DAT-Heads Digest #278
Contents:
SCMS Buster Kit (=?ISO-2022-JP?B?GyRCMkNGIyEhQDU/TRsoQg==?=)
Re: DIY Microphones (John Schulien 6-9453)
RE: Citibank ext warranty? (Ron Cobb)
Re: Length of Tom Petty shows? (Len Moskowitz)
Damon's deal (DrewStorms@aol.com)
PRO DIGITAL IS GREAT! (Harry C Nye IV)
Re: Damon's deal (Seth Breidbart)
starting a list of digital out cd players/transports ("RICHARD E. EGGLETON")
From: =?ISO-2022-JP?B?GyRCMkNGIyEhQDU/TRsoQg==?= <PXN05667@niftyserve.or.jp>
Subject: SCMS Buster Kit
Date: Fri, 28 Apr 1995 00:43:00 +0900
Dear DAT-Heads,
Akizuki Denshi in Japan sells the DIY SCMS Buster Kit.
I finally succeeded in building my machine. An excellent engineer from Italy
found the secret. This is very important.
Giorgio said (April 15):
> After a carefull check of the printed circuit board I found an undocumented
> "feature" on it. On the component side there is a route which goes between
> chip "Mansell" and chip "Prost", its shape is like _______/------- . Simply
> cut it in the middle to open the circuit. Now the SCMS manager can be used
> at 44.1 kHz without any limitation. It can write 00, 10 or 11 just moving a
> three way switch.
This machine is very sensitive to a kind of electrical noise. It doesn't
send out good signal when I turn on/off the window light of my DTR-80P
in the middle of the duplication.
If you want this kit, please e-mail me. The price of the kit is 4300 yen
(including 700 yen for 2 optical terminals). The kit does NOT have the case,
RCA coaxial terminals, switches etc. The manual is in Japanese, but
illustrations help you. I do not say it's easy to build. To be honest, I faile
d
once.
I will trade one kit for 9 or 10 DAT's. I DO NOT accept money.
From Masato Kato <pxn05667@niftyserve.or.jp>
From: John Schulien 6-9453 <jms@uic.edu>
Subject: Re: DIY Microphones
Date: Thu, 27 Apr 1995 09:17:38 CDT
> Date: Tue, 25 Apr 1995 22:19:41 -0400
> Anybody out there have info on home brew microphones? I've seen a little bit
> in the FAQ about using a panasonic electret capsule, but no details on how to
> actually build one. I've also seen info on Radio Shack PZM mods, but I have
> yet to figure out exactly which RS mic that is. Any help is greatly
> appreciated.
I built a pair of homebrew microphones based on the Panasonic capsules
back in 1993. These microphone capsules are an amazing bargain,
considering how well they perform.
For microphone capsules I used Panasonic part number WM-063T, available
from Digikey (1-800-DIG-IKEY) as part number P9932-ND, and last time
I checked they cost $2.57 each.
Looking in a recent catalog, there is another part, WM-60AT, Digikey part
number P9967-ND, $2.26 each, with a better advertised S/N ratio
(>58 dB as opposed to >38 dB for the WM-063), but I have no experience
with these cartridges.
Here's the basic microphone circuit, from the Digikey catalog:
+9V Battery
|
\
/ 2.2K ohms
\
+----+ | 1.0 uF
|Mic |--------+-------||---------
| | Signal out
| |--------+------------------
+----+ |
Battery ground
I used polypropylene capacitors and metal film resistors.
If you are building a stereo pair, you can drive both of the
microphones off the same battery. Each microphone element
needs its own resistor and capacitor however.
I puzzled over enclosure schemes for a while. I tried a pair of earbud
earphones as microphone enclosures and didn't like them. I wanted
to be able to clip the microphones to my glasses. I finally settled on
the following setup, which turned out to be very similar to the Core
Sounds Binaural product, although the CSB microphones appear to be
made out of some sort of custom brass pressing that looks like a bullet
shell.
I scrounged up a cheap pair of walkman-style headphones, and cut off and
threw away the headphone part, saving the wire.
I bought a thin brass tube from the hardware store, and cut two 1 cm
long sections. I drilled a small hole just wide enough for the headphone
wire in each one, filed off the rough edges, and soldered one end of each
brass tube to the flat side of an alligator clip as follows:
|><|
|><|
|><|-----------------+
|><| |
|><| () |
//|| |
// ||-----------------+
// ||
The idea here is to be able to clip the two microphones onto your
eyeglasses, so the two holes should be on opposite sides of the
tubes, relative to the direction of the alligator clips.
then I ran one of the two wires from the headphone cord through each
hole, and soldered each pair of leads to a microphone cartridge. It is
important to solder the inside signal wire to the + contact and
the outside sleeve wire to the - contact. The - contact is the one
that is connected to the barrel housing of the cartridge.
