[Alwayswantmore]

As far as I can tell, this thread will be a Head-fi first...

Not because it centers on 650s at a time when K701’s appear destined to become the crowd favorite under $500

. And not because the equipment in question is being run in balanced mode. In fact, this threads uniqueness has nothing to do with what’s THERE -- rather, it's what's NOT THERE that breaks new ground...

Honey, I sold the headamp!

This thread will focus on the ability / inability to obtain high fidelity while dropping a traditional headamp (and one interconnect) from the audio chain.

Could this be a first?

Despite extensive search and a call to Wadia, I could not find anyone running the config I’m about to explore in this thread. Yet, at least according to the specs, it should work. And based on less than 24 hours burn-in, I’d say it has great potential.

So, here’s the deal...

I already own a fine CDP in the Wadia 830. And I’m NOT in a position to drop a ton of money into getting one of these...

So my goal is to see how well I can do using my current CDP and a tentative budget of ~ $500.

What’s in it for you?

To the extent this config works, headfiers will gain additional options when planning to upgrade your systems.

I also hope this thread fosters dialog on the following:

1.) $ for $ how does this config compare to the alternatives?
2.) How do 650s balanced stack up to K701s unbalanced?
3.) How do K701s balanced stack up to 650s balanced?
4.) What are the sonic characteristics of the various 650 replacement cables?

Please note the word DIALOG. I am not saying I will have access to the equipment needed to make these determinations. Rather, I hope Headfiers with experience in these areas weigh-in on these topics.

So please join me in this discovery.

Cheers, Kent

BTW: This will likely be presented in Blog format. If you want more background on how I got to this point, see sig for a link to my journal.

 

[Alwayswantmore]

Burn-in: ~39 hours

It's now time to introduce the stars of our show...

- Wadia 830 CDP
- Sennheiser HD650
- Moon Blue Dragon V2 balanced

 

[Alwayswantmore]

Burn-in: ~42 hours

So how does it sound? Hummmm... I’m thinking Lexus ES 330...

My recent listening experiences are limited to extremes: My very fine 2 channel system on one end of a spectrum, and Meier’s Corda Aria / Ety ER 4S on the other. Both rigs sound good in their own right, but neither makes a good benchmark for this thread.

So here’s my plan...

I'm going to the Nashville meet in a couple of weeks. By then my new rig should be burned-in and ready for prime time. At the meet I plan to obtain feedback from headfiers with more experience than I. Plus I’ll have an opportunity to broaden my exposure to head-fi rigs. This experience, coupled with feedback from the forum should provide enough data to nail down how this config stands up to more traditional alternatives.

Here’s some perspective...

If I were to equate my recent audio experiences to cars, I'd categorize what I’m hearing as a Lexus ES 330...

My 2 channel = GS: Fun to drive, relatively good handling, with a luxurious and comfortable interior. Not a Porsche 911 nor the new Mercedes S550, but still represents a level of refinement and performance most people will never attain.

HD 650 / BD V2 Bal / Wadia = ES 330: Smooth and quiet, making it a nice daily driver. Also representing a good value. If no clear alternatives surface in the next couple of weeks, this is something I could easily live with.

Aria / Ety ER4S = Prius: While a number of alternatives came to mind, in the end I choose the Prius to represent this rig. Primarily because (IMHO) IEMs can not be easily compared to full size cans. Yet they offer a number of benefits not found in conventional cans.

 

[skilpad]

System Wadia 861 + Sennheiser 600/650
Currently used on unbalanced output
Works just great
The outputstage uses a BB BUF634 (will easily drive a 300 Ohm Headphone)
You could play around with gain setting's to maximize the output volume
(using the maximum bits available)
I ended-up using the second lowest gain setting (you will have to open-up the Wadia to set the dip-switches though)
Hope this helped

 

[Alwayswantmore]

Quote:

Originally Posted by skilpad System Wadia 861 + Sennheiser 600/650 Currently used on unbalanced output Works just great The outputstage uses a BB BUF634 (will easily drive a 300 Ohm Headphone) You could play around with gain setting's to maximize the output volume (using the maximum bits available) I ended-up using the second lowest gain setting (you will have to open-up the Wadia to set the dip-switches though) Hope this helped

861, you're my hero!

Opened mine up last night. I'm on the same setting. I could probably go to lowest setting and still be OK.

BTW, have you done any A/B to dedicated headphone amps? Any recommendations for cables? What I hear is good, but I still lacks detail compared to my 2 channel.

 

[TheSloth]

I'm a little surprised to see that the output stage of a Wadia uses the BUF634. I would have expected a discrete output stage. Also, as monolitic buffers go, I always found the HA-5002 to be somewhat more transparent.

