DefQon

Wonder when Cavali will go from mosfets to SiC's....

What revision offboard are you using? I don't see any 4686's populated just 2 big transistors on each board.

Would be great if you could open that set up Chris so we can learn about the dampening type/method used inside the cup. Thanks

Thanks going to try without em. EDIT: Confirmed, thermistors were to blame when I de-soldered them the opposite side of the ceramic coating was bit bubbly looking on both, bypassed the selector switch completely from the secondary windings of the trafo's directly to the output line-out to speaker terminals and I can finally listen to music with bass, there is still a bit of distortion in the lower registers if I have the volume past 90db's or so which is about my listening level when I'm in the mood, but I think that's more to do with the nature of the fixed bias in the electret transducer rather then the adaptor or something else at fault. Looking back at the service manual for the ECR-500 makes more sense given that the primary windings from both trafos are connected to the stator -/+ and the secondary windings through the earspeaker-out/speaker selector switch and the speaker line-out are for low-frequency control, which explains why there was severe volume collapse and distortion in the lower registers when I bumped up the volume on bass heavy tracks, the faulty thermistor (voltage/thermal sensor) acts as a bridge for the secondary windings for output and would drastically heat up and cut off as if it was detecting too much current from my integrated amp. I still want to replace the thermistors with a direct replacement to safeguard over load situations, it says PTH 465 Kurata on the ceramic thermistor, what's a replacement for it? Thanks again.

Can i remove the thermistors completely? What's the purpose of them being there?

I've got a ECR-500 adaptor box with the electret headset. Thing thing distorts on high volume with bassy tracks and the volume drops down if I turn the volume up to high which ends up kicking in the over-spec protection relay circuit in my integrated amp to prevent clipping and damage to the speaker terminal outputs. It sounds quite nice on moderate volume with normal not so bassy music but as soon as ample amount of bass kicks in, volume drops and distortion occurs. I've cracked open the ECR-500 and the adaptor, reflowed solder connections, by the looks of the adaptor innards I think the two step up transformers are not original, according to the service manual the trafos are provided for low-frequency. There is also a PTH 465 rated thermistor pair connected to speaker terminals in the adaptor and the line out to speaker terminals, once I play bassy music on high volume, the thermistor gets really hot to touch and the volume drops and distortion occurs with the ECR-500's. They are parralled with a 3watter 27ohm resistor for each channel which I've replaced with two 15ohm 3watt Panny ERG resistors in series for 30ohms as I was thinking the resistors were losing there resistance and to be blamed. Afraid not. Any insights on what is happening? I don't think its the ECR-500 itself but the adaptor, if somebody could post some pics that'd be great. Re-wiring my chopped up ECR-400 and going to see if I get the same problem with that one. Ok tried my ECR-400 besides one massive channel imbalance (I opened up one driver), same problem as the ECR-500. Me thinks the adaptor is at fault, so after some quick searches on the google.jp, it appears the transformers in my ECR-500 are original but some soldering marks are present (aside from my own) on the wiring to the terminal strips. Here's a stock unit: http://zigsow.jp/portal/own_item_detail/242527/ On that one the negative phase (black wires) that connect up to an integrated amp is soldered to the terminal strip on both ends of the 27ohm resistors. On my one both transformer black wires and the terminal out are connected to adaptor speaker out and then a black wire is bridged to the 27ohm terminal strip, could this make a difference? Maybe I'll play with it some other day. For now there is definitely some magical leprechauns pulling tricks within the adaptor. Anyway attached a picture I made in Paint as of use for anybody wanting to re-wire or knowing the pinout for the ECR-500 4P pin, DMM'd all the leads so could be of great use.

Things are getting smaller and smaller. Me like.

I've been on the hunt for years now after any of the older Ergo's, Jecklins and Koss ? floats but no dice. They are hard to come by.

How many you need?

Depends I bought mine from Aliexpress from a seller selling a whole bunch of jfets and rare transistors including the 1968. Purchased 10 for cheap and passed them onto a friend who has a diy BH based off headwize but needed a few because he shorted them by accident, tested the 1968's fine and has been rocking solid since with no fireworks and abnormal behaviour in the amp.

Hifiman HE-1000 Kitchen Edition:

I'm still kicking myself for missing out on a deal on our local ebay for a mint condition $1.2k Stax O2 MK1 just before Xmas. Forgot to place snipe bids as I was at work.

That new Hifiman headphones looks fucking ridiculous and puts the U in ugly, something you'd expect to find from your kitchen cupboards. I'm looking forward to reports of how they will fall apart when early adopters get there hands on them.

