MHDT Havana DAC
Jun 2, 2012 at 2:15 PM Post #1,936 of 2,680

Stephen Murphy

100+ Head-Fier
Joined
Feb 3, 2004
Posts
151
Likes
0
Quote:
Hi.
 
I have bypassed the PCM56P chipset, as instructed, but there is almost no sound on the output (it requires to rise the volume at the amplifier at 100% and it is still too low). I am not surprised, because inserting a resistor of such a low value from signal to ground is decreasing it too much. If that resistor is needed, it will probably require more gain at the tube stage.
 
Here are the detailed steps:
 
1.- Remove R25 and R26

 

 
2.- Link pin 13 of the PCM56P chipset with the opposite extreme of R25, R26 (the one connecter to the tube grid).
3.- Connect the resistors (220R in my case) in between this point and Ground.

 
4.- Undo everything. This is not working.
 
I will appreciate any suggestion
smile.gif

 
I hope you will get an answer to this question. There have been many posts here saying how bad the Havana opamp approach is. It would be nice to see how to bypass it in pictures and also get someone's listening impressions of the difference before and after.
 
Jun 2, 2012 at 7:07 PM Post #1,938 of 2,680

Stephen Murphy

100+ Head-Fier
Joined
Feb 3, 2004
Posts
151
Likes
0
Thanks for the clarification Robert. Hopefully Niamex can post his findings so we can determine if that mod is worth pursuing.
 
While I'm at it, thanks as well for all the great information you have posted to this thread. It has been very valuable for me and many other people, I'm sure. 
smile.gif

 
Jun 11, 2012 at 3:16 PM Post #1,939 of 2,680

robeeert1

100+ Head-Fier
Joined
Dec 29, 2008
Posts
396
Likes
14
I'm just sitting and thinking  if there is a sense to post something more about the output caps in the Havana.
 
I mean V-caps CuTF which I have the opportunity to install in Havana and observe what they do in there.
They're priced nearly half of the DAC itself, so it seems to be senseless to use them there.
So these are for extreme modders,
They turn the Havana to another higher sound level, you're going to become a slave of this sound.
They simply create a quality level of their own. Extremely opened and mild, truth, not bloomy, the mids are reference - no dispute, I never heard so good caps like CuTF before (heard many)
 
There are no other caps which can compete with CuTF.
biggrin.gif

 
Jun 12, 2012 at 2:52 PM Post #1,940 of 2,680

loserica

100+ Head-Fier
Joined
Apr 14, 2009
Posts
459
Likes
22
Quote:
I'm just sitting and thinking  if there is a sense to post something more about the output caps in the modified Havana.
I mean V-caps CuTF which I have the opportunity to install in Havana and observe what they do in there.
They're priced nearly half of this DAC, so it seems to be senseless to use them there.
So this is a post for extreme modders,
they will turn your DAC to another higher sound level, you're going to become a slave of this sound.
They simply create a quality level of their own. Extremely opened and mild, truth, not bloomy, never heard so good caps like these before (heard many)
This is my opinion, you may feel different
biggrin.gif

 
Robert, 
I think that, this comment strengthens what you said here:
 
"Their sound, (CuTF) has significantly more robust body compared to Aura-T or VCap TFT, giving you a more of an anchor around the mid-midrange, as opposed to more of upper-midrange/treble anchoring of Aura-T or TFT.  I know there are some people who feel  Teflon caps are "lean" in low-midrange/upper-bass area, which I don't really agree with.  However, with the new caps, one tends to realize how much more music resides in this area.  However, this does not mean this area is exaggerated or bloated like overcompensated  bass-reflex 2-way bookshelf speakers because linearity and transparency are excellent throughout all the ranges.
The other thing that makes an impression is just how DETAILED these capacitors are.  Once again, combined with robust density, detail resolution is unparalleled, especially in the mid-midrange region.  Other capacitors that I love, including Mundorf silver-in-oil and AmpOhm PIO, just cannot compete with the amount of detail in these areas.  The good oils types tend to "massage" out recordings' rough edges slightly for beauty, but bad recordings have nowhere to hide with the new caps.  This also means top-notch recordings with top-notch equipment WILL show you things you've never heard before, so be careful with where you use these new caps.  With power comes responsibility, as they say.
There's no need to mention other usual parameters such as bass, dynamics, imaging, soundstaging, etc because these aspects are in line with what's best out there.  It's just that the special combination of extraordinary  body and resolution just does not exist anywhere else.  Another quality to note  is that unlike certain teflons and "audiophile" caps, there does not seem to be any *extra* sheen or highlighting of the uppermost frequencies to flatter dull recording/systems.  If your system has been tuned to sound just right around these more "flashy" caps, you may need to re-tune your system with the new VCaps in place, but the effort would be worth it".  
 
