VOGONS


First post, by Spirantho

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Hi everybody,

First post here - be gentle!

One of my retro-based hobbies involves running PC bridgeboards on my Amigas. I have an NEC V30, a 286, a 386, and a 486SLC2/50 (soldered on board what was a 386SX A2386SX 😀 ).

In my quest for ultimate speed (in other words, enough to run Ultima VII), I have overclocked the ISA bus to 13.5MHz. This works perfectly with the graphics card (my trusty Cirrus Logic Thunderbolt ISA 1MB SVGA) and my IDE card (FutureTech PowerIDE thingy). However, I have now tried about 8 sound cards and none of them work. I knew this was going to be difficult, ISA sound cards being as finicky as they are, but nonetheless even the later Yamaha OPL-based cards don't work.

Does anyone know a sound card that works with stupid ISA bus speeds?

Thanks for any help!

(By the way - is my .sig ok? My real intention isn't to advertise my shop but I like people to know about it. Don't want to break any rules though).

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Ian Gledhill
http://www.mutant-caterpillar.co.uk/shop/ for all your 8-bit and 16-bit needs!

Reply 1 of 7, by keropi

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Welcome!!!

I had a GG486slc in my A4000D and used a sl2/50mhz upgrade... You are correct, vga+i/o seem to work fine as is (in my case stock ISA speed) but I had troubles with sound... 16bit sound cards worked but once you played a "heavy" game then the sound would play erratically and midi would slow down... I just used 8bit soundblasters from that point on and everything was perfect, to my understanding the GG has a limited ISA bandwidth or something and using a 8bit sound card relieved it... I can't comment on overclocked bus though, maybe it's too much for the bridgeboards

🎵 🎧 PCMIDI MPU , OrpheusII , Action Rewind , Megacard and 🎶GoldLib soundcard website

Reply 2 of 7, by Spirantho

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Hi Keropi,
Good to see you again - not seen you on A.org for a while. 😀 It's because of you I got the SLC/2 upgrade in the first place, I think.
I never had problems with sound on my GG, but alas it's broken now and I need to repair it or replace it. Hence why I'm using the A2386SX instead.

By the way, I just found a source for the Cx486SLC/2-50 for $45 each! 😀 Seems like utsource.net have them, and they provided me with my ZIP RAM for my 2386SX so they do have some pretty scarce stuff!

The problem with the overclocked bus, by the way, isn't that the sound doesn't work - it's that the chipset is never found by the Plug'n'Play driver or Windows 95 (which works just great on my 50MHz A2386SX 😀 ). Very odd.

--
Ian Gledhill
http://www.mutant-caterpillar.co.uk/shop/ for all your 8-bit and 16-bit needs!

Reply 3 of 7, by keropi

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🤣 I thought I've seen the username somewhere before... nowdays I only post on amibay and some local forums for all things amiga 😉
UTSOURCE is a great asset, they carry many old obscure stuff too ... but from what I understand you are using a PnP card? don't you have an older card that has jumpers? I could never get anything pnp to work reliably on my GG486 setup , I had too much hardware cramped in the amiga so it's no surprise... even the csppc might had something to do with that, cache enabled or disabled GG was tricky to setup...

🎵 🎧 PCMIDI MPU , OrpheusII , Action Rewind , Megacard and 🎶GoldLib soundcard website

Reply 4 of 7, by Anonymous Coward

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I wonder if there would be a way to add an extra divider to only one of the ISA slots so that it worked at exactly half the speed of the others.

"Will the highways on the internets become more few?" -Gee Dubya
V'Ger XT|Upgraded AT|Ultimate 386|Super VL/EISA 486|SMP VL/EISA Pentium

Reply 5 of 7, by Spirantho

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I'm still looking for a complete non-PNP soundcard... they seem quite hard to find! I have a Soundblaster II 8-bit card but I'm not sure that'd cope and may well negate the advantage of overclocking the ISA bus in the first place. Going to keep looking!

--
Ian Gledhill
http://www.mutant-caterpillar.co.uk/shop/ for all your 8-bit and 16-bit needs!

Reply 6 of 7, by elianda

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I don't see the connection between ISA-PnP and stability at higher clock rates?!?

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Reply 7 of 7, by keropi

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elianda wrote:

I don't see the connection between ISA-PnP and stability at higher clock rates?!?

on a real pc maybe there isn't but on a bridgeboard inside an amiga that activates the passive ISA slots on it's busboard you can have all kind of strange things ... not to mention the custom BIOS for this 😊 😊 😊
The bridgeboard also shares peripherals with the amiga (floppies, ports, keyboard, mouse , hard drive partitions and even part of the ram in some cases for transfering files)... plus back then PnP was not even released as a standard (1991) so there is no guarantee the custom BIOS would work OK with pnp managers/hardware... those bridgeboards are really a huge hack IMHO and in no way independent as a SBC

🎵 🎧 PCMIDI MPU , OrpheusII , Action Rewind , Megacard and 🎶GoldLib soundcard website