VOGONS


CVX-2 : covox adapter

Topic actions

First post, by dreamblaster

User metadata
Rank Oldbie
Rank
Oldbie

Hi,
I am testing 2 covox adapter PCB prototypes :
CVX-1 : through hole, 1% resistors (2 different values)
CVX-2 : SMD adapter, 0.1% resistors or 1% resistors (all same value, same batch, for best accuracy)

I have been playing with a low pass filter cap and like your feedback, what sounds best ?
I tested with crystal dream demo on the CVX2 (0.1%) :

10nF ? https://youtu.be/TVaPQ41huBY
100nF ? https://youtu.be/wcqD_SzOz_c
5nF ? https://youtu.be/w8gLaZD46ew (ADDED)
1nF ? https://youtu.be/RaZH5dXw1eY
no cap ? https://youtu.be/bn-spjT_A-A

What do you think sounds best ?
Which other demos / games / music software (that support covox adapter) are recommended to try with the CVX adapters ?

Attachments

  • CVX2.JPG
    Filename
    CVX2.JPG
    File size
    83.94 KiB
    Views
    3225 views
    File license
    Fair use/fair dealing exception
  • CVX1.JPG
    Filename
    CVX1.JPG
    File size
    96.05 KiB
    Views
    3225 views
    File license
    Fair use/fair dealing exception
Last edited by dreamblaster on 2016-12-26, 14:32. Edited 2 times in total.

Visit http://www.serdashop.com for retro sound cards, video converters, ...
OPL2LPT, OPL3LPT, X2, S2, S2P, MCE2VGA, ... many projects !
Special vogons LPT bundle : https://www.serdashop.com/Parallel-port-retro-sound-bundle
Thanks for your support !

Reply 1 of 448, by stamasd

User metadata
Rank Oldbie
Rank
Oldbie

That is a very nice addition to your lineup.

I have a hard time deciding if I like the 10nF or 1nF more. The 100nF sounds very subdued with a lot of high frequencies loss, and the no-cap is a bit too harsh IMHO.

I/O, I/O,
It's off to disk I go,
With a bit and a byte
And a read and a write,
I/O, I/O

Reply 2 of 448, by Scali

User metadata
Rank l33t
Rank
l33t

Yea, 100nF is definitely too muffled.
I think 10nF is acceptable. It affects the sound slightly, but it remains bright enough.
The difference between 1nF and no-cap seems negligible.

I think my vote goes to 10nF.

http://scalibq.wordpress.com/just-keeping-it- … ro-programming/

Reply 3 of 448, by Beegle

User metadata
Rank Member
Rank
Member

I prefer rougher sound in general.
100nF is way too muffled and as said already, loses many high frequencies.
10nF is a little bit too soft to my personal taste.
1nF sounds right to me.
unfiltered is acceptable to me, but may not be to other ears. So 1nF to me seems to be the balance.

The more sound cards, the better.
AdLib documentary : Official Thread
Youtube Channel : The Sound Card Database

Reply 4 of 448, by stamasd

User metadata
Rank Oldbie
Rank
Oldbie

Can you test with 4.7nF or 5.6nF? Though that would be nut-picking. 😀

I/O, I/O,
It's off to disk I go,
With a bit and a byte
And a read and a write,
I/O, I/O

Reply 5 of 448, by dreamblaster

User metadata
Rank Oldbie
Rank
Oldbie

Yeah I will test with 4.7nF, will order such caps. This may be the sweet spot.
Will add a video with 4.7nF as soon as I have them.

Visit http://www.serdashop.com for retro sound cards, video converters, ...
OPL2LPT, OPL3LPT, X2, S2, S2P, MCE2VGA, ... many projects !
Special vogons LPT bundle : https://www.serdashop.com/Parallel-port-retro-sound-bundle
Thanks for your support !

Reply 7 of 448, by stamasd

User metadata
Rank Oldbie
Rank
Oldbie

You can solder 2 of the 10nF caps in series, that will give you roughly 5nF for a quick test.

I/O, I/O,
It's off to disk I go,
With a bit and a byte
And a read and a write,
I/O, I/O

Reply 8 of 448, by dreamblaster

User metadata
Rank Oldbie
Rank
Oldbie

yeah good idea
will do, will test with 2 x 10nF in series == 5nF
then later will test with 4.7nF, should sound the same

Visit http://www.serdashop.com for retro sound cards, video converters, ...
OPL2LPT, OPL3LPT, X2, S2, S2P, MCE2VGA, ... many projects !
Special vogons LPT bundle : https://www.serdashop.com/Parallel-port-retro-sound-bundle
Thanks for your support !

