[loserica]

Quote:

I spent much money for the DAC itself and upgrade, I can confess it sounds great now (after deep surgery), but
it would sound much better without the OPAMPS.
 
If I had known tha Havana used internal OPAMPS, I would have never even considered it to buy.. !!!!

Robert,
I bought Havana second (but very care), I think for 750 dollars and I made upgrades about 750 dollars... With every upgrade I felt an improvement in sound and obviously I enjoyed very much!

Although a respectable friend gave me different suggestions (told me that in this price category -  about 1.500 $ can I find other offers, with a high quality, also! but probably, referring to "OS" category dac's... Because I started to hate resale hi-fi components, I had enough in the past five years,... I decided to keep Havana and inspired in this thread, I made some changes step by step. After all, I think it was more comfortable to buy another dac; I was not forced to change anything, because of cheap components and mediocre quality.
Now I would change further some things, such as resistors (S. Tantalum), Non-polar Blackgate capacitors (47uF), R-Core transformer, another tube, etc.,  but unfortunately, I have other financial priorities, and I think pretty much as we changed...
 
I think our sin is that we allowed to make Havana other than exist the manufacturing!; and we must bear sole responsibility for our decisions, although is not very easy...I wasn't forced to do this and I did it over with great pleasure!
 
Now I can only think and pray : Christmas, beyond all these passions, I was a good boy, ... please give us the most beautiful gifts that you own (if you're generous and good heart will understand what I mean).
Yours faithfully,


 
 
 

 

 

[mafaldich]

So basically you demand mhdt to turn in the schematics because you were tricked into buying havana . I think I understand the logic now. Well...good luck.
Quote:

 
MHDT advertised their Havana was not using OPAMPS that's why I had purchased it.
I was deceived and now I'm demanding the schematic to remove low quality internal OPMAPs out of the circuit.
I spent much money for the DAC itself and upgrade, I can confess it sounds great now (after deep surgery), but
it would sound much better without the OPAMPS.
 
 
So Dear MHDT, do not cheat us any more about your non-opamp brilliant constructions and disclose the schematic so we could
clean up this constructional mess.
 
 
If I had known tha Havana used internal OPAMPS, I would have never even considered it to buy.. !!!!
 
 

 

 

[robeeert1]

Quote:

So basically you demand mhdt to turn in the schematics because you were tricked into buying havana . I think I understand the logic now. Well...good luck.


 
 

 
Let the MHDT choke with the schematic, we have already managed to get rid of the shiiitty opmaps without it.
I work on another project based on TDA1541A crown chip. There will be new ultimate quality DAC,
with analogue section based on tubes, not tricks.
 
 

 

[nsk1]

$750 in upgrades to Havana? 

You're f... killing me.

 

[rx79ez08]

You know what is funny.  I look at the datasheet of TDA1541A and there are two internal op amps at the output stages, one at each channel......
I still don't get what the big deal is, the DAC chip got an output opamp buffer, big deal, the overall product sound good, that is all that matter isn't it?

 

[robeeert1]

Quote:

You know what is funny.  I look at the datasheet of TDA1541A and there are two internal op amps at the output stages, one at each channel......
I still don't get what the big deal is, the DAC chip got an output opamp buffer, big deal, the overall product sound good, that is all that matter isn't it?

 
 

 
It's very simple to omit internal op-amps. ))
(some chips have only current outputs - no internal op-amps, and some of them have both current and voltage outputs - then you may choose to use internal or external op-map)
 
And you are using op-amps and tubes in one circuit. Tubes for a good look and taste only.
 
 
 

 

[robeeert1]

It is not a big deal, overall product sounds good,
 
Merry Christmas and a Happy New Year to you and all users of the Havana.
 
Cheers,

 

[robeeert1]

 
Quote:

 
If the opamp is supplying of amplification would the gain be the same with or without the tube in place?
 
