PDX DAC

bhobba

In the Young DAC thread there was a bit of discussion about the PDX DAC.  It is a DAC made by Lenehan Audio on the Gold Coast in Australia.  To find a bit more about it check out the review:

http://www.digitalaudioreview.net.au/index.php/audio-reviews/digital-source-reviews/item/188-lenehan-audio-pdx-base-level-dac

It is not a NOS DAC and its valve output stage is very transparent. The review above is of the base level model - the level 2 is even better and at that level is one of the two best DAC's I have ever heard - and of recent times I have heard quite a few.

As one of the the best DAC's guys out my way have available the level 2 was used in the Transport vs Computer comparison where computer audio using an Audiophilleo2 finally bested the transport.  This is the DAC I am getting built with the John Kenny I2S Hiface built in and will be used to compare to the Audiophilleo2.  For further information about the John Kenny check out:

http://sites.google.com/site/hifacemods/

http://www.digitalaudioreview.net.au/index.php/audio-reviews/digital-source-reviews/item/184-j-kenny-modded-m2tech-hiface-mk2

I will keep you guys posted on what eventuates.

Thanks

Bill

coops

Bill the Audiophilea isn't a DAC, valve output stages are not 'transparent' you may enjoy the sound but that is not the same thing.
Keith.

Alan

Transparent is viable as a descriptive term for valves keith- others feel the same about describing some horn speakers thus.

bhobba

Bill the Audiophilea isn't a DAC, valve output stages are not 'transparent' you may enjoy the sound but that is not the same thing.
Keith.

Hi Kieth

I am sorry if anything I said was unclear.  The Audiophilleo2 is a USB to SPDIF converter and was used to feed the SPDF input of the PDX.  The transport was used to feed the same input. Direct comparison, and I have had a chance to do it myself, showed the the Audiophilleo2 was better.   This has been confirmed by a number of very experienced listeners.  The next comparison will be between the Audiophilleo2 feeding the same DAC and a special version of that DAC I am having built that has a John Kenny I2S modified Hiface inbuilt.

I don't know what valve output stages you have listened to but in my, and many others I know, experience they can sound very transparent indeed.  Remember sounding transparent is different to measuring well.  Low distortion for example can be achieved by applying large amounts of feedback but people describe that as sucking the life out of the music.  Valves are inherently more linear than transistors and require less feedback - that is one reason they can sound more transparent.  But in reality both SS and valve gear can be designed to sound transparent.  I have heard both.

Thanks

Bill

bhobba

Transparent is viable as a descriptive term for valves keith- others feel the same about describing some horn speakers thus.

I am scratching my head about that.  Both valves and transistor amps can be designed to sound transparent (ie trigger the brain into thinking this is real - its a common term used in Hi Fi) and I have heard both SS and valve gear do it eg I own both the PDX and Tranquility DAC's and they both sound transparent - the PDX is valve and the Tranquility is SS.  While both are transparent interestingly the Tranquility may have a slight euphonic quality to it and not the PDX.

Thanks

Bill

coops

Bil Hi, what does 'transparent' sound like?
I take transparent to mean that the signal is unaltered, this is not the case with valves, they sound very nice, but transparent no.
Keith.

bhobba

Hi Kieth

Transparent means they sound like it is unaltered.  In my experience both transistor and valve amps can sound like that - which of course can be different to how they measure.  Are you saying in your experience it is not possible for valve gear to sound like that?  Or are you saying valve gear inherently measures worse?  If so I don't agree with that either - valve gear can be designed to measure just as well as SS and to sound just as transparent.  What I will say is a lot more mediocre SS gear has been designed than valve gear which turns some high quality produces off SS gear and more towards valves.  I know the designer of the PDX and he definitely is in that camp.  He designed the output stage of the PDX to sound transparent and it does.

An acquaintance recently compared a top of the line and much more expensive Modwright amp with my Leben CS300XS.  The Leben clobbered it.  However I know of people that compared my Leben to a LFD - that was much closer and in fact was a draw - the Leben was judged to be slightly more transparent in the midrange - but the LFD had much better bass grip.  It all has to do with the implementation.

