Mod your Caiman

[StanleyB]

Since nobody has yet started off a thread in The Drawing Board for modding the Caiman, I guess the honour is left to me..

Going back to when people started experimenting with opamps, the LM4562NA came up as the most favoured one. However, many continued in their search for more bass. The overall feeling was that the LM4562NA pulled up a bit too early in the bass delivery department. But it has not been an easy search for a practical and cheap solution. Initially I settled on the LM4562HA. But I could hear, through A/B testing, that the HA offered a bit less detail. So I went about looking for my own cost effective solution, which is as indicated in the following pic.



The mod has only been designed and tested on the LM4562NA!!! I don't know how it will sound with other opamps. What I can say is that you could use a larger resistor for less bass ( up to 68K in fact). I am using 27K for the LM4562NA. The cap is 100nF.

Please make sure that you:
1. Trim the ends of the components,
2. Bend the parts back so that they don't touch the case when you close it!!!!!
3. Only attempt this mod if you are technically capable of removing the top PCB without breaking it.
4. Got access to the right parts and tools.

The bass will be on the same level as the HA, or maybe even the THS4032. However, it is far more solid and controlled.

Stan

[lovejoy]

...and there was me planning a quiet Sunday morning.

Thanks Stan, fantastic work as per. Off to check what I've got in the bits box.

Of course you know that more bass = rematch with the CDS2 coming up ;-).

[lovejoy]

Bingo! A couple of X7R 100nf caps left over from my TeddyReg build. Time to get the iron out...

[StanleyB]

Don't jump straight for the 27K resistor. Try 27K to 68K first. i.e: INCREASE the resistor for less bass.

I got 12" bass units, and the floor vibrations are,..well... dynamite. I can feel notes that I can't even hear.

[lovejoy]

Cor, you weren't kidding!

Only 8" bass units in my Arcs, albeit with 10" passive radiators at the back, but the 27K resistors made the bass way too prominent. 18K is much more like it, but I may ease off a little further. But not before I've played all my Dub albums ;-).

That is some serious bass

[StanleyB]

The resistor value does appear to be a difficult one to decide upon. Try MORE than 27K for LESS bass... I think.

I am going to fit a 50K preset instead so that I can play about with the settings.

[lovejoy]

Yes, it's a strange one. I switched to 12K and that seems to have more bass than the 18K, which in turn had less than the 27K, although the 12K doesn't seem to swamp the sound like the 27K did.

I am rather liking what the 12K does at the moment though, so I shall stick with that for a bit and see how it goes.

[StanleyB]

This looks more and more like a preset job just to find the optimum value. I'll give that a go after F1.

[leo]

Come on guys, give this a go

I tried 16k and then 68k, certainly seems more bass with 16k , 68k seems brighter and more forward

What I did was use a cut up 8pin DIL socket (middle pin cut) soldered where the original ceramics was and then soldered a few different R+ 100nf as seen bellow allowing quick comparisons

Will need to compare a few more

[Adrian B]

Hi all

I've just received my Caiman and won't be modding it till I have a sense of the basic sound. And this will take time as I have no digital interconnect yet! But, a descriptioon of the circuit changes would be helpful to avoid mistakes made by simply copying the photo.

Stan, the DAC arrived safely on Fri - thanks

Ta

Adrian