Caiman passive output mod revealed

[MartinT]

Just be very careful with those Polymers mate, they can be leaky electrically

Will do, thanks for the warning.

[MartinT]

Have the Nichicon KZ in now, keeping the lid off the DAC to make for quick changes. These are nice and have at least the bass quality of the Nichicon bipolars before being properly run in. Lovely mid and sweet top. They're staying in for a while.

I have eliminated the Elna Silmic II as have too light a bass balance for coupling use.

I wonder, Leo, if you could draw up a table and populate it with our findings for each cap?

[StanleyB]

Hi Stan,

Just out of curiosity, did this new mod come to you by chance, or from experiments towards a more streamlined DAC only project with minimal components in the path?

Sorry for missing your question James .
It was a combination of luck and planning that caused me to try out the mod. I used to offer it by special order on the TC-7510, but the output was only suitable for AUX input on an amp. The Caiman output is a bit higher. The passive mod is about -3dB down on the normal CD input on an amp.

I was busy testing some non-polarised caps with the intention of finding out if they are good enough to use. The one method I use to judge the sonic qualities of a capacitor is by connecting it between a DAC output and a preamp. Not very scientific, but it works for me. As the findings of others have shown, it's an extremely rewarding method .

[AndrewR]

Note for Black Gate users. Performance of my Black Gates are really fluctuating quite a bit. Last night they were quite bass light - so I recommend sticking with then for a couple of weeks to fully assess before changing for anything else.

Andrew

[MartinT]

The thing about running in is that you must keep music flowing through the DAC otherwise the relay is in the mute position and the caps won't have a charge across them.

I run Sky HD on MTV during the day while I'm at work.

[Buggleskelly]

Hi guys.

been reading the posts with great interest and having been trying out the passive mod on both of my 7510's - Mk6/3 & Mk6/4.

The Mk6/4 also has had the Mod21 pt1 /1 done, both have lower noise 5V regs - National LNM3405T5 stuffwed in too. Both run on a 12V lead acid battery.

I've got the M6/3 running Silmic's and MK6/4 with Nichicon Muse. The Mk6/4 did have Nichicon FGs but I swopped out when I got the Muse.

Findings so far - first impressions:

Silmic: I haven't found them to have a light weight bass yet. I'm listening while I'm writing this and they sound good, top end needs to settle a tad on some more brighter recordings - need more soaking in. I used these for the 7510 MOD21 pt1/2 and did like them there at all - they made it too creamy the crispness on cymbals went and vocals seemed to lose there edge. But in this mod they sound very good.

Nichicon FGs : Top end can seem a bit too hard but they do give the music a bit of snap. As noted female vocals seemed more effected by this slight hardness. Most prolly need soaking in like most of these high end caps.

Nichicon Muse : haven't really listened to the much. Intiall impression was these are good and more towards the Silmic with the FG snap. Needs a lot more listining :-)

I've got some Black Gates on Parts Connexion - thanksto the modder who gave the tip on where to get them , nice one So when I get these I'll give them a spin.

I've just changed over amps to really get the benifits of this mod. I'm now using the class A 20W toob amp and it knocked my socks off how good this simple mod is. Bang for buck or what! so gawd knows what you guys are getting with the Caimen - must sound really top draw.

I don't have problem with the reduced output as my passive pre TVC has got boost switches which lifts the gain by about 6dB so that's helped.

I can tell you it's nice to do these cheap mods as toob rolling gets pretty expensive.

Cheers guys for great postings and pointers.

Cheers / Stevie

[StanleyB]

Now that the dust has settled a little I have had time to rethink the mod wiring.
The latest suggestion for trying out the mod requires only two pieces of wires. That means that you can try the mod out before deciding if you want to invest in two expensive caps.
Remove the line output opamp.
Solder two pieces of wires to the outer pins on the connector on the left side of the PCB (looking at the DAC from the front).
Push the bare ends of the left wire into pin 1 of the empty IC socket.
Push the bare ends of the rightt wire into pin 7 of the empty IC socket.



This way of doing it allows you to also add some improvements to the headphone section. The muting circuit is also fully functional, and there is a bit of HF filtering to remove some of any HF noise.

If you add the 68nF caps mod ( reddish caps in the picture) by replacing the 100nF ones (blue or yellow on the original PCB), the headphone amp performance will be almost indistinguishable from the original layout. With the THS4032, and some non-polarised caps I am trying out, my HD800 and D7000 have not pulled away significantly from my K701 and HD650 in terms of musicality, detail, and clarity. So for headphone users this alternative way of adding the mod is well worth a go.

[Peter Galbavy]

Thanks to Stan for both the mod and those caps I just picked up earlier. I can't doa proper comparison since only earlier this morning did I put a pack of five heavy floor tiles under each speaker (sep. by blutak) and the bass resonances vanished. Now the bass (with this mod) is back so I need to do more appreciating before coming to a conclusion.

[leo]

Have the Nichicon KZ in now, keeping the lid off the DAC to make for quick changes. These are nice and have at least the bass quality of the Nichicon bipolars before being properly run in. Lovely mid and sweet top. They're staying in for a while.

I have eliminated the Elna Silmic II as have too light a bass balance for coupling use.

I wonder, Leo, if you could draw up a table and populate it with our findings for each cap?

What about a new thread or maybe doing it as a poll ? Thats if I can work out how to do one, never done a poll before

[leo]

The thing about running in is that you must keep music flowing through the DAC otherwise the relay is in the mute position and the caps won't have a charge across them.

I run Sky HD on MTV during the day while I'm at work.

Exactly! This is one reason why I'd like to find a good alternative to the BG's, I don't like the fact their performance goes up and down and tend to sound better when they've had constant voltage across them for a while.