The Headcase Stax thread

[oogabooga]

I couldn't find this answered in the previous 300+ pages - but I'm a bit confused with the issue of "polarity" with respect to connecting my Parasound 1500 to an SRM-006t via XLR.

According to the SRM-006t manual (p.5), the XLR input polarity is:

1=ground

2=cold

3=hot

According to the Parasound 1500 manual, its output polarity is:

1=ground

2=+ signal

3=- signal

Am I correct to assume + means hot, and - means cold? Do I need some kind of "crosslinked" XLR cable (i.e. 2->3 and 3->2) to hook the two together? I'd appreciate any help/insight on this - I don't want to just plug cables in and have something blow up...

[cetoole]

You can just plug it in, all that will happen is absolute phase will be switched. If you think you can hear this, the parasound has a button on the front panel which inverts it.

[spritzer]

The amp might even invert phase on its own (i.e. some are wired up the wrong way around) so this isn't a big deal.

[Kabeer]

Hi Guys,

I have two questions:

a) If a stat amp has balanced xlr input, can I just use a normal rca>xlr adaptor cable to hook up my normal rca equipped DAC?

If the stat amp as a 600v bias output, is it safe to use Pro Bias stax cans on it (well the O2mk1) without damage? (i think i read of spritzer testing higher volatages but not sure if this is something safe for a layman)

Thank

[oogabooga]

You can just plug it in, all that will happen is absolute phase will be switched. If you think you can hear this, the parasound has a button on the front panel which inverts it.

The amp might even invert phase on its own (i.e. some are wired up the wrong way around) so this isn't a big deal.

Thanks to both of you, I appreciate it.

[spritzer]

a) That should be just fine for 99% of the amps out there since the RCA input is configured just like that. The only oddity is something like the Woo WES which can't perform the phase splitting necessary for this to work. Either transformers or a phase splitting circuitry is needed then.

Such a small difference should have no effect what so ever and in my experience you only run into trouble at 750-800V with the Pro bias Lambdas. The SR-007 doesn't mind that though but I couldn't hear any benefits from pushing the voltage like that.

[HeadphoneAddict]

a) That should be just fine for 99% of the amps out there since the RCA input is configured just like that. The only oddity is something like the Woo WES which can't perform the phase splitting necessary for this to work. Either transformers or a phase splitting circuitry is needed then.

Such a small difference should have no effect what so ever and in my experience you only run into trouble at 750-800V with the Pro bias Lambdas. The SR-007 doesn't mind that though but I couldn't hear any benefits from pushing the voltage like that.

As far a I know, I have the only WES without any single ended inputs and 12AU7 phase splitters. Are there others like my demo unit missing those?

My RCA are wired up as loop out and I saved a ton of money on the demo amp. I use an ISOmax transformer to feed my single ended phono preamplifier into the WES balanced inputs. I do have to use a Neutrick XLR gender changer since the transformer is made for connecting a balanced DAC to a single ended amp, but it works both ways.

Cheers.

[spritzer]

There are no other WES amps sold without the phase splitting circuitry that I'm aware of and I doubt they would unless somebody wants an XLR only unit. Since we are on the topic, the ESX is dancing right on the edge of working as a phase splitter. Simply putting in a another set of tubes (same type, age, make etc.) will result in mild imbalance but since the amp was supposed to use ECC81's that is really the issue.

[HeadphoneAddict]

Spritzer, are you still getting a BHSE?

[cetoole]

There are no other WES amps sold without the phase splitting circuitry that I'm aware of and I doubt they would unless somebody wants an XLR only unit. Since we are on the topic, the ESX is dancing right on the edge of working as a phase splitter. Simply putting in a another set of tubes (same type, age, make etc.) will result in mild imbalance but since the amp was supposed to use ECC81's that is really the issue.

Make the input stage a real differential pair with tail to b-?

[spritzer]

Spritzer, are you still getting a BHSE?

Yup, I'm also building a few ultimate old school Blue Hawaii's (built in a chassis milled from a solid block of aircraft grade aluminum with the usual audiophile candy) and Kerry's version. My old BH will be off to the US soon.

