white instruments eq 4100a mod?

[RSFiesta]

Hi there!
This is my first GS post! Just registered. I'm pretty nervous...
I usually find almost any information on audio gear via google "gear-XY gearslutz", for example "1178 jim williams mod gearslutz".. but this time it's different. So here we go:

I bought a white instruments 4100a EQ on ebay, for 360$ including shipping to europe. I love the sound of it and it's really what I ecpected for special colour, even for some mastering jobs (f.e. making old demotapes shine).
But the altogether sound, especially when you hit bypass, is a bit muddy and lacks dynamics. This could be partly because in and out are not balanced, maybe because of impedance issues (?), and/or due to old and scratchy pots.
Subjective signal quality improves a lot when it's run through the coils and you put in a slight amount of bass and treble, whatever you want to enhance. It's pretty much a "turn in" device, I think...
But the sound of the coil bands is so sweet that I would like to see it as a possible mastering eq for that special colour.
I'm convinced this unit could be easily pimped in sound quality by changing f.e opamps, caps...

The circuit is based on A1 4741 5 opamps, I think. The eqing is done by 20 coils, so it has 10 bands, like a octave band grafic eq (30, 60, 120, 250, 500, 1k, 2k, 4k, 8k, 16k).

Can anyone recommend me a replacement? which caps? Which pots can I use?

I'm pretty good at soldering, but I'm not good in electronics to make sure not to blow it up when I change anything. (except caps maybe)
so maybe someone has some simple advice for me.

Thanks for any advice!
Richard

[sonic dogg]

Sounds like it needs re-capping. On bypass it should sound like nothings there at all. I used to have a pair of 31 bands. Good for corrective surgery to bad micing technique......which I needed in abundance at the time!

[RSFiesta]

Of course - that's the first thing to do.
Next thing will be cleaning and maybe replacing the pots: They're pretty worn off...
Anyone used the 4100a for stereo bus?
The sound of the filters is really awsome and very musical.
(I thought as well about trying the Black Lion am/cha1...)
I don't have budget right now for a 5-8k mastering eq... Spent all money on new studio rooms, vintage mikes, trident console and quested monitors
Any other experience? Anyone knows the 4100a xformer option? These transformers are not easy to find on the net; Could be a nice sound, plus makes the unit balanced...

[original_min]

Hi, congratulations on the new eq.

In my opinion 'the first thing to do' is get hold of the information you need.
You have schematics? Info from others who have been in a situation perhaps similar to your own? You have googled '4741 op amp'? Studied the datasheets? Etc'.

While you are arming yourself with a working knowledge of the machine, get hold of some 'Caig Deoxit', spray that into the pots and work out the dirt and dust.
It often takes some time to get the pots clean and scratch free.
Cleaning, leaving overnight then following up with another clean wouldn't be unreasonable. Instructions are on the can.

I personally think it's important to have a real plan in mind before launching into anything serious like recapping, replacing pots & upgrading op amps. For me I'd want to know about it's 'stock' personality before anything else, though electrolytics can stand in the way of that sometimes.

The White Instruments website seems decent, and call me old fashioned but a chat with someone technical at White about what you are trying to achieve could be very worthwhile. Techs usually love chatting about gear, that's not the problem.


You only have 1 eq, so take your time.

[RSFiesta]

Thanks!
But it's not at all my first EQ. I've got four in my outboard, plus mixers (studer 089 and two soundcrafts) with nice sounding eqs in the studer. I'm getting a refurbished trident 80B/tsm hybrid for my new studio by april, with plenty of good sounding eq channels. But I fell in love with the sound of the white, it's got "aura".

It's the first outboard gear I would love to pimp. -except for having removed softsat from my drawmer 1968, some tricks with old keyboards and hifi-stuff (Oh and my Commodore Amiga was heavily modded back then ... )

I prefer the white over my SPL qure and also the Orban 622 (which is cool btw) - not even talking about all the boring plugins I've got... It's got attitude, but not enough headroom.

I'll first replace the caps (which is less serious than changing opamps).
And: I will talk to the people at white instruments, they may have advice for me.

cheers!
Richard

[original_min]

Oh I am sorry Richard!

For some reason it sounded like you were modding your one and only White eq,
and that it was your first diy.
Now it seems you have every available spare stuffed in your cupboard!!

Naughty!

Peace

[RSFiesta]

Np.
Got some really good audio equipment and did almost anything from audiophile classical and jazz recordings over ultralowbudget heavymetal demos to drum&bass remixes - but I'm not into DIY modding yet

My next thread shall be more entertaining, I promise
Richard

[NEWTON IN ORBIT]

Hi, I think a TL074 would be a direct drop in replacement, thought about doing this to mine. The 4741's aren't that bad, but are a little veiled sounding.

I have no idea if the tl074 is going to be any better though, as it's not a real hifi chip either.

The 4741 Harris are in a lot of old Neumann eq's, Soundworkshop 1280's etc. I think people deal with it by just boosting top end.

I think these would probably sound even better with some new LME chips in them.

I don't know where the dark top is coming from, or what the bottle neck is. It could be the transformers? Big, honking transformers...

Did you say you have already modded your old units? What did you do?

Right now, I just use mine the way you wold a 560 or something, on bass guitar once in a while.

If they could be opened up on the top, it would be cool to use them lots of places. The low bands on bass though, even as is, are really nice and musical. It sounds like any good eq, where it sounds as if you are working with the "note" rather than just messing with frequencies.

If that makes any sense at all. I know they are both the same thing.

Thanks,
john

[RSFiesta]

The 4741's aren't that bad, but are a little veiled sounding.

"veiled" quite hits the point. And it's not only a frequency thing - it sounds a bit like 80's HiFi...
It doesn't have transformers. It's the version with standard plug-ins. You can put plug-ins that make a crossover network for bi-amping, or transformers. No idea how they sound like, but provide balanced in/out. Could be worth trying!
Of course it won't probably get cleaner that way.

Maybe it's all done with recapping, but the bypass switches are an issue too- when I tried the unit first, the left channel was too low until I switched a couple of times. A bit of alcohol helped.
Now it seems like the right channel is louder than the left, especially when gain is turned up.

I actually like the high bands, they are sounding velvet and "cloudy", in a good sense.

It sounds like any good eq, where it sounds as if you are working with the "note" rather than just messing with frequencies.

That's the nice thing about it. It doesn't bring up noise so much, it brings up the music in it.

Did you say you have already modded your old units? What did you do?

I changed transformers in the qure (still not good), I experimented with 2 different valves in my TLA C1 (big difference between clean/boring to crunchy/lofi).
I cut the zener diode bridge in the 1968 to disable soft clipping, which is an easy trick that someone from drawmer has posted somewhere here on GS.
I "modded" my first A/D converter (8bit22kHz on Amiga 500 ^^) several times using different opamps, just out of interest - until I ultimately blew it up.
I was 13 at that time and one of tnose kids that have to open up anything, loose the screws and then keep it that way

So that's about my experience. So I thought: Let's blow up some really valuable gear! Next project is modding my electroharmonics NY2A, replacing all the pristine parts by really cheap ones and see how it sounds :}