By gosh, I think you're onto something here. Hee Hee
- 4,266 Posts. Joined 8/2009
- Location: San Francisco
- Select All Posts By This User
Leben CS 300 is excellent amplifier. Who own this amp, this person can simply connect excellent electrostats STAX with this amp and obtain great combination. I think the compare with pure electrostatic amps is always great idea.
This is a fairly interesting concept, how would the "best" of the speaker amps running a WEE to stax compare to dedicated stax amps... I know that my unmodded stax transformer box running off an average speaker amp sounds woeful...
Any info on the transformers that you are using Jack? are they custom?
My WES and my SS eXStatA were noticeably better than the WEE prototype driven by my 8-watt ZDT amp (using a high quality cable). In comparison to those amps with the O2 Mk1, the WEE sounds more compressed and flat, with less micro-detail than these direct drive amps. However, the WEE was noticeably better than my stock SRD-7 Mk2 and SRD-7 Pro. Basically the WEE prototype had better detail and dynamics and was a good bit more efficient than the stock Stax boxes. It was also more forward and less laid back sounding than the Stax boxes. With the WEE I could turn down the ZDT volume from 2 o'clock to 12 o'clock and get the same volumes as with the Stax pro-bias transformers.
In the past I've enjoyed the Stax SRD-7 pro bias with 5-12 watt speaker amps driving the O2, but the WEE takes things up another notch. On a budget I'm positive that it will drive an O2 Mk1 better than something like an SRM-1 Mk2 Pro, which was very inadequate when I tried it with O2 in the past. But how the WEE would compare to a better mid-level Stax amp I cannot say, since I wasn't able to compare them. I also haven't heard the final production WEE, which I am told sounds better than the prototype. I'm tempted to get a WEE for myself, just as a backup to my WES.
I've spent a lot of time comparing transformers vs. dedicated amps and the good dedicated amps always win out. These are transformers far superior to the Stax/WEE units and much, much bigger. Some of them even cost more for a single unit then a Blue Hawaii costs to build. Add to this the most advanced bias supplies ever designed for headphones (far superior to those fitted to any amp/adapter) and yet the transformers just can't match the utter indifference to the load the good amps have. They always sound colored and with less bass/treble control then I'd have liked. The end result isn't bad but my own preference is for the amp to not have any sound of its own and just leave that to the transducers.
For these tests I always used various Class A SS amps since it makes very little sense for me to feed a transformer with a tube amp. Why have a high ratio transformer step down from the tubes down to 8ohm to just feed the same signal through a second transformer to get it back up to high voltage/high impedance? It makes a lot more sense to do what Frank Cooter is doing, take a SET amp and fit it with a low ratio (1:1.5 or even less) phase splitting transformer to drive the headphones directly. This causes a lot less issues and is the only realistic way of making a fully DHT based electrostatic amp for those that want that kind of thing. KG's 12 tube, fully DHT equipped design costs about 4K$ just for the tubes alone...
One thing that people should also be aware of, is the unnecessarily high stepup ratio of the Stax/WEE boxes. Now if you are using 3W amps then you need this kind of stepup but anything above 10W and this just causes distortion. Unlike an amp where the extra voltage swing can only bring improvements (higher slew rate, running the amp far away from its limits etc.) the higher the stepup ratio, the more non-linear transformers get. When the first Stax transformers were introduced in 1960 amps were very different to what we have today but they always stuck to that rather high ratio (1:20-1:30 depending on vintage and model) burning up countless headphones when people weren't careful with the volume control.
Thanks for the replies spritzer and HPA.
I was thinking along similar lines that dedicated was the way to go. Whilst my rationale was not as technical as your spritz I like to keep my audio chain as simple as possible. Every other component just takes something away.
It seems quite reasonable to me.
Considering that the price will cover R&D, parts, labour, and of course all other costs of running a business (housing, electricity, website, warranty, ...)
