The Headcase Stax thread

[purk]

1 hour ago, Jon L said:

Has anyone tried a good tube preamp to drive the Carbon, to drive 009, in order to tube-roll the preamp side to tune the final result a bit?  Is it an absolute no-no or a possibility?

Can you do that at a source end?  I am just using the Yggy into either the BHSE, and Carbon....and honestly I like them just about equally with maybe a tad to the BHSE.  I'm using NOS Holland XF4.  Note that I do like the SR009 to begin with.

[mwl168]

I have a later version of the 009 and have used it with HV, Carbon, BH and SRX Plus. I have not purposely compared the pairings in a systematic way, mostly I just enjoy listening to the music.

I do like the combo of the 009 with the SRX Plus a lot! 

[purk]

8 minutes ago, mwl168 said:

I have a later version of the 009 and have used it with HV, Carbon, BH and SRX Plus. I have not purposely compared the pairings in a systematic way, mostly I just enjoy listening to the music.

I do like the combo of the 009 with the SRX Plus a lot! 

I bet the SRX Plus does sound amazing. 

[spritzer]

2 hours ago, Jon L said:

Has anyone tried a good tube preamp to drive the Carbon, to drive 009, in order to tube-roll the preamp side to tune the final result a bit?  Is it an absolute no-no or a possibility?

Show me any good tube preamp and we can look into this.  I don't think you can find one though... 

[skullguise]

39 minutes ago, spritzer said:

Show me any good tube preamp and we can look into this.  I don't think you can find one though... 

I imagine adding anything in the chain would offset what good/fun you could do with tube-rolling.  At worst, maybe some kind of line-level tube buffer, but those are probably worse-built in general than many tube amps.

[spritzer]

My point was that why on earth would you fuck up one of the cleanest amplifier circuits there are with a tube preamp, as I've never seen one that is well designed and will not do more harm than good.  To me tube rolling is just a practice that makes no sense, especially in circuits like the BHSE/T2.  Sure they will sound different, has anybody ever matched the quad of tubes to each other (?) but are there any actual improvements?  You know, the real stuff...stuff we can actually measure?   Not soul of the music, how it makes me feel bullshit. 

This does bring us to what is "tube sound".  Since I received three emails just now from Carbon owners laughing at the retarded notion Mulveling put forward on HF that the Carbon doesn't have "tube mids", what the actual fuck is that?  I mean seriously, can anybody tell me?  I mean his Carbon isn't a Carbon, it is a badly built mess of V0.1 boards when we are at V6.0 for my "production" version.  That amp must be doing something truly fucked up shit but I'd really like to know what.  For me tube sound is just distortion so when people claim some tubes sound "warmer", yup that's more distortion for you. 

I know to many of the idiots out there I come off a 009 hater but in actual fact, they just aren't that good but how many haters would set out to design a special amp for something they hated?  Ehh none but these clueless fuckers really can't get their head around that the Carbon was my project from the beginning to try and improve the 009.  I drew up so many different ideas from super simple to crazy complicated shit but this one proved to be the best.  More power into the top end plus some other neat things which didn't always follow what we'd normally do. 

Since it was pointed out that my T2 wasn't working and I fucked it up.  Mine was the second one built and suffered what any amp can, shorting through the insulators on the transistors which blew up an entire channel, making it unfit for repair.  What I did was to completely redesign the T2 amplifier board, spent probably 10 hours just fixing layout issues making it the best board yet.  Built and my amp works perfectly, still not better than a Carbon which any fool would know from looking at the design.  As Kevin pointed it out so nicely when I proposed doing an all SS T2; "why bother, we have the Carbon".  Yeah, he was right and I'm still sitting on probably the largest stash of T2 parts in the world.  I could easily build 150 amps so why wouldn't I?  Because the Carbon is better... 

I also find it so funny that we keep having the same arguments and this is identical with the Cavalli/Woo Audio/RSA/Single Power etc. supporters.  They have zero technical knowledge or any clue what they are talking about but this is what makes it funny...arguing with the people who actually designed the stuff.  I don't think you can get any more retarded than that... 

