The Stax thread (New) - Page 58

That would certainly have an effect and I expect something like the O2s that like higher voltages would need a higher slew rate to truly shine.

Yes, I'd agree with that completely.

I've been digging but so far have found nothing.

There are some resistors and caps on the audio transformers secondary but it's not much. I think that it is more down to level matching the panels and some other acoustic tricks.

In direct comparison the Micro Seiki MS-2's lack bass but with normal listening it isn't that noticeable. It's kind of like the He90, you aren't really aware of how bass light they are until you compare them with something bass demanding. They are missing more then two octaves compared to the SR-007 but the midrange and highs more then make up for it.

Last but not least, mylar drivers need at least 100 hours of run in. Fresh drivers sound like dog crap on a sandwich but they get better quickly and are good after about 100 hours. There is a good reason for this effect because the film is covered with small wrinkles that hinder it in performing as it should and it needs to vibrate to iron these out and become a uniform surface. The resistive also needs to burn off some extra particles until it settles in.

What the...
That can't be a good thing.

We are trying to figure out what kind of voltages an amp must put out to drive the step-up transformers so we can take full advantage of the dynamic range of our headphones. Some of the Stax amps (and others) do not have enough voltage drive to run the phones to their full dynamic potential. We would never use a 3 watt SET to drive a Martin-Logan CLS. Not enough power. The numbers tell us no. All we are doing is finding out the voltage potential of a given amp and calculating what the voltage would be after a certain turns ratio of a step-up transformer. That’s all! This is not a conversation about specifications vs. subjective listening. If a thermometer tells me the water is scalding hot it will keep me from getting burned.

Some of us are also planning DIY step-up transformer projects and this information is necessary in the design.

AudioD

Hee hee. When I say that about Acoustat's MK-121, people eye me skeptically. For those who want to see for themselves, the Quad ESL's schematic can be found here.

That's quite an endorsement. I hope Charivari is reading this. To what do you attribute this prowess?


Sounds plausible. Where'd you find out about this?

Uhhh.... yeah i've been around for a while. I know what were talking about.
But so far FROM MY PERSONAL EXPERIENCE ,there is more to it than this simple calculation to figure out the rms output. As in the numbers dont always jive with the end result. So SETTLE DOWN and keep an open mind.

First of all, thank you very much for all that info. The Tele's I'm running are the real one's, no dimple, double getter, made at the ULM plant in W. Germany. I just purchased a matched quad of Mullard dual getter XF2's, 2 branded as Rogers, and 2 branded as Philips. After I get them and burn them in for a while I'll post impressions of the differences between the XF2's and the Tele's.

Sounds like you may be planning a major overhaul of that Blue Hawaii! I wish you the best of luck. I'm not quite that brave but will be very curious about your results!

Thanks again!

Carl,
To have a flat bandwidth out to 20Khz and a output voltage of 350 volts would require at least 44 v/ms. 50Khz would be 110 v/ms. I will see if I have any info from Stax.

AudioD

I'm open. I have experience too.

Happy listening Enough said.

AudioD

It's all good.

Wait, does the power rating say anything about its voltage output? If P = I*V = I^2*R, I won't be able to determine the voltage just from the power-into-load rating. Or am I wrong and how do I know I'm not getting a high current, low voltage amp?

A 30 to 50 watt amp (rated into 8 ohm load) is putting 15 to 20 volts into that load. Remember that these are static results into a resistive load. Most modern amps today can still put this out into a reactive load as the SRD-7. You don't really need a high current amp. As long as the 20-30 watts is rated into 8 ohms you will have plenty of voltage. I used a Dynaco ST-35 amp (17 watts on the 8 ohm tap) driving my SRD-7/SRX-III with supurb results. The key is to listen to different amps. They all sound different.

This is rather like my opinion of the Sigma pro and for that matter the low bias Sigma and the Sigma rebuilt with 404 components. The 404 rebuild makes a real improvement over the basic pro, in treble and detail. Both are more dynamic than the low bias, but sometimes I like the increased ambience that you get with low bias.

While I have been wrapped in the Sigma/404 for the last several months, the last week or so I have been going back to the basic Lambda 404 run off the Stax 717 amp. An application of Silclear on all contacts (ic's,power plugs,pins) gives the 404's much more oomph and seems to reduce the 404's deficiencies, i.e. treble etch and weak midbass. The sound is much more exciting and even recordings which had been unlistenable on the 404's are sounding pretty good.