Connecting Headphones with no factory Headphone Jack

inspiredsports

I have a pair of Sennheiser HD 570 (I believe 64 ohm), and a pair of Superlux HD 681 (32 ohm) headphones.

Both work fine with my old solid state NAD preamplifier that has a standard 1/4" female headphone jack. However, I've just purchased a vintage Conrad Johnson PV-7 tube preamp that does not have a headphone jack. The Conrad Johnson preamp does have a SECOND standard (RCA) OUTPUT, so it is capable of driving 2 power amplifiers at the same time.

I figured I could just use one of those cheap "Y" Adapters (2X Male RCA to 1X Female 3.5 Mini Stereo) to hook the phones to that second Conrad Johnson preamp output mentioned above.

But . . . the sound is just wrong, and I don't want to damage my preamp or headphones. I could be mistaken, but I don't believe the preamp is made to drive either 32 or 64 ohms from these RCA outputs.

I'm wondering what circuity is used in factory installed headphone jacks to accommodate the wide range of from 32 (or fewer) - 300 ohms that various brands and models of headphones present to the jack?

Yes, I know I should buy a headphone amp, but I just spent my upgrade budget upgrading my Musical Fidelity X10v3 tube buffer. Maybe I can use the tube buffer to impedance match?

Pauly

inspiredsports wrote: »

Yes, I know I should buy a headphone amp, but I just spent my upgrade budget upgrading my Musical Fidelity X10v3 tube buffer.

Start saving for yet another amp

Pauly

inspiredsports

Pauly wrote: »

Start saving for yet another amp

Pauly

Yep, I guess so.

halo71

Well....never seen or heard of it being done on a hifi amp. But I have seen guitar amps modded before with a headphone jack. Might try to Google that. Just a thought.

EDIT: I, by a long stretch, am no expert on the subject. But something like this might be an option. Didn't read up on it much though. But there seems to be a ton of info on doing what you want out there.

http://www.paia.com/proddetail.asp?prod=9605K

EDIT #2: On second thought. Not so sure I would be cuttin' into a vintage CJ either.

gdb

You might want to ask RichP over at Carversite! He would most likely have your answer.:)

http://thecarversite.com/yetanotherforum/default.aspx?

inspiredsports

gdb wrote: »

You might want to ask RichP over at Carversite! He would most likely have your answer.:)

http://thecarversite.com/yetanotherforum/default.aspx?

Thanks.

I've never been a big headphone user so I hadn't thought about what goes into driving loads much higher than 4, 6, or 8 ohms.

My old gear generally had a 1/4" headphone jack, and I plugged in and everything worked fine. Now I'm learning there was always a specialized circuit behind those 1/4" jacks, and cost cutting is perhaps why many more modern designs don't have it.

I've decided that no matter how much I want to use headphones, I don't want to be drilling into the Conrad Johnson. If there was a simple adapter that would plug into a left/right pair of RCA outputs on my preamp and provide a 3.5mm mini or 1/4" jack, I would possibly go for that.

Otherwise, I now in the hunt for a good Musical Fidelity X-CAN v3.

dorokusai

Yeah, just get a head-amp. You can pick up a MF soda can on the cheap.

inspiredsports

dorokusai wrote: »

Yeah, just get a head-amp. You can pick up a MF soda can on the cheap.

Yep. I'm guessing it will be the same "cheap" route as my MF X10v3 tube buffer.

$200 - X10 v3 tube buffer obtained from CP member
$900 - 2 pairs MIT Shotgun IC's
$230 - Rock Grotto "Little Pinkie" PSU
$250 - Shunyata AC Power Cord
$180 - Revelation Audio Labs Passage Reference Cryo DIN power cable
$270 - Rock Grotto rebuild (new tubes, caps, resistors)
$25 - Isopod Vibration Dampers
$45 - Herbies Tube Dampers


Total cost of $200 buffer . . . $2,100.

The sound quality improvement it yields . . . PRICELESS !!! :eek:

dorokusai

I guess it all depends on how you look at it The MF head-amp is pretty nice, sure there are better but we're not talking much money here. I've owned the soda can thru the v8.