In any case, adding a headphone amp can't possibly improve on the sound of the BUF634, as it's going to be there no matter how many stages you put after it and is a perfectly capable headphone driver. So I'll bet that what are experiencing from your 'direct connect' method is the best SQ that your Wadia can offer. You could always piggy-back another one on top of each if you felt like modding/voiding your warranty (

) to reduce the output impedence and increase the slew rate.

 

[Alwayswantmore]

Quote:

Originally Posted by TheSloth I'm a little surprised to see that the output stage of a Wadia uses the BUF634. I would have expected a discrete output stage. Also, as monolitic buffers go, I always found the HA-5002 to be somewhat more transparent..

A translation for non-techies would be greatly appreciated.

Quote:

Originally Posted by TheSloth You could always piggy-back another one on top of each if you felt like modding/voiding your warranty ( ) to reduce the output impedance and increase the slew rate.

Warranty is long over. Is this something I should consider? If so, how would it likely impact the SQ? BTW: Output impedance is less than 15 ohm in balanced -- zero in single ended.

TheSoth, your sig indicates HD 650s balanced and K701s. How do they compare in your opinion?

Thanks.

 

[TheSloth]

Quote:

Originally Posted by TheSloth I'm a little surprised to see that the output stage of a Wadia uses the BUF634. I would have expected a discrete output stage. Also, as monolitic buffers go, I always found the HA-5002 to be somewhat more transparent.

Hah, 2 months ago I wouldn't have understood a word of that!

The BUF634 is a collection of transistors on a small silicon die, often termed a 'monolithic opamp', usually optimised to minimum power consumption and heat dissipation. A discrete opamp does the same thing, however it is made up of discrete components that can be selected, matched and optimised for the individual circuit by the designer, spread and heat sinked to allow pure class A operation and greater current draw.

There is some debate in the DIY forums as to whether there is any point to stacking output buffers. The BUF634 just happens to be very easy, in that all you have to do is stick another one directly on top of it and solder it on. This halves the output impedence. In this case, it's not a big deal, but the lower the better. Even with HD-650's I found some improvement in transparency by doubling output buffers. You can always quadruple and beyond, but there is almost no point going beyond 2.

Edit: I'm somewhat confused by the difference in the output impedence between the single ended and balanced modes. I am assuming they use the same output design, with the balanced output just having double the electronics. In such a case, the output impedence of the + and - ends of the balanced electronics should be equal to that of the single ended output. Can you post a picture of the output stage?

Edit: My K701's are too new to comment really at this point, and they are single ended compared with my balanced reference

 

[Alwayswantmore]

Thanks TheSloth,

I got the impediance from this linked review in Stereophile (see the first page of Specifications).

Here is a picture of the inside. I assume the output stage is where the plugs terminate...

EDIT: let me know if you want a zoom with higher res on a particular part.

 

[TheSloth]

Well the board you can see there actually doesn't seem to house the XLR's, or the output electronics. From the angle, it seems that they are on a board that is unfortunately buried beneath the one visible in the picture. What are those top two RCA's? It looks like a digital output board.

Edit: on coser inspection, that board is a digital output board, with analogue fixed line outs in between. Right?

 

[mattigol]

Hi there,

and thanks for posting.

1) I remember someone giving an extensive report on Wadia > balanced HD650 about two months ago, but I can't find the thread. IIRC he liked it very much and preferred it over quite a big-league rig.

2) I have been discussing the same concept with Sven Berendsen lately, as a heavy mod to my CDP1. Could very well materialize.

M.

 

[Alwayswantmore]

Burn-in: ~60 hours

Another reader pointed me toward a good review of the BD V2.

Another good review of Senn cables (this one however covers version one BD).

This recent thread also focuses on Senn cables.

BTW: The sound continues to improve. I'm have having a difficult time leaving my listening room when it's time to go to bed

 

[Alwayswantmore]

Quote:

Originally Posted by TheSloth ... on coser inspection, that board is a digital output board, with analogue fixed line outs in between. Right?

I had never taken time to think about it, but my unit has an optional digital input board. That's what we are seeing in this picture.

 

[Alwayswantmore]

Burn-in: ~72 hours

Spent the last hour with Eric Clapton's Unplugged -- a live recording. At least with this CD I'll retract my wish for a brighter high-end because the tonal balance was perfect. I honestly believe that burn-in is making a big difference in SQ. I would be proud to play this rig for my audiophile friends.

Some headfiers have reported that HD 650s will continue to improve for the first couple hundered hours. If this is true, I'm a very lucky man

I'm still interested to go to Nashville in 2 weeks and hear what 650s sound like on other headamps.

 

[granodemostasa]

the 650 took about 150 hours for me. Also, the blue dragon is said to take weeks to stablize, i got mine used so i dont' think that's a problem, but just in case i've been leaving mine to plausibly burn in.... so far nothing has changed on the BD only that i'm noticing more as i subject it to different types of music.