[boozcool]

Quote:

Originally Posted by Mr.Mantas /img/forum/go_quote.gif boozcool switched out the two BB PCM56P chips for a pair of AD1856NKs, but he didn't report back about SQ after that All he said is that Havana became dead silent.

Hey guys, sorry bout the MIA

I gotta say, switching out the chips is not as easy as it sounds. The slots on the DAC are very strong/durable, but hold the chips in a bit too well as the pins on the chips have a tendency to bend when removing them.
I bought the AD1856NKs from a supplier on HKin.com for roughly $35 shipped. Perhaps it was the fact that the AD1856NKs were not new when I bought them, or maybe the pins are normally so weak/fragile compared to the PCM56P, but one of the pins on an AD1856NK ended up chipping on me

The chips themselves were only $3 a piece, but shipping was $25 via DHL. FWIW, I would definitely recommended buying a couple of extra ones just incase

In terms of differences in SQ, due to the limited usage, its a difficult to point out specific strong and weak points. Overall though, I found the AD1856NKs to sound a bit more dynamic and lively, whereas the PCM56P chips were a bit more laid back and smooth. I can't honestly say that I preferred one over the other, as they both sounded equally impressive

On a side note, the replacement MHDT sent me for the faulty chip was a PCM56P Korea, and compared to the PCM56PK Japan which originally came with the DAC, I could notice no discernible differences

 

[Mr.Mantas]

Thank you boozcool for useful and practical information

 

[kostas]

about the tubes.
I've changed from stock tube to ericsson 2c51 gold pin and the differences were huge in terms of soundstaging (more layers) detail - tremble accuracy. Now I'm using JW 396a which is even better in everything, more balanced, fuller bass. The impressive is that it has even more detail in mid - high region which was a good surprise. I'm staying with western electric. best choice so far.

 

[Crassus]

Sorry about the slight offtopic, but all I've been able to find are the WE369A tubes (made in USA with yellow print). I quess this isn't the JW/d-getter tube or is it (it says in the mhdt pages that WE 396A/2C51 O-getter is a second class tube so I don't want to mix these up). How do you distinguish between these two?

 

[s1rrah]

Quote:

Originally Posted by Crassus /img/forum/go_quote.gif Sorry about the slight offtopic, but all I've been able to find are the WE369A tubes (made in USA with yellow print). I quess this isn't the JW/d-getter tube or is it (it says in the mhdt pages that WE 396A/2C51 O-getter is a second class tube so I don't want to mix these up). How do you distinguish between these two?

The JW branded variant will have the same yellow text but with a "JW" too ...

 

[pzm9pzm9]

JW tubes are marked as JW. aren't they? mine does have yellow JW mark.

 

[regal]

I like the concept of this DAC but even after 40 pages it seems no one knows anything about it.

1. What is the tube stage? Is it SRPP like most chinese tube DAC's ?
2. What is used for I/V ? I'm guessing a resistor, it blows my mind that people are changing the DAC chip without even considering the I/V impedance. There is probably a huge room for improvement by upgrading the I/V resistors.
3. What is the digital reciever?
4. HV power supply is ?


Also every NOS filterless DAC I have run across has an issue that needs discussed. Its difficult to explain ,so here I will try. If you send a test tone over say 16khz a filterless DAC will have aliasing which will for example deflect a 17khz tone into a 14khz. This is why I quit using NOS DAC's, however they do have a lot of good qualities so I would be interested to see some measurements of this DAC.

I am a huge fan of tube DACs (especially with an R2R chip.) I built a Pass D1 and converted it to a tube output, so I am enthused to see this Havana but we need to know whats inside.

 

[s1rrah]

Quote:

Originally Posted by regal /img/forum/go_quote.gif 1. What is the tube stage? Is it SRPP like most chinese tube DAC's ? 2. What is used for I/V ? I'm guessing a resistor, it blows my mind that people are changing the DAC chip without even considering the I/V impedance. There is probably a huge room for improvement by upgrading the I/V resistors. 3. What is the digital reciever? 4. HV power supply is ? Also every NOS filterless DAC I have run across has an issue that needs discussed. Its difficult to explain ,so here I will try. If you send a test tone over say 16khz a filterless DAC will have aliasing which will for example deflect a 17khz tone into a 14khz. This is why I quit using NOS DAC's, however they do have a lot of good qualities so I would be interested to see some measurements of this DAC. I am a huge fan of tube DACs (especially with an R2R chip.) I built a Pass D1 and converted it to a tube output, so I am enthused to see this Havana but we need to know whats inside.