I would take sprizters comment of the 507's being bad from the new Lambdas with much weight they are pretty bad and unbalanced sounding. If you can't get an O2 mk1 or 009 look into the vintage Lambda frame earspeakers as they all round better then the new stuff I.e Lambda/pro/signature, Nova signature, 202's etc.

Well got some ESL speaker repair kit gonna make me some ESL headphones. Should be fun assuming I don't electrocute myself in the process of testing.

Well both had white cotton dampening outside, took them out as it sounded worse with them. Right now I'm hearing decent low-end bass and laid back mids but afsdfkljsdflskdfj treble, some sibilance present as well and the that annoying highs you get from some Beyer's. I should hunt down another pair that is straight out in working condition. Can't be my amp as I tested it off a loaned Dynahi.

Man the K340's are shit sounding, both pair of mine how the fuck can anyone like these?

Nope it sure isn't. I would definitely like to find a way to restore all the SR-3/5's I have that are all yellow without resorting to using bleach. Tried it once and it did more damage then good. There should be a mild abrasive industrial cleaner that removes the outer yellow layer restoring like new finish to the plastic.

Spritzer, maybe a small portable mini KGSSHV in the future?

Yeh it sure is confusing. Was looking at that yesterday. EDIT: I made a post about the imbalance in the mids with the assumption of thinking one of the electret drivers was failing "losing charge" in my AKG K340's in this thread little few pages back. Spritzer corrected me that there is no chance of an electret driver losing charge if stored for a long time in proper "storage conditions" (aka not under the sun or humid areas). If an imbalance has occurred and storage conditions were ok imbalance with an electret diaphragm can only be pointed to a physical connection problem. I guess Birgir wasn't bullshitting me, I managed to test this with buying 2 more K340's from Japan and Germany. Both K340's had missing magic to the mids imbalance problems, as described by the sellers. Spritzer's hypothesis or personal experience confirmed true to what he said. K340 A from Germany had been stored away for almost 30 years, the seller being an old, retired gentleman didn't have any equipment left to test it so was sold as-is. K340 B from Japan had been stored away for god knows how long but obvious evidence of being stored under sunlight conditions (headband deteriorated to being sticky and earpads perished etc and more). So I opened up both 340's. K340 B's electret diaphragm was yellow in colour and had this hazy glaze to the shiny silver membrane, I accidentally poked it with my screwdriver and it made a hole crispy style. There was no way fixing it and from the obvious physical condition of being under the sunlight for all this time, I disposed it only keeping the dynamic driver, baffle's, screws and the plastic headband elastic holders and cups. Opened up K340 A and like my personal pair no obvious damage was seen. So I measured the resistors on the pcb, what should be 56kohm the imbalance side measured 232kohm's. Took both 56kohm resistors out and replaced it with some 62kohm 2w Kiwames, re-assembled headphone and aye presto! No missing upper mids on the imbalance side. So from what I experienced I went back to my personal pair, measured both resistors, both read 56kohm's. But there is more to a resistor then just it's specc'ed resistance rating, so out they went and in went some 62kohm Kiwames, while I was at it recabled internal wires to some pure silver solid core wires. Re-assembled and fuck me it worked. Initially while dicking around with K340 A I accidentally soldered in 560ohm resistors and that cut off any frequency above borderline mids, there was hardly any treble or highs or upper mids and lower treble, just bass from the dynamic driver and huge distortion if I turned the volume high. But it is odd the resistor bands read green, blue, brown and gold which is 560ohm's, measured them with my dmm after my findings and they were 56kohm's, fucking AKG cheeky bastards. So for those on the line of thinking TL:DR, my point is, if anything electret is stored away in ok conditions then an imbalance issue is most likely indeed a physical connection error. For those with K340's experiencing imbalance/missing in the upper mids may replace the resistors for the magic to come back. If your pair was under the sun for a long time, best dispose them.

At least you can still buy lots of genuine c4686's at fairly cheap prices. Unlike a1968's.

Think it was either the 717 or 727 cannot remember off the top of my head can be modded to a 350v limited "low power" kgsshv. Antonyfist (Tony) was the first to mod his with helpful instructions on the procedure from K.G. You can PM him on head-fi or email him but he is not very active on that site.

http://www.aliexpress.com/item/Teflon-Chassis-Jack-for-Stax-Headphones/1386475435.html Looks nice.

Mind blown and this is ESL based speaker coming from the same company that manufactured your computer monitor. http://www.ecinews.eu/index.php?option=com_content&view=article&id=2258:the-benq-portable-electrostatic-speaker&catid=14&Itemid=300690 http://www.digitaltrends.com/home-theater/benq-evolo-first-ever-electrostatic-bluetooth-speaker/

I do have about 10 2705's but the on semi stuff are extremely cheap to pass up on.