[buson160man]

I have followed threads relating to the use of vintage receivers as headphone amplifiers. I have owned a set of audeze lcd2 v2 headphones for at least a couple of years and over that time I have been somewhat underwhelmed by its performance with a number of headphone amps that I have either owned or have auditioned at meets shows etc.
  After following those threads I thought it was time to check out one of these vintage receivers and see how they might sound with the lcd2s. I checked out a couple of stores before I happened on a recapped concept 16.5 . I did not know anything about the concept brand of receivers. After some research I found out that concept was a house brand that the pacific stereo chain produced while they were in business. The concept 16.5 was their top of the line offering . It sold for around 950 usd back in the late seventies . That was a good sum of money for a receiver back then.
   The concept 16.5 is a substantial unit weighing in at around sixty seven pounds . It is not exactly a looker being pretty much of a plain jane looking unit with a faux wood case. The unit is silver on silver pretty hum drum looking compared to the pioneers , sansuiis and Marantz receivers of the day .  No flash appeal here . But under the bonnet things look pretty impressive indeed . The unit has a dual mono power supply complete with two substantial frame transformers one for each channel .
    Well enough small talk lets get down to the business of describing this monsters performance as a headphone amp. I initially played the unit for a  hundred hours before I did any serious listening . I upgraded the fuses in the unit with a pair of isoclean 7 amp fuses
 I let things settle in for a couple of more weeks and I feel that while there may possibly be further improvement it probably will not be that much or noticeable at this point. I feel things have settled in sufficiently enough to warrant commentary about its performance.
    Well the comments I will be making are for the units performance as a headphone amp. Earlier I had expressed my somewhat reserved opinion of the lcd2 . Well that opinion has definitely changed . The comcept 16.5 is one fine sounding headphone amp for the lcd2. The lcd2 is now alive in a fashion that I have not heard from them before. They now have that stand up and alive quality that they are capable of. The clarity the dynamics the power the extension at both ends the soundstage  they are all there now .
    I have to say the difference between the various cd recordings that I have been playing are much greater than they were with at least my headphone amps. I would have to say that the differences are probably greater due to the huge power reserves that this monster brings to the game. The receiver was rated at 165 watts rms into 8 ohms and 250 watts rms into 4 ohms per channel with both channels driven.
    The loudest level I dare listen at is at the 9 oclock position of the stepped volume control .This puppy just loafs at that setting the heat sinks do not even get mildly warm after hours of listening.
     I have to say that I find the comments that people make about the excellence that these vintage receivers make very good sounding headphone amps to be right on . The concept 16.5 could and probably would more than hold its own with a lot of the top drawer dedicated headphone amps made today. Maybe in some ways especially power a lot better .
   I have heard a number of high powered headphone amps and save for perhaps the ray samuels high powered amp none of them came close to the kind of powerful sound that is coming out of my concept 16.5. The 16.5 had a reputation for driving loudspeakers with an authority that was more akin to a separate power amplifier and I guess that seems to hold true with headphone listening as well .
    I guess horsepower does count  for something . I would appreciate any comments from any fellow concept 16.5 owners. Perhaps maybe some tips about parts upgrades that improve the performance of the 16.5. I did see some blogs about the concept 16.5 refurbishing done by a repair shop in California called oddly enough pacific stereo (no affiliation with the long defunct stereo chain) . But living in the Midwest I do not want to chance shipping this monster across the country. I am open to suggestions for upgrading the receiver any ideas would be appreciated.
  Well time for some more listening.

 

[buson160man]

 Are there any other concept 16.5 owners out there ? If there are I would appreciate any opinions you have of the receiver or any other input relating to the 16.5 .

 

[kazsud]

Nice impression!

 

[buson160man]

 I would like  add some observations to what I have stated before in my evaluation. These are things that seem to have developed since my original observations of the 16.5. I guess the receiver has broken in more since my original observations . The 16.5 has an ability to separate the instruments like no headphone amp that I can remember hearing . Recordings have never sounded this resolved before and stay that way at the highest volume level that I dare to listen at which is 5 on the stepped attenuator . But I have to say that sometimes I just cannot attain the correct volume level to listen at , similar to the problem that I have had with my burson ha-160 with its stepped attenuator . One step is too high in volume but the step lower is too low .But the quality of reproduction is nowhere near what it is with the concept 16.5 .
   The grip and power o the low end is astounding. I have played some percussion recordings that sound so incredibly palpable as to suggest the real thing.
    The ability to separate various instruments is also accompanied by the ambiance of each individual instrument in a way that I have never heard from any headphone amp that I have heard. I guess I am hearing why the concept receivers are held in high esteem among a lot of vintage receiver collectors. I would like to add that the isoclean fuses do make a noticeable improvement to the sound of the 16.5 .I highly suggest that if you have a concept 16.5 you try upgrading a least the two line fuses like I have. You will not be disappointed.