http://www.head-fi.org/t/284863/orgy-of-capacitors-the-cap-thread/285
 
Jun 19, 2012 at 12:47 AM Post #1,941 of 2,680

gliderboy

New Head-Fier
Joined
Jun 19, 2012
Posts
1
Likes
0
Robeert,
 
After reading this thread and initially being attracted to this DAC over claims of "no opamps" which was debunked here long ago , you now appear to be saying that your heavily modded DAC still uses theses derided internal chip opamps?  If so could I ask if you feel it is not anything that can be remedied?
 
Jun 19, 2012 at 1:59 AM Post #1,942 of 2,680

redcat2

100+ Head-Fier
Joined
Nov 6, 2008
Posts
187
Likes
13
Hi,All here is a review of the Havana from my view point, i have let this burn in now for around 350 hours and have come to the Havana form a basic Paradisea so to my basic thoughts,
The first thing is the unit is so much better build quality all so there is now no earth hum which always seemed to be there on the Paradisea unit first thing i noticed was how silent the sound and space was all most like a black silence very nice, i could here more detail the little sizzle in the end of the sound i could not here before, at 150 hours burn in the unit changed quite a bit and i found it to be a little chesty and vocals coming to far forward at around 200 hours this settled down and then the bass came in more as well. Now that we are at 350 hours i like the sound there is so much more depth and space in the sound and the unit seems to have settled down now.
 
Jun 20, 2012 at 9:05 AM Post #1,943 of 2,680

rosgr63

Headphoneus Supremus
Joined
May 11, 2009
Posts
4,653
Likes
201
Location
Audiophile Purgatory
If one uses a Balanced Stockholm or Havana in a Single End mode are both tube sections on?
 
Jun 24, 2012 at 9:21 AM Post #1,944 of 2,680

niamex

100+ Head-Fier
Joined
Jun 3, 2010
Posts
102
Likes
12
Quote:
Stephen,
Niamex(Ignat) seems to be the only person who bypassed the built-in op-amps, send him PM or wait for him to appear on the thread and answer the question.


I am sorry guys I am so busy with some other stuff and simply had forgotten this project /in the meantime I have already a grandson - DAVID/ so no sense to make any suggestions before I go back there - probably end of the summer. I live now at the seaside where I miss my audio rig but as far as I remember I HAVEN:T disconnected any resistors there - just disconnected the existing connection to the grid and connected instead the grid to pin 13 plus a resistor of 161 ohms to ground. It means I was eventually using some  existing grounding because the volume was lower than original but still OK.
I hope I am of some help.
Best regards,
Ignat
 
Jun 25, 2012 at 9:44 PM Post #1,947 of 2,680

redcat2

100+ Head-Fier
Joined
Nov 6, 2008
Posts
187
Likes
13
Had an issue today with noise coming from the right channel very low when a CD would start up, tracked it down to the Bendix tube pulled out and cleaned up the feet? What do you call those, bits replaced back in Dac all is well.
 
Jun 26, 2012 at 12:39 AM Post #1,948 of 2,680

rosgr63

Headphoneus Supremus
Joined
May 11, 2009
Posts
4,653
Likes
201
Location
Audiophile Purgatory
Redcat they are called pins
 
Jun 26, 2012 at 2:00 AM Post #1,950 of 2,680

rosgr63

Headphoneus Supremus
Joined
May 11, 2009
Posts
4,653
Likes
201
Location
Audiophile Purgatory

Users who are viewing this thread

Top