Refurbishing a Hafler DH-110 (or How Haflerfreak Got His Groove Back)

[HaflerFreak]

I DID IT! I did it! I did it!
I made my little 110 new again!
It's a miracle, it's like....... butter.
I cannot express how amazing this is, it's just that good. This thing sounds absolutely magical.

You may not believe how I did it.

After trying the highest quality caps I could find, I turned my DH-110 into ‘The Amazing Aural Holography Machine’ with no less than XICON and Nichicon caps! That’s right. And I’m not ashamed to say it – truth is truth whether you want to accept it or not.

If you would like to read my previous attempts at recapping this preamp, the original thread is here:
How to destroy your high-end audio equipment...
The above thread details what caps I have tried with this unit. After trying Panasonic FM, FC, Elna Silmic II, Nichicon HE I finally found some caps that actually make this thing sound almost 'better than new'.

Oh MAN I wish you guys could hear this thing, it's like I don't even have 2 speakers anymore, just a super detailed, 3-D, single soundstage. Simply incredible sound.


Solution to the DH-110 rebuild:
Use Nichicon VR for the 50V 1000uF PS caps
Nichicon VZ for the 50V 22uF PS caps
XICON low ESR 25V 470uF caps for the rails
XICON NPRL series non-polar 50V 22uF caps for C22/122
Nichicon BP 35V 4.7uF for the muting circuit caps

Yes, I am aware XICON caps are not date coded, and I do think it is unfortunate, but I check all the caps prior to install.

I would also like to detail a testing procedure that I used to compare the rail caps.
Comparing Caps Haflerfreak Style (this is for 25 volt caps):
I have an 18.5 Volt, 0.5 Amp wall wart that I plug into a Variac.
I slowly turn up the Variac and bring the cap under test to the full 18.5 volts through a 1000 Ohm resistor.
Let cap charge for about 30 minutes.
Measure the voltage drop across the 1K resistor.
Discharge cap through an appropriate resistor.

If I am not mistaken, this is a very basic indicator of ESR. The lower the voltage reading across the resistor, the lower the ESR. The number is irrelevant except for comparison in the same rig.

Here were my numbers:
Original 20 year old IC caps = 0.4 to 0.6 mV
Elna Silmic II ============0.2 to 0.3 mV
Panasonic FC============0.5 mV
XICON Low ESR==========0.3 to 0.4 mV

You would think the Elnas would sound great with those numbers and their hemp fiber paper and all, but they did not. Boomy bass and no clarity. Worst top-end of all the caps.

As I said, the XICON low ESR really took the cake. At this point, I am looking forward to many more years with my ol' 110.

Thank you DIYaudio, Merry Christmas all!