Let's talk Jim Williams mods (HD24)

I'm hoping if Jim reads this, he won't have too much of a problem with it. I've talked to the guy a few times and he's really one of the nicest people in the world. And he provides a service, upgrading gear, for tons of people who don't have the time or intent to learn it on their own.

I'm thinking about his HD24(XR) mod right now. It's $750 I believe and he replaces input coupling caps and all the opamps w/ burr browns. Something else too, I forget. Anyway, I know the guy pretty much came up with these mods on his own. But I get the sense that most of what I would be paying for is labor. Which is fine.
I don't know. I just wish I knew enough to open that thing up and recognize exactly what would be essential for upgrading. I mean, replacing opamps and caps is not hard. It's just that I have to go find the right opamps, and make sure I know which are the input coupling caps. I wonder if the labor has a lot to do with the difficulty of opening the unit up and getting at everything.

Anyway, comments?
I'd sure love to find out exactly what he does and do it on my own.

do you have pictures of the inside of a unit? if you have detaied pictures of the boards then we can definately tell you which ones to change.

Okay,

It took me awhile, but I took some pics of the inside of this thing.
Inputs- http://img307.imageshack.us/my.php?image=inputs6sz.jpg

Outputs- http://img307.imageshack.us/my.php?image=outputs7oh.jpg

Daughterboard- http://img307.imageshack.us/my.php?image=daughterboard6ho.jpg The daughterboard connects the inputs and the outputs to the main PCB

Main PCB- http://img141.imageshack.us/my.php?image=mainpcb2ih.jpg

This is the PCB that connects connects the HD to the Main pcb- http://img348.imageshack.us/img348/2516/harddriveconnections6ay.jpg

The front of the PCB that connects the Hard drive to the Main PCB- http://img141.imageshack.us/img141/1687/frontofhdconnections4yj.jpg

Power supply- http://img141.imageshack.us/my.php?image=powersupply0uy.jpg

This is a Jim Williams quote from gearslutz:

"The XR mods include the low noise fan and fan filter intake foam to keep the innards clean. The psu is rebuilt with very high voltage poly film caps. All the 30 quad opamps are changed to BurrBrown OPA4134 quad surface mount opamps. The input caps are bypassed with high voltage poly film caps to let the air through. Another advantage of the XR cards is the D/A outputs are direct coupled. Good if you like really deep tight bass."

This is another quote by somebody on gearslutz. i'm not sure if this is all still accurate or not.

"This is what Jim did to Skeetch's unit some time back.

"Re: Jim's Masterlink Mod

Mine was the first one he did (I managed to get him the schematics from Alesis) and it sounds great. Here's what gets done to it:

- install National LM6172 dual opamps at 3000/us slew rate.

- install larger Rubycon Z series electrolytic caps to extend the low end (and did it ever!!)

- install .01 uf wima poly caps on the input, MIT's on the output.

- increased the power supply bypass caps and installed .1 uf mono ceramic bypasses.

- Bandwidth limiting caps were used on certain stages.

- The opamps used as followers were cut and changed to closed loop buffers."

I've got to look at my notes to describe exactly what Jim's doing. As I remember, he's putting in BurrBrown OPA4134 opamps in, new caps and a quieter fan. I'm really stoked about it. I'll post when it comes in."



I'm guessing the opamp replacement and input and output caps are going to have the biggest effect.

I'm wondering if you guys can take a look at the pics and maybe give me some pointers. I'm not obsessed to the point where I want the exact Jim Williams mod. For example, I don't really feel like I need to replace the fan.

I'm not exactly sure where the input coupling caps are though. Or the output caps. So, if you guys can help me out a bit, maybe i can try to do the best I can with this and save myself a bunch of money.

I hope it gets rid of that non ground sensing balanced output nonsense. That is a pain for unbalanced gear.

Well, try to change a SMD chip, just one. Totally possible but must be done with the right tools (SMD Desoldering station) and A LOT of patience....

just my 2 cents

:guinness:
Fabio

[quote author="Bauman"]Well, try to change a SMD chip, just one. Totally possible but must be done with the right tools (SMD Desoldering station) and A LOT of patience....

just my 2 cents

:guinness:
Fabio[/quote]

word. those things have alot of pads.

heres two pages that might give you some tips on the larger SMD chips...
(scroll down)

http://www.ucapps.de/mbhp_opl3.html
http://www.ucapps.de/mbhp_usb.html

SMD is easier than through hole if you have experience. a quick and dirty method is to put a huge amount of solder across the legs of the soics and run them up and down until they are all bubbling and quickly flip the chip off the board. I do it probably 10 times a day on shitty prototype pcbs.

I see that he removed the output coupling caps.. I am sure that he is betting that whatever you plug your unit into has either input coupling caps or some kind of offsetting device/circuit.

he is also using the Z "muse" caps i see, but there isn't much difference between those and the HE caps.

I would like to see the input circuits and how he changed the followers..

Thanks guys,

Svart,

Where are you seeing that he removed the input coupling caps, and also that he's using the Muse series Nichicons?

Are you saying that based on this or another description of the mod? Or are there pics somewhere of a Jim Williams modded HD24XR?

I certainly wouldn't replace the HE's in my unit with Muses. I've compared quite a bit actually, and I prefer the HE's anyway.

By the way, my name happens to be Jon Williams. I just realized the JW initials may strike people as wierd because the thread is about the Jim Williams mod.

Guys,

Okay, if I'm way outa my leauge here, let me know please.

these are the things I feel like i can do, with a little help:

1.install National LM6172 dual opamps at 3000/us slew rate.- (If this is a direct replacement i can do it, just need to know what to replace and where it is. I'm not sure if the 3000/us slew rate is just a rating for the opamp though, or if that's something I'm going to have to adjust with a scope or something like that)

2. install larger Rubycon Z series electrolytic caps to extend the low end-Yes, I'm wondering how much larger to go though, and which lytics he's replacing. If they're the HE's I'll likely pass on this task


-3. install .01 uf wima poly caps on the input, MIT's on the output. -Yup, I can do this, just need to know where these caps are. prolly on the input and output boards, but are they the el cheopo films or the tiny little lytics near the 1/4" connectors?

- 4. increased the power supply bypass caps and installed .1 uf mono ceramic bypasses. -well, i'm not sure about this. I can increase the power supply bypass caps, but I'm not sure about installing ceramic bypasses.

- 5. Bandwidth limiting caps were used on certain stages. -I have no idea here.

- 6. The opamps used as followers were cut and changed to closed loop buffers." I definately have no idea here.

7. putting in BurrBrown OPA4134- I can do this, but I'm not sure where the chips are that I'm replacing.

Anyway, I'm not looking for anybody to explain to me the things I don't have any idea about. But if i can do the easy stuff, I'd be really happy.

[/i]