Time for some Stax SR-Sigma love......

[Nebby]

I'm guessing.....Alpha pot

[spritzer]

Nope, quad 20K RK27 which I pulled out of my KGSS. This was done on purpose because I wanted the amp to sound the same before and after but only add the balanced connection.

That is naturally a true input switch and not the DPDT stuff Stax uses. I see many mini-xlr's in my future.

[John Buchanan]

Nice work, Birgir!!! I bet that SRM 1 Mk 2 now sounds VERY nice.

[spritzer]

It is a brilliant amp and sets the bar quite high for what 400$ buys you.

[John Buchanan]

A Stax Sigma Pro is now on its way to sunny Perth. Couldn't resist, so a Sigma Pro vs Sigma/404 comparison will eventually happen. Happy days!

[n3rdling]

Did you get the one off audiogon? If so, what do you plan to do about the missing inner wool?

[John Buchanan]

Did you get the one off audiogon? If so, what do you plan to do about the missing inner wool?

It's the earpad netting that's missing, I believe. The photos show no netting and plenty of mineral wool. I have a spare set of earpads for the Sigma.

[n3rdling]

Oh nice

[edstrelow]

It's good to have both the Sigma Pro and Sigma/404. Do you still have a low bias model?

I keep a Sigma Pro in my office and the Sigma/404 at home, each happily running off an SRM1Mk2. The 717 is a bit better with them but the older amps are still pretty decent.

I will be curious to see what your impressions are. About 2 years ago at an headphone meeting in LA I had both hooked up to my 717.

I did a comparison of all three some time back on a different site.

[John Buchanan]

Ed, my normal bias Sigma was sacrificed many years ago to the Sigma/404 transformation. So it will only be a Sigma Pro vs Sigma/404.

What were other people's impressions of the Sigmas at the meet. So few people have heard them. I would expect most people would be unhappy with the Sigmas (far too dull) compared with the Sigma/404s.

I run my phones off the Stax SRM Monitor, which is basically an SRM 1 Mk2 with a switchable diffuse field equalizer.

Edited September 2, 2011 by John Buchanan

[n3rdling]

I don't remember much about what Ed's Sigma/404 sounded like but I remember telling him it sounded more extended to me. I had both the Sigma and Sigma Pro and recently sold the Pro as I liked the normal bias model more.

[edstrelow]

I'll let you draw your own conclusions first.

[spritzer]

I'm with Milos on this one, the Sigma Pro was always a poor substitute for the normal bias model off an amp that really can push them. The 404 version was better still and not as bloody hard to drive.

On a similar note, why have we never built a Sigma/303? It's a much more natural choice given how the cable fits and has the same drivers. I guess I could always get out of retirement and make one last set...

[John Buchanan]

I'm with Milos on this one, the Sigma Pro was always a poor substitute for the normal bias model off an amp that really can push them. The 404 version was better still and not as bloody hard to drive.

On a similar note, why have we never built a Sigma/303? It's a much more natural choice given how the cable fits and has the same drivers. I guess I could always get out of retirement and make one last set...

Go Birgir!!!

[spritzer]

Looks like that Sigma/303 will be a reality...

[HeadphoneAddict]

Looks like that Sigma/303 will be a reality...

That sounds cool - I really liked the Sigma 404 more than the Sigma Pro. I've never heard the normal sigma though, but I feared that it might sound as rolled off and lacking the fine micro-detail as the Sigma Pro. In that regard I thought my SR-Lambda and SR-5 gold edition were a bit better in a direct comparison. The Sigma 404 narrowed the gap with better extension and micro-detail, but with a superior soundstage to my Lambdas. I actually liked the Sigma Pro and 404 sound stage more than my K1000.

[edstrelow]

I'm with Milos on this one, the Sigma Pro was always a poor substitute for the normal bias model off an amp that really can push them. The 404 version was better still and not as bloody hard to drive.

...

What amp would that be?

I really don't listen to the low bias Sigma much, preferring the pro and 404 variants. But when I listen to them with my late model SRA12 (which claimed to be improved and has a PS Audio Noise Harvester pluged in the back ) I am often surprised how good they still sound. And when I run them from the SRD6 transformer, their dynamics are improved even more and the frequency response seems flatter. Unfortunately, the transformer reduces ambience and detail.

Sometimes I think they have a certain sweetness of sound that the high bias models lack. At any rate I have never been inclined to sell them or canibalize them to make another Sigma/404.

[John Buchanan]

Stax Sigmas high bias earspeakers compared – Pro vs Sigma/404.

These 2 Sigma high bias phones essentially differ in 2 main ways.