[arnaud]

Birgir,

So, for you, main issue with the SR009 is the lack of top end extension on all amps prior to the carbon including the T2?

About measurable performance, give me a break. The 207/507/L500/L700 sound clearly different yet we can't tell fuck from looking at the measured FRF such as the pretty clean measurements Tyll makes at InnerFidelity.

About the BHSE responding to tubes, or lack thereof, you can call people fool all you want, there's absolutely no question it sounds subtly different when switching tubes, including the midrange where it's pretty sure you won't find a measurement method to highlight the differences. I never bothered trying to measure because, heck, even less subtle differences between shades of lambdas don't easily show up in measured graphs. For the SR009 in particular, it really does quickly sound shouty in the BHSE with production tubes (hyped chinese crap or else). As I recall, you listen at pretty healthy levels so I can bet the 009 sounds like torture for you.

You can despise all you want the likes of Mulveling or Purk, these guys have, ime, a pretty good track record at discerning good from bad sounding stuff and I often find I jive with their experiences. Yours, no offence but, not much. That does not change anything to your brilliant engineering skills but, at least for the subjective part, you'll have to excuse some of us if we don't quite hear the same greatness and faults as you do...

arnaud

Edited July 22, 2016 by arnaud

[n3rdling]

Speaking of measurements, just how much roll off are we talking at 20kHz and at what SPL?

[spritzer]

We all know the FRF graphs are utterly useless, they are just fodder for noobs who don't realize that test tones and the equipment used to analyze them just can't cut it.  That's not saying the ear is a measuring tool, it's pretty much the worst piece of shit instrument it is, especially when coupled to our highly suggestive brains but it can do one thing easily...multi band analysis.  I also don't see how this has anything to do with amplifier measurement though, these are totally different worlds as with the amps we can measure exactly what we need to know.  I do think that the headphones can be properly measured too but the FRF graph is just the same as the age old THD spec.  Utterly meaningless. 

Sure, the amp sounds different when changing tubes, nobody has said otherwise and how could anybody doubt that?  You are changing an active component of the circuit so it will naturally change.  My preposition was, has anybody swapped out tubes with identical specs?  Actually put them on a curve tracer and map two identical quads.  Then compare them in a blind test plus thorough full spectrum analysis of the amp.  Then report back...  A quad of EL34's is not the same as another quad of EL34's.  I've done this with 6S4A's and all those "facts" about how they sound...well it is all bullshit.  It helps to have hundreds of quads all matched within 1%. 

As for those two hapless souls, I don't despise them.  I couldn't care enough to not like them but they are just epidemic of the HF issue.  They know nothing about what they are talking about but the constant verbal diarrhea means people think they do.  Think krmathis and HPA back in the day.  Post enough and people thing you might have a single clue as to what you are talking about.   Some idiot in the Shure KSE-1500 thread said it the best, you have to listen to me as I have more expensive gear than you. 

[purk]

Birgir,

You can say all you want but don't call Mulvelling a "retard".  He is a brilliant guy and even a better person if you actually know him.   We can agree to disagree but calling someone a retard when he simply beg to differ from your point of view and this case a matter of sonic preference is just a little too far.

[luvdunhill]

I had totally forgotten about krmathis!

[DefQon]

What is this version 0.1 boards you speak of? Who built mulvelings Carbon?

[purk]

The same person who built mine and also the same one who built two working DIY T2s as well as a balanced HEV90.

[3x0]

Seems like a waste of energy all-around in arguing positions that aren't really worth defending.

The SR-007 Mk-whatever, SR-009, SR-Omega, HE90 etc. are so hilariously far from ideal that no state-of-the-art amplifier will really save them from themselves no matter the circuit properties, 60-year-old tubes or magic fairy dust.

This is why I usually always post the same shit to those looking towards serious high-end audio: listen and draw your own conclusions. Flights and trials are chump change compared to the four or five figures required for these systems and it doesn't make sense to rely on any opinions from strangers on the internet. It shouldn't matter if someone decides to go with SR-007 + Carbon or SR-009 + WES as long as either keeps their owner dumb and happy.

I'm sure the Carbon sounds fucking fantastic and I can't wait to hear it. And the SRX-Plus looks like it'd make a cute little baby brother for the T2...

