Caiman Mods

[TheGreenManalishi]

Ok, usual swift change of plan as i had the good fortune of a few quid coming my way.

Current Set Up-
Flac>Duet>Caiman>Novo plus PSU1 and HD650's

Now ive ordered a Solo Graham Slee (apparently Senn themselves use this amp on dems?), and due to my Great Dane puppy ive had to order some Russ Andrews cable for my HD650's (grrr).

So i need to make sure source is A1 etc, happy with my Caiman but on the advice of someone im sending it in to be modified (budget £150), but as i know absolutely bugger all about Opamps etc etc then i wondered if you guys could give me an idea what i should be asking for mods wise?

[leo]

I use a Caiman based modded 7520 with a Solo SRGII as I have other sources too, sounds great tbh I'd give the new stuff a good running in before even thinking of doing any mods, let things settle down and take it from there

Regarding op-amps, their down to personal taste with this dac, I'm currently using THS4032 but the chosen type used in the Caiman is also very good

[StanleyB]

happy with my Caiman but on the advice of someone im sending it in to be modified

So who is this guy that is fleecing you then? I'll take that £150 and offer you a couple of improvements.

[TheGreenManalishi]

Thanks guys - its precisely that im impressed with the Caiman that im sure that it can be a long term source (*but lets face it im sure another 150 quids worth of components would improve it?)

My thought process was that a 500quid headphone amp might be a little too revealing for the DAC?

S

[StanleyB]

As I mentioned, pass me the 150 quid. I designed the DAC, so there is no better person to get an additional 150 quid worth of sound out of it...

[shuggz]

Thanks guys - its precisely that im impressed with the Caiman that im sure that it can be a long term source (*but lets face it im sure another 150 quids worth of components would improve it?)

My thought process was that a 500quid headphone amp might be a little too revealing for the DAC?

S

Improve it in what way? do you have a reference point or are you just taking this persons word as gospel.
You might find that you could reap more rewards from simply changing the toslink/coax cable.

[StanleyB]

The bad thing about driving high-end headphones like my Sennheiser HD800 is that a high-end headphone amp is required to get the best reproduction.
The good thing is that the Caiman headphone amp is capable enough to compete against stand alone high-end headphone amp.

But driving the larger and more revealing HD800 drivers requires a bit of extra attention in the circuitry if the intention is to extract every bit of sound in the digital stream.

[StanleyB]

To drive the larger HD800 drivers with the least possible distortion requires a larger damping ability from the headphone driver opamp. I selected the THS4032CD for that job, but hope to try out the TPA6120 as well.
I have always believed that capacitors in the signal path should be non-polarized. That's what they use in speakers after all. But finding low voltage small footprint non-polarized caps can be a tricky thing. I did manage to source some 47uF/16V types to replace the 4uF/16V polarized ones in the Caiman headamp. I also used the same caps in the opamp bias circuit. I'll keep an eye on that to see if it makes a difference or not.

The red caps are 68nF, instead of the original 47nF on PCB. This change gives a bit more width to the bass spectrum.
The 100pF caps in the HF feedback path of the headphone opamp has been removed. This was only decided upon after I fitted the new regulators (see next pic). Without the special regulators, the sound was a bit grainy with the caps removed.

The HD800 has a 300 ohms impedance. So I adjusted the gain of the amp upwards. The 68K resistors in the headmp feedback loop have been replaced with some 94K ones I had in my component box. I reckon 100K would be just fine as well.

[TheGreenManalishi]

If youre serious then that would be great Stanley.

[Carson]

Is there much more the Caiman can give for £150 of mods?

Not that I am considering it, just curious