Hopefully we'll see a 3way roundup with the stax box and the japanese one (illusion?). Compared to the standard stax amps ...
Until then, it looks nice but not THAT nice ... it's not chord or ayre nice. I used a wa6se maxxed briefly, woo build quality is great but it's far from the "milled from a solid metal block" school.
399$ would make this product a success ... IMO :)
One thing that people should also be aware of, is the unnecessarily high stepup ratio of the Stax/WEE boxes. Now if you are using 3W amps then you need this kind of stepup but anything above 10W and this just causes distortion.
It is not true. High efficiency transformers are the key to quality and performance. In several meets, we used a 50-watt solid state amp to drive the WEE and we had never get distortion. Certainly, you need to control the volume so your phones would not blow up.
To clarify, the WEE's minimum input voltage is 5 volt, which translates to 3 watts of power (below 3 watts will still work but you will not get enough voltage swing for Stax). You can use your 1000 watts amp or higher if you need to. At the end, you need to control the volume through your speaker amp.
Please PM or email us if you have any other concerns.
I have to disagree with you here. When you increase the number of turns in a transformer then is becomes less linear i.e. it adds distortion. No way around this with any transformer design but the distortion may indeed not be audible. Now this non linear nature does extend to the frequency response and how the amp handles the wild impedance swing of the ESP transducers and that might be more clearly audible. As for quality the key is what nobody wants to do with transformers, larger cores and better core materials.
I don't understand where you get the idea that a 10W+ amps can cause distortion? You sounded as it is a fact I hope you are not basing on speculation. We used 8 to 50W in several meets and received good comments. We also just tried it on a 200W and hear no distortion. The distortion you may refer to can be detected by test equipments only.
Ideally, the step-up ration is 1:1. However, you will need a very high power amp (probably beyond 1000 watts) to get enough voltage swing for Stax. High power amps, unfortunately, have higher chance to get distortion, difficult to build and cost much. There are simply not many amps that have 1000 watts output.
It is true that all output transformers are not linear, limiting by the currently technology we live in. However, the keys are to reduce the non-linearity. Indeed, we spent a good amount of time in order to develop the technique and use the right materials to make these transformers. I can tell you that this are the secret ingredients to the WEE. There are existing step-up output transformers out there available to buy. The problem, however, is that these products are not meant to use in the electrostatic headphone application and you will get a good result.
The bottom line is that if you need the best out of the Stax you will need a dedicated amp.
You are completely, utterly misunderstanding what I wrote. What I said was that in this day and age we have no need for 1:25 transformers to drive Stax phones since we have an abundance of power at hand. The first Stax transformers were introduced in 1960 and it was a very different world so one needed a higher ratio but that isn't the case now.
As for distortion being audible we only hear about 5% THD or more so if the system is outputting that much then you have serious issues. That said, distortion much lower then that does affect the sound quality even if you can't hear it directly. One can't hear odd order or crossover distortion found in so many bad SS amps directly yet the effects are clearly audible.
In what way would dedicated step up transformers be any better then dedicated step down transformer which is what an output transformer really is? Sure you can cut down capacitance but any good transformer maker will do that anyway. You could also spec bifilar wound transformers but nobody but McIntosh makes these anymore due to cost. As for any secret ingredients, I don't buy it. Every time a MOT pulls this card I think about Single Power and all the patents he had pending which was why nobody was allowed to open up the boxes...
. Every time a MOT pulls this card I think about Single Power and all the patents he had pending which was why nobody was allowed to open up the boxes...
I don't have an opinion in the Woo Audio - spritzer debate but inferring Woo Audio business practices are related to SinglePower does not appear to be appropriate. I believe you have made your point concerning the inadequacies of using a transformer. Indeed, Jack acknowledges that an amp would be better than the Wee. However, it appears that Woo Audio is not going to halt production of the Wee so why don't we wait for it to be produced and then whoever uses it can provide their opinion on the sound.