[Dave R]

Deleted.

Edited July 23, 2016 by Dave R

[sorenb]

11 hours ago, spritzer said:

I mean his Carbon isn't a Carbon, it is a badly built mess of V0.1 boards when we are at V6.0 for my "production" version.

So how does the Carbon v5 (or v6 for that matter) boards differ from your V6.0 "production" version, apart from yours is a bit smaller and have extensive ground plane?

[astrostar59]

18 hours ago, Jon L said:

Has anyone tried a good tube preamp to drive the Carbon, to drive 009, in order to tube-roll the preamp side to tune the final result a bit?  Is it an absolute no-no or a possibility?

There are many DACs with tubes in and that would allow an element of tube rolling to tweak the sound. In my (limited) experience I prefer to miss out the pre-amplifier as it is just another device that can change the sound, unless the DAC line stage really requires it to drive the next device. It is possible to get great results with a power amp driving speakers as well using a passive, though results can be mixed and it depend on the design of the line stage in the DAC and keeping the interconnects as short as possible helps.

[sorenb]

11 hours ago, arnaud said:

Birgir,

...

About the BHSE responding to tubes, or lack thereof, you can call people fool all you want, there's absolutely no question it sounds subtly different when switching tubes, including the midrange where it's pretty sure you won't find a measurement method to highlight the differences. I never bothered trying to measure because, heck, even less subtle differences between shades of lambdas don't easily show up in measured graphs. For the SR009 in particular, it really does quickly sound shouty in the BHSE with production tubes (hyped chinese crap or else). As I recall, you listen at pretty healthy levels so I can bet the 009 sounds like torture for you.

...

arnaud

for what it is worth I did a a few observations in rgrds to different tubes in my Blue Hawaii before I change the CSS in the output for a T2 style CSS..
I have three sets of matched quads EL34's: 1 new set of Harmonix's and two NOS Mullard xf2 db getter brown base

There are quite a substantial difference between the Harmonix and Mullards to my ears, whereas I definetely prefere the latter.

As I recall  the amp behaved very differently looking at the scope. At 1 and 5kHz squarewaves at various levels, the Harmonix seemed to behave less optimal and seemed to introduce more phase shift in comparison to the Mullards. Especially at high volume levels the Harmonix seems to loose their breath quite quickly.

As mentioned these are only brief observations but seems to support the observations from a lot of other people, @mulveling, @arnaud, @purk among others.

[wink]

10 hours ago, luvdunhill said:

I had totally forgotten about krmathis!

...  and,   the great  middling, unique patrick82   The Judge rulez......

Edited July 23, 2016 by wink

[johnwmclean]

On 22 July 2016 at 7:27 PM, spritzer said:

Another point of reference are the almost 10 people who own a Carbon and a BHSE.  All of them prefer the Carbon with the 009 and that makes perfect sense from a technical point of view.  One of them even recently got a brand new BHSE and asked me what he should do with it...the Carbon was much better.    Most of this is due to the superior high frequency driving potential.  This was a large part of the design process but it naturally works just as well for the 007's.  More HF power means they aren't as dark as they used to be.  The BHSE will roll off a bit so this is a change to the better. 

Yep. The SR-009s with the Carbon is my preference over the BHSE, the Carbon is right up there at just about DIYT2 level.

From my listening tests the Golden Reference Low Voltage supplies have also pushed performance considerably, it’s exclusion from a build is something that may weigh in.

[sorenb]

On 7/22/2016 at 11:27 AM, spritzer said:

Another point of reference are the almost 10 people who own a Carbon and a BHSE.  All of them prefer the Carbon with the 009 and that makes perfect sense from a technical point of view.  One of them even recently got a brand new BHSE and asked me what he should do with it...the Carbon was much better.    Most of this is due to the superior high frequency driving potential.  This was a large part of the design process but it naturally works just as well for the 007's.  More HF power means they aren't as dark as they used to be.  The BHSE will roll off a bit so this is a change to the better. 

 

16 minutes ago, johnwmclean said:

Yep. The SR-009s with the Carbon is my preference over the BHSE, the Carbon is right up there at just about DIYT2 level.

