Many AV Receivers/Stereo Integrated amps do NOT use opamp powered headphone jacks
Jun 25, 2014 at 8:45 AM Post #214 of 221
 I have just joined the party Saturday. I have been reading about the use of old vintage stereo receivers for driving headphones. I have been particularly interested in the higher powered receivers from back in the 70s when the monster very high powered receivers were born. The pioneers seem to have a very strong following. But there are a few others as well.
   I have been reading about them a lot lately. I was looking for one as a possible alternative to a dedicated headphone amp for driving my audeze lcd2 v2 phones. In my search I came across a concept 16.5 at a local stereo emporium that sells used equipment along with some new equipment. I went to the store with my lcd2s and listened to  it with my phones and a pair of kef speakers. At first I was disappointed in the sound when the unit was powered up. Things sounded a bit raw unrefined and rather two dimensional. But to be fair you have to give things a chance to warm up before you can make any assessments about  how it sounds. Well after a few three cds things started to get better sounding. I listened for a bit longer but I started to sweat a bit from the leather pads on the phones and the salesperson switched to a pair of kef speakers he hooked up to the receiver. The speakers sounded pretty good with the receiver and as things started to warm up some more the speakers were sounding very good. By now I had dried of and went back to the lcd2s. Well now things sounded a lot more promising.
 well I bought the receiver and had the receiver delivered to save my back.
   The concept 16.5 was a house brand receiver sold by pacific stereo a stereo chain back in the 70s and 80s.At the time they were the largest stereo chain in the country even though they had stores that were mainly on the west coast. they had some stores in the Midwest as well. The concept 16.5 was their top model being rated at 165 watts rms at 8 ohms. This thing is a monster weighing in at a hefty 67 pounds. So I decided to give my back a break and have the unit delivered.
  The store delivered the unit and boy this thing is bulky.
  I will be making some observations the next couple of weeks about how the receiver sounds in my set up.
 
Jun 27, 2014 at 12:25 AM Post #215 of 221
I've owned a lot of vintage amps over the years and I have never had any issues with the headphone ports. I've been running a NOT vintage HK 3490 for around 3 years or so now...and I have always thought the headphone out (which is fed off main amp but with HP) sounded great. I think it puts out more than enough power for any headphones out there. It performs nearly as well as my headphone tube amp but I have to admit the tube amp is slightly nicer sounding now even though the tube I'm using is nothing special. I assume as I roll better tubes it will further the lead over my HK. BUT the HK sounds good, puts out loads of power and doesn't have any of the strange noise some people complain about. I think i got a HK built on Monday.
 
Jul 26, 2014 at 4:23 PM Post #216 of 221
Question. Can anyone tell from these nudies? Basically what do you think? I'm probably going to look at one of these a short drive away and slightly cheaper. But just as clean. Worth a look?
 
http://www.ebay.com/itm/SONY-TA-AX-500-AUDIOPHILE-INTEGRATED-AMPLIFIER-80-WPC-MM-MC-PHONO-CD-DIRECT-/271554608440?pt=Vintage_Electronics_R2&hash=item3f39ea7d38
 
you can see from the photos the headphone out is the very farthest thing to the left. Izzat one of them cheap opamp thingys or you think thats the good kind? This is a 1983 model.
 
Mar 1, 2015 at 11:35 PM Post #217 of 221
Thread resurrection!
I got curious-so I plugged in my old Denon DRA 635R (1992) to compare to my 2007 Yamaha RXV-657 headphone out.
My source is an Oppo BDP-105D with a pair of HiFiman HE-560 headphones. I may prefer the Denon!
I will need more listening.
 
Jul 20, 2015 at 7:44 PM Post #219 of 221
I will be getting a pair of Hifiman HE-400 on Thursday. I plan to drive them for movie watching with my HK 7550HD Home Theater Receiver. I found that the service manual had a schematic that showed the opamp configuration. To me the receiver sounds pretty good but wondering what others think on the topology design.  This confirms the first post that HK does use opamps in some designs and not just resistors.
 
 
 

 
Jul 21, 2015 at 7:30 PM Post #220 of 221
I've been using the 63 Ohm Sony MDR-V6 headphones with a Sony stereo STR-DE185 receiver. Previously the phones were directly connected to the phone output of an iMac. Through the STR-DE185 receiver the V6 sound has dramatically improved. I look forward to connecting to the STR-DE185 either a 24 Ohm Sony MDR 7520 or a Sennheiser HD 600. Based on what I've been reading here, the prospects seem good.
 
Electronic schematics are a mystery to me. These images come from the Sony STR-DE185 Service Manual:
 

 

 
Aug 18, 2015 at 4:33 PM Post #221 of 221
I've found this thread just on time when I was playing recently with my PM6004 headphone out and found it pretty damn good with weight, decent dynamics and that kind of warm tonal balance which suits my Beyers T90 pretty well. I even consulted service manual to see how headphone output is done on this amp model and it is directly sourced from the actual amplifier discrete section without any opamps etc. just via the 2W 330Ohm resistor. Sounds very well, did you find yourself feeling the same sometimes? Probably also it's related to the fact that T90 are 250Ohm, but I don't know what is the output impedance of the PM6004 HP out, probably 120Ohm or around 60Ohm, anyone know?
 

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