Reply 9 of 448, by keropi

User metadata
Rank l33t++
Rank
l33t++

I like all of them ? 🤣 I'd say 10nf as well - just to be on middle ground
there is also Pinball Fantasies that has some great mod music , maybe you can test with that as well?

cT89QGt.gif Amstrad PC7486SLC-33 wanted , click me for AmiBay ad!

Reply 10 of 448, by Scali

User metadata
Rank l33t
Rank
l33t
dreamblaster wrote:

Which other demos / games / music software (that support covox adapter) are recommended to try with the CVX adapters ?

Crystal Dream 2 also has LPT DAC support I believe, and should have a better quality mixing routine than Crystal Dream 1.
Fast Tracker II also has LPT DAC support (select 'Sound Player' on LPT1, even has an LPT1+LPT2 stereo option), with the same routine as CD2 I believe. Should be great for playing any MOD or XM song.
Inertia Player is a player with support for LPT DAC that should play a wide range of tracker formats.

http://scalibq.wordpress.com/just-keeping-it- … ro-programming/

Reply 11 of 448, by dreamblaster

User metadata
Rank Oldbie
Rank
Oldbie

okay, I tested with 5nF (2x10nF in series)
https://youtu.be/w8gLaZD46ew
(I'll add the link to the first post)
Is this better than 10nF or 1nF ?

Visit http://www.serdashop.com for retro sound cards, video converters, ...
OPL2LPT, OPL3LPT, X2, S2, S2P, MCE2VGA, ... many projects !
Special vogons LPT bundle : https://www.serdashop.com/Parallel-port-retro-sound-bundle
Thanks for your support !

Reply 13 of 448, by Scali

User metadata
Rank l33t
Rank
l33t
dreamblaster wrote:
okay, I tested with 5nF (2x10nF in series) https://youtu.be/w8gLaZD46ew (I'll add the link to the first post) Is this better tha […]
Show full quote

okay, I tested with 5nF (2x10nF in series)
https://youtu.be/w8gLaZD46ew
(I'll add the link to the first post)
Is this better than 10nF or 1nF ?

It's slightly more subtle than the 10nF, but still takes off a bit of the brightness/harshness.
I think 5nF might be the way to go.

http://scalibq.wordpress.com/just-keeping-it- … ro-programming/

Reply 15 of 448, by dreamblaster

User metadata
Rank Oldbie
Rank
Oldbie

Very good, I ordered 4.7nF caps.
Thanks for your help, I will pm you all 😉

Visit http://www.serdashop.com for retro sound cards, video converters, ...
OPL2LPT, OPL3LPT, X2, S2, S2P, MCE2VGA, ... many projects !
Special vogons LPT bundle : https://www.serdashop.com/Parallel-port-retro-sound-bundle
Thanks for your support !

Reply 16 of 448, by James-F

User metadata
Rank Oldbie
Rank
Oldbie

I think we are forgetting that the filtering is there to avoid terrible sounding aliasing, just like in the sound blaster cards.
Yes, high value will not sound good with music when compared to how HiFi modern music sounds, BUT to low value will make aliasing very clear in sound effect.
Most of the audio meant to be played on the Covox is 11kHz, thus everything above that is filtered out, again, just like in the SB card.

I think some game with sound and music should be a more fair comparison.


my important / useful posts are here

Reply 17 of 448, by stamasd

User metadata
Rank Oldbie
Rank
Oldbie

Here's an idea: add 3 or 4 different caps and a jumper head... let everyone choose which one they like.

I/O, I/O,
It's off to disk I go,
With a bit and a byte
And a read and a write,
I/O, I/O

Reply 18 of 448, by gdjacobs

User metadata
Rank l33t++
Rank
l33t++

Add a two position clip socket and people can just wham in whatever barrel caps suit them.

All hail the Great Capacitor Brand Finder

Reply 19 of 448, by Kamerat

User metadata
Rank Oldbie
Rank
Oldbie
dreamblaster wrote:

Which other demos / games / music software (that support covox adapter) are recommended to try with the CVX adapters ?

Pinball Fantasies.

DOS Sound Blaster compatibility: PCI sound cards vs. PCI chipsets
YouTube channel