Thanks

Bill  

sq225917

It's nice to see some new products coming together that integrate turnkey solutions from respected technology houses, even better that they have breathed on by well known modders to achieve better results.  

m2tech products with improved power supplies are very much in vogue so it's nice to see them being integrated in this way. I'm sure the designer could just license the hiface direct from Marco. If his RF design skill was up to par it would be less hassle than shoehorning in parts- he could even offer a real warranty on it.

jkeny

I agree with Bill, tubes can sound very transparent given a good implementation just as SS also can - there are no sacred mantras in audio!

Alan

That's the one! I couldn't agree more.

bhobba

That's the one! I couldn't agree more.

Hi John and Alan

Thanks for chiming in.  Although not a common one there is definitely a misconception in some circles that valve gear is in some way inferior to SS - and conversely (the converse is a bit more common though). I remember when I did a formal comparison of the PDX to the Tranquility Signature - 5 guys were present. Two died in the wool valve guys were present and they poo pooed the Tranquility.  To my ears it was a close thing with the edge going to the PDX (extended listening however of the Tranquility revealed its qualities and the gap became even closer - so close I would judge them to be about the same - with perhaps a slight edge to the PDX).  Another guy present was in my camp.  Interestingly the designer of the PDX was there and he was the most forceful in touting just how good the Tranquility was.  I chatted to him later and he said it was because in both valve and SS he knows how hard it is to get output stages that transparent.

As an example of SS gear that does not sound transparent I will mention the Burson DAC.  I got one based on a stellar 6 Moons review.  It was supposed to be scary close to the best out there.  It aren't - it has a warm sound that when you first hear it your say - hey thats nice.  But when you compare it to a genuine transparent bit of gear - SS or Valve - its like a blanket has been put over the speakers and muffling the sound.  That is a non transparent piece of SS gear that has IMHO been designed to sound euphonic.  And this is from a comp[any known for touting the benefits of SS over valve.  I know they are working on a stand alone DAC (their current offering is a combined DAC/pre amp/headphone amp) and I can only hope it is better.  I on-sold mine virtually straight away.  That said though it certainly is still worth a listen - I know some guys that really liked it.

Thanks

Bill

sq225917

There's a universal truth learnt from 6moons, 'internet opinions are worthless'

coops

Bill Hi, how do you measure transparency, presumably you measured these devices and found some to be more 'transparent' than others?
Keith.

bhobba

Bill Hi, how do you measure transparency, presumably you measured these devices and found some to be more 'transparent' than others?
Keith.

Hi Keith

Like your appreciation of a fine wine or a piece of art you don't measure it - you learn what is by listening to gear and comparing it to live events.  I mention again heaps of negative feedback can give distortion figures unbelievably low and you would say it must sound better than say a well designed SET with good but not great distortion figures.  Yet in listening tests the SET is usually preferred - a lot of feedback sucks the life out of music.  I have spoken to a number of amp designers over the years and they all say the same thing - they have no idea exactly what makes an amp sound good beyond a few things such as avoiding a lot of feedback but know it when they hear it.  And just like when you hear the Burson compared to the PDX it is easy to spot using transparent gear - especially speakers.

You have been asking a lot of questions - now I have one for you.  Why to you think qualities like transparency in an amp are measurable?  Why did you presume I 'measured these devices and found some to be more 'transparent' than others?'  Presumably you believe all the important qualitaties in Hi Fi are measurable.  Why is that? 

Thanks

Bill

coops

Bill Hi, if you insert a piece of equipment into a chain and it has no ,absolutely no effect , then it is 'transparent'
with all due respect you are just describing subjective changes that you prefer, there is nothing wrong in that, ultimately one must choose the sound you prefer, but it has nothing to do with transparency.
Keith.

bhobba

Bill Hi, if you insert a piece of equipment into a chain and it has no ,absolutely no effect , then it is 'transparent'
with all due respect you are just describing subjective changes that you prefer, there is nothing wrong in that, ultimately one must choose the sound you prefer, but it has nothing to do with transparency.
Keith.

