Caiman passive output mod revealed

[leo]

Well for me so far the 47uf FK's are the ones Their fast, detailed and have the lowest distortion out of the ones I've tried , in comparison the polypropylenes and polyester sounded quite strained , excuse the description but they sounded plasticy in comparison to the FK's The BG NX Hi-Q's was too soft. I tried a couple of polarised Nichicon FG's but these was sharp almost glassy in the high's . I've not tried the non polar Nichicons or Rubycons here yet

A note of warning, be very cautious with polymer based caps, these do tend to be electrically leaky so can give some unpleasant results used as coupling

BTW, the caps (TC1,TC4) going to pins 11 and 18 of the dac chip internal bias have quite an influence on the sound especially with the passive out mod, folks with the stock tants finding the sound a little bright can try changing those to something like Silmics , BG's, Nichicons etc if they wish.
I've now fitted a pair of used 10uf BG N's here and will have a good listen when its had chance to settle down, oh I had one spare used 100uf 25v BG FK so decided to stick that on part of the dacs decoupling (replacing the stock electrolytic TC1 ) I can go back to the stock caps easy enough if they don't suit

[James G]

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?

[AndrewR]

Well for me so far the 47uf FK's are the ones Their fast, detailed and have the lowest distortion out of the ones I've tried , in comparison the polypropylenes and polyester sounded quite strained , excuse the description but they sounded plasticy in comparison to the FK's The BG NX Hi-Q's was too soft. I tried a couple of polarised Nichicon FG's but these was sharp almost glassy in the high's . I've not tried the non polar Nichicons or Rubycons here yet

Hi leo,

Glad to see you are having at least as much success out of the FKs as I am - I just love their bass, gorgeous texture and amazing levels of ambient info. Quality is fluctuating and generally improving as they are breaking in - will probably take two weeks. I'd be keen to read your thoughts on the Rubycon Bipolars - which might lead to another order from Tirna. Silmics or Cerafines on the outputs might be worth a try as well.

Andrew

[chrism]

Okay guys, before you get your soldering irons out, leo's post (number 106) inspired me to remove the op-amp board and directly insert the 47uF caps into the PIN3A socket in the board underneath.



From back to front of PIN3A (actually called "PIN3B" on the lower board) the connections are:

o Cap A +ve
o Cap A -ve
o no connection
o Cap B -ve
o Cap B +ve

I happened to find I had some spare 16V Blackgate 47uF (FK Series) - while I've previously had a rough time breaking in BGs in valve amps in the past, these are starting to improve quite rapidly (15 mins now).

The great thing about doing it this way is that I can swap in/out caps to find my favourite - probably a better final result than sticking with the first or second iteration that's been soldered in. Also better for the resale value when upgrading to any lovely future recipe exiting Stan's front door

Just using headphones, but the sound is already more "direct" and far better bass. Also starting to get some more texture to the sound. The volume setting on my amp had to be adjusted from 73/100 to 90/100.

Might consider making a standalone headphone board. Anyone know the name of the PIN3A and PIN4A connectors?

Andrew

Sorry to be thick - does this mod improve the variable out and retain use of the volume control (i.e. Caiman used as a preamp). I only ask because I have no way of testing first (only have a multimeter) and really like my speakers and am scared to try it!

Regards

Chris

[Covenant]

It doen't look like Hifi Collective have the Black Gate 47uf FK's in stock. Anywhere else they are available?

[StanleyB]

Sorry to be thick - does this mod improve the variable out and retain use of the volume control (i.e. Caiman used as a preamp).

Yes it does, but bear in mind that the volume level is at least 3dB less without the line opamp.

[Peter Galbavy]

OK guys, help an ignorant tool out. I am at work, there are a couple of Maplin's branches within walking distance and I would love to try the non-destructuve version of this mod over the weekend.

Given Maplin's typical stock, what should I go for - happy to get a few different pairs. Can anyone take the time to look at what they do and point me at the right spec in their catalogue ? From the thread I don't want anything too high in voltage specs and never lower (than 15V).

Would grwatly appreciate it. A quick search gets me 8 types: http://www.maplin.co.uk/Search.aspx?criteria=47uF

[StanleyB]

Hi Peter, I can't see anything useful on their site. I have a couple of non-polarized 47uF/16V to try. You can pass by after work and have a pair if you wish. I have one Rubycon you can have as well. Dunno if I can find another one though.

[NRG]

OK guys, help an ignorant tool out. I am at work, there are a couple of Maplin's branches within walking distance and I would love to try the non-destructuve version of this mod over the weekend.

Given Maplin's typical stock, what should I go for - happy to get a few different pairs. Can anyone take the time to look at what they do and point me at the right spec in their catalogue ? From the thread I don't want anything too high in voltage specs and never lower (than 15V).

Would grwatly appreciate it. A quick search gets me 8 types: http://www.maplin.co.uk/Search.aspx?criteria=47uF

Trouble is those Maplins caps are all pretty crap TBH, the SE looks like it may be the best of them, the AT96E or AU01B. There's only 2.5v across the cap in cct so a 6.3v would work OK.....

[NRG]

It doen't look like Hifi Collective have the Black Gate 47uf FK's in stock. Anywhere else they are available?

Try the standard ones if Nick has them, there's not a huge difference between them TBH

I'm going to continue to use the standards for now and try the replacing the two caps Leo mentioned above, if that doesn't improve the vocal presentation then I'll knock up a linear supply and try that...