REVIEW: HLLY DMK-IV DAC / headphone amp / pre-amp) - Page 3

This looks interesting:

AUNE Mini USB DAC + Headphone Amplifier MK2

are the opamps user replaceable?

i think i would buy a dmk-iv if the OPA2132 was installed (assuming it's better)

Yes, In the next month we will use OPA2132 instead of OPA2134

http://www.hllyelectronics.com/downl...ts/OPA2132.pdf
http://www.hllyelectronics.com/downl...ts/OPA2134.pdf

Datasheet is similar,But real sound have some difference! some Diyers in china said OPA2132 is better!

Thanks

can the current chips be replaced with the new ones?

David, if I may suggest I would encourage HLLY to install a socket for the Headphone amp and to provide the user w/ a list of op-amps that would be compatible. This way the end user could experiment with a few op-amps and find the best sound for him/her.

The unit has been burning in since I received it 9 days ago, thus an additional 215 hours for a total of about 315+ hours. I did a quick comparison with an external amp being fed w/ the line out of the HLLY and the internal amp is a lot better than when I first listened to it. I will say that the OPA2134 is good but not my favorite op-amp, for example I prefer: AD8620, LM4562, AD8656, AD8066, to name a few. Of course it depends on the overall circuit implementation and the mentioned op-amps should be taken with a grain of salt.

Another item that would affect the sound is how clean or dirty the A/C is. I have a filter installed as well as a ferrite core around the power cable supplying the HLLY. These two items may be helping.

More to come.

Thanks , installing a socket for the Headphone amp is a good idea!
We will have a special Headphone amplifier for DIYER in the future, with more sockets, with a list of op-amps that would be compatible!

Yes, with more burning, we also found the sound is better, we will try the OPA2132 and let the DMK-IV be a stable product and will not make more change! But we will have two other DAC products based on the DMK-IV in half year!

Of course we will offer sample to you and Rob for test!

David gao

Yes, OPA2134 and OPA2132 is compatiable! But you need some sold skill if you need to replace the OPA2134 with OPA2132,hehe


David gao

Soldering surface mounted components is beyond the basic skill I have. I know of a few DIYers who are capable but I would not trust myself to do so on the HLLY or on any other gear.

Thanks David, I would love to try the new equipment.

OK, Miguel! We will have tube buffered DAC soon, We will send it to you for test and advice!

By the way, do you test the power amplifier?


David gao

a NJM4580D would be a better choice IMO, it's a great chip to drive headphones.

swap the AD797AR for AD797BR, put a gold plated DIP8 socket w/ a NJM4580D..and we're talking!

Hi Davie, what power amplifier. The back of the HLLY DMK-IV I have does not have speaker outputs. If you mean the line out, yes I am using the line out to feed a Graham Slee Solo SRGII.

I just did an small back and forth between the HLLY headphone out and the Solo SRGII being fed via the HLLY line out. I used two headphones a wooded SR80 and the HE5. The source was a Philips DVD player that has "been around for a while". Any ways the result was consistent, the bass is deeper/tighter/punchier with the Solo SRGII, the soundstage was better defined w/ depth and width on the Solo SRGII, the high mids and the highs were pretty even, and the Solo SRGII exhibited a bit better musicality. I should mention that it was easier to hear these differences with the wooded SR80 Grado than the HE5.

What does this tell me? That the HLLY DMK-IV is a good deal. The DAC section is very good much better than the price would lead you to believe. The headphone amp now with almost 400 hours is much tighter, clearer, and w/ more detail than at 100 hours of burn in as I received it. No, it is not a killer unit since the Solo SRGII w/ PSU1 sounds better but it should since it sells for $700 versus the price of the HLLY DMK-IV. If/when David can improve on the amp out section then it will be a very nice unit to own for those wanting a second rig or starting out on the hobby although I feel the DAC section will keep many very happy for a while.

BTW David, if your new unit has speaker outputs then it would be an interesting option for those who own an AKG K1000. It would make a nice office rig to cover a few scenarios.

Miguel,

My sentiments exactly. For the price the unit is well worth it. Would LOVE to hear it with updated headphone circuit. But none the less I am VERY happy with the sound of my HLLY. The built in features are an added plus for me.

I wish David and his company all the luck with their business. It is refreshing that he listens to the consumer in order to update his products and make them better for future purchasers.

Today I took the HLLY to a mini meet w/ gjkphd and vorlon1. Both enjoyed the sound of the DAC out which was feeding via an splitter a Solo SRGII w/ PSU1 and a HiFiMAN EF5. They also seemed to like built in headphone out although one chose the Solo SRGII and the other the EF5 as their favorite out of the three.

Dear Miguel, Thanks for your praise for the DAC sound, like you said, you prefer some other OP AMP chips like AD8620, LM4562, AD8656, AD8066 and so on, we will try all these chips and select one, so making the DMk-IV be a stable product, I think some people like its functions!

Also next step we will develop another two DACs with better component soon, like AD797BR , CS4398 (DAC) , or PCM1704, these two DAC will be available in half year

About the power amplifier, I means we will have some tripath power amplifier amplifier for test, this is only speaker power amplifier, DAC is not included, if you are interested in these kind of products, we can offer sample for test!

--David