No piece of equipment will have absolutely no effect so under your definition no piece of equipment can be transparent.  However under mine it can be - and even very transparent.  Its good to know the definition we each adhere to.  I believe it goes beyond mere subjectivity in describing how close it is to live events.  I also suspect my definition is the more common among high end audiophiles.

Thanks

Bill

sq225917

I suspect you might be wrong there, Transparency has a very strict meaning, because it references the known standards of audibility.

Transparent: A piece of equipment that renders no audible change to the signal. Equipment that introduces distortion only below the level of audibility. 

The only way you can test that with any validity is to measure it against known audible standards. Just because you think you don't hear distortion doesn't actually mean there isn't any or that it is below audibility- because you could just be wrong.

The joy with audio analysers and laboratory grade microphones is that they are seldom- if ever- wrong. I on the other hand along with everyone else on this forum are entirely fallible. 

You can only measure transparency- or state an opinion that you 'think' something sounds transparent- they aren't the same thing.

bhobba

Transparent: A piece of equipment that renders no audible change to the signal. Equipment that introduces distortion only below the level of audibility. 

How do you determine what is audible without listening to it and hence introducing subjectivity?  For example I have an acquaintance very sensitive to mosfet mist (and no I won't get into a discussion on what that is - last time I did it ended up with one person basically making snide remarks along the lines I was a know it all smartass - if you are really interested I will contribute to a thread about it if anyone wants to start one) but others I know like it thinking it sounds more real. Although I have to say I think once they get a bit of 'tutoring' from my acquaintance who goes along to a lot of live events they will likely change their minds. My definition has subjectivity built right from the start.  I believe transparency is what tricks the brain into saying this is real ie sounds like what I hear at live events.  But really as long as we each understand what we mean by transparency then no confusion can result from reading each others posts.

Thanks

Bill

sq225917

Bill, I go with what the AES says we can and can't hear. Their members have thousands of man years spent researching this.   So anything below .1% THD and frequency response flat to .3db will do as starters, we can talk specifics about types of distortion and distribution of specific frequency products if you like. 

If you have measurements for the output of that valve stage that show it's transparent, that's good enough for me. Someone's word never would be, ears are not measuring devices.

I can't say I've ever heard any hifi that I could mistake for a real music event, not even in a recording studio.

bhobba

Bill, I go with what the AES says we can and can't hear. Their members have thousands of man years spent researching this.   So anything below .1% THD and frequency response flat to .3db will do as starters, we can talk specifics about types of distortion and distribution of specific frequency products if you like.  If you have measurements for the output of that valve stage that show it's transparent, that's good enough for me. Someone's word never would be, ears are not measuring devices. I can't say I've ever heard any hifi that I could mistake for a real music event, not even in a recording studio.

Due to the feedback issue distortion is not a measure of transparency.  We seem to be going around in circles here.  Measurements are not a good inidicator of a piece of gear sounding transparent.  The key word is 'sounding' - you must hear it to determine that.  No hi fi system can reproduce things well enough to be mistaken for real events.  But some systems and pieces of gear get closer to it than others.

Hopefully I can avoid these types of discussions in future by saying sounds transparent. 

Thanks

Bill

Alan

I know what you mean Bill, 'transparent' as a descriptive term of character makes sense to me. I haven't yet confused it as meaning technically and measurement transparent.

 - (Pre-emptive) MODERATING -

I can't decide whether or not to step in here, but to be fair this thread is about Bill's experience with the PDX DAC. There is a chap on your wigwam thread Simon who is also way off topic, isn't there?

I say live and let live chaps. This forum is about being a nice place to be - let's make sure Bill still sees it like that towards the end of the day please. Things are fine so far, I'm just asking we keep peoples feelings in mind as I'm off to work & can't stick around today.

bhobba

I can't decide whether or not to step in here, but to be fair this thread is about Bill's experience with the PDX DAC. There is a chap on your wigwam thread Simon who is also way off topic, isn't there?

From my perspective everything is OK.  I now think by saying sonically transparent these off at a tangent discussions can be avoided.  At least I wont be drawn on it any more since I think nothing is to be gained from it.

Thanks

Bill