked it out with a tiny screwdriver,
working one side at a time, sometimes turning the slotted screwdriver
against the socket, until it was loose.  I took it out.  The new one's
leads were, of course, at the wrong angle for the socket.  I bent them
inward by pressing one side's leads on the table, while angling the
chip package more to a right angle.  I did this with both sides leads,
and then the EPROM fit. I watched the index, to ensure that pin 'one' was
in pin receptacle '1.'  The silkscreen shows IC indices.

The old RAMs were soldered in.  I have desoldered and replaced chips
from multi-layer boards in my work, so I knew this was difficult and risky.
I held up the chassis and board with two heavy little boxes.
I cut out the chips near the body of the package, leaving the
pins in the holes in the 2-layer printed-circuit board.
I cut the solder-side ends of the pins,and but off MOST of the
top of the pins too.  I would need some pin to grab with needle-nose
pliers when necessary.

Then I could gently heat up the pins with a low-wattage (15W probably,
Weller SP23 with pencil tip) soldering iron, and suck out the pins with the
solder sucker one by one. Sometimes I had to use needle nose pliers or
diagonal cutters to pull out the leads after the sucker sucked out only the
solder.  When you do this, you run the risk of pulling off pads and etch,
and pulling out the via plate-through, so be certain the pin is loose
as you try to grab it.  Heat it up without the pliers, test its looseness
with the pliers, and pull it out fast, or all the heat will flow into the
pliers and the solder will harden, and you'll pull out the plate-through.
I had to clean it up afterwards with solder wick (which is dangerous for
etch) and more sucking of solder.  Sometimes I had to melt more solder into
a via in order to have something to heat up and suck out.

I put in tin low-profile sockets for the new RAMs to make it easy to replace 
them if I blew one with static.  A static-caused fault doesn't show up 
sometimes for a while.

It took 4 hours, with dinner and a couple phone calls, and watching TV
while working.  I worked slowly to avoid problems.  Rushing this work
destroys etch, which was on .05 geometries.

The upgrade didn't destroy my own programs.

It seems to work fine.

SPX90 reverse-engineering:
I counted the following ICs, as well as unlisted discretes and transformers:

Fujitsu MB81464-12  64K * 4bit 120ns RAM, kit has 6 of them.
	that implies a twelve-bit word, and I now have 128k word of
	sound memory for 2 seconds. Reasonable, given it's stereo.
old RAM was M5M4416P-12, 16K * 4bit.  This kit quadruples the sound
	memory.
YM3807
YM3804
	I think Yamaha has started selling its chips.
HD6303 up internal clock, 128 bytes ram
HD6350 asynchronous communication interface adaptor 
	perhaps for MIDI
EPROM Toshiba TMM24256AP obviously a 256K bit eprom, but I can't find it
	in ic master.
74LS266
74HC logic: (high-speed CMOS pin-for-pin of 74 ttl series)
	74HC04 inverter
	74HC74 F/F
	74HC595 serial-in parallel-out octal register
	2* 74HC273 octal f/f
	2* 74HC166 serial/parallel in, serial out
	74HC02 nand
	74HC163 4 bit counter
	74HC74 f/f
	74HC174 d f/f hex
	74HC245 octal transceiver
	74HC139 s:4 dmux dual
	74HC373 octal latch
	74HC138 3:8 dmux
	74HC14 hex schmidt trigger
	74HC367 hex 3-state buffer
	74HC244 octal buffer

toshiba tc 5565 pl-15 8K * 8 CMOS static RAM, presumably for the microprocessor
	120ns
Burr Brown 2 * PCB54HP 16-bit monolithic digital-to-analog convertyers 3us setting 96dB .001% fsr linearity, .0025% max tpd .02% max thd
	operates on +/- 5 to +/-12
midi interface 1* 4556DE JRC 1:4 dmux?
5 * 4558 dual opamp
Toshiba TC 4053BP 3 spdt CMOS switch
7815, 7915, +/- 15V regulators
2 * TD 62003 
 TD 62506
HD 14549BP * 2 successive approximation, presumably to build an ADC
	with one of the burr/brown convertors.  So how is stereo done?
	probably by latching and sampling/holding alternate channels.
XA542a0 tbp28l22n

I noticed that the pedal inputs are wrapped around a big fat ferrous toroid.  
I don't know if that's the coupling into the circuit or acts as a filter.

The SPX90 now boots up with a message similar to SPX90II, V1.1.
This process was very difficult and not recommended for those who have
never done similar work professionally.  Spend the $30 and have the 
service guy do it.

Tom Janzen Digital Equipment Corp. 111 Locke Dr Marlboro MA 01752

The toroids are probably RF filters to keep the pedal wiring from acting
like antennae. The FCC is very nasty about microprocessor based anythings
that are for home and/or office (or studio) these days.

				/ted

    hint:
    
    If you are desoldering, DONT try to save the chips.
    
    1. cut the chips off their legs as close to the chip itself
    
    2. unsolder the legs and remove them 1 by 1.
    
    you trash the chip, but its cheeper than trashing the board or etch.
    

    gee, uh, that's what I said.
    Tom