The Stax thread (New) - Page 49

No, not at all...*cough*...Well...yeah....okay...I admit it....I do.

Thats quite a lot for a Sigma Pro. Your best bet if you plan to keep them is to use a Stax adapter and a power amp to drive them. They need a lot of voltage and the lower priced amps can't give that much.

Mouser sells the right one. You don't even need a transformer since it is only an isolation device for 230v but I do not recommend it.

The RMS value is 70.7% of the P-P value.

I went for it too but alas it became too much for me..... IIRC it went for about Yen46,500 ~ US$744? Too much just too much and I thought no one caught on to it and I could have gotten my hands on it. Dang. FYI there was also a non-pro Sigma on auction as well and ended about 6 hours ago.

From my reading it's using the transformer to get 500V from a 230V supply so I assume it would still be necessary. I could be reading it wrong though, it doesn't show the connections to the primary. I do have an account with Mouser but their site is acting up for me currently. Have to take a look another time.

You do not need a 500v transformer for this. A simple adjustable voltage doubler is enough. Kevin posted once an adjustable always on bias supply that would work and it used a simple 117/230v -> 230v transformer.


Large

I haven't built this one yet but I have built something similar without a transformer for testing and it works. Not something that I would put into one of my amps though.

Ah, I see what you're getting at. I was just assuming you meant replacing the transformer in the existing circuit on that site. But yes, I'm more familiar with a voltage doubler circuit like that and it would let me use a much cheaper transformer so it's a win all round. Many thanks for the suggestion.

The Ciuffoli design is just too much for my tastes. Jensen film caps are good but the Vishay film caps are much more reliable and thats what counts here.

From what I understand, the Sigma Pro needs quite a powerful amplifier. Would the SRM-1 do a decent job?

It should be ok but I haven't tried them with it.

Has anyone calculated voltage swing for adapter-fed Stax?

I'm still sort of in the hunt for an SRD-7 Pro, and also possibly looking at building an adapter. I'm not at all sure how you'd calculate the available voltage swing out of such a contraption. Has anyone tried? Since OIIs need a healthy swing to sound their best, I'd planned on using a healthy SS driver to my future adapter, one that puts out over 400 watts into a 4 ohm load, around 300 into 8 ohms, iirc. But how much voltage swing does this translate to at the 'phones?
Those of you who've tried SRD7 with OIIs, please weigh in with your opinions. How does it sound compared with something like the KGSS?
Somehow, the whole transformer idea seems kind of bass-ackwards to me, honestly, like putting a cart in front of a horse. Still, Carl and others endorse it, so I'm still looking at the possibilities. Also, anyone with ideas on using the less efficient (generate less voltage than SRD-7) high dollar Swedish transformers and how that would affect drivability and voltage swing on OIIs, please chime in.
Thanks.

I thought maybe this the appropriate place to ask: can someone who has had some experience with both the O2 and the 4070 side-by-side compare them? At this point, I know that my next rig will be an e-stat one. I pretty much narrowed down amplification to the KGSS for the following reasons: I like SS, I liked all of KG's dynamic designs, the KGSS+O2 synergy has been reported on more than on e occasion from people whose ears I trust, and it is decently priced.

So if anyone can give some impressions on how the 4070 stacks up to the O2, I would really appreciate it. I won't be able to get this e-stat rig until the fall, but I like to plan ahead if possible.

X2.


may I add SONY R10 into the equation ?

The R10 is not an electro-stat, and for the record, I didnt' like it when I heard it, well not enough to warrant the purchase anyways. In fact, outside of Stax, I am just not a big fan of Japanese high-end headphones.

I can only go on what my ears tell me. I spent hundreds on a 3030 system and was extremely happy with it for a few weeks, then (because of what I'd read on this website) snapped up a set of SR-Xs and an SRD-6 (SB) transformer (solely to hear the SR-Xs).

Never mind about the SR-Xs (their status is well-established amongst the cogniscenti here), what shocked me was how good the SRD-6 was (driven by a decent amp: a Naim 32.5/140) compared to the SRM-313 and an SRM-1 Mk 2, of which the latter is also well-lauded on these pages.

This was not what I wanted to know! Having just spent 6 times the money of the SR-Xs/SRD-6 for the 3030, I really wanted the latter to be 6 times better, or at least twice as good! It wasn't so: listening through the SR-Xs was loads better on the SRD-6 than the 313 or SRM-1.

Personally, I believe that, in common with most non-flat earth hi fi manufacturers, Stax Japan can't really do stunning electronics, so, even though a transformer should be sh*t, they actually do less harm (again, when driven by a good power amp) than the Stax amps.

Like you, want I now want is a transformer box that'll drive Pro earspeakers, but surely one of you egg-heads out there knows how to up the bias voltage on an SRD-7 (mains bias version) so I can try it for free (or almost for free, just a few simple components?). My soldering iron awaits!