 

[Flackanator]

I own two 16.5 receivers at the moment, I also have many other concept models including a few 11.0 models which in my opinion are more musical than the 16.5 both the 11.0 and 16.5 are beasts on power, I live in Missouri and I sent a 11.0 to Jeff of Pacific stereo to be refurbished with whatever it needed, I sent a pretty decent unit to begin with and spent quite a bit, quality was good and the turn around was quick. That 11.0 is my main rig, the concept line are unique in their sound and dynamics to my ears, I love them.

 

[buson160man]

I own two 16.5 receivers at the moment, I also have many other concept models including a few 11.0 models which in my opinion are more musical than the 16.5 both the 11.0 and 16.5 are beasts on power, I live in Missouri and I sent a 11.0 to Jeff of Pacific stereo to be refurbished with whatever it needed, I sent a pretty decent unit to begin with and spent quite a bit, quality was good and the turn around was quick. That 11.0 is my main rig, the concept line are unique in their sound and dynamics to my ears, I love them.

 My 16.5 has broken in since I made my comments and it is astounding sounding with my akg 701 phones. It is the best headphone amp that I have heard . I would like to make a suggestion to you. Upgrade the fuses on your concept receivers . I upgraded the two rear panel fuses with isoclean 7 amp fuses and the change was very  noticeable. Since the power cord is captive obviously that is not possible but replacing the fuses is tantamount to a power cord upgrade. The change was very much for the better similar to what you get with a power cord upgrade.   The pacific stereo rebuild looks to be very worthwhile . How much was the entire upgrade with shipping and how far did Pacific Stereo take it.
  My concept was recapped and obviously cleaned up so it is not worthwhile to go further at this point without the cost  escalating a lot more.
   The recap job used what looks to be standard electrolytics but it is sounding very good now that the receiver has broken in. I wonder what the 16.5 would sound like with really good caps like say  cerafine electroytics or something comparable along with the film cap upgrades. I use my 16.5 exclusively as a headphone amplifier.
   My preferred headphone is my akg 701 because of its better soundstaging ability and more resolute presentation. The lcd2 v2 is nice but I find it to be not the most explicit performer. The bass is excellent but the sound is a bit towards the warmer side of neutral and as such is not as revealing as the 701.
  That is why I prefer the 701 to the lcd2 v2. I know a lot of people would say I am nuts for thinking that way but I have found the 701 to be the better performer when it comes to hearing exactly what the original recording sounds like.
   You are right about the dynamics the concept receiver is much more dynamic sounding than just about any headphone amp that I have heard. It truly makes the listening experience one that stands out and very exciting. I am marveling at how different sounding the cds sound that I play on my set up. You are also right about the concepts unique ability to realistically reproduce recordings in ways that I have never heard from any headphone amp.

 

[buson160man]

 You have two 16.5s I am envious. I live in a small apartment and I do not have the space to amass a collection. I am lucky to have the space for one of these monsters (really I do not). But as long as I have space on the floor for it it will remain a staple and my preferred headphone amp. I really can not imagine any sanely priced headphone amp could hold a candle to the beast. I have heard some esoteric amps including the latest cavallis and none of them can touch the beast for performance.

 

[buson160man]

I have been following e pricing on the concept 16.5s and the prices are definitely on their way up. I recently saw two units on the net one restored and going for about  three grand and the other unrestored and going for two grand . I was very lucky to get my recapped unit for a grand last year .

 

[Thenewguy007]

  I have been following e pricing on the concept 16.5s and the prices are definitely on their way up. I recently saw two units on the net one restored and going for about  three grand and the other unrestored and going for two grand . I was very lucky to get my recapped unit for a grand last year .

 
Where have you seen them posted at?
I only seen a few on Craigslist & for local pick up only.

 

[buson160man]

   
Where have you seen them posted at?
I only seen a few on Craigslist & for local pick up only.

 Basically on the net ebay and such. I saw this week a couple of problematic 16.5 units for less than a thousand. But with those I think it could be a crap shoot. One was not working at all and the other was but would cut out after a bit . Living in California I imagine there could be a lot more of the concept units around . Plus the pacific stereo(no relation to the long defunct chain) guy who does remarkable restorations on concept units is in your area . If I lived in California I would definitely have mine upgraded . Maybe not all at once but in steps to his top level upgrade . I am sure  it would be a world beater headphone amplifier with his upgrades . Living in the Midwest there are a couple of shops that could possibly do some parts upgrades. I am thinking about checking that possibility out. So far between the fuse upgrade and replacing the metal jumper plugs between the pre out and amp in with  a proper interconnect cable has made a worthwhile improvement in sound .