8 - Upgrading from 64 to 128 voices

Author: sgeorge, Posted on: 21 August 2020 14:52

The advantage the E6400 Ultra has over the E5000 Ultra is that it can be upgraded from 64 to 128 voices. It has all the requisite components installed to support it except for 3 main chips.

The downside is, you'll never find any upgrade kits on the market for them.

If you could find one, it would be really simple, you just plug three chips into the motherboard!

Since we dont have a kit, we need to make one.

Enter the donor Proteus 2000.

This sweet little P2K was purchased without a ROM in it, making it more or less useless, but in full working order. Not bad for 73$!

Lets take a look inside

We can see an early revision mainboard (There were two, a 1998 and a 2000) layout. It also came with OS1.03, which was the first release, so this is an old one!

(For no reason at all I did upgrade the P2K to the latest OS2.26 and ran diagnostics which gave a 100% pass to the G+H chips.)

Looking closer, this is what we are after!

We only need 1 of the "G" chips, IC402, and two of the "H" chips, IC413.

The Proteus 2000 has 2 "G" chips, each one responsible for 64 voices, and 4 "H" chips responsible for 32 filters each.

Our E6400 Ultra already has 1x "G" and 2x "H", so these three chips will bring us up to 128 voices and turn it into an E4XT!

Interestingly the IC413's in the P2K were manufactured on 9915, the IC413 in my E6400 Ultra were 9916, one week after.

The IC402 in the P2K is 9912, vs my E6400 being 9915... 3 weeks.

An oddity I just find interesting. I imagine E-MU didnt get chips fabbed very often in great qunatities.

So, we must say goodbye to this P2K, as its going to give its life so our E6400 can be upgraded.

Removing surface mount chips is not something I'm good at, so I'm going to dremmel around the chips pcb, stick them on a nice flat frypan on the stove to supply heat enough to melt the solder and pick the chips off..

Once done, the two IC413s will just drop into the PLCC sockets, but the IC402 will need to be soldered on.

Now, the upgrade kit has the IC402 on a PGA board, but I dont know the PGA pinout to make one, so we are just going to solder it directly where it would be.

What? dead bugs? No, I just hot air removed them and they are on their backs. They do need a little cleanup. I need to make sure none of the pins on the IC402 are bent.

All soldered, plccs pressed into place.

Aaaaaand... hit the power... here we go, 128 channels!

So, one last thing to talk about with this upgrade, on the board is a jumper called "ID". I never had verification if its required for 128 channels or not.

The schematics are not clear.. but I tested it and here are the results.

With _NO_ jumper installed (open pins), when you boot up it says

  • "Software: EOS v4.70"
  • "128 channel card installed"
  • "Effects installed"
  • "MIDI Option card installed"
  • "128mb of Sound Memory installed"

With the jumper installed (pins closed), it does not print that line 128 channel card line;

  • "Software: EOS v4.70"
  • "Effects installed"
  • "MIDI Option card installed"
  • "128mb of Sound Memory installed"

Either way, it shows 128 channels in the About screen.

If you put the jumper there, and you only have a E5000/E6400 with 64 channels, and boot up it will show 64 channels so it tests them either way.

tags: Audio, E-MU, E6400 Ultra, EOS4, IC402, IC413, Proteus 2000, Sampler


rvense said on September 09, 2020 15:01:30;
      I've been wanting to try this for a long time, but I've never dared. Good work!

Also happy to have the ID jumper mystery cleared up. I think I tried stuffing it on my 64-voice Ultra, and it froze during boot around where the number of voices is normally printed.
Dan said on February 04, 2021 12:56:06;
      Hello Mr. George,
Congrats on this modification and a big thanks to the web page and documentation of this mod. I have a Proteus 2000 in my lab at the moment, and I suspect it to have a faulty G-II chip. Seeing this post, I'm guessing that you may actually have an extra G-II chip not being used. I was wondering if you would be interested in finding a new home for this chip for the dead P2K I've got. If you still have it and would be willing to part with it, please let me know. I'd be happy to take it off your hands.
Stu said on February 05, 2021 21:48:41;
      Hey Dan, I do have spare G chip, but your better of buying one from EPR Electronics they have NOS G chips IC402's AMI version.
Jan said on October 22, 2021 19:02:44;
      Hi Mr. George,
you presented here an interesting project and congrats for your success!
May I ask you some questions?
How did you do the desoldering and soldering of the ic´s in detail? What kind of challenges had to be taken and how did you solve them?

Thank you in advance and
Beste Grüße
from Germany

Stu said on October 28, 2021 16:45:50;
      Hi Jan, I used hot air to desolder the IC's from the proteus 2000. For soldering the chip to the Ultra, it was very easy as the 6400 board from the factory has solder on the pads, so I just lined the chip up and used a 1 or 2mm chisel tip on my soldering iron to go over the legs. I didnt add any solder, all you needed was on the board already.

Jan said on October 31, 2021 09:09:05;
      Hi Stu,
I think I will try to get a mainboard of the proteus 2000 line and copy your presented "surgery".Unfortunately it´s not that easy to find a proper "victim" at a reasonable price in Germany.
I mailed EPR Electronics but didn´t get an answer until now.

Thanks for your response:-)
Beste Grüße
Adam said on May 23, 2022 20:30:40;
      Regarding "The advantage the E6400 Ultra has over the E5000 Ultra is that it can be upgraded from 64 to 128 voices.", I'm pleased to report that I just performed this upgrade on my E5000 Ultra and it works just as for the E6400. I documented the upgrade in the Facebook "E-MU Sampler Users" group.

My G and H chips came from an E-mu Planet Earth that I upgraded to 128 voices by swapping in and re-flashing a board from a donor ROM-less P2000 I bought cheap off eBay. I decided 128-voice E5000 was more useful to me than a P1000 (plus I harvested other stuff from the board to repair other P2K variants).

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