Coupling caps in DAC output

I just received my Dack 2.0 DAC and it sounds sweet and smooth after a few days of burning in. Yet, I am not too sure on its bass because it doesn't have the punch that my Assemblage ver 2.7 is delivering (after changing all the caps to Panasonic FC and the output opamp to OPA627BP).

I saw the Dack 2.0 has two output caps in parallel. One 3.3uF Auricap with the red lead pointing to the output RCA socket and one 0.1uF Sonicaps with the -ve to the output RCA socket. My questions: -

1. Does it mean that it is adopting the Black Gate E-Cap nonpolar concept - with two caps with oppositing poles in parallel? What are the pros for this arrangement? Or is it a manufacturing fault?

2. I've tried to parallel another Jansen Copper Tube 0.1uF to the output caps and the bass immediately becomes more punchy. What would it be IF I disconnect the Sonicaps 0.1uF and change it to Jansen? I don't want to do it immediately to void my warranty.

3. If I want more punch, should I replace the sonicap or auricap with original value or change the value of caps?


Here's ho Parts Connexion explains the paralleling of different caps (types/values):

5a. All critical caps changed to the best Film and Electrolytic types....(2) Rel-Cap TEFLON TFTExotica
bypasses (2) for the new (2) AuriCap metallized polypropylene coupling caps +
"paralleled" BLACK GATE FK-Series coupling caps (2), replacing the cheapest quality generic
electrolytic caps in the stock unit. This double-bypassed coupling cap hybrid gives us the best of
all worlds - bass and dynamics provided by a "quality" high value electrolytic; the tonal purity of a
world-class film cap; and the speed, delicacy and high frequency sparkle achieved by adding a
Teflon bypass cap!

Personally, I prefer a single, good cap and my current choice goes to V-Caps:
Peter would know better than I, and his suggestion is corroborated by empirical audio's recommended MOD to:

"Chris VenHaus' Teflon V-caps really add ultimate clarity to the high frequencies that is missing when using only the Multicap Polystyrenes or the V-cap oil caps."

Also, Ack's own "Hi Rez Option" entails adding:

"Super-fast, low-dissipation Teflon output coupling capacitors are added to enhance texture and speed in the high frequencies. Requires 250hr break-in period."

I'm not certain whether Ack uses VH Audio's teflon caps, though. Probably not since the hi rez upgrade is $85 and empircal's teflon V-Cap mod is $175.


2003-12-07 11:57 am
My suggestion when it comes to coupling is to compare V-Caps with Black Gate 4.7uF / 50V C type at one tenth of the price. I have tried V-Cap (oil) 4.7uF and was very disappointed with harsh unnatural sound. Paralleling with smaller values should be avoided as well. I played with this a lot and to me, single coupling capacitor always sounded better - definition, more space - better 2 and 3D.

Thank you for all the inputs. The new DAC is not yet burn in therefore I'll give it more time. Changing to V-Cap would be the last option because firstly it is not available in Hong Kong and secondly, it is very $$$$$.

The bass is still disappointing up to this morning but the fact is I can only turn on the DAC for 4 to 5 hours in a day because of the battery. 5 days x 5 hours = 25 hours would still be very green for a new DAC. I'll try to make an AC supply with + - 12V this weekend and hope it will mature earlier.

If eventually the bass is still disappointing and I decided to use only one coupling cap, should I go for a higher uF or lower uF?

Usually higher uF produces bigger bass.

You should be able to charge the batteries while the DAC is powered, if it's not possible, I recommend modyfying it. I have my DACs always on for best performance, otherwise it may take up to an hour to reach optimum performance.

Since BG N caps are expensive, you might try them for coupling (4.7u or 10uF) . Up till recently that was my preferred choice. I connect the longer pin to the RCAs.
I'm not sure if they are better, it's just that I preferred them in that particular application.

I'm using Rikens for I/V resistors and they go well with BG N caps.

When I changed Rikens to Caddocks TF020, I didn't really like the sound that much and V-Caps sounded better than BG N. Also, V-Caps didn't sound good with Rikens.

Depending what your priorities are, you might go for different caps though. I didn't try any Mundorf product yet.