Then I smeared a little silicone sealant on the sides of each microphone
cartridge and inserted them flush with the end of the tubes. I
checked with an ohmmeter to make sure that the silicone sealant
was providing insulation between the cartridge and the brass
enclosure, and let the whole thing dry overnight.
Next step was to build the battery box. I used a plastic radio shack
remote control box with a built-in 9 volt battery door.
I drilled two holes in the end plate and screwed in two 1/8" three
conductor audio jacks. I wired the inside of the battery box as follows:
The sleeves were connected together and to the 9V battery ground.
The tip and ring connections were each connected via the circuit
shown above:
+-----/\/\----- to 9V battery clip +
Input jack | Output jack
|
+--+ Ring--------+---||------------------------------Ring +--+
+--+ Tip----+---||--------------------------Tip +--+
| | |
| | |
| +----/\/\------ to 9V battery clip + |
| |
+-------------------------+------------------------------+
|
To 9V battery clip -
Note that when the microphone is not plugged in, no current flows
and the battery does not drain. Once the microphone is plugged in,
current begins to flow through the microphone. Hence there is no need
to remove the batteries when the microphones are not in use if you
unplug the microphones from the battery box. The current drain
through these microphones is given as 0.5 mA per cartridge, and I
am still using the same 9V battery I installed back in 1993. The
microphone power supply range is 2-10 volts; battery consumption
is not an issue with these microphones.
Make sure you label the two jacks IN and OUT. If you were to
reverse them you would send 9 volts into the microphone input of
your deck and probably damage it!
To use the microphones, you need a 1/8" to whatever-your-deck-accepts
connector. In the case of a Sony D7, that would be a 1/8" to 1/8"
wire. Connect the microphones throught the battery box as follows:
/------------+ +-------------------+
/ +-|--|-+ |
/\ | | +-----|----+
/ \ | I O | | Mic in |
/ \ | n u | | |
/ \ | t | | |
() () +------+ +----------+
mics battery Recorder
box
I compared these microphones to a pair of Len Moskowitz' Core Sound
Binaurals, and aside from the clearly superior construction of the CSB
mics, I felt that the performance of these homebrews approached, but
did not quite equal the CSB mics, although I could not really say why,
although possibly the following might help explain.
The following is a repost of an exchange that appeared somewhere on
usenet back in 1993. I attempted the described modification, but was
only successful in destroying a cartridge. The cartridges are very
small and delicate.
On 8 Jul 1993, kludge@grissom.larc.nasa.gov (Scott Dorsey) wrote:
> In article <211hho$p5r@Panix.Com> moskowit@panix.com (Len Moskowitz) writes:
>> William Spencer writes:
>>> moskowit@panix.com (Len Moskowitz) writes:
>>>> Properly configured, the capsule in question in this thread can handle
>>>> sound pressures well above 120 dB.
>>> How do you properly configure it then?
>> (Hem...Haw...) Unhh, you have to modify them a bit. Don't ask me how.
> There really aren't too many mods that can be made to them.
> The big one, and the most popular, is to alter the entrance hole in the
> front of them. The way these things are designed, there is a chamber in
> front of the diaphragm which has a resonance around 23 KHz. This results
> in a much more extended high end which is nice and flat in amplitude, but
> has some phase nastiness. If you increase the size of the hole, you can
> make it much less grating at the expense of some of the highs. You can
> also make a tapered hole, which also seems to improve the off-axis
> response a bit, too.
> Dunno about any mods which would help performance at high SPLs, but then
> I have never had a real problem with the things in such environments. They
> do tend to have a problem with very heavy bass hits, I will admit, but I
> have clipped them into trombones and saxes without much of a problem. The
> real trouble with brass instruments is that the waveform they produce is
> so sharply peaked.
Here is the section from the microphone FAQ on Panasonic microphone
elements:
>
> {39} What kinds of capsules are typically used in 'stealth' microphones?
> What's good/not good about them and why?
>
> Several DAT-Heads have written or posted on the problems with the small
> electret capsules used in stealth mics. The capsule almost universally
> preferred for these is the Panasonic WM-063, or the WM-060, which is
> theoretically the same but with a phenolic circuit board rather than epoxy.