1. The headphone cable used for the original Sigma Pro was the same as the one first used on the Lambda Signature – not as wide as the one used for the Sigma/404 hybrid, which was first seen on the Lambda Nova Signature.
   
2. The drivers are different also – the Sigma Pro uses the reported 1 um Lambda Signature driver, whilst the Sigma/404 uses the (2 generations) later 1.35 um drivers first seen in the Lambda 404.
   

Otherwise, the shells of the 2 earspeakers, apart from minor colour variations, are identical. The Sigma Pro appears to be slightly more efficient.

In my set up so far, the two have been compared through the Studer D730 -> Apogee Mini-DAC -> Audio Research LS5 Mk2 -> Suder A68 -> Spritzer Pro modified SRD-7 bias + transformer box.

As seems to be the order of the day, the results are not what I expected. The Sigma Pro is far better than its reputation and bests the Sigma/404 in a couple of areas.

Firstly, the deep bass is slightly more evident and the mid bass is much tighter and less resonant. Bass drum has slightly more punch rather than smeared thud. This has been one of my only criticisms of the Sigma/404.

The midrange is about the same with both, but the treble is slightly more evident with the Sigma Pro. It’s close to a line call there, however.

As for dynamics – the Sigma Pro does dynamics somewhat better than the Sigma/404. The Lambda Signature driver/cable just sounds a little faster than the 404 driver/cable. This tends to alleviate some of the complaints about a mushy low end.

The original Sigma low bias was far too rolled off at the top end in particular, despite the magical Sigma midrange being present there. It appears that either the Signature or 404 driver implants are a successful remedy to this, and gives a phone that had huge promise a push into reference territory.

In summary, despite every single report to the contrary, I’m loving it! Flame suit on, hearing aid batteries fully charged LOL. Stax SR-009? Who freakin' cares!

Edited September 5, 2011 by John Buchanan

[graben]

Thanks for the impressions. I was looking forward to hearing what you thought. If you like the midrange of the Sigma you should try a Gamma, or SRXMk3. I prefer their midrange to any Lambdas.

[John Buchanan]

Thanks for the impressions. I was looking forward to hearing what you thought. If you like the midrange of the Sigma you should try a Gamma, or SRXMk3. I prefer their midrange to any Lambdas.

I had an SRX Mk3 and didn't like it. Deficient bottom end - too bright. The original Sigma replaced it without any regrets whatsoever. The Sigma Pro or Sigma/404 are even better. I've never even seen a Gamma. The Sigmas may have Lambda drivers, but they don't sound like Lambdas.

Edited September 5, 2011 by John Buchanan

[John Buchanan]

Just replaced the old (mesh disintegrated) Sigma Pro pads with new ones - the mineral wool stuffing was catching the edges of my ears. The set looks brand new now, and is sounding fantastic. The comments I made about diffuse field equalisation of a Lambda apply to this phone in as well - high hats in particular sound very natural, rather than the pressure-pak hiss sound !

[edstrelow]

Glad to hear that you like the pro's. I have never understood the bad rap they have been getting. Some people even saying the low bias model is better. It seems as if the pro's really like your transformer set--up. Is there anything in which you find the Sigma/404 better?

However, I find that used with my Stax 717 amp, it's a good phone but not as good as the Sigma/404. My results are almost the opposite of your's in that regard, the 404 has better definition, treble and bass. I had both phones set up in my 717 at the LA Canjam some years back and I didn't hear anyone say the pro was better. About the only comment I heard was that it had a more prominent midrange, which is similar to saying it has less bass and treble.

But you are using a transformer, and these do tend to transform the sound. Certainly my experience with my low bias transformer and low bias Sigma is that the transformer gives better dynamics and a flatter frequency response than amps such as the SRM1Mk2, but that it loses detail.

[John Buchanan]

Glad to hear that you like the pro's. I have never understood the bad rap they have been getting. Some people even saying the low bias model is better. It seems as if the pro's really like your transformer set--up. Is there anything in which you find the Sigma/404 better?

However, I find that used with my Stax 717 amp, it's a good phone but not as good as the Sigma/404. My results are almost the opposite of your's in that regard, the 404 has better definition, treble and bass. I had both phones set up in my 717 at the LA Canjam some years back and I didn't hear anyone say the pro was better. About the only comment I heard was that it had a more prominent midrange, which is similar to saying it has less bass and treble.

But you are using a transformer, and these do tend to transform the sound. Certainly my experience with my low bias transformer and low bias Sigma is that the transformer gives better dynamics and a flatter frequency response than amps such as the SRM1Mk2, but that it loses detail.

