Nigel
Been here a while!
Watching over Gotham City keeping us safe
Posts: 2,064
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Post by Nigel on Jun 7, 2006 15:35:41 GMT
Hi, I'm reading with interest elsewhere that the Cary 300B integrated amp matched with the Sennheiser HD650's is the audiophile connoisseurs choice of ultimate rig. A couple of questions. Is the Cary amp simply a 300B amp with a particular good headphone circuit? Or does the headphone circuit run through, sorry about my ignorant choice of words, the legendary 300B valves? The point is the Cary costs a lot but it does a lot more than just provide a headphone opportunity, so surely, if you remove the headphone bits & bobs out of the amp this part couldn't be too expensive to manufacture. Also, are there any other 300B based headphone amps available & can't you geniuses design a nice DIY one? Then I will have the ultimate rig of choice. (Frothing at the mouth already with anticipation). If Pinkie makes me one. I want it & I want it now. Best, Nigel
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Post by PinkFloyd on Jun 7, 2006 17:48:08 GMT
Rick's the man to ask about 300B amps Nigel, I'm sure he'll be here soon. As for the Cary, I've seen inside one of these amps and it was a right old dog's dinner I , personally, wouldn't touch them with an insulated bargepole.
Mike.
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rickcr42
Fully Modded
Rest in peace my good friend.
Posts: 4,514
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Post by rickcr42 on Jun 7, 2006 19:18:59 GMT
The Cary is I beleive a straight power amp with a headphone tap,likely a resistor matrix.The Manley is a "true" 300b line stage/ headphone amp so maybe better suited being designed from the start for the task : www.manleylabs.com/containerpages/300b99.htmlYes but it would cost a small fortune to make even fully DIY in design. First DHT tubes alone are expensive as hell when compared to the typical IHT triodes we use for line stages and headphone amps. second DHT means generally higher noise levels and for headphone use not acceptable so DC heaters are a must as is an ultra quiet B+ supply or you will hear background noise during all silent bridges between music-again not acceptable for headphone use. Next is the matching of the tube to the driver and with DHT's having a high output impedance your choices are either transformer output coupling or multiple parallel devices on the output-both expensive again with multiple 300B matched valves being insanely expensive for driving cans. Yes the 300B sounds awesome used as a line stage/headphone driver but how many are willing to spend close to $1,000 for a DIY amp ? I am thinking maybe the 2A3 is better suited (or if you like PP amps a 45 PP ) for line stages/headphone amps due to the dead-on 2-3 watts power with every example of a commercial 2A3 headphone amp getting raves all "DHT' would be maybe a 5842 voltage gain stage,2A3 output stage,all heaters DC regulated,Lundahl or Sowter iron,hybrid Tube/SS B+ recitfier, maybe a pentode CCS on the front end even this is way too expensive for "play time" so any attempts would have to be serious and not just to do it
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Nigel
Been here a while!
Watching over Gotham City keeping us safe
Posts: 2,064
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Post by Nigel on Jun 7, 2006 19:37:30 GMT
Oh well. I guess that's the end of that then. Cheers Rick.
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rickcr42
Fully Modded
Rest in peace my good friend.
Posts: 4,514
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Post by rickcr42 on Jun 7, 2006 21:48:53 GMT
Was a great question man so I hope you don't think i was slamming your post.
I am and have been intrigued with an all out all DHT headphone amp/line stage for a damn long time with experiments in that area,non optimised experiments,promising as hell but layout is everything as is power supply noise not to mention the sheer size of the amp with no way around it unless you go to a two box design with the ps box located on the floor behind the rack.
Hell the damn tubes are bigger than many amps !
HUGE bad boys that need a very high voltage B+ so the power trafos also huge then there is the heater supply iron,the power supply chokes,the output matching transformer,all film and foil or PIO caps,large power resistors and possible a CCS board for the fron end which if all solid state could be weasled away at the bottom of the tube sockets but if a pentode or hybrid means more top plate real estate and the amp starts to take on BEAST proportions and that means shelf space
At some point I am determined to do an 801 or 2A3 SE line stage/headphone amp but when I do it will be the only project in the loop until it is 100% finished or scrapped as a good idea gone bad.
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