You should email MHDT Labs ... even though their English is a little difficult at times, they are very receptive to technical inquiry. Their email is mhdtgang@yahoo.com

Personally, I wouldn't know the first thing about your questions ... I'm no DIY sort ...

I just love the way it sounds in my system.

Good luck, though.

.joel

 

[Crassus]

Quote:

Originally Posted by regal /img/forum/go_quote.gif I like the concept of this DAC but even after 40 pages it seems no one knows anything about it. 1. What is the tube stage? Is it SRPP like most chinese tube DAC's ? 2. What is used for I/V ? I'm guessing a resistor, it blows my mind that people are changing the DAC chip without even considering the I/V impedance. There is probably a huge room for improvement by upgrading the I/V resistors.

1) I don't know about the tube stage but 2) I thought they chose the PCM56P because it has both current and voltage output? MHDT have mentioned that one chip from Analog Devices is also compatible so people aren't exactly using random chips.
Quote:

3. What is the digital reciever? 4. HV power supply is ?

3) The receiver is CS8414. Don't know the answer to the fourth question.

 

[donunus]

By the way guys and gals, My cousin is selling his modded Havana with extra tubes including the badass ericsson 2c51 for a decent price and is sending it to me soon to post for sale on headfi. I will do some listening to see how much better the mods made the havana first and report here

 

[OutdoorXplorer]

Quote:

Originally Posted by donunus /img/forum/go_quote.gif By the way guys and gals, My cousin is selling his modded Havana with extra tubes including the badass ericsson 2c51 for a decent price and is sending it to me soon to post for sale on headfi. I will do some listening to see how much better the mods made the havana first and report here

Please post pix with impression ya.

 

[Flea Bag]

Hi Guys,

I've been away for quite a long time and have recently came back looking for a nice 'musical' DAC. Long story short; I've done my research for months now and have decided on the Havana.

However, I lack open shelf space for the thing and it will almost certainly have to be placed in my crowded audio rack where ventilation 'may' be an issue. As such, and to play on the safe-side, I thought it'd be good to have the tube raised as high above the Havana's 'hole' as possible. Could you guys advise me on which socket/extender I should buy from this place or any other recommended place?

As long as I have the right number of pins, any version of the extenders should fit right?

I'm completely new to tubes though I do know I'll eventually buy some 'Cryoed' Western Electric tubes too! Any advise on that would be greatly appreciated too! Thanks in advance!

 

[Towert7]

Quote:

Originally Posted by Flea Bag /img/forum/go_quote.gif Hi Guys, I've been away for quite a long time and have recently came back looking for a nice 'musical' DAC. Long story short; I've done my research for months now and have decided on the Havana. However, I lack open shelf space for the thing and it will almost certainly have to be placed in my crowded audio rack where ventilation 'may' be an issue. As such, and to play on the safe-side, I thought it'd be good to have the tube raised as high above the Havana's 'hole' as possible. Could you guys advise me on which socket/extender I should buy from this place or any other recommended place? As long as I have the right number of pins, any version of the extenders should fit right? I'm completely new to tubes though I do know I'll eventually buy some 'Cryoed' Western Electric tubes too! Any advise on that would be greatly appreciated too! Thanks in advance!

Some tubes run really hot, but the guys at MHDT labs have the tube running below full voltage, so the tube does not get very hot (it gets warm to the touch at most).

In this case, I don't think a tube extender is going to do anything.
Others can chime in.

 

[DarKu]

after 3 hours of runnig the Havana, the tube itself in just barely warm, i think i will not be an issue.
Flea_Bag you will love it !

 

[donunus]

Flea_bag,
If you can wait a little while... maybe a week or two. I will receive the modded havana with some WE, stock tubes, and LM ericssons. I think my cousin will be selling it for $750 shipped even coming with the expensive tubes and mods!!! A badass value if you ask me