[leeperry]

Quote:

Originally Posted by david-gao /img/forum/go_quote.gif "The sound from the headphone out, on the other hand, was decent, but un-inspiring . The sound was a little soft at both frequency extremes. It lacked deep bass weight, and the bass was a little light overall, although punch in the mid-bass was good. The fact that even the Denon D7000 seemed to lack a little bass weight versus what they produce normally was a little disappointing." I think the sound of Headphone out is because of OPA2134, DMK use the OPA2134 in front of headphone amplifier circiut which is Lehmann design! Like Rob said the DAC out is wonderful, so the AD797 is good, also Lehmann design is no problem of course, so I also think the "lacked deep bass weight" is because of OPA2134, Maybe we will do some test and replace a better OPA soon! Thanks -- david gao

ahhhhhhhh, yes! it needs two LT1028ACN8 badly, OPA2134 is junk.

and please put four AD797BR instead of AR, they are well worth the very small price difference

it would also be nice to add a BNC S/PDIF input instead of RCA, and a 24/96 USB chip instead of 16/48...then I would die to buy it off your hands

 

[HillyBilly]

.

 

[leeperry]

hehe ok, this amp looks pretty half-*rsed at this point...NEXT!

 

[david-gao]

SO now waiting for the comment from Miguel, Rob has shipped the DMK-IV to Miguel, hope will see the comment soon!

I also found it is because of the OPA2134, should use high end OPA

 

[mrarroyo]

Rob, the unit arrived today and I will set it up during next weekend. BTW, the volume pot fell off as I took it out of the box. It is back on!

Thanks and more to come.

 

[david-gao]

Quote:

Originally Posted by mrarroyo /img/forum/go_quote.gif Rob, the unit arrived today and I will set it up during next weekend. BTW, the volume pot fell off as I took it out of the box. It is back on! Thanks and more to come.

OK, Miguel, Hope you will offer a detail review about DMK-IV and offer some good advise!

Thanks in advance!

David gao

 

[mrarroyo]

I have not forgotten to post, but instead I have been burning in the unit. So far it has an additional 122 hours. Cheers.

 

[bastogne]

how does it sound ?

 

[david-gao]

Waiting for the Review and advice!!

 

[mrarroyo]

Well today I opened up the unit and fixed the loose RCA, while open I tightened all just to make sure. Since it was open I chose to add a bit of Dynamat as I have done to some of the gear I own. BTW, the unit runs on the warm side as compared with other SS gear I own. It does not get hot and I can leave my had on the top surface indefinitely.

I have listened to the HLLY being fed by both a Philips DVD player using a Blue Jean Cable coaxial cable as well as an iPhone using an ALO Bamboo Dock. I have used a Senn HD580 w/ an HD650 cable and a vintage Onkyo 32 ohm headphone circa 1981. When I first received the HLLY with about 150 hours of burn in I found the sound grainy and the bass lacked impact. Now that it has close to 300 hours I find most of the grainy presentation is gone, and the bass tighter and has better definition and more impact. So far the additional 150 hours of burn in have helped the internal headphone amp.

I am waiting for the return of my Graham Slee Solo SRGII w/ a PSU1. I will feed the Solo via the RCA line out of the HLLY and will compare the sound with the internal amp in the HLLY. I will also use the USB input to see how the HLLY DAC and headphone out sound as compared not only with the Graham but also w/ a PinkFloyd modified X-Can V2 w/ a Little Pinkie PSU.

 

[david-gao]

OK, Glad to see the DMK's Sound become better after burning!
We will use better OPA in the next version of DMK IV!


David gao

 

[Skylab]

Quote:

Originally Posted by mrarroyo /img/forum/go_quote.gif Well today I opened up the unit and fixed the loose RCA, while open I tightened all just to make sure. Since it was open I chose to add a bit of Dynamat as I have done to some of the gear I own. BTW, the unit runs on the warm side as compared with other SS gear I own. It does not get hot and I can leave my had on the top surface indefinitely. I have listened to the HLLY being fed by both a Philips DVD player using a Blue Jean Cable coaxial cable as well as an iPhone using an ALO Bamboo Dock. I have used a Senn HD580 w/ an HD650 cable and a vintage Onkyo 32 ohm headphone circa 1981. When I first received the HLLY with about 150 hours of burn in I found the sound grainy and the bass lacked impact. Now that it has close to 300 hours I find most of the grainy presentation is gone, and the bass tighter and has better definition and more impact. So far the additional 150 hours of burn in have helped the internal headphone amp. I am waiting for the return of my Graham Slee Solo SRGII w/ a PSU1. I will feed the Solo via the RCA line out of the HLLY and will compare the sound with the internal amp in the HLLY. I will also use the USB input to see how the HLLY DAC and headphone out sound as compared not only with the Graham but also w/ a PinkFloyd modified X-Can V2 w/ a Little Pinkie PSU.

Thanks Miguel! Interesting. I did give the HLLY 100+ hours of break in before my review - but maybe it needed even more I guess. Will look forward to your comparisons.

It does sound like HLLY believes that the headphone amp still needs a better op-amp, though

 

[david-gao]

Yes, I think OPA2134 is not good enough, maybe OPA2132 is better!
I will try OPA2132 and see what will happen!!

david gao

 

[spartan123]

This is the same that i have found with my unit. The longer it burns in the better it sounds. I have easily around 600+ hours on my unit now. It has burned in nicely. It is quite enjoyable.

Would love to try it with the OPA2132's installed.

 

[david-gao]

Yes, burning make the Lehmann circiut works better, so the sound is better, so maybe we should do more burning work before shipping!

David gao