From my listening tests the Golden Reference Low Voltage supplies have also pushed performance considerably, it’s exclusion from a build is something that may weigh in.

I guess this will make a lot of potential buyers of the BHSE very happy, as they might be getting a bargain when all those real Carbon owners soon will dump their BHSE in the classifieds 

[spritzer]

To get back to some actual R&D here, I've been doing some testing and I think the HE90 500V is highly optimistic.  The drivers simply don't have the headroom built in that the Stax designs have and Senn were inserting plastic washers to try and stabilize the drivers.  Well also to try and make the stators not crack but that's a different matter...  Going down to the ~430V range might be beneficial to their performance but this warrants more investigation. 

11 hours ago, purk said:

Birgir,

You can say all you want but don't call Mulvelling a "retard".  He is a brilliant guy and even a better person if you actually know him.   We can agree to disagree but calling someone a retard when he simply beg to differ from your point of view and this case a matter of sonic preference is just a little too far.

It is quite retarded to argue with the designer of something and claim you know better based on no technical knowledge at all.  Just based on how one "feels" about it.  Better call that massively retarded. 

There has never been any doubt that the BHSE rolls off, it has been known since 2003 which is why the new grounded grid exists.  That is the Carbon take on the same circuit, cleaned up to not have those issues.  Doesn't mean the BHSE isn't a great amp but time moves on and we thankfully improve things and aren't stuck in a rut.  I also suspect that we will see some major improvements as the new headphone R&D comes underway. 

2 hours ago, sorenb said:

So how does the Carbon v5 (or v6 for that matter) boards differ from your V6.0 "production" version, apart from yours is a bit smaller and have extensive ground plane?

Quite a bit actually... 

[johnwmclean]

 

8 minutes ago, sorenb said:

I guess this will make a lot of potential buyers of the BHSE very happy, as they might be getting a bargain when all those real Carbon owners soon will dump their BHSE in the classifieds 

No. Justin's BHSE will always retain value, it’s always been a bargain 

[sorenb]

Just now, johnwmclean said:

 

No. Justin's BHSE will always retain value, it’s always been a bargain 

as the BHSE is rarely found in the classifieds and suddenly having almost ten available (I guess that is more than one), you might even be able to choose a yummi color too 

[kevin gilmore]

I posted this over there, will post here.

if I had time I would find to do a way to do the graph that shows frequency response relative to output voltage, maybe in a few days if people don't get it

so here is how this works

Required Slew Rate = 2 x π x Frequency x Peak Voltage  x K

we can argue about K later, different people have different ideas about the value.The load is a capacitor and it takes a particular amount of current to charge/discharge the capacitor at a particular frequency and voltage.

Lets reference the maximum peak to peak output voltage of the amplifier at 1khz as 0db.

Now lets calculate what amount of current is needed to do 20khz at 0db at the same peak to peak voltage into one standard headphone load, 120pf

Now lets figure out (and this part gets complicated) how much more current is needed to guarantee .01% thd at 20khz at 0db. taking into account the open loop gain.

Its clear that some of my earlier amplifiers with output currents in the range of 5ma to 10ma cannot do full voltage swing at 20khz. But will do a full flat frequency response at less than full voltage swing. So the question is how loud do you listen and how much actual audio content is at 20khz relative to 1khz.

It is my opinion that 20ma however is enough to do full voltage swing even with 500V power supplies.

2sc4686,2sc3675,2sc5466 etc, cannot do more than about 10ma before they eventually blow up. Even with lots of heatsinking. And ixta3n120 has so much output capacitance that even with impossible current numbers it could never get there from here.

Cree C2m1000 however can run at at least 30ma at 500V power supplies, is ultra low output capacitance etc. So is the current flavor of the decade output device, till something better comes along.

A couple of people think that the carbon is a bit bright at 20ma, and have turned their units down to 18ma. This is one way that the amplifier can be tuned.

The performance of an el34 at 20ma begins to effect the lifetime of the tube. Significantly.

emission labs 20B work fine at 20ma, but have a stupid price and questionable long term reliability.

There is no free lunch.

Edited July 23, 2016 by kevin gilmore