spritzer

Simple enough to add BNC connector but are those RCA they are using for DC switching?

Belden hookup wire yet again...

Case in point that we should step up the border security a bit. We are apparently letting the crazies in now...

Yeah, with a gain of 10 it would be possible but with a gain of 2 it would be extremely low level indeed. Running them from the Pro output could work...

Our B22 has a Zobel network which helps the amp deal with inductive loads. It certainly wouldn't hurt when driving the transformers. Also what we are talking about here is driving the Stax phones directly from the Beta for extremely low level listening.

The ES drivers are a reactive load so the impedance varies wildly with frequency but the B22 should cope with that. Perhaps the best way would be to have two outputs, one direct from the Beta, the other fed through transformers.

Belated happy birthday!!

There is no way to use this unbalanced, a single ended ES driver will sound like crap with very high THD. It has to be driven by a balanced amp or at least a balanced output stage which has a phase splitter in front of it. The transformers are center tapped so they take care of this plus impedance matching. The transformers are really just tube output transformers used backwards.

The bias supplies are fixed so no way to increase the bias. As for the caps, they are there but not to couple, they are bypass caps. The ground would have to be taken from the B22.

They are most likely something custom made. It's not like there is a drought of high-end transformer manufacturers in Japan. Hashimoto, Tango, Tamura are the high end candidates but they likely used something more basic. If you want to go custom then why not contact Electraprint? Kabeer ordered from them and for 10W units they are huge. To find the correct values to get a quate take an 8 ohm input, multiply it by the desired ratio and square it to find the impedance of the secondary. Stax used 1:25 transformers but less then that would also work.

I have a friend in the "biz" up here and according to him Sony and Samsung (the other big names probably as well) are limiting production to starve the market and thus making sure that the prices stay high.

Didn't the Exemplar use 6dj8's or some of the variants?

Happy Birthday!!!

I'm sure they were made in the far east but the ones I was referring to are the companies that offer ultra cheap boards.

The odds of a Stax headphone breaking down are rather slim and if something were to break I'd send it to Japan rather then have Yama's butcher it. I've seen their handy work and it wasn't pretty. Might be a couple of isolated incidents but Stax in Japan does top notch repair work.

Hell no!! I'm going to track down and buy the unit rumored to be here in Iceland though. Having them made in China wasn't going to be much cheaper and the quality can be pretty shitty. Fine for prototyping though.

The Stax transformers are around 1:25 so they step down the impedance 625 times. Lower ratios are certainly possible and the Lundahl LL1630/PP would do the trick.

If you are just going to use the Beta to drive the phones then you have no need for the transformers in the SRD boxes and can just leave them out. How the B22 will behave into the load is something I'm not sure about. The transformers step up the voltage but also step down the impedance which the amps "see". We are talking 100K+... \

Some extra sockets would be a good idea since with the transformer you'd have to recase it and Stax sure loved to epoxy them in except on the most recent boxes.

Then it should work well.

That one would work if it is linear, not log. Freaking huge though...

Good to know since I have quite a few transformers to order...

A built in voltmeter would never work, the input impedance is too low. I really don't think that a pot would work in the shunt position, the more I think about it. If it were say a 5M pot and adjusted way down then that would be just asking for trouble. Putting a resistor in series would kill off most of the adjust ability while making sure the supply worked as it should. Now if you could find a 10M pot for the series position then that should work and give an adjustment range from 600V and down to less then 200.

4 hours maybe with all parts precut and bent into the correct shape.

To pick this up from the PM's, there are some issues with having a variable bias since depending on how it is implemented, it could put too much load on the voltage multiplier and thus pull down the voltage. There are two options here, put a pot on the series or shunt positions. The series has to be rather large in value to go all the way down to 100V or so and I don't think I've ever seen a 10M pot that is any good. The shunt can be smaller but if that is adjusted all the way down then the bias voltages could sag. The is also the issue of having a meter good enough to be able to get an accurate reading off the bias supply. Standard meters will not work though the VC99 talked about in the Fluke 179 thread seems to work ok and it is quite cheap.