That's pretty nice, and not uber expensive also 😉

Only possible gripe I'd have with them is they are the slower chips ending with "-7" instead of the "-6" I usually see, but that might not be much of an issue, depending on what you plan to use them for.

The manual of the gravis ultra sound says that you need 70ns chip.. Normally its NEC brand..but those are hard to get.

Actually there is no difference. You may use any 256×4 chips in any combinations, up to 100 ns.

There is the explanation:
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Date: Tue, 27 Apr 1993 17:02:33 +0100 (BST)
From: Simon Watson <Simon.Watson@durham.ac.uk>

I am an electrical engineer and logic designer. Some people have wandered about the DRAM speed issue and if it was ok to use faster DRAMs than the 100ns type and if it would have an effect on the performance of the GUS.

Most computer memory access logic is timed by some sort of clock circuit. This clock is used to tell the logic how long to wait for data to become valid after sending DRAMS the address. Once designed this wait period is constant unless special provisions are made to change it. The GUS does not have any user option to control its wait time for DRAM. Therefore it is designed to wait for a time appropiate for 100 ns accesses DRAMS. Putting faster DRAMS in the GUS will not hurt it but will not speed it up either. It will simply give the DRAM the address it wants to access, wait , and then use the data presented by the DRAM. It cannot tell that the DRAM gave it the data faster than expected.

Why did they use 100 ns DRAMS when now all you can find are 70s or better? It takes time to bring something to market. 100s were probably what was available at the time so that was what the timing called for. Or perhapes the chip that uses the drams cannot use the data any faster than that. So they wrote the spec to be conservative and use the least expensive chip availble at the time.

To access memory at a sample rate of 44100hz * 32 voices only requires one access every 708 ns. The DRAM speed is put to use during DMA transfers from the mother board to the GUS.
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Robin4 wrote:

The manual of the gravis ultra sound says that you need 70ns chip.. Normally its NEC brand..but those are hard to get.

It may "need" 70ns, but that indicates that 60ns is perfectly usable 😉

I do not say that you cant use 60ns.. I only follow up what i read in de manual of that soundcard.. So that iam sure it will work.. If i go from the desired specs, maybe i get problems that the memory upgrade wont work.

Robin4 wrote:

I do not say that you cant use 60ns.. I only follow up what i read in de manual of that soundcard.. So that iam sure it will work.. If i go from the desired specs, maybe i get problems that the memory upgrade wont work.

The thing is that you must be sure the memory chips are of the same type and "70ns or faster". It's like when you want to buy something that's €10 (70ns). But you can still buy that item if you have €20 (60ns), because it's the same, but only more 😉

I have used some chips with more then 70ns and I had problems. The sound was cracking. Also when I ran GUS ram test program it showed me errors. I replaces chips for 70ns (I think) and it worked perfectly.

Ok tnx for the comment. Then those will work on my cards also.

This is for Gravis Ultrasound v2.4? Not sure on the number of pins or if it was all the same between revisions, etc.

http://www.gravisultrasound.org/catalog/img/gus-24f-big.jpg

I don't think so. The linked auction appears to be for SOJ chips and the Gravis Ultrasound Classic uses DIP. The SOJ chips physically won't fit on the card.

You need PDIP. I've done more reasearch. It has to be 20pin 256k 4bit 70ns DRAM. I've found this http://www.ebay.com/itm/Mosel-Vitelic-V53C104 … s-/140360333573

but you would need to solder it somehow to the board, which I'm more than willing to do. I'm wondering if someone knows of a better way though. 386SX boards would have this type of RAM but most people seem to have scavenged the RAM from the boards already.

I think you could use 16bit stuff too but you'd have to ground the extra data lines to complete the circuit. I'll probably had to get that mosel vitelic and just make a network of wires all over the place. 256k x 4bit searches pull up 80, 100 and 120ns which is all useless for this.

PDIP just means plastic DIP, pretty much every RAM chip of this type will be plastic, and its not usually referred to as PDIP, merely DIP. So I wouldn't worry about that part.

The ones you've linked are, again, SOJ package chips.

various Amigas used 256x4 DIP RAM so you might try amibay.com, in fact they will probably have someone selling new old stock.

On my Gravis Ultrasound Classic v3.4 I have 1MB of these chips:
KM44C256BP-7

I know its SOJ, but you could hand solder the wires to the board. Wouldn't be fun but it could work.

I'll try amibay.com and post updates on it. The games I wanted to play with this card like Doom, Heretic, etc. require 1mb upgrade or else it could potentially lockup.

On a side note, how rare were these cards? I waited for a good long while to find an original (non max, ace, etc).

I found your chip, it requires a $25 minimum order and $7.50/sh at http://www.questcomp.com/QuestdetailsInv.aspx … YesOnly&inv=yes

I'll try AmiBay first though, the card wont be arriving for a week or so.

Here it is at http://www.memoryten.com/004932.htm but it says 80ns but the -7 would clearly indicate 70ns? Lol. Hopefully it would be a typo.

Memory Ten had what I needed. Thanks for your help!

Will this module work a GUS MAX? It uses SOJ but I'm not sure the number of pins, etc.