> They sound different, though. The capsules are available from Digi-Key
> (1-800-344-4539) for about $2. You have to buy a bunch and sort them,
> because there are major differences in sound. There are several problems
> with this capsule; some are endemic and some can be fixed.
>
> Some complain that the output is too low; this can easily be fixed with a
> gain stage. Using a higher voltage and larger load resistor (7-9 volts and
> 10K, for instance) rather than the 1.4 volt that's normally found in
> tie-clip mics will also help and raise the maximum output level before
> clipping. The output cap can be changed to a bigger and better kind. A
> 200-300 uF elcap bypassed with 0.5 of 1 uF of mylar or polypropylene makes
> a difference.
>
> The more difficult problems are noise and harshness. Because the active
> area of the diaphragm is so small, the output is low, so the FET
> contributes a lot of noise. You can fix this by opening the capsule,
> discarding the FET and reassembling the mic in a new housing. Then you can
> use a good FET and a 2-10 gigohm resistor for bias (which can cost more
> than the whole mic capsule), instead of the diode leakage current that is
> used in the "FET-IC" to bias the FET. You can also make the new housing
> with an opening to the front that is as big as the active area of the
> diaphragm, rather than the 2 mm hole covered with fuzz that's there now (a
> Helmholtz resonator is formed by the hole, the fuzz and the space behind
> it, which pushes up the HF response, but creates a pole that makes phase
> problems, thus harshness).
>
> There are better capsules around, but they are hand-made and not cheap. You
> can use metal diaphragm instrumentation mic capsules, for instance the
> standard 1/2" from B&K, ACO Pacific, or Larson-Davis. But these cost $580
> (ACO) to $777 (B&K). There are other electret capsules (Sennheiser,
> Lectret), normally available only to manufacturers, that aren't much
> better. I have made a study of all the other available electret capsules
> (Primo, NMB, Hosiden, Bo Sung, Pan, and others) but keep coming back to the
> Panasonic.
>
> There are some other mods that can be done to improve the Panasonic
> capsule. They are generally the result of extensive experiment and are
> considered proprietary by those who developed them. The critical issues
> include: stabilizing the aging of the diaphragm and the back-electret
> film, getting the front of the diaphragm out into the air as much as
> possible, keeping the back of the diaphragm/backplate structure sealed from
> the air as much as possible, keeping the mic housing still while only the
> diaphragm moves, and operating the FET stage in the middle of a wide linear
> transfer function. Okay, I haven't given away any secrets, but inquiring
> minds ought to be able to work good solutions based on this list of
> problems. [dj]
- John
From: Ron Cobb <cobbre@ctrvax.vanderbilt.edu>
Subject: RE: Citibank ext warranty?
Date: Thu, 27 Apr 1995 12:29:06 -0500 (CDT)
The news is that Citibank once offered an extended warranty on products
purchased with a Citibank card. I have been a Citibank card members since
1988, and this was a cool bonus....but about a year after beginning the
program they discovered the tremendous amount of money they would lose in
the long run, so about a year and a half ago, they cancelled the program.
Items purchased and registered while the program was active are still
covered, but you can no longer register. Sorry...it was great while it
lasted.
ron
From: Len Moskowitz <moskowit@panix.com>
Subject: Re: Length of Tom Petty shows?
Date: Thu, 27 Apr 1995 14:52:25 -0400
That interpid taper Kurt wrote:
> Does anyone out there know how long the Tom Petty shows are running from this
> current tour?
The show at NYC's Madison Square Garden ran under two hours. It was the
first time security ever bothered me -- I lost about half-an-hour of the
show :^(
Len Moskowitz
Core Sound
moskowit@panix.com
From: DrewStorms@aol.com
Subject: Damon's deal
Date: Thu, 27 Apr 1995 17:15:27 -0400
Robert Fish <rfish@us.oracle.com> wrote:
>Damon <damon@eden.com> wrote:
><>Over the years this averages out to be around $9 per two hour DAT.
>
>Boy have they got *your* number, Damon! Yikes! Brand new panasonics
>can be had for $6; brand-spanking new Maxell Data Grade 90meters are
>only $7.50. You're not really offering anyone a "deal" here...
>
>Rob
Correct me if I'm wrong, but DATs haven't always been $6, so, depending on
how long he's had them, it'
s very possible that the average was $9. Add to that the fact that they
might be worth more filled (especially to someone with only one deck), it
doesn't strike me as a ripoff. I mean, I don't want them, but I'm sure
someone will.
