[rajacat]

A few days ago I decided to bypass the Obbligato Golds with some Russian T-3 0.1uf teflon caps that have been previously burned-in on my old DAC. I've found that they've opened up the top end nicely with more air and more realistic handling of such things as top hats and violins. These teflons are huge but thanks to the wide open spaces in the MP-D2, fitting in was no problem.
 

 

[aneep]

Hey Rajacat,
this is cool and to be honest, I have never tried out using bypass caps since the reviews were always mixed. But might turn out to be interting if I can find some cheap caps. Do you have any idea as to what the ideal cap value should be? 
Cheers

 

[KobeeDog]

If anyone is interested, I posted a review of the MP-D2 here:
 
http://audioreview.ca/default.aspx?pagename=review&reviewID=7664

 

[aneep]

  If anyone is interested, I posted a review of the MP-D2 here:
 
http://audioreview.ca/default.aspx?pagename=review&reviewID=7664

Hi KobeeDog,
 
your's is one of the articles which pointed me in the direction of the MP-D2. Nicely written. I do wish Jerry would include a balanced volume pot in the dac. It would completely eliminate the need for a preamp for those like who want to run the dac in balanced mode. But, I think that the current circuit board does not allow for that.

 

[KobeeDog]

Thanks
 
Yes, a balanced pre-amp section would be very nice to have. I did notice quite a sound difference between the RCA and XLR outputs. A remote would also be nice. Then you would have a definite keeper.

 

[rajacat]

  Hey Rajacat,
this is cool and to be honest, I have never tried out using bypass caps since the reviews were always mixed. But might turn out to be interting if I can find some cheap caps. Do you have any idea as to what the ideal cap value should be? 
Cheers

10:1    IOW if you have a 1uf cap then a 0.1uf bypass cap is supposedly optimum. However this seems to be a loose rule. The MP-D2 has 2.2uf output caps but I used 0.1uf bypass caps and they work well. I think that you should use bypass caps that are of similar quality the bypassed caps. The Russian teflons generally regarded as high quality although they have an extended burn in time. I'm not an expert in this area so I'm not speaking authoritatively.

 

[rajacat]

  Thanks
 
Yes, a balanced pre-amp section would be very nice to have. I did notice quite a sound difference between the RCA and XLR outputs. A remote would also be nice. Then you would have a definite keeper.

Did you use the RCAs with the on board volume pot? If you did that might account for the noise or loss of transparency. 

 

[KobeeDog]

I used the RCA's with both the pre-amp section engaged and disengaged. Either way, there was still a noticeable difference in sound quality with XLR.

 

[marantzfan]

I ordered an MP-D2 a couple weeks ago but the Chinese New Year held up shipping till just yesterday.  I got an email stating my DAC is on it's way and I'm pretty excited. 
 
My current DAC is an ifi micro iDSD/iUSB but being a tube guy, the idea of a DSD dac with a tube output stage AND the ability to even roll capacitors was just too much to pass up.  That and a buddy of mine recently got one and has been raving about it.
 
I'm considering the 6h30pi based on previous comments in this thread and possibly Jantzen Z-Superior capacitors as those are what I've used and been happy with throughout the rest of my system.

 

[rajacat]

  I used the RCA's with both the pre-amp section engaged and disengaged. Either way, there was still a noticeable difference in sound quality with XLR.

How would you rate the difference? More transparent, better separation, quieter....? The problem with XLR is that tube and cap rolling become twice as expensive. Four Jupiter Copper 2.2uf caps cost more than $400. That can add up fast. Also if an XLR vol. control was added it would have to be of very high quality to beat a quality XLR separate pre. and it wouldn't have the connection options of a good pre. The included RCA pot doesn't look to be particularly good; more of an afterthought. 

 

[rajacat]

Well... a pair of Mundorf S/O just arrived in the mail. I'll pull the Obligato/Russian teflons out and give them a try. I bought them used and they have about 6 months on them but haven't been used recently. I don't think that anybody else here has tried these in the D2.
Also a pair of 6N1P-EV Matched Pair Gold Grid Mil. Voskhod tube E88CC  arrived from Russia. I'm going to change the caps first and let them run in for a few days and then pull the Amperex 6DJ8s and give the Voskhod' a try.

 

[KobeeDog]

  How would you rate the difference? More transparent, better separation, quieter....? The problem with XLR is that tube and cap rolling become twice as expensive. Four Jupiter Copper 2.2uf caps cost more than $400. That can add up fast. Also if an XLR vol. control was added it would have to be of very high quality to beat a quality XLR separate pre. and it wouldn't have the connection options of a good pre. The included RCA pot doesn't look to be particularly good; more of an afterthought. 

 
Both connections are quiet, in fact, even putting my ear up to the speaker, I could hear no hum or hiss. The XLR just sounded clearer and more precise.
 
I agree - the volume pot does seem like sort of an afterthought.

 

[rajacat]

Whew, not so easy muscling these caps in without cutting the leads short thereby destroying resale possibilities. 
Maybe once you find your ideal cap, it would be better to solder them in place. You could solder them to the binding posts but soldering to the board would be best although it would require removing the posts. That would necessitate taking the board off.

 

[aneep]

Hey Rajacat, 
While I agree that running a balanced setup doubles the cost, in my experience there is definitely a positive gain from running the MP-D2 in the balanced mode. And it is exactly what you have asked a couple of posts back. in direct comparison to the single ended mode, balanced mode is more quiet, and there is a marked improvement in tonal density, separation, soundstage and while transperancy remains the same, clarity is definitely more. Bass especially improves the most. I run my He500's through the Audio-gd master 9 and there is a marked improvement in gain and drive.  Just MHO.

 

[rajacat]

  Hey Rajacat, 
While I agree that running a balanced setup doubles the cost, in my experience there is definitely a positive gain from running the MP-D2 in the balanced mode. And it is exactly what you have asked a couple of posts back. in direct comparison to the single ended mode, balanced mode is more quiet, and there is a marked improvement in tonal density, separation, soundstage and while transperancy remains the same, clarity is definitely more. Bass especially improves the most. I run my He500's through the Audio-gd master 9 and there is a marked improvement in gain and drive.  Just MHO.

aneep,
 
You're exacerbating my audionervosa.

 My problem is that both my very transparent diy Tortuga LDR passive pre http://www.tortugaaudio.com/and my tweeter amp are single ended. I run a bi-amped rig with modified Heathkit W5m tube monoblocks powering waveguide CD tweeters. The midwoofers are 15" AE TD15m's that have an amp that can be run balanced or single ended. Multiple subs take care of the deep bass.
 
I could modify the Tortuga to run balanced but it take some work and money. However my Heathkits, which sound fabulous, are single ended. Would I gain anything if I converted to balanced when my most important amp is single ended? I'd have balanced on the pre input but rca's on the output. I'm not sure that it would be worth the hassle to make a substantial change in my setup to accommodate balanced. A lot of this could be system dependent or so I like to think. Maybe building or buying better dac to pre cables could recoup some of the SQ lost by going RCA. I note that some very high end pres only offer single ended. http://www.6moons.com/audioreviews/leben5/preamp_2.html
Also, although this is Head-Fi, I'm just running speakers at this time although that could change.
 
...Roy