Crystal source

MIDIbox FM
1

Hello

Again im the clueless of the bunch here.

Ive found a 14.318 crystal with the right form factor named “CTS KNIGHT”, is that A TTL ?

are there TTL and CMOS crystals? what are the chances its not the right thing?

I also could salvage a 14.318  from one of the many SB clone cards containing the YMF/YAC’s that i found, one would think with certainty that THAT one would do the trick right?

There are soo many unknowns in my MBFM.. i made 2 SIDs and one Secret Chip midiBox, but

the leads are so small everywhere on that PCB, and parts have been gathered in many places, so

i can only pray that its going to do anything once powered…

2

What is a “Secret Chip midiBox” ???

There’s a difference between a crystal and a crystal oscillator.

A crystal is (often) a two-pin component in a metal can.

The crystal oscillator in the OPL3 module is (often) a four-pin component in a metal can, and contains the crystal and other components so it will output a pulse waveform.

Unfortunately, in the sound cards I have, they have 14.318 crystals, not crystal oscillators, another chip on the card is using the crystal to generate the pulses. There are crystal oscillators on the sound cards but they’re the wrong frequency.

3

What is a “Secret Chip midiBox” ???

Some unfinished (but working) 80s video game sound chip MIDIBox, that will stay nameless until finished.

http://www.midibox.org/forum/index.php?topic=8026.0

Really im just waiting for someone to recognise the tune in that “hacked_emulator.mp3” :slight_smile:

Ive modified an open source emulator to send specially constructed MIDI CC to my board,

directly accessing the registers without much translation.

There’s a difference between a crystal and a crystal oscillator.

A crystal is (often) a two-pin component in a metal can.

The crystal oscillator in the OPL3 module is (often) a four-pin component in a metal can, and contains the crystal and other components so it will output a pulse waveform.

Unfortunately, in the sound cards I have, they have 14.318 crystals, not crystal oscillators, another chip on the card is using the crystal to generate the pulses. There are crystal oscillators on the sound cards but they’re the wrong frequency.

Im a programmer, and frankly the electronic nomenclature is to me a huge bunch of random numbers, there are some standards,

for caps numbers and resistor colors, but for other components?

These are the two “whatever you call 'em” … is one of them suitable for this? Can anyone guess with the picture?

These are four pins alright. the “cardinal” one was on a “Media vision PROAUDIO 3D”, which had a YAC and a YMF.

The CTS Knight one, well i lost the packaging.. 

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4

Hi,

I´d say they both should work. They are oscillators and as they come from sound cards with opl, they must be suitable. I would keep the second one as a spare if the first one doesn´t work. One thing I noticed: Thorsten states a 14.318000 MHz oscillator in the order list, while yours are 14.318180 MHz. But that´s a difference of only 0.01%, so I doubt there will be any noticeable tuning error.

Seppoman

5

The second osc comes from a new-old stock surplus store, and it had a packaging which i sadly lost.

as far as Mhz are concerned, the YMF262.PDF just says “14.32 Mhz”.

I haven’t checked the programming code if there are tables made according to a “wanted frequency”,

or if the frequency is defined as a variable from the PIC to the YMF, and the YMF assumes the clock to be something fixed.

Im at the point where i only need to do a friggin ±12vdc supply. I tested the 5vdc voltages everywhere and they were fine, (this is using the Cardinal Osc) … so does that mean the crystal is ok for the job?

In other words, in order for the YAC’s to output 5vdc signals out , does it need to be clocked?

6

One thing to note regarding the orderlist:

I’ve recently ordered the oscillator with the given partnumber “OSZI 14,318000” at Reichelt - what I’ve got is an 14,31818 MHz one.

Mike

7

Typically when you see “14.32” or “14.318”, it’s just rounding the 14.318180 MHz down to fewer significant digits.  AFAIK they should all work fine.