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Philips EM6721 BALANCED Electret, anyone knows them? - Page 2

post #16 of 48

Any decent speaker amplifier is capable of driving even an 800-ohm headphone with no trouble-- it's the portable gear that chokes on high (or low) impedance. Unless this [unspecified] Onkyo is an unusually bad amp-- I'm assuming it's a 2-channel stereo receiver-- I'm afraid it's the sound of the headphone itself that you find "lame". I'm assuming the headphone is wired properly and the cable is in good condition.


As a last resort, try driving the headphone from the speaker terminals. It's possible, though not likely, that the Onkyo has a separate (and bad) headphone amplifier built into it. Try it by having a friend hold the wires on the plug: both black speaker terminals to the sleeve, left and right red terminals to the tip and ring, respectively. If this sounds better, you can solder up a simple adapter. Hope this helps.

post #17 of 48

good idea about the adapter Wualta, sometimes a person can overlook the simplest solution ( me )

post #18 of 48

Problem is, we don't know what kind of plug he has. It could be a DIN. By the '90s, I think DIN connectors were beginning to disappear from Euro home audio. Well, we'll see.

post #19 of 48

i have standard jack plug in. this is Onkyo integrated Tx-41 AMP from 90's.this amp has standard 6,3 mm for phones.also i have Harman Kardon HD720 CD player ,but that plaayer dont have enough power to play this Philips electret  on 800 ohms.

post #20 of 48

If your TX-41 looks like this, 




...it's from the early '80s and it puts out about 33 watts per channel at 8 ohms. At the speaker outputs, this should be enough to drive the Philips electrets. If it doesn't, then something's wrong. Amps of the '70s and '80s were able to drive 2000-ohm Sennheiser headphones with no problem.

post #21 of 48

I could post this in a couple of well placed PM's but instead out here for all the world to see would be best for future headphonites.


In the course of things I ended up with a Stax electret cable, which will be going into the Philips asap so that I can run these off either the SRD-6 or SRD-7Pro adapters here.

Should be interesting.


I may even get em done tonight, just a simple wire snip to bypass the transformers in the cups and solder it up.

Not as versatile nor as quickly/easily reversible as the TRS-to-speakerwire adapter cable, but this has to be tried.

Edited by nick n - 8/25/12 at 12:11am
post #22 of 48

thx for your replay. yes, this is it. that amp i use. this phones sound good with this tx-41.but lame . it's good in wide spread of instruments but lame in punch,if you understand me?

post #23 of 48

Have you tried turning up the bass to see how the headphone accepts it?

post #24 of 48



this is the equipment.Onkyo tx-41, Harma Kardon cd player and philips as you can see. On the back side are my hand made loudspeakers that are on 1ohm,amplified with JVC ks- a202 2X100 WATTS

post #25 of 48

Not that there would be many folks in this situation with these 80mm drivered cans, a spare Stax electret cable. and adapters to run them off but:





  Spot the difference below. Something was hiding in the first picture.










Edited by nick n - 9/18/12 at 10:56pm
post #26 of 48

mine is standard 6.3 mm cable.

post #27 of 48



this is the cans.  Philips  em6721 Balanced Electret Headphones that i own

post #28 of 48

how old are this philips phones?

post #29 of 48

I am not too sure about how old they are, I looked through a bunch of old Philips catalogs and didn't see them but I doubt because of the model number they would be any earlier than late 80's. SO late 80's or up. I don't have a box to look at.


The reason I put a different cable on mine ( which were the exact same 6.3mm TRS cable as yours were before ) is that running them directly off the speaker terminals would be better, but since Stax makes electrets and I also have a few adapter boxes the Stax headphones hook up to, I replaced with a Stax Electret cable. ( note: not full bias cable )

These Stax Adapter boxes ALSO run off speaker terminals but have the big transformers inside to step things up beyond that so these sound much better now. I also did a bunch of mods to bring down the treble peaks.


I also removed the tiny transformer in the earcups which realllly limits these and causes distortion if pushed too hard. They crap out. Another person found the same thing with some Audio Technica electrets ( specifically AT-707 TRS jacked rarities ) that had the same tiny transformers in the earcups. They also caused distortion.


There is a "Silistor C" TS-4601 thermistor ( thermally variable resistor ) on the Stax cable end right inside that black bulge there. That is stock on the stax cable.

Filled the rest of the cup space with some special acoustic filler to add some body to the music.

After all this and plugging them into a Stax adapter they sound night and day different than stock.


If anyone decides they want to sell their stock pair let me know :)  This is a bit of an expense to do this mod unless you have some scrap spare parts lying around like I did, and of course the adapters.

Edited by nick n - 8/26/12 at 4:54pm
post #30 of 48

A big Facebook "like" on this one, Nick. If it's at all possible, use better transformers. This applies to any electrostat, whether speakers or headphones. I'll bet the impedance the amplifier sees drops a bit from 800 ohms. Can you measure it?

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