For example with the Paradisea I think you can run it without the tube with no problems with gain, same with the EE minimax Dac. In those cases it appears that the opamp is supplying the gain.
 
However in the Havana if you don't have a tube in place the gain is almost nothing.

 
 
Tubes should be used for amplification of a weak current.
 
In both cases (Paradisea and Havana) the op-amps are supplying the amplification and the gain is the same with or without the tube.
Tubes are used for changing the characteristic of the sound in both cases, they simply spoil it.
 
<<<However in the Havana if you don't have a tube in place the gain is almost nothing.
 
No, you're wrong, the gain is the same with or without the tube in place. The op-amp does the work.

 

[loserica]

Quote:

$750 in upgrades to Havana? 

You're f... killing me.

Definitely worth it, because differences in sound between the stock Havana  and Havana modded are substantial! Otherwise I could not bear to hear him so "anemic". Agreed, at vocal timbre level, texture, refinement, Havana doesn't sound bad either before, but at the level of focus, speed, dynamic, detail,  etc., differences are very important.
If adding all these a good digital signal, and Legato do this very well, sound huge increase in terms of transparency, stage presence, separation between instruments, decay and audio layering. Other financial fun...

 
Overall satisfaction is guaranteed!

 

[robeeert1]

Quote:

Robeeert
 
My Havana most definitely has no gain when I take the tube out.  The first time I did it by mistake and wondered why hardly no sound. I did it on purpose a second time just for kicks and right before I typed this I did it a third time.  My Havana is feeding my amp directly with a passive volume control between the two. There is no mistake, when I take the tube out their is NO gain.
This is not a case of perception.
 

There is no gain because you brake the circuit, itt is normal.
 
 

 

[loserica]

Quote:

Does that $750 include the cost of labor or only parts?
 
I am guessing that it is parts + labor, because I am only at $220 or so and another $120 should be enough to finish the job with replacing all the caps in the unit. 
 
The biggest expense was the V-Caps, which could have been avoided had I done some smart shopping.  I recently heard a Havana with Sonicaps Gen I and it was fantastic, seemed like even more extension and separation during heavy passages. The details of instruments really stood out during complex passages.

Only parts, fathead: 2 x V-Cap OIMP, Auricap (Audience) Film capacitors, ELNA electrolytic capacitors , HI-Fi Tuning Fuse, WE 396A(JW) tube, tube damper (from EAT), 2 x chips PCM-56P "K" grade, 2 conectors (WBT pure silver), bnc conector, diodes,...

Labor: advantage of a very good friend electronics.

 

[loserica]

Quote:

Lionel,
Jumpers are to set the voltage (230V or 115V) on the stock transformer. In the case of R-Core in our circuit they are not needed, (omitted), you can leave them where they are or remove completely. (I suggest to remove).
 
Great sound improvement is obvious.
 
Set the LIVE line correctly for better sound quality !
Check the lines on IEC plug not on connector inside the Havana.
 

 
Robert,
Please elaborate a little, how the sound improves by changing the transformer? What changes actually received? Thank's!
 
 

 

[robeeert1]

Loserica,
 
I heard definitely even better timbre and more natural sound. Absolutely no overshoot or ringing when trumpets hit or when soprano kicks into high gear.
I replaced one cap yet then and received reference bass (replaced Nichicon with BG F series 100uf25V - the one marked on photo). I remember I adored the change.
I know there are some people on this forum who replaced the transformer as well. Let's wait until someone else share his impressions.
 
Cheers,
 

 

 

[robeeert1]

According to Jiun cap improving the bass response was the one next to C5, I left it with original value 47uF and changed it for BG FK (super welcome change).
And marked on photo was originally 100uF and stayed 100uF but changed only for BG F series. (you can really feel reference bass response after that change)

 

[robeeert1]

Quote:

The cap just above the one you pointed out IS the only cap next to C5 and has a original value of 47uf....correct?
 

 
The one above I pointed out (the only one next to c5) is originally 47uF, pointed out one is originally 100uF.