Just my $1/50,
drew
From: Harry C Nye IV <hcnyeiv@esu.edu>
Subject: PRO DIGITAL IS GREAT!
Date: Thu, 27 Apr 1995 17:26:10 -0400 (EDT)
Went to pro digital to pick up my Digicon SCMS stripper today, Paul
modified the Units to ste them to "00" he has a great business AND some
great deals. he has some items of interest for sale that he gets
ocassionally.
right now he has the following items that some people may want to look
into.
Brand New Sony 1000 Dat Decks (never sold, NOT B sstock either) Prices
to low, I can mention, so call him no joke
The Tascam DA 30 MKII $1150
He also has some refurbs, and Fixes DAT decks, He also has the GEL
cell packs for D3 users for $69.
his number is 610-328-6992
tell him Buck told you to call
take it easy
Buck
From: Seth Breidbart <sethb@panix.com>
Subject: Re: Damon's deal
Date: Thu, 27 Apr 1995 17:32:52 -0400
>><>Over the years this averages out to be around $9 per two hour DAT.
>Correct me if I'm wrong, but DATs haven't always been $6, so, depending on
>how long he's had them, it's very possible that the average was $9.
The highest price I've paid was $9, back around 1990. Any sort of
average would be less (unless he really got taken, which is possible.
Before dat-heads, a lot of people didn't know any better than to pay
their local store $12 or even $15).
>Add to that the fact that they
>might be worth more filled
That would be selling the music, which is a no-no around here.
Seth
From: "RICHARD E. EGGLETON" <reggleto@osf1.gmu.edu>
Subject: starting a list of digital out cd players/transports
Date: Thu, 27 Apr 1995 18:58:36 -0400 (EDT)
this is just a start, I have a lot of work to do tonight, and will
continue this list for the next several days
ACCUPHASE
DP-90 CD TRANSPORT....Toslink fiber & coaxial output....$7,595
DP-65 CD PLAYER ....Toslink fiber & coaxial output....$5,995
ARCAM
DELTA 270 CD PLAYER...2 Coaxial outputs..................$1,600
ALPHA 5 CD PLAYER.....Coaxial output.....................$ 899
AUDIOLAB
MODEL 8000CDM CD TRANSPORT....Coaxial & balenced AES/EBU..$2,100
AUDIO RESEARCH
CD1 CD PLAYER...ST glass fiber-optic, BNC, coaxial, AES/EBU
XLR, and TOSLINK digital output............$2,995
BITWISE AUDIO TECHNOLOGIES
MUSIK SYSTEM CDT-ONE CD TRANSPORT...Balanced AES, Coaxial-BNC
& glass-ST digital outputs..................................$2,450
CALIFORNIA AUDIO LABS
TERCET MKIV CD PLAYER....Coaxial digital in/out.............$1,495
DELTA CD TRANSPORT ....Toslink Fiberopitic & coaxial......$ 895
ICON MKII CD PLAYER......Coaxial output.....................$ 895
DX-1 CD PLAYER...........Coaxial output.....................$ 595
CAMELOT TECHNOLOGY
MERLIN CD TRANSPORT......Coaxial output.....................$ 1,195
CARVER
SD/A-390T 5 DISC-TUBE CD/CHANGER..Coaxial output............$ 750
SD/A-360 5 DISC CD CHANGER........Fiberoptic output.........$ 500
CEC
TL1 CD TRANSPORT..................Toslink & ST fiber optic,
coaxial BNC..................................................$4,950
COUNTERPOINT
DA-11a CD TRANSPORT.....one toslink optical & two BNC electrical
add $200 for AES/EBU Balanced output..price w/o options......$1,495
CREEK
CD42 CD PLAYER....AES/EBU RCA Digital Output.................$1,100
DENNON
DP-S1 CD TRANSPORT...AES/EBU XLR, AT&T ST Toslink............$8,000
DCD-S1 CD PLAYER.....AES/EBU, Coaxial & fiber-optic..........$5,000
DCD-S10 CD PLAYER....Coaxial/fiberoptic in/out...............$1,500
DCD-3000 CD PLAYER..." " " " " " ...............$1,200
DCD-1015 CD PLAYER..." " " " outputs...............$ 500
DCD-815 CD PLAYER...Coaxial output..........................$ 300
DCM-560 5 Disc Changer.." " ..........................$ 600
DPA DIGITAL
T1 CD TRANSPORT.......Coaxial & Toslink Fiber-Optic outputs..$1,595
I will start with E tommorrow. later on
rich
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