VOGONS


Reply 20 of 25, by jaZz_KCS

User metadata
Rank Oldbie
Rank
Oldbie
dr.zeissler wrote:

The Pinball games support lpt-dac-directly, but you use vsb with it? interesting.
what machine are you using? cpu/chipset

1] Due to my quite misleading phrasing it made it look like I would use VSB with the CVX4 for the 21st Tables. Of course there is no need, since the game directly supports lpt-dacs.

2] But since I confuzzled you I had the urge to actually try it with the VSB... And as I feared with various success...

I got - at one point - SB emulated digitized sound output through VSB (with Sound Blaster I set) on the CVX4. But results differed throughout all the tests. Could also be due to the flakey and weird built-in prot-mode that these games use (?) (at least true for "Illusion")

Tested on Compaq Contura 400c (486DX2/40), as well as IBM Thinkpad 760EL/ELD (Pentium 133) hybrid. The latter one had always had problems with the 21st tables for some reason...

Reply 22 of 25, by Paralel

User metadata
Rank Member
Rank
Member

What is the frequency range for the CVX4? (assuming no low-pass filter cap is used).

I want to find out if my thinking is correct, if without a low-pass filtering cap then technically it has no maximum frequency cut off.

So, with Dip 8 off, and the other 1-5 Dips off, the frequency range should be DC to Infinity, right?

Reply 23 of 25, by Jepael

User metadata
Rank Oldbie
Rank
Oldbie
Paralel wrote:

What is the frequency range for the CVX4? (assuming no low-pass filter cap is used).

I haven't measured yet. It should not be too hard to measure. But most likely the frequency range is "good enough" for the material that is played through it.

With a plug like this, it all depends on your PC parallel port driving it, your audio cable, and your amplifier input.

So even if I measure how it works in my system, it won't work identically in your system.

I actually built mine with no caps, and with matching attenuator than in original plug to match output impedances.

Paralel wrote:

I want to find out if my thinking is correct, if without a low-pass filtering cap then technically it has no maximum frequency cut off.

So, with Dip 8 off, and the other 1-5 Dips off, the frequency range should be DC to Infinity, right?

Only if you live in ideal world. Real world components such as ICs, components and cables don't quite work like that.
The longer the audio cable, the more it has capacitance, and the more it blocks high frequencies.

Besides that poses another issue, if the plug has bandwith up to something sensible like 16kHz, and game plays something at 8kHz sampling rate, you get distortion from aliasing since you really should have a DAC reconstruction filter which blocks everything from 4kHz and above.

Reply 25 of 25, by Jo22

User metadata
Rank l33t++
Rank
l33t++

Hi! Is this thread still alive ? I just remembered there also was a great patch thread for Telarium games that got posted early this year.
These games may also work fine with Covox and TEMU, as it seems.

Anyway, I just remembered it because today I bought a book titled Rendezvous with Rama on eBay. :)

"Time, it seems, doesn't flow. For some it's fast, for some it's slow.
In what to one race is no time at all, another race can rise and fall..." - The Minstrel

//My video channel//