Make the input stage a real differential pair with tail to b-?

...or just put some transformers on the input. I have some cheap Hammond's here but never felt the need to fit them in the ESX, even if the layout was designed for them in mind (or rather Lundahl's). Finding the right 7n7/7f7's was all it took to get rid of the small imbalance.

[Beefy]

Finally finished refurbishing my SR-Lambda today. They ended up getting new drivers, cable, backing foam, mineral wool, headpad and earpads......

I'm running them at 200+V bias from the Exstata, and none of the shenanigans of the old drivers are showing up. No squeal, no crackle, just sweet music

[Hopstretch]

Noice!

[cetoole]

Are you going to break open the old drivers to try and figure out what was wrong with them?

[Beefy]

I think it was from the front dust cover on the bad driver, which was really loose and floppy. By gently blowing on it I could hear it 'flapping in the breeze' (this was probably the crackling noise), and I wouldn't be surprised if it was loose enough to be able to touch the front stator. I'm almost positive that dust would have been able to get in as well.

[charliex]

The advice you'll get here is that next you need a source upgrade, before the inevitable O2. I have to admit that they were right.

Then my weak link at the moment you say is my Cambridge DacMagic? If so, then what recommendation(s) before I go the O2 route?

[HeadphoneAddict]

Then my weak link at the moment you say is my Cambridge DacMagic? If so, then what recommendation(s) before I go the O2 route?

Well, I went for the PS Audio Perfectwave DAC. There are many others that I will let people recommend here.

[The Monkey]

Then my weak link at the moment you say is my Cambridge DacMagic? If so, then what recommendation(s) before I go the O2 route?

My advice is to buy at least 10 DACses and have them haunt you until you can't take it anymore.

[dreamwhisper]

My advice is to buy at least 10 DACses and have them haunt you until you can't take it anymore.

[Smeggy]

With only 2 of the same DACses, I'm obviously well below my allotted number and should expand my DAC collection with an electrostatic DAC.

[Currawong]

charliex: The guys here tend to recommend older, discontinued PCM1704 or PCM63-based DACs, such as Parasound, Assemblage and Sonic Frontiers. Keep an eye on the "Forsale Elsewhere" thread for those. I recommend Audio-gd DACs, which are, from what I've seen and experienced, fairly similar good value. Certainly the second-hand DACs, sometimes available for as little as $300, are going to walk all over anything new at that kind of price and considerably higher. Anything along these lines is going to be great with your 404/T1 rig. You may find O2s too mellow and your rig too "polite" (to pinch The Monkey's description from a while back) overall in the end though, as they are considerably different-sounding to Lambdas.

[spritzer]

I'd go with any of the good 1702/1704/PCM63 dacs but they could need some TLC to perform up to spec. The ADCOM got a lot better simply by swapping out all the cheap/nasty caps for fresh new ones.

In other news, I just got back from a visit to the local Sennheiser dealer where we pitted the ESX/SR-007mk1 against the Auditor/HD800. Same source (Rotel DVD player) with the Auditor being fed by the XLR looput on the ESX. It's been a while since I heard the HD800 but the different level of class we are dealing with here more then surprised me. The music was some promo stuff from Sennheiser to promote their mics and the 800 fell flat on its face in terms of a coherent soundstage and anything resembling real bass output.

[morphsci]

Some of the "guys" here would probably also recommend taking a look at some of the pro units especially those made by metric halo/sonic studio.

[Beefy]

the 800 fell flat on its face in terms of a coherent soundstage and anything resembling real bass output.

Was it the HD800 that fell flat, or the Auditor?

I haven't really paid much attention to that amp, but what little I have seen was very mixed.

[spritzer]

A bit of both I guess. I've heard the HD800 under better circumstances but it's been a while and I don't think the difference was this clear then. That said the ESX is far from the best amp I could have used so it made for a fair fight.

Has anybody internal pics of this SPL stuff? They weren't up for some exploratory surgery on my part...