kevin gilmore

the transistors do not have to be matched. the above bom i believe is correct the other one had the older power supply parts

I'm going to get some of the regular version (not the A part) and test, to be safe you should probably run only +/-475. This part at least for now is not discontinued.

Now he tells me after spending $150 on even more connectors (that i likely already had, but was to lazy to go and find them) i'm unaware of any balanced headphone amps with 5 pin xlr's. But i'm sure someone will show me one. You would make the mini adapter the same way you make the 1/4 inch adapter. Tie the 2 headphone negative terminals together.

I'll actually be making the balanced hd800 cables first. The wire is already a twisted pair of #22. ( 7 strands of #30) 1957 was evidently a great year for teflon cable. I think think that everyone should be making their cables with a 4 pin xlr, then make 4 pin xlr to 1/4 adapters, and 4 pin xlr to dual 3 pin xlr adapters.That covers everything. The only reason why i was going to make new cables is that the ones that came with birgirs set were absolute garbage. The new audeze cables are great, and you can already buy a version with the 4 pin xlr. $80 retail. Less if you know where to go. Birgir has to write up a 4 page review of the cable first. Then i'll design the cable to sound like the review.

So if Liquid Fire is what you get when you eat flaming mexican then what is Liquid Lightning?

you want the new board layouts which i have sent to you.

Works for me in the winter. In the summer, not so much.

There is a big difference between decent and stellar. I think one of the smaller and older firstwatt things would probably sound fantastic. 4 wire ONLY. One of these days, i may try it. 50 watt amplifier into 8 ohms is about 7 watts into 60 ohms which is still WAY too much for lcd2's. However it actually is about right for he6's

Birgirs were definitely rev1 or earlier, original cable and box, otherwise hard to tell. The originally supplied cable is mechanically horrible. Mine are rev2's and they certainly don't have a soundstage problem with the right amplifier. SR-009 still better at just about everything except low thunderous bass. I'll be making up some balanced cables soon from a roll of pure silver teflon from 1957. Practicing my weaving on cheap teflon first.

The new dynahi power supply seems simple enough. Most of the size is due to the electrolytics anyway. If you really want to use this as an integrated amp, a much more massive power supply is going to be required. And then the size is mostly capacitors and the transformer anyway. This thing actually works just fine on a completely unregulated power supply which is what i'm testing it on now, because i don't have a regulated supply that puts out 5 amps.

So it turns out that the lme49830 is pretty much a dynafet on a chip, with diamond buffers driving the fets. SO... combine with the semelab-tt lateral audio mosfets, and the result is something super sweet, and easy to build, about $50 in parts per channel. Combine 4 channels with my balanced preamp, and have one serious kickass thing guaranteed to drive anything, he6's and k1000's included. At about 2 orders of magnitude less distortion than that other thing. And more than 10 times the available output current. at... 20hz to 20khz... .1mw .05% thd (most of which is noise) 1mw .01% thd 100mw .005% thd 1w .0003% thd many watts <.0001% thd http://gilmore.chem....u/blackhole.jpg Works great at +/- 30 volt supplies, But also works all the way up to +/-100 volt supplies. 30 volt supplies highly recommended especially balanced, because lets face it, enough is enough. Suitable for driving say ten thousand pairs of sr-009 at the same time (400 volts peak to peak) A bit more work to do, but getting close now. 3.2 x 3.6 inches plus required external heatsinks.

Great. then post your impressions of the 3 amplifiers over there for the poor sap that evidently does not understand.

Alex told me he was a physics professor at a california university at CJ010. I had no reason not to believe him. But the current stuff certainly makes more sense given what he is doing, and i have a lot less respect for him now. Also makes sense because alex has said that he designs strictly with a voltmeter and does not have any of the standard test equipment one would expect a decent audio designer to have access to.

The sacd of dark side of the moon, as good as it is, should not be used as a reference disc. Wish you were here is much better, but still there are all sorts of flaws that are evident when you listen on good gear. All of the analog productions discs (verve et all) are way better for use as reference discs, as well as the recently recorded beethoven piano sonatas discs.

Worse, much worse. Alex is a senior tenured theoretical physist. You know... big bang, quantum mechanics, and string theory

Actually for the same amount of flux i think the r-core is both bigger (longer path) and therefore slightly heavier. But it is very close in any case. The primary to secondary isolation probably makes no real difference in this case.

Got an email back from toshiba (and subject to translation) the 2sc4686a part was introduced march of 2010 with a planned production run of at least 5 years. No plans to discontinue. So i don't know what is going on yet.

I can't seem to find the end of life date, but back order is 6 weeks, i suggest people buy them now.

justin just pointed out to me that at least according to the mouser website, the 2sc4686a part has been end of lifed by toshiba. This is not what i was told by toshiba, but who the fuck knows. People should put in lifetime buys now just in case. I just did.

The headphones are nominally 60 ohms. Most of those old classic amps had at most 16 ohm taps. So to get enough voltage to match the current needed, you have to bump the theoretical power. So say 5 watts into 16 ohms turns into the equivalent of 15 watts into 48 ohms. I have a couple of quad II's in the basement i should dig them up and see if they still work, they definitely had 16 ohm taps, maybe 32 ohms ?? (nah) The radford, i know nothing about. For those hooking up to MC240's and MC275's do it in 4 wire mode, or remember that the 4 ohm tap is actually ground, so you would tie the 2 x 4 ohm taps together and that is headphone ground, then use the 16 ohm taps. Otherwise the amp is going to get mighty pissed off.

OH boy was this not the way to handle things. I have given lil-knight over $1k for circuit boards. Got absolutely every single thing i ordered. So have many other people here.

The sun never sets on the Stax Mafia!

Looks similar to the krell master reference. Also an older boulder amplifier i think. I really do want to build a second T2, so if you can have more of those chassis made, i'm definitely interested.

The world seems to be going lower impedance which i think is a really good thing for noise. Rays darkstar and sr71B have a 1k input impedance.

Yes, DHT push pull is great. What would be even better is to find a way to get someone to wind an output transformer with the mcintosh cross coupled cathode winding. A pair of 300B's done that way would be a great headphone amp. Here is my opinion on power levels. The amp needs to be able to put 5 watts into 50 ohms. So on amps with 16 ohm taps, it needs to be at least a 15 watt amp. On amps with only 8 ohm taps, it needs to be 30. So an old tube dynaco if you can find one that works probably sounds very good. The atmasphere is in fact push pull OTL tube. scott... you know that sand and tubes is verboten