Ed, I would have been happier saying the same as you. There is certainly not a whole lot of difference between the two Sigma high bias. And I got this one for a lot less money than a Sigma normal and going for the conversion. As you have said many times, it's interesting how these Lambda drivers behave in a different shell. Am getting some original Sigma ear pads to apply to the Sigma/404 and then I can do a rematch.

I should have kept the SRM-717 and the SR-007 Mk1, but the room was starting to look like a hifi showroom - check out my profile.

Edited September 9, 2011 by John Buchanan

[edstrelow]

I have no trouble with people who disagree with my opinions about equipment as long they have actually had a proper chance to hear the items in question. I think comparisons made by persons with both items are the most reliable information you can get.

What ear pads have you been using? I can't imagine that these phones would be sensitive to pad, although most other designs are.

Your finding the Sigma pro as good or better than the Sigma/404 would certainly irk the guy on HF who dismantled a pro to turn it into a Sigma/404 at a cost of about $2,050.00! He also got an SR009 at the same time and immediately put the Sigma/404 up for sale. He says he doesn't like the sound of anything now except the 009. He should have listened to the pro when he had them to see if this was going to be his cup of tea. The sigma pro and Sigma/404 are more alike in sound than any other 2 phones you are going to find. Still, the 009 must be a pretty stiff competitor and he may also need some cash to cover the cost of the 009's.

I made my Sigma/404 from my own low bias set which had a broken arc and cable. I had previously sent a broken low bias to Stax Japan to make what is now my Sigma pro. (They don't seem to do that any more. ) Thinking about repairing the second low bias unit, I thought, why not do a pro upgrade as well, and since the original pro parts were probably not available, just go for the 404 parts. The entire repair and parts cost about $600.00.

However I also immediately picked up another Sigma low bias because I had none left. The guy only wanted $175.00, which is pretty cheap compared to current prices. But I could see that unlike, say the Lambdas ,they were going to get pretty scarce.

[John Buchanan]

I have no trouble with people who disagree with my opinions about equipment as long they have actually had a proper chance to hear the items in question. I think comparisons made by persons with both items are the most reliable information you can get.

What ear pads have you been using? I can't imagine that these phones would be sensitive to pad, although most other designs are.

Your finding the Sigma pro as good or better than the Sigma/404 would certainly irk the guy on HF who dismantled a pro to turn it into a Sigma/404 at a cost of about $2,050.00! He also got an SR009 at the same time and immediately put the Sigma/404 up for sale. He says he doesn't like the sound of anything now except the 009. He should have listened to the pro when he had them to see if this was going to be his cup of tea. The sigma pro and Sigma/404 are more alike in sound than any other 2 phones you are going to find. Still, the 009 must be a pretty stiff competitor and he may also need some cash to cover the cost of the 009's.

I made my Sigma/404 from my own low bias set which had a broken arc and cable. I had previously sent a broken low bias to Stax Japan to make what is now my Sigma pro. (They don't seem to do that any more. ) Thinking about repairing the second low bias unit, I thought, why not do a pro upgrade as well, and since the original pro parts were probably not available, just go for the 404 parts. The entire repair and parts cost about $600.00.

However I also immediately picked up another Sigma low bias because I had none left. The guy only wanted $175.00, which is pretty cheap compared to current prices. But I could see that unlike, say the Lambdas ,they were going to get pretty scarce.

Ed, I put the sculptured Lambda 404 pads on the Sigma/404 (instead of the non-sculptured Sigma pads) when the original mesh started falling to bits, thinking that although they altered the angle of incidence, they also sealed around my noggin a little better. Another shoot out is planned when the new Sigma pads arrive for the Sigma/404, so all will then be the same for the 2, except the drivers and the cords. The Sigmas really need the mesh - that mineral wool touching the pinnae isn't a great idea. The Pros had no mesh at all when they arrived and were a bit itchy with the mineral wool. Fixed now with some spare Sigma pads I had lying around.

Ed, regarding disagreeing with your opinions, that hasn't happened often. Have you ever said any Sigma was bright?

$2050 - holey moley - deduct say $500 for a Lambda 404 donor and another $200 for the Frankenstein transplant, and you have him paying $1350 for the Sigma Pros. I hope they were NOS! Mine were $700 and were as close to NOS (apart from the ear pads - easily fixed and cheaply) as is humanly possible in phones that are at least 15 years old.

PS, what are the serial #s of your Sigmas? Mine are 05331 (the Sigma body) and 08813 for the Sigma Pro.

PPS, A Sigma body with Lambda Pro drivers would be yet another version.

PPPS, edited the original post.

Edited